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E.B.P.L. USER GUIDE AND LANGUAGE

1. 2 1 Agent Characteristics The initial Agent is shown in the class diagram in Figure 2 1 Posi ti on Poi nt3 brai n Brain groundPlane GroundPlane Centroi d Poi nt3 tenv Envi ronment Draw Update Colli deFunc ti on Figure 2 1 Agent Class Diagram The main element of the Agent is the brain This is a separate class which contains the brains instructions as well as the memory for the agent This will be discussed in more detail in Section 2 2 All the Agents must also be aware of the Environment which is created within the main development system from the f1 script This script is responsible for setting the number of Agents created the volume of the environment what objects live in the environment and any Terrain Although the system is designed to be flexible there are still a few built in variables for the Agent to allow quick access to environmental variables The Position attribute allows the current Agents position to be stored This may then be used to calculate the flock center within the main environment The current flock center Centroid is calculated as the average position of all the Agents in the Environment for each cycle of the system Each Agent is then made aware of this It is up to the user if these variables are used within a EBPL program and they do not actually have to be set 2 2 Agent Brain At the heart of the Agent brain is a series of Stacks and the Opcode interpreto
2. bool HitAgent boolean flag set to indicate that the Agent has hit another Agent CHAPTER 4 FLOCKING 43 bool HitAgent false GLfloat GPYlevel the ground plane level of the Agent float GPYlevel 38 GLfloat CentroidWeight The weight the CentroidDir vector is multiplied by to calculate the new direction of the Agent so it can flock center float CentroidWeight 100 0 GLfloat FlockAvoidWeight The Weight the FlockAvoidDir vector is multiplied by to calculate the new direction of the Agent when it has hit a member of it s own flock float FlockAvoidWeight 100 0 float Radius 2 0 float Radius2 1 5 GLfloat Hunger will be used to make Agent hunt for food when hungry float MinCentroidDist 10 0 Vector CentroidDist 0 0 0 0 Vector nVel 0 0 0 0 Vector acceleration 1 1 1 0 Vector force 0 0 0 0 Vector mass 150 150 150 0 Vector EnvAvoidDir 0 0 0 0 Vector Velocity 0 0 0 0 Vector VelDiv 1 1 1 0 float NoiseType 2 0 float NoiseScale 1230 0002 Point Centroid 0 0 0 float Ylevel 0 0 float dist 0 0 InitFunction Randomize Dir 2 0 2 0 2 0 SetGlobalPos Pos RandomizePos MinCentroidDist 28 AddD MinCentroidDist 4 RandomizePos CentroidWeight 50 RandomizePos NoiseType 5 Randomize NoiseScale 2000 UseNoise NoiseType NoiseScale End DrawFunction PushMatrix Translate to the Agents Position Translate Pos Rotate the Agent to the correct orientation RotateX xrot RotateY yro
3. Set the Colour Colour 1 0 0 0 0 0 Polygon Vertexf 0 5 0 2 0 Vertexf 0 5 0 2 0 0 Vertexf 0 5 0 2 0 Vertexf 0 5 0 2 0 2 Vertexf 0 5 0 2 0 0 Vertexf 0 5 0 2 0 glEnd Now draw the Poly s as Lines to give the agent an outline shape CHAPTER 4 FLOCKING LineSize 1 0 Colour 1 0 1 0 1 0 LineLoop Vertexf 0 5 0 2 0 2 Vertexf 0 5 0 2 0 0 Vertexf 0 5 0 2 0 0 Vertexf 0 5 0 2 0 2 Vertexf 0 5 0 2 0 Vertexf 0 5 0 2 glEnd 0 0 0 PopMatrix End float Ylevel 0 0 UpdateFunction End Set HitAgent FALSE Call UpdateAgainstCentroid Mul ADir FlockAvoidWeight Mul CentroidDir CentroidWeight Add Dir ADir Add Dir CentroidDir Normalize Dir fpush Pos y fpop Ylevel Add Pos Dir Set NextPos Pos Add NextPos Dir Call CalcAngle SetGlobalPos Pos SetD ADir 0 0 0 SetD CentroidDir 0 0 0 if Ylevel lt GPYlevel SetD Dir y 1 float dist 0 0 Function UpdateAgainstCentroid GetGlobalCentroid Centroid Set CentroidDist Centroid Sub CentroidDist Pos Length CentroidDist fpop dist if dist gt MinCentroidDist End This function calculates the Agents orientation based on the pos Set CentroidDir Centroid Sub CentroidDir Pos and the NextPos use Vector tmpPos 0 0 0 0 Vector tmpPos2 0 0 0 0 Function CalcAngle fist set the vectors to subtract Set tmpPos NextPos Sub tmpPos Pos Fpush tmp
4. 5 1 Agent Resource File ARF The Agent Resource File allows the user to define and load the positions of the Agents and their initial orientation The file format is as follows Number Of Agents to load Pos x Pos y Pos z Dir x Dir y Dir z All the values in the file are separated using a space and the newline terminates the record When the LoadARF fl command is encountered the arf file is loaded and the Agents InitFunction is called The position value is loaded into the Agents global variable Pos and the direction to the Dir variable These may then be accessed using the following Opcodes Vector Dir 0 0 0 0 Point Pos 0 0 0 GetGlobalPos Pos GetGlobalDir Dir Figure 5 1 shows the Layout program in action This allows the user to interactively place agents in the environment and save the results to an arf file 53 CHAPTER 5 AGENT RENDER 54 E FlockLayout ParamFile new arf www dec bournemo El x Figure 5 1 Agent Layout program The following examples all use an arf file to configure the initial position of the Agents The file used is as follows 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 c22c20o0o000o0o0000000000000000 Es Hs a fas as gt Fw wpe BS ass ss gt gt a ss ys gt q ass ss 5 2 Using the AgentRender The following example shows a series of Agents configured using an arf file When the simulation starts the Agents all move in the same d
5. Function CalcAngle fist set the vectors to subtract Set tmpPos NextPos Sub tmpPos Pos Fpush tmpPos x Fpush tmpPos z use atan2 to calc the angle fatan this gives us the angle in radians so we convert it Frad2deg finally we align it with the world geometry Fnegate Fpop yrot AddD yrot 180 0 now we align the z rotation Y Pos y NextPos y Set tmpPos NextPos Set tmpPos2 Pos swap the y components Fpush Pos y position 44 CHAPTER 4 FLOCKING Fpop tmpPos y Fpush NextPos y Fpop tmpPos2 y now subtract the two Sub tmpPos tmpPos2 zrot asin Y r Length tmpPos Fpush tmpPos y Fdiv asin convert it to degrees frad2deg Fpop zrot End Point TempP 0 0 0 Vector Norm 0 0 0 0 Point P1 0 0 0 0 Point P2 0 0 0 0 float x 0 0 float two 2 0 Vector d 0 0 0 0 Vector NDir 0 0 0 0 CollideFunction LoopBin SphereSphereCollision HitAgent Pos Radius2 NextPos Radius2 ifelse HitAgent TRUE GetAgentI Pl Pos GetAgentI P2 NextPos Set Norm P2 Sub Norm Pl Dot x Pl P2 Mul x two Set d Norm Mul d x Set NDir Dir Sub d NDir Set ADir NDir Set P1 Pos Set P2 NextPos Set Norm P2 Sub Norm Pl Dot x Pl P2 Mul x two Set d Norm Mul d x GetAgentI NDir Dir Sub d NDir SetAgentI NDir ADir SetD CentroidWeight 0 SetD CentroidDir 0 0 0 SetD FlockAvoidWeight 100 SetD CentroidWeight 1
6. Program 12 Agent4 bs Agents interacting with terrain the Agents position Point Pos 30 0 0 Vector Dir 0 0 0 0 0 0 0 0 Point NextPos 0 0 0 CHAPTER 6 TERRAIN INTERACTION bool TRUE true bool FALSE false The rotation of the Agent in the X plane float yrot 180 0 The rotation of the Agent in the Z plane DrawMode flags loat WALK 0 0 loat RUN 1 0 loat DrawMode 0 0 loat Frame 0 0 The Agent Start Point oint StartPoint 0 0 0 ool HitAgent false loat Radius 1 5 loat ZposEnd 40 0 loat CurrZpos 0 0 loat NewSpeed 1 5 loat MaxFrame 15 0 float StartWalk 30 0 Vector NormalSpeed 0 0 0 6 0 InitFunction configure initial Agent position GetGlobalPos Pos GetGlobalDir Dir Set StartPoint Pos UseAgentRender RandomizePos Frame 15 End DrawFunction hh hh hh 0 00 Fh ho th th PushMatrix Translate to the Agents Position Translate Pos Scale 5 0 5 0 5 0 RotateY yrot RenderMaterial 3 SetAnimCycle DrawMode RenderFrame Frame RenderAgent PopMat rix End UpdateFunction SetGlobalPos Pos Add Pos Dir Set NextPos Pos Add NextPos Dir fpush Pos z fpop CurrZpos if CurrZpos lt ZposEnd Set Pos StartPoint Set DrawMode WALK Set Dir NormalSpeed AddD Frame 2 if Frame gt MaxFrame SetD Frame 0 SetGPYlevel Pos End Point AiPos 0 0 0 CollideFunction Set HitAgent FALSE LoopBin 65 CHAPTER 6 TERRAIN INTERACTION Sphere
7. float EndLife 10 0 colour value for the particle Point PColour 1 1 1 the direction to emit the particle Vector EmitDir 0 0 0 0 wind vector to Vector Wind 0 4 variable used float phi 0 0 float theta 0 0 float EmitAngle 1 to emit we use add to the particle 0 0 6 0 to calculate emit direction 14159276 the following algorithm D x cos theta sin phi D y sin theta sin phi D z cos theta Function Emit RandomizePos theta EmitAngle RandomizePos phi EmitAngle fpush theta fsin fpush phi fcos fmul fpop EmitDir x fpush theta fsin fpush phi fsin fmul fpop EmitDir y fpush theta fcos fpop EmitDir z End initialise the particle InitFunction Call InitParticle End Function InitParticle set initial position to 0 SetD Pos 000 SetD NextPos 0 0 0 SetGlobalPos Pos create a random colour RandomizePos PColour 1 0 1 0 1 0 reset the life SetD Life 0 0 create a random life for the particle RandomizePos EndLife 15 calculate the emit direction Call Emit End DrawFunction PushMatrix 28 CHAPTER 3 PROGRAMMABLE PARTICLES Translate to the Agents Position Translate Pos set the colour Colour PColour draw the particle as a line Lines Vertex Pos Vertex NextPos glEnd PopMatrix End UpdateFunction move the particle Add Pos EmitDir add the wind Add P
8. 0 0 0 InitFunction create a random position for the Sphere Randomize Pos 20 10 20 End DrawFunction Colour 1 0 1 0 1 0 save the gl transformation matrix PushMatrix Translate to the Agents Position Translate Pos Draw a sphere of radius 2 Sphere 2 0 8 8 restore the gl transformation matrix PopMatrix End UpdateFunction do nothing End CollideFunction do nothing End CHAPTER 1 INTRODUCTION 4 The script to configure the environment is detailed below First the world bounding box is setup to be centered at 0 0 0 with a width height and depth of 80 The AgentEmitter is then set to load the Agents with the GettingStarted comp compiled brain script Configure the bounding box for the simulation WorldBBox 0 0 0 80 0 80 0 80 0 2 2 2 50 specify the output file to read to outputfile outfile out create a camera to view the scene Camera 0 80 40000 O 1 0 800 660 45 0 1 33 0 1 450 0 Create an emitter for the Agent with 50 Agents AgentEmitter 0 0 0 0 0 0 50 0 0 0 0 0 0 0 O GettingStarted comp Specify a path PathFollow 0 20 0 2 10 30 5 20 1 4 25 2 5 Specify the ground plane GroundPlane 20 0 0 4 0 0 5 1 4 1 Running the simulation To run the simulation first the brain script needs to be compiled as follows BrainComp GettingStarted bs GettingStarted comp Then the simulation is run by using the following commands ebpl GettingStarted fl Chapter 2 ebpl Language
9. 1 SetGlobalPos GetGlobalPos o o onoo ee 72 2 SetGlobalDir GetGlobalDir ee ee ee ee 72 3 SetGlobalCentroid GetGlobalCentroid 0 0 00000 00 ae 7 2 4 SetGlobalCollideFlag GetGlobalCollideFlag Liz 6 SRtGPY level ii is A Sat BM a Ree ee Ee 7220 PUSHGIRYDCVEl 2 3 4 fot S airea a od of doh hd a Solin ea hated COlSiOMs ste eee Bop eK be AAA Rito Pt ate EW iw ee ee Ra Gy ee de 7 3 1 Environment Collisions 2 a FUNCIONA a he ee le A ee a eA GR Oe eh a Galli S a e tol A tte he tebe A Y eshte Reed ABT a Aa be IN An eek tite LN Cd Bins and Other Agent Access 2 e MiniGh Opcodes 5 a ah oe att oh SS eel Gea Gee bide ee gy es Gok o Seed Teh LS arra hats S stich ey ay O Tel 2 e R tateY DA eat te Sat A Bae BU A alt Rylan A ASI Rotate d icv sot te Be ge pe ee Radiol Rite Hoe eRe Dh Se Rete peg Se PAS PUSH Matrix se 235 fe ee A es ee Bote ee Pet ation Bae BTN ele ek I ee TAD POpMatrrx ti Siig iaia A A SS AA AA TAO Wranslate eos ede Loe A oe RS id Ee A ee Oe et alee Tell AL E Rae aa st eee WAL So ae GAS Shai dee eee BY USES NET cs Soke one E Oe Aso Bt ae E ERE BO Se ee Ba TERI BOE whee E ar Ara Cea aie end ehic Ge tase RE A AN eee Hotes Gonder Teh AO Emelo0p ie cad bom dit hgh SG ay oak Po Boe ed Ue E oe ds TIAS sl SAE HE oe MS Dad aR eae Ete ott a oI Es ASS O aA forge vb a So Be oe Spe te MS Reh tg hee Be OL IE Re adh 6S Meo NS Beh TALLAS VETE a hho ee es el A BE BB de
10. 61 65 70 87 RandomSeed 91 RenderA gent 22 56 58 61 65 69 80 RenderFrame 22 56 58 61 65 69 80 RenderMaterial 22 56 58 61 65 69 80 Reverse 85 RotateObj 89 RotateX 16 20 36 43 44 49 76 Rotate Y 16 20 36 43 44 49 56 58 61 65 70 77 RotateZ 16 20 36 43 44 49 77 Rotations 16 INDEX Scale 16 20 44 56 58 61 65 70 Set 25 29 35 37 38 41 44 46 50 51 55 62 65 66 69 71 83 SetAgentl 38 41 45 51 61 62 66 70 71 76 SetAnimCycle 22 56 58 61 65 69 80 SetD 25 28 30 37 41 44 46 48 50 51 57 59 61 62 65 66 70 71 84 SetGlobalCollideFlag 45 49 51 71 74 SetGlobalPos 28 29 31 36 37 43 45 46 49 50 56 58 61 65 73 SetGPY level 65 70 Smooth 79 SolidSphere 17 58 78 Sphere 3 17 31 78 SphereEnvObjCollision 14 48 51 75 SphereEnvObjectCollision 13 75 SphereSphereCollision 12 38 41 45 51 61 70 74 Sub 35 37 38 41 44 45 50 59 62 66 71 83 SubD 31 70 84 Translate 3 7 16 20 25 29 31 36 43 44 49 56 58 61 65 70 77 turbulence 42 turbulence 42 undulate 42 UpdateFunction 3 7 25 29 31 37 45 49 56 59 61 65 70 75 UpdateRate 47 55 64 68 90 UseAgentRender 22 55 56 58 61 64 65 68 69 79 UseNoise 42 43 49 87 VarObj 7 VectObj 92 Vector 6 9 11 16 25 28 30 35 37 41 45 48 50 51 53 56 58 62 64 66 68 69 71 73
11. BR ii TRA POM STZE rc do ai a e Joke tend ni a Med AAS Enese a A a o Reh eth he ey TANG Sphere ui suk A ee BA ae Gee Ble ee ES TAAT Cylinder 3 e eee eh e a ag A a RS GE Bare SE AE ES w RE ASANO ACO QUE reg oes She ae emits Bes bine Ara lc ida Soe Saude de Antro Soman Gee AD ondaa TAT AO 6 ee peas yk ee Ge ee ee ee Be ee ae i Se en aa ee AgentRendem 5 28 a sk be mae the hee GY Gad aA Be bom de he SA ba mei Float Stack ODpcodes 0 ea Re eR AA BERS OR ew Reed See O O cee bce at cy ae ae eden ate deb hae Bae ee weeded See T92 Fpushd raras e annro Sake e ble rl ee et FPOP sore ORs Sait isk ae ee ase A er its actin wate Ope SE Ke e Dd PALO Radda ache sn hae Sats Gus cede age Sage hy eS Ben code Fee Be Pe ii CONTENTS 7 10 2 Fsub 7 10 3 Fmul 7 10 4 Fdiv 7 10 5 Fdup 7 10 6 Fsqrt TAO Frad2 Dee ocio e He ee BR eR ee ye ES 7 10 8 Fatan 7 10 9 Fsin 7 10 10 Fasin 7 10 11 Fcos 7 10 12 Facos 7 10 13 Fnegate TAQ AA ES tack Trace a eo 2a A Eth el eR es ES TAL Variable OPpcodeS iio AE ASE PS A os AA 7 11 1 Add 7 11 2 Sub 7 11 3 Mul 7 11 4 Div TALS Set 7 11 6 AddD 7 11 7 SubD 7 11 8 MulD 7 11 9 DivD 7 11 10 SetD 7 11 11 Length TALLO NOA s s i a aee ee ee a eh nee e he ee gs ed s 7 11 13 Dot 7 11 14 Reverse TA LAS Randomize lt a A A A gee 7 11 16RandomizePos 0 a 7 12 Structure Opo d sst a dct wah eee ha a eae ae baw eae ks 7 12 1 C
12. EE 20 3 Programmable Particles 24 3 1 Simple Particles ersi ads a Be BB EN eS 24 3 2 gt Cone Emit Particles ipa 3 8 be ats dhs tm eo Ga aka la Sd el ee Soe Gag 26 S221 Wind VECTOR Ba ye tale OR A Me ES 27 3 3 Projectile Motion Particles cona rang e mesim res ee ee a oe eee 29 4 Flocking 32 431 Aussimple Flock In SDPL oi oa tor ee e Bos ES BG Re AA hue 33 42 Advanced Flocking wus E Oe ee hed eee eee BS we ae ded eee 38 4 3 Avoiding Objects sii koe ii Sy ee eee aoe ee eer Sede eed 47 5 Agent Render 53 CONTENTS 5 1 5 2 5 3 5 4 6 1 7 1 7 2 7 3 7 4 7 5 7 6 7 7 7 8 7 9 7 10 Agent Resource File ARF 2 2 o o e ee Using the AgentRender La la ie E eb ak ee es Using arf to set Agent target points 2 ee ee Agents with Collisions 4 jae aaa e Se Bak Shee e Ae a es Terrain Interaction 6 0 1 Loading Terrain sce e s dee oe See sedge a ae ee ee eds Complex Agent Interactions using CallLists o o Language Reference Variable OtaX ai Ahi E A Se a eb eg E O A A A A E hE ee ee TZ A Pointe ri dr e ees Gt ee Be o Bede onde Mi bcd Tele d MECO S E cout rd Soba a E a eke de 1 1 78 1 A Tle I BOO cis se fhe pst ancien 5 yp sae Bes Tes Pes was Ee og he My eet ae Ty ee tele ee Mah toy eek amp TES FUZZY ers Sette Ra Sl 4 Roch ge Bh einer Ne BSS Sele GAR A Boden eared Agent Global Variables s s t 2 fins e eens es bl eR eh ee peed es ee Bes 72
13. EnvObj EnvObj 0 6 6 0 EnvObj 4 30 61055 EnvObj 20 0 12 0 0 0 6 0 6 0 6 0 5 0 EnvObj 0 0 18 0 0 0 6 0 6 0 De EnvObj 20 18 0 0 6 0 6 0 5 0 EnvObj 20 0 18 0 0 0 6 0 6 0 6 0 5 0 AgentEmitter 30 0 0 0 520 0 7 0 3 0 33 0 6 0 0 EnvObj comp PathFollow 0 20 0 0 10 001000 2000 lockedCentroid 0 0 0 0 0 6 5 0 0 W Flock ParamFile EnvObj fl www dec bournemouth ac uk staff jmacey flock html Press h for Menu x Figure 4 6 Agents Avoiding Objects The Agents again have a series of Variables as in the previous examples but the interaction with the EnvObj objects are handled by the function CollideAgainstEnvOb CHAPTER 4 FLOCKING 48 Function CollideAgainstEnv0Obj SphereEnvObjCollision HitEnvObj NextPos Radius2 EnvAvoidDir if HitEnvObj TRUE SetD CentroidWeight 0 SetD FlockAvoidWeight 10 0 SetD EnvAvoidWeight 6129 0 Randomize EnvNoise 0 2 0 2 0 2 Add EnvAvoidDir EnvNoise if HitEnvObj FALSE SetD CentroidWeight 72 9 SetD FlockAvoidWeight 5100 0 SetD EnvAvoidWeight 6120 0 Program 8 EnvObj bs Avoiding Environment Objects the Agents position Point Pos 30 0 0 Vector Dir 0 0 0 0 0 0 0 0 Point NextPos 0 0 0 bool TRUE true bool FALSE false The rotation of the Agent in the X plane float xrot 0 0 float yrot 90 0 The rotation of the Agent in the Z plane float zrot 0 0 Vector ADir is the Average direction of th
14. Fcos 10 fcos 27 28 82 Fdiv 9 35 38 45 50 fdiv 81 Fdup 10 fdup 30 31 81 fl 5 14 47 55 64 67 Flat 79 Float 6 8 16 17 22 85 float 8 16 17 22 25 28 30 36 37 41 43 45 48 50 56 58 60 65 69 70 72 76 80 87 Fmul 9 fmul 27 28 30 31 81 Fnegate 10 35 37 44 50 59 62 66 71 82 fNegate 70 Fpop 9 14 20 35 38 44 45 49 51 62 66 70 71 fPop 44 49 fpop 27 28 30 31 37 44 46 50 56 58 59 61 65 70 81 86 Fpush 9 14 20 35 37 38 44 45 49 50 59 62 66 70 71 80 fpush 9 27 28 30 31 37 46 50 56 58 59 61 65 86 Fpushd 9 81 INDEX fpushd 9 70 FRAD2DEG 10 Frad2deg 10 35 37 44 50 59 62 66 71 81 frad2deg 35 38 45 51 FrameOffset 91 Fsin 10 fsin 27 28 82 Fsqrt 10 81 FStackTrace 10 FstackTrace 82 Fsub 9 fsub 30 31 81 Function 7 8 11 14 25 27 28 30 31 35 37 44 46 48 50 51 58 60 62 66 69 71 86 Function9 37 Functions 7 Fuzzy 6 8 73 GetA gentl 38 41 45 51 61 66 70 76 GetGlobalCentroid 37 44 50 73 GetGlobalDir 53 55 56 61 65 70 73 GetGlobalPos 53 55 56 58 61 65 69 73 GetGPYLevel 74 GetNoiseValue 42 46 51 87 glEnd 18 20 25 29 31 36 37 43 44 49 59 78 Global Variables 7 glVertex3f 22 Goal 90 GroundPlane 4 38 47 55 92 GroundPlaneTex 92 i 70 71 If 15 if 11 15 25 29 31 37 38 4
15. NULL to generate random values for the simulation otherwise srand 2 is used to give the same values each time 8 1 1 9 Camera Allows the user to override the camera Camera f eyeX f eyeY f eyeZ lookX lookY look2Z f upX f upY f upZ i W i H f va f asp f near f far eyeX eyeY eyeZ eye Position lookX lookY lookZ look at point upX upY upZ a vector to indicate which axis is the up direction W H the width and height of the screen area va the view angle asp the aspect ration near far the near far clip planes 8 1 1 10 CamFollowCentroid This command allows the Camera to be attached to one of the AgentEmitters centroids CamFollowCentroid i index f Xoff f Yoff f Zoff Index the index of the AgentEmitter for the camera to attach the look point to Xoff the X offset from the centroid for the Eye point of the camera Yoff the Y offset from the centroid for the Eye point of the camera Zoff the Z offset from the centroid for the Eye point of the camera 8 1 1 11 FrameOffset This sets the frame offset for the output file by default frames start at 0 FrameOffset i offset offset the offset added to the frame numbers in the output file 8 1 1 12 RandomSeed Sets the seed for the random number generator to the value time NULL which is the current system time In theory this should make each run of the system different but this will change depending upon the random number gene
16. Noise Index Value turbulence 0 marble 1 undulate 2 noise3 3 turbulence2 4 Table 4 1 ebpl Noise functions To use noise the noise generator must be initialized as follows float NoiseType 5 0 float NoiseScale 0 0 RandomizePos NoiseType 5 Randomize NoiseScale 2000 UseNoise NoiseType NoiseScale The GetNoiseValue opcode is used to access the noise table it is passed a value to return to and a seed value to generate the noise from this is shown in the following example Point Pos 0 0 0 Vector NoiseValue 0 0 0 0 GetNoiseValue NoiseValue Pos 4 2 0 5 Complex Flock ebpl code The following code shows the Agent brain code for the Complex Flock example Program 7 ComplexFlock bs Flock using Noise the Agents position Point Pos 0 0 0 Vector Dir 0 0 0 2 0 1 0 0 Point NextPos 0 0 0 bool TRUE true bool FALSE false The rotation of the Agent in the X plane float xrot 0 0 float yrot 90 0 The rotation of the Agent in the Z plane float zrot 0 0 Vector ADir is the Average direction of the Agent calculated from hits with any agents in the current bounding sphere radius This is used with the FlockAvoidDir weight to set the Flock avoid Direction Vector ADir 0 0 0 0 flock avoid dir Vector CentroidDir is the direction to the flock center from the current agent position This is multiplied by the Centroid weight Vector CentroidDir 0 0 0 0
17. being put onto the top of the stack 7 9 1 Fpush The fpush opcode pushes a floating value onto the stack any variable type may be pushed onto the stack but with tuple data types which element to be pushed must be specified Fpush Pos x pushes the x component of the Point pos Fpush yrot pushes the float variable yrot CHAPTER 7 LANGUAGE REFERENCE 81 7 9 2 Fpushd The fpushd opcode allows a direct floating point value onto the stack as follows Fpushd 23 2 pushes 23 2 onto the float stack 7 10 Fpop The fpop opcode takes the value from the top of the stack and places it into the variable if a tuple data type is used the x y or z destination must be specified fpop ypos places the tos value into ypos fpop tempPos y places the tos value into tempPos y 7 10 1 Fadd The fadd opcode takes the top two values from the stack adds them and places the sum back onto the stack 7 10 2 Fsub The fsub opcode takes the top two value from the stack subtracts them and places the result back on the stack Note if the stack contains 2 and 4 the result will be 2 4 2 7 10 3 Fmul The fmul opcode takes the two top values from the stack and multiplies them and places the product back on the stack 7 10 4 Fdiv The fdiv opcode takes the two top values from the stack and divides them and places the result back on the stack Division by 0 is trapped by changing any 0 value with a 1 and printing a warning to the console in d
18. correct agent direction Function CalcAngle fist set the vectors to subtract Set tmpPos TargetPoint Sub tmpPos Pos Fpush tmpPos x Fpush tmpPos z use atan2 to calc the angle fatan this gives us the angle in radians so we convert it Frad2deg finally we align it with the world geometry Fnegate Fpop yrot AddD yrot 90 0 End find the target point and set the direction Function UpdateAgainstTargetPoint Set TDir TargetPoint Sub TDir Pos Length TDir fpop dist if were on the target point stop if dist lt MinDist Set TDir ZERO Set Dir ZERO 59 CHAPTER 5 AGENT RENDER 60 Set Pos TargetPoint Set Resting TRUE End move the agent Function CalcDir Set Dir TDir Normalize Dir End 5 4 Agents with Collisions The following example takes the code from section 5 2 0 6 and adds collision detection Figure 5 4 Agents with Collision detection The Agents look for the nearest Agent and if the Agent is going to collide the Agent in front Speeds up and the Agent behind slows down This produces a simple crowd simulation The ebpl code for this example is as follows Program 11 Agent3 bs Agents AgentRender with collisions the Agents position Point Pos 30 0 01 Vector Dir 0 0 0 0 0 0 0 0 Point NextPos 0 0 0 bool TRUE true bool FALSE false The rotation of the Agent in the X plane float yrot 180 0 The rotation of the Agent in the Z plane fl
19. o oo 30 Collision avoidance algorithm adapted from jr01 Len01 40 ebpl Code for Agents reflection o 0 0 0 0 0000000004 41 Calculating if a point is within a triangle o 64 vi Chapter 1 Introduction ebpl is a development environment for the production of animations using multiple Agents within a user specified environment additionally ebpl also allows for the production of particle systems with user pro grammable particles 1 1 ebpl structure The ebpl system is split into two parts the AgentBrain programming language and the simulation envi ronment The Agents brain is programed using a simple script language which is compiled to an object file This object file is then loaded into the Agent brain within the ebpl system with additional environment configuration handled by a separate script file 1 2 BrainCompiler The Brain compiler is used in the following way BrainComp SourceFile bs compiledfile comp Although the example above uses a bs and comp extension the compiler does not require any specific file names If the compilation is successful the compiler will report that everything is OK and save to a comp file If there is an error the compiler will report the problem and what source line number the problem occurred on On occasion the program will hang this is due to the parser getting stuck to stop the compiler the ctr e keys can be p
20. of the Agents within the bin are compared with the current Agent For convenience and speed EBPL has two built in collision detection routines however these and others may also be implemented within the EBPL language itself These routines take as parameters variables from the EBPL script 2 3 4 1 SphereSphereCollision The SphereSphereCollision opcode takes five parameters as outlined below SphereSphereCollision bool Hit Point3 Posl float Radl Point3 Pos2 float Rad2 The collision detection is calculated using the Position of the Current Agent and any other Agents in the current lattice bin Each Agent has a Radius for the bounding sphere and if the spheres collide the Hit flag will be set to true CHAPTER 2 EBPL LANGUAGE 13 2 3 4 2 CylinderCylinderCollision The CylinderCylinderCollision opcode takes seven parameters as outlined below CylinderCylinderCollision bool Hit Point3 Posl float Radl float Heightl Point3 Pos2 float Rad2 float Height2 The collision detection is calculated using the Position of the Current Agent and any other Agents in the current lattice bin Each Agent has a Radius and Height for the bounding cylinder and if the cylinders collide the Hit flag will be set to true 2 3 5 Environment Collisions Collisions with objects within the environment are processed by two built in functions At present only Planes and Cubes are supported 2 3 5 1 Env Object Collisions EnvObjects as shown in Figure 2 4 are repr
21. the emitter The algorithm used is shown in Algorithm 2 Algorithm 2 ConeEmitter modified from jr01 To emit a particle in a cone we define the EmitAngle to be in the range 0 7 Generate two random numbers 8 and based on the EmitAngle The Direction vector Dis then calculated as follows Dx sin 0 cos Dy sin 6 x sin D cos This can be converted into ebpl code as follows CHAPTER 3 PROGRAMMABLE PARTICLES Program 3 ConeEmitParticles bs Particles Emitted in a Cone float phi 0 0 float theta 0 0 float EmitAngle 3 1415926 Function Emit RandomizePos theta EmitAngle RandomizePos phi EmitAngle fpush theta fsin fpush phi fcos fmul fpop EmitDir x fpush theta fsin fpush phi fsin fmul fpop EmitDir y fpush theta feos fpop EmitDir z End 3 2 1 Wind vector Y Flock ParamFile ConeEmitParticle fI www dec bournemouth ac uk staff jmacey flock html Press h Bx Figure 3 3 Cone Emit Particles with wind and different cone angle 27 Figure 3 3 shows the same system with a different EmitAngle and a Wind vector added to the x and y value of each particle The full source for this example is shown below CHAPTER 3 PROGRAMMABLE PARTICLES Program 4 ConeEmitParticles fl Full Listing the particles position Point Pos 0 0 0 Point NextPos 0 0 0 0 0 life of the particle float Life 0 0 particle end life
22. values A solid version of the sphere may also be drawn using the SolidSphere opcode as follows SolidSphere radius 12 12 sphere using a variable value SolidSphere 0 02 20 20 sphere using direct float values CHAPTER 7 LANGUAGE REFERENCE 79 7 7 17 Cylinder The Cylinder opcode draws a cylinder using either floating point variable of direct value for the radius and height of the cylinder the other two arguments are stacks and slices which can not be changed once set 7 7 18 Colour The colour opcode sets the current drawing colour it takes 3 floating point values for red green and blue or a Point variable type Colour 0 3 0 2 1 0 Point colour 0 1 0 Colour colour 7 719 Lighting At present only the GL_LIGHTO light is enabled in the system This has a default position of 0 0 0 and a default colour of white To enable and disable the lighting in the system the following opcodes are used turn lights on EnableLights turn lights off DisableLights The shade models used for rendering may also be set The default value is smooth shading which is slower To change the shade model use the following opcodes turn on smooth shading slower Smooth turn on flat shading faster Flat 7 8 AgentRender To use the AgentRender module both the fl and brainscript files need to have the following instruction added UseAgentRender This tells the environment and the brain that the Agen
23. we aen can get m en a e fi n remember that ni is a unit vector in the direction of n From this we obtain the result r a 2 a e 1 11 which is the direction of the reflected Agent This is then repeated for Agent 2 to determine the new direction for the other Agent CHAPTER 4 FLOCKING 41 Algorithm 5 ebpl Code for Agents reflection This is shown in the following ebpl code Point TempP 0 0 0 Vector Norm 0 0 0 0 Point P1 0 0 0 0 Point P2 0 0 0 0 float x 0 0 float two 2 0 Vector d 0 0 0 0 Vector NDir 0 0 0 0 CollideFunction LoopBin SphereSphereCollision HitAgent Pos Radius2 NextPos Radius2 ifelse HitAgent TRUE GetAgentI Pl Pos GetAgentI P2 NextPos Set Norm P2 Sub Norm Pl Dot x Pl P2 Mul x two Set d Norm Mul d x Set NDir Dir Sub d NDir Set ADir NDir Set Pl Pos Set P2 NextPos Set Norm P2 Sub Norm Pl Dot x Pl P2 Mul x two Set d Norm Mul d x GetAgentI NDir Dir Sub d NDir SetAgentI NDir ADir SetD CentroidWeight 0 SetD CentroidDir 0 0 0 SetD FlockAvoidWeight 100 SetD CentroidWeight 100 SetD FlockAvoidWeight 50 LoopBinEnd End 4 2 0 4 Noise Function Each Agent has the ability to access a noise function based on Perlin Noise eta98 This value is generated by a built in noise function and can be calculated from any tuple data type There are five built in noise functions as shown in Table 7 4 CHAPTER 4 FLOCKING 42 Noise Type
24. 0 Index the index of the object to rotate this is based on the sequence that the objects are added in the script file starting at 0 angle the angle to rotate in degrees xAxis yAxis zAxis are flags to indicate which axis to rotate around setting any of these to 1 0 will rotate around the axis specified all can be set in one go i e RotateObj 0 25 1 1 1 will rotate 25 in all 3 axis 8 1 1 4 Goal Goals are timer based objects which can attract the flock Any number can be added to the AgentEmitter they are drawn in Red in the display Goal i index f Pos x f Pos y f Pos z f TimeToActivate Index which AgentEmitter to attach the goal to Pos sets the central position of the goal TimeToActivate The time when the goal is active 8 1 1 5 OutputFile This sets the name for the output file to save Agent data to OutputFile s Filename Filename file to save to 8 1 1 6 OutFileFrameSkip The set the number of frames to skip between writes to the file This value defaults to 5 OutFileFrameSkip i skip skip the frame skip rate 8 1 1 7 UpdateRate Set how many times the simulation is update per redraw This value will run the agent update but not display the results until all the updates have been done UpdateRate i rate rate how many times to update per display update CHAPTER 8 FL SCRIPT REFERENCE 91 8 1 1 8 RandomSeed The tells the simulation to set the seed to a random value using srand time
25. 0 ool ALIVE true loat WALK 0 0 loat RUN 1 0 loat SWING 5 0 loat PUNCH 4 0 PF PY hos hhh os Hh hh O Hh hh FH th th Fh Ol loat DEAD 3 0 loat NEUTRAL 2 0 loat DrawMode 0 0 Point NextPos 0 0 0 Vector ZeroVect 0 0 0 0 loat Choice 0 0 loat ChoiceVal 50 0 loat AgentILife 0 0 float EndFrame 8 0 DefineCallList DrawFunctions CallListItem DrawFunctions Walk CallListItem DrawFunctions Punch CallListItem DrawFunctions Swing CallListItem DrawFunctions Neutral CallListItem DrawFunctions Dead Function Walk Set DrawMode WALK End float Frame 0 0 Function Punch Set DrawMode PUNCH SetAnimCycle DrawMode RenderFrame Frame RenderMaterial Material RenderAgent End Function Swing Set DrawMode SWING SetAnimCycle DrawMode RenderFrame Frame RenderMaterial Material RenderAgent End Function Neutral Set DrawMode NEUTRAL SetAnimCycle DrawMode RenderFrame Frame RenderMaterial Material RenderAgent End Function Dead Set DrawMode DEAD SetAnimCycle DrawMode RenderFrame Frame RenderMaterial Material RenderAgent End InitFunction UseAgentRender GetGlobalPos Pos hh hh 69 CHAPTER 6 TERRAIN INTERACTION GetGlobalDir Dir Fpush Pos z Fpop Material Randomize Frame 8 Set NextPos Pos Add NextPos Dir Call CalcAngle get a random speed value RandomizePos SpeedZ 2 0 fpush SpeedZ fpushd 0 1 Fadd ifel
26. 0 5 SPO 2301 S55 S20 Ay AZ Ze O 4 2 Advanced Flocking Figure 4 5 shows a flock of fifty Agents using a different Agent avoid algorithm and Perlin noise eta98 turbulence based on the Agents Position CHAPTER 4 FLOCKING 39 WY Flock ParamFile ComplexFlock fl www dec bournemouth ac uk staff jmacey flock html Press h for X Figure 4 5 A flock using complex avoidance and noise functions The Agents have a number of built in weights and vectors as in the previous example However the Agents use a different avoid function as shown in the following section 4 2 0 3 Agent Avoidance routine Algorithm 4 shows the new collision avoidance algorithm used in the new flocking system based on the calculation of reflected rays normal to a surface Algorithm 5 shows the ebpl code for the routine CHAPTER 4 FLOCKING 40 Algorithm 4 Collision avoidance algorithm adapted from jr01 Len01 gt The above figure shows the movement of an Agent having a direction a hitting the Agent Normal L and reflecting in an as yet unknown direction r The vector n is perpendicular to the line Angle 91 must equal angle 62 e e The above figure shows a resolved into a portion m along n and a portion e orthogonal to n Because of symmetry r has the same component e orthogonal to n but the opposite component along n so r e m Because e a m it follows that r a 2m Now m is the orthogonal projection of a onto n so
27. 00 SetD FlockAvoidWeight 50 LoopBinEnd End float gpy 0 0 UpdateFunction SetGlobalCollideFlag FALSE SetGlobalPos Pos Call Move Call UpdateAgainstCentroid Call CalcDir CHAPTER 4 FLOCKING Call CalcAngle PushGPYlevel fpop gpy fpush Pos y fpop Ylevel SetGlobalPos Pos SetD ADir 0 0 0 SetD CentroidDir 0 0 0 SetD EnvAvoidDir 0 0 0 End vector NoiseValue 0 0 0 0 Function Move Set acceleration force Div acceleration mass Add Velocity acceleration Set nVel Velocity Div nVel VelDiv Add Pos Dir Mul Pos nVel Set NextPos Pos Add NextPos Dir Mul NextPos nVel Set ADir Dir r r Function CalcDir Mul ADir FlockAvoidWeight Mul CentroidDir CentroidWeight Set Dir ADir Add Dir CentroidDir GetNoiseValue NoiseValue Pos Add Dir NoiseValue Normalize Dir Set the force to be the current Direction so we can calculate the new acceleration in the next iteration Set force Dir Store the Average dir to be the current dir Set ADir Dir End CHAPTER 4 FLOCKING 4 3 Avoiding Objects 47 Figure 4 6 shows five hundred Agents avoiding a series of EnvObj objects The environment is configured using the following fl script WorldBBox 0 0 0 80 0 80 0 40 0 5 2 5 520 OutputFile birds out OutFileFrameSkip 1 UpdateRate 1 Camera 0 80 0000001 800 660 45 0 1 33 0 1 450 0 Randomi ze GroundPlane 20 0 0 4 0 0 7 EnvObj EnvObj EnvObj EnvObj EnvObj
28. 8 50 51 56 57 59 61 65 66 70 71 86 ifelse 11 15 41 44 45 50 59 61 66 70 86 ImageGroundPlane 92 InitFunction 3 7 25 28 30 36 43 49 55 56 58 61 65 69 75 Length 11 35 37 38 44 45 50 59 84 lerp 22 LightingOff 19 LightingOn 19 LineLoop 18 20 37 43 49 78 Lines 18 25 29 31 59 LineSize 18 20 37 43 49 78 LoadARF 53 94 LoadArf 55 64 68 lockedCentroid 47 55 LoobBinEnd 74 LoopBin 12 38 41 45 51 61 65 70 74 96 LoopBinEnd 38 41 45 51 62 66 71 marble 42 Mul 37 41 45 46 51 83 MulD 84 Noise 41 42 87 noise3 42 Normal 7 14 75 Normalize 11 37 38 46 51 60 84 obj 53 ObjTerrain 64 68 Opcode 5 OutFileFrameSkip 47 55 64 68 90 OutputFile 47 55 64 68 90 outputfile 4 38 Particles 24 PathFollow 4 38 47 55 64 68 94 PathStep 94 Plane 14 75 Point 3 7 11 16 17 19 25 28 30 36 41 43 45 48 49 53 56 58 60 61 64 65 68 69 72 74 77 79 83 87 Points 18 PointSize 18 78 Polygon 18 20 36 43 44 49 77 PopMatrix 3 16 20 25 29 31 37 44 49 56 58 59 61 65 70 77 Position 5 PushGPY Level 74 PushGPY level 20 44 46 49 50 PushMatrix 3 16 20 25 28 31 36 43 44 49 56 58 59 61 65 70 77 Quad 77 Quads 18 Randomize 3 12 25 31 36 42 43 47 49 51 58 70 85 87 RandomizePos 12 27 28 31 36 42 43 55 56 58
29. 84 85 87 vector 46 Vertex 7 19 25 29 31 59 78 Vertexf 18 20 31 36 37 43 44 49 78 WorldBBox 4 38 47 55 64 68 89 97 Bibliography A1103 eta98 jr01 Len01 MW99 Par02 Ree83 Ree85 Rey87 Rey99 AliaslWarefront www alias com Silicon Graphics Ltd USA 2003 Ebert etal Texturing and Modeling A Procedural Approach AP Professional second edition 1998 F S Hill jr Computer Graphics using OpenGL Prentice Hall second edition 2001 Eric Lengyel Mathematics for 3D Game Programming amp Computer Graphics Game Develop ment Series Charles River Media first edition 2001 Tom Davis Dave Shreiner Mason Woo Jackie Neider OpenGL Programming Guide Addison Wesley third edition 1999 Rick Parent Computer Animation Algorithms and Techniques Morgan Kaufmann first edition 2002 W T Reeves Particle systems A technique for modeling a class of fuzzy objects Computer Graphics Proceedings of SIGGRAPH 83 pages 359 376 San Fransisco 1983 W T Reeves Approximate and probalistic algorithms for shading and rendering particle sys tems Computer Graphics Proceedings of SIGGRAPH 85 pages 313 322 1985 Craig W Reynolds Flocks herds and schools A distributed behavioral model Computer Graphics 21 4 25 34 1987 Craig Reynolds Steering behaviors for autonomous characters Game Developers Conference 1999 1999 98
30. Agent in the system for each iteration of the environment User defined functions are generated by the Function keyword and can be called from within any of the main built in functions 7 5 Call Lists Call lists are a way of creating switchable function calls depending upon an ordinal variable value The creating of a call list is a two stage process as shown below DefineCallList TestList CallListItem TestList foo CallListItem TestList bar First a call list name is defined to make storage for the Function pointers to be allocated to the list Next list items may be added to the list To use a CallList within a function the following code is used float ListValue 0 function foo called CallList TestList ListValue AddD ListValue 1 Function bar called CallList TestList ListValue 7 6 Bins and Other Agent Access The only time other Agents value may be accessed is within the LoopBin structure There are two methods of accessing the data of other agent by use of the SetAgentI and GetAgent methods as follows Set NDir to be the ADir of the other Agent SetAgentI NDir ADir Get the Dir of AgentI and set it to NDir GetAgentI Dir Ndir 7 7 MiniGL Opcodes A simple subset of the OpenGL drawing commands have been implemented in the script to allow the Draw function to produce images These allow for simple line point and 3D primitives to be drawn and are intended as a simple method to visualize the Agents behavio
31. Dir2 Dot DotResult Dir Dir2 7 11 14 Reverse The Reverse opcode reverses negates the current variable Vector Dir 1 0 2 01 Reverse Dir 7 11 15 Randomize The randomize opcode sets the variable to random values within a range based on seed value passed Randomize Dir 2 1 0 1 1 1 Randomize yrot 4 0 7 11 16 RandomizePos The randomizepos opcode sets the variable to random positive value within a range based on zero to the seed value passed RandomizePos Dir 2 1 0 1 1 1 RandomizePos yrot 4 0 7 12 Structure Opcodes The structure opcodes are used to define functions and call functions and make decisions 7 12 1 Call The Call opcode will call a function within the script Call CalcAngle CHAPTER 7 LANGUAGE REFERENCE 86 712 2 Function The Function Opcode defines the beginning of a function block It must be terminated by use of an End opcode as shown below Function CalcAngle fpush yrot fpop yrot End 712 3 If The if structure can be used on all data types and is constructed as shown below if dist gt MinCentroidDist do something All if statements must use the open and closed braces however if statements may be nested At present if only works with two defined variable types so if a comparison against a static value is required the static value must be define as a variable 7 12 4 Ifelse The ifelse structure can be used on all data types and is constructed as shown
32. E B P L USER GUIDE AND LANGUAGE REFERENCE JONATHAN MACEY 21st August 2003 Contents 1 Introduction 1 ET EDPEST UCILS sson e A a aa A A da EAS 1 1 2 BrainCompilet de s Tona Bare A Pe EA E p S 1 1 3 EDPLproLra is sirg a A a ar 1 1 4 Getting started ocio a e A ee 2 1 4 1 Running the simulation e 4 2 ebpl Language 5 2 1 Agent Characteristics us e da E a ns E PS 5 22 Apent Brain s Eoso tt O A A Eh A A AA AS RS 3 2 23 Braimutacks sia pde taa rs Ba Gus af le a do ae Ba 6 2 2 2 Global Variables vii e it Be ee td oe ee s 7 232 9 War tables iii A AAA BG RA AAA ARA 7 PR NS IN 7 229 Call AA A AN 8 2 3 EBPL language Structure o es ay oeaio i e e e ee 8 231x Stack Operations i ea ada a e we Gok co Ses 8 2 32 Variable Op rations s 2 te Py has ES a E Se Py dk 11 2 33 VariablesOpcodes lt 4 4 2 22 para a Ee eh ah es 11 DI COMISION S erie eek oc A Bip Meee Recodo Sree A Ee Se Fs tid ote ASE 12 2 3 5 Environment Collisions 20 00 e 13 2 3 0 Structure Opcodes Visca dee Board Se ae Seg ip ee eed 14 24 Drawing kody ee be he ee ol ae Ae a e eR ld eee 15 24 1 MimiGL Opcodes 2 620 ee ee 15 24 2 Affine Transforms ogs ee a a a ER A ee Ee eee ee 15 24 3 Drawing Primitives s sesa saa a e a SR OR ee a ad 16 24 4 late Dawne io ss a o a Soe Be ds 17 ZAS MiniGhl Example 2 2 8 2 data Ry Bb BH a at hha a RS 19 ZHAO ApentRendet 2 004 oe ee ee Pee Aad See EE BGS OR Pos Ret
33. GL Line Drawing types e 18 MiniiGle drawing 40h a e op ety E a 19 AgentRender module with 6 animations cycles o o 21 Sample Agent Render model frames e e 21 Simple Particle system Created in EBPL a 24 Cone Emit Particles raais ai ri ii eked 26 Cone Emit Particles with wind and different cone angle 27 Projectile particles s u orin erae ea a aa Ge Bey a Sele ads 29 Avsimple Flock Rey8 TI 62 at ou Pi a AGL e ed ee be 32 Steering Flocking rules Rey99 o o e 33 Acsimple Flock t iini maa AA de ble ered de ba eats 33 Spherical Geometry jrOl o o a 34 A flock using complex avoidance and noise functions 39 Agents Avoiding Objects ers we ee ee ek eee Be ee ek ee ee ee ee 47 Agent Layout program 2 ee 54 AgentRender Agents with different animation Cycles o ooo 55 Agents moving to position set in arf file o 57 Agents with Collision detection o e 60 Agents Interacting with the Terrain en 63 Agents Fighting yew Bee e Coe be ee ee ee ae 67 Agents Bighting Close Up Bor 2 4 AH ee Rae ee ee ee ea a 67 List of Algorithms Du Bu nDN Ke MiniGL Drawing Example Reynolds Boids Rey87 20 ConeEmitter modified from jrOl o a 26 Projectile Motion modified from LenO1
34. MountainHMC bmp 0 4 3 1 2 3 Camera 0 2 100 00001 0 800 660 45 0 1 33 0 1 450 0 AgentEmitter 30 0 0 0 26 0 7 0 3 0 33 0 6 0 0 Fight comp PathFollow 0 20 0 0O 10 0 O 10 0 0 2000 LoadArf 0 Fight arf With the Agents initial position loaded using the following arf file 18 D 12 9 6 ao AY 3 208 6 20 9 20 12 20 15 20 34 0 18 20 34 0 0 20 34 0 0 20 3400 When the program starts the Agents are assigned a position based on the arf file The Agent direction is then used to determine which colour the AgentRender material is set to The Agents then move towards each other and when they collide the Agents decide upon a punch or swing animation cycle The Agent is also given a Life value and each time the Agent interacts with another Agent this value is decremented If the life reaches zero the Agent is set to Dead and the other Agent assumes the Neutral position The code for this program is as follows Program 13 Fight bs Complex Agent interactions using call lists and AgentRender the Agents position Point Pos 30 0 0 Vector Dir 0 0 0 0 0 0 0 0 bool TRUE true bool FALSE false CHAPTER 6 TERRAIN INTERACTION The rotation of the Agent in the X plane loat xrot 0 0 loat yrot 90 0 The rotation of the Agent in the Z plane loat zrot 0 0 loat Material 0 0 loat Radius 1 4 loat ZERO 0 0 ool HitAgent false loat SpeedZ 1 0 loat Life 10 0 loat DrawCallListindex 0
35. Pos x Fpush tmpPos z use atan2 to calc the angle fatan this gives us the angle in radians so we convert it Frad2deg finally we align it with the world geometry Fnegate Fpop yrot these for temp storage in the calc angle function 37 CHAPTER 4 FLOCKING AddD yrot 180 0 now we align the z rotation Y Pos y NextPos y Set tmpPos NextPos Set tmpPos2 Pos swap the y components Fpush Pos y Fpop tmpPos y Fpush NextPos y Fpop tmpPos2 y now subtract the two Sub tmpPos tmpPos2 zrot asin Y r Length tmpPos Fpush tmpPos y Fdiv fasin convert it to degrees frad2deg Fpop zrot End CollideFunction LoopBin SphereSphereCollision HitAgent Pos Radius NextPos if HitAgent TRUE calc average GetAgentI ADir Dir Add ADir Dir DivD ADir 2 Normalize ADir Set Dir ADir SetAgentI Dir ADir LoopBinEnd End 38 Radius And the ebpl fl script for the configuration of the environment Configure the bounding box for the simulation WorldBBox 0 0 0 80 0 80 0 80 0 2 2 2 20 specify the output file to read to outputfile outfile out create a camera to view the scene Camera 0 80 40 00001 0 800 660 45 0 1 33 0 1 450 0 Create an emitter for the Agent with 50 Agents AgentEmitter 0 0 0 0 0 0 50 0 0 0 0 0 0 0 0 SimpleFlock comp Specify a path PathFollow 0 20 0 2 Specify the ground plane GroundPlane 20 0 0 4 0
36. SphereCollision HitAgent Pos Radius NextPos Radius if we have hit if HitAgent TRUE get the position GetAgentI AiPos Pos if were in front move faster ifelse AiPos lt Pos SetD Dir 0 0 1 7 SetAgentI Dir Dir SetD Dir 0 0 0 2 otherwise slow down SetD Dir 0 0 0 2 SetAgentI Dir Dir SetD Dir 0 0 1 7 SetAgentI HitAgent HitAgent LoopBinEnd End Vector tmpPos 0 0 0 0 Vector tmpPos2 0 0 0 0 Function CalcAngle fist set the vectors to subtract Set tmpPos NextPos Sub tmpPos Pos Fpush tmpPos x Fpush tmpPos z use atan2 to calc the angle fatan this gives us the angle in radians so we convert it Frad2deg finally we align it with the world geometry Fnegate Fpop yrot AddD yrot 90 0 now we align the z rotation End 66 CHAPTER 6 TERRAIN INTERACTION 67 6 1 Complex Agent Interactions using CallLists Figure 6 2 Agents Fighting The following example shows complex Agent interactions using the AgentRender module and terrain as shown in Figures 6 2 and 6 3 This example uses CallLists as well as an arf file to load in the initial Agent positions Figure 6 3 Agents Fighting close up The environment is configured using the following fl script CHAPTER 6 TERRAIN INTERACTION 68 WorldBBox 0 0 0 80 0 80 0 80 0 2 2 2 24 OutputFile fight out OutFileFrameSkip 1 UpdateRate 1 UseAgentRender ObjTerrain 20 NewTerrainTri obj
37. al 7 12 2 Function 7123 If 7 12 4 Ifelse 7 13 Debug 7 14 Noise Function 8 fl Script reference 8 0 1 Keys 8 1 Flocking System Script File Format scr a pO a NS ea Sk 8 1 1 Environment Parameters 2 2 0 0 0 e a eee 8 1 2 Emitters Bibliography lil List of Tables 2 1 22 2 3 2 4 2 5 2 6 4 1 7 1 7 2 7 3 7 4 EBPL variable types 2 Be ee ER a ee wae 7 EBPL variable types 6 4 4 64 2b Gea ae a BO ek oe de ae se 7 Stack Operation Prefix 0 00000 000000000000 8 Line Drawing styles MW99 2 2 0 20 000000022 eee eee 18 AgentRender Opcodes a ss rs Fi wk at BO SR ae a eee 22 Material Types Gi s etico GR RS eee ke bee A ee Be we eae Bie bs 23 ebpl Noise TUNCUONS ela be wn i ee ee ee Ok OE Oe PN ee ee 42 EBPL variable types 24 55 de a Re ae be we A ee 75 Ag entRenderOpcodes op oe oso ers eR OE AA A eS 80 Material Types sects Sn te Send a ii ai E a eine Boden oe pcia da 80 ebpl Noise functions ds ae Aad A a ha ae he Ba 87 List of Figures 1 1 1 2 2 1 2 2 2 3 2 4 2 5 2 6 2 7 2 8 3 1 3 2 3 3 3 4 4 1 4 2 4 3 4 4 4 5 4 6 5 1 2 5 3 5 4 6 1 6 2 6 3 EBPL environment flow chart 00 000 a 2 Getting Started 50 Random Spheres o e Agent Class Diagram J e eh pd AR Agent Bram Structir ua io e a E Sat Aw bs VarObj Class diagram e s e et y ee a e Agents avoiding an EnvObj ee 13 Mini
38. al rules 4 1 A simple Flock in ebpl Figure 4 3 shows a simple flock using the rules outlined in the previous section Flock ParamFile SimpleFlockfI www dec bournemouth ac uk staff jmacey fockhtml Press h for MP Figure 4 3 A simple Flock The flock is programmed to follow the flock center attached to the path but to avoid collisions with each other and match speed Each Agent has a number of variables used to determine it s Position and orientation These are as follows CHAPTER 4 FLOCKING 34 e Pos The agents position NextPos Where the Agent will be in the Next cycle used for collision detection and orientation Centroid Weight how much the agent should try to move to the flock center e MinCentroidDist how far the Agent should move away from the flock center before turning back FlockAvoidWeight how much the Agent should try to avoid the other Agents Radius the bounding sphere radius of the Agent used for collision detection HitA gent a flag to indicate if the Agent has collided When the simulation is executed the Agents are emitted in a random direction once the flocking mode is turned on using the space key the Agents will try to head towards the flock center Next the Agents are tested for collisions if there is a collision the Average direction of both Agents is calculated and the Agents new direction is set to this This allows the Agents to merge together and match velocity Finally t
39. angle points so b To P b2 T P and bg Th P To determine if the Point is within a triangle we calculate the dot product of the triangle points with their point normals Test bi e PN Testo by e PN and Tests bs e PN3 If all the Test values are lt 0 then the point is within the triangle and the Y height offset value is calculated using linear interpolation of the triangle points 6 0 1 Loading Terrain Terrain is loaded using the ObjTerrain fl command The parameters used are as follows ObjTerrain f Ylevel s Filename obj s TextureName bmp f AgentHeightOffset f Scale X f ScaleY f Scalez Ylevel The level of the groundplane Filename obj The name of the obj file to load TextureName bmp The name of the file to use as a texture for the groundplane AgentHeightOffset The value to add to the Agents Y value Scale X Y Z The scale in X Y and Z for the obj file This pre scales the obj file before loading The following fl file shows the loading of terrain for the example in Figure 6 1 WorldBBox 0 0 0 80 0 80 0 80 0 2 2 2 120 OutputFile agent out OutFileFrameSkip 1 UpdateRate 1 UseAgentRender Camera 0 2 100 00001 O 800 660 45 0 1 33 0 1 450 0 AgentEmitter 30 0 0 0 25 0 7 0 3 0 33 0 6 0 0 Agent4 comp PathFollow 0 20 0 0O 10 001000 2000 LoadArf 0 AgentLayout arf ObjTerrain 20 NewTerrainTri obj MountainHMC bmp 0 4 3 1 2 3 The ebpl program for this example is as follows
40. ariables from the EBPL script 7 3 0 1 SphereSphereCollision The SphereSphere collision opcode takes five parameters as outlined below SphereSphereCollision bool Hit Point3 Posl float Radl Point3 Pos2 float Rad2 The collision detection is calculated using the Position of the Current Agent and any other Agents in the current lattice bin Each Agent has a Radius for the bounding sphere and if the sphere collide the Hit flag will be set to true CHAPTER 7 LANGUAGE REFERENCE 75 7 3 0 2 CylinderCylinderCollision The CylinderCylinder collision opcode takes seven parameters as outlined below CylinderCylinderCollision bool Hit Point3 Posl float Radl float Heightl Point3 Pos2 float Rad2 float Height2 The collision detection is calculated using the Position of the Current Agent and any other Agents in the current lattice bin Each Agent has a Radius and height for the bounding cylinder and if the cylinders collide the Hit flag will be set to true 7 3 1 Environment Collisions Collisions with Objects within the environment are processed by two built in functions At present only Planes and Cubes are supported but the environment has been designed to be extensible and add more object types including obj objects 7 3 1 1 Env Object Collisions EnvObjects are represented as a cubes with a bounding sphere When the SphereEnvObjectCollision Op code is used the parameters passed to the routine are checked against all of the EnvObjects contai
41. ata types can be added together easily but a tuple to float will cause problems The opcode is used as follows Add Pos Dir add a point to a vector Add yrot zrot add two float variables CHAPTER 7 LANGUAGE REFERENCE 83 7 11 2 Sub The Sub opcode works on any data type but care must be taken with the mixing of types For example tuple data types can be subtracted easily but a tuple to float will cause problems The opcode is used as follows Sub Pos Dir subtract Dir from Pos Sub yrot zrot subtract two float variables 7 113 Mul The Mul opcode works on any data type but care must be taken with the mixing of types For example tuple data types can be multiplied easily but a tuple to float will cause problems The opcode is used as follows Mul Pos Dir multiply Pos by Dir Mul yrot zrot multiply two float variables 7 11 4 Div The Div opcode works on any data type but care must be taken with the mixing of types For example tuple data types can be subtracted easily but a tuple to float will cause problems The system automatically traps division by zero errors by setting the divisor to 1 if it is a zero value The opcode is used as follows Div Pos Dir divide Dir from Pos Div yrot zrot divide two float variables 7 11 5 Set The Set opcode is used to assign one variable from another it may only be used with variable of the same type as follows Point Pos 1 0 1 Point Pos2 0 0 0 Set Pos Pos2 Set P
42. be defined in the script before it is used Fuzzy CloseEnough 0 03 7 2 Agent Global Variables There are five built in Agent Global variables these may be used to either set or get values from the Agent Class 7 2 1 SetGlobalPos GetGlobalPos The global position opcodes are used to set and get the global position of the Agent The position value is used to calculate the flock center Centroid and if this is to be used in the simulation the GlobalPos variable must be set It is used in the following way set the global pos flag Point Pos 0 0 0 GetGlobalPos Pos get the global pos flag SetGlobalPos Pos 7 2 2 SetGlobalDir GetGlobalDir The global dir opcodes are used to set and get the global direction of the Agent The direction value is not used within the simulation system but the Dir value is from the arf file so getting this value can be used to configure the initial Agent direction get a direction value Vector Dir 0 0 0 0 GetGlobalDir Dir 7 2 3 SetGlobalCentroid GetGlobalCentroid The global Centroid opcodes are used to set and get the global Centroid of the Agent The Centroid is calculated every frame by finding the average position of all the Agents If the Centroid is required the user can access the flock center by these opcodes get the flock center Point Centroid 0 0 0 GetGlobalCentroid Centroid CHAPTER 7 LANGUAGE REFERENCE 74 7 2 4 SetGlobalCollideFlag GetGlobalCollid
43. below ifelse dist gt MinCentroidDist do something do something else All if statements must use the open and closed braces and at present ifelse statements may not be nested however if statements may be placed within an ifelse construct At present ifelse only works with two defined variable types so if a comparison against a static value is required the static value must be define as a variable 7 13 Debug The Debug opcode prints to the console the variable argument Debug Pos The DebugOpOn and Debug Op Off opcodes turn on and off the printing of the current opcode to the console CHAPTER 7 LANGUAGE REFERENCE 87 7 14 Noise Function Each Agent has the ability to access a noise function based on Perlin Noise eta98 This value is generated by a built in noise function and can be calculated from any tuple data type There are five built in noise functions as shown in Table 7 4 Noise Type Noise Index Value turbulence 0 marble 1 undulate 2 noise3 3 turbulence2 4 Table 7 4 ebpl Noise functions To use noise the noise generator must be initialized as shown below float NoiseType 5 0 float NoiseScale 0 0 RandomizePos NoiseType 5 Randomize NoiseScale 2000 UseNoise NoiseType NoiseScale The GetNoiseValue opcode is used to access the noise table it is passed a value to return to and a seed value to generate the noise from this is shown in the following example Point Pos 0 0 0 V
44. code calls giBegin GL_POLYGON to start drawing with polygons 7 7 8 Quad The Quad opcode calls g Begin GL_QUADS to start drawing with quads 7 7 9 Point The Point opcode calls g Begin GL_POINTS to start drawing with points CHAPTER 7 LANGUAGE REFERENCE 7 00 7 7 10 LineLoop The LineLoop opcode calls g Begin GL_LINE_LOOP to start drawing a line loop 7 7 11 glEnd The glEnd Opcode calls glEnd to end the current drawing mode 7 7 12 Vertex The vertex Opcode takes either a point or a vector data type and uses the x y and z values to produce a vertex using gl Vertex3f x y z Vertex Pos draw a vertex using a point Vertex Dir draw a vertex using a vector 7 7 13 Vertexf The vertexf opcode draws a vertex using direct floating point values for the x y and z values as shown below Vertexf 0 5 0 2 0 0 7 7 14 PointSize The PointSize opcode sets the current point drawing size PointSize 2 0 set the point size to 2 0 I NJ j u E pu o O DN pi N O The LineSize opcode sets the current line drawing width LineSize 4 0 set the line width to 4 0 NJ I jua N Y gej a O The Sphere opcode draws a sphere using either a floating point variable or direct value for the radius of the sphere the other two arguments are stacks and slices which can not be changed once set Sphere radius 12 12 sphere using a variable value Sphere 0 02 20 20 sphere using direct float
45. dd ADir Dir DivD ADir 2 SetAgentI ADir ADir LoopBinEnd End Vector EnvNoise 0 0 0 0 Function CollideAgainstEnv0Obj SphereEnvObjCollision HitEnvObj NextPos Radius2 EnvAvoidDir if HitEnvO0bj TRUE SetD CentroidWeight 0 SetD FlockAvoidWeight 10 0 SetD EnvAvoidWeight 6129 0 Randomize EnvNoise 0 2 0 2 0 2 Add EnvAvoidDir EnvNoise if HitEnvObj FALSE SetD CentroidWeight 72 9 SetD FlockAvoidWeight 5100 0 SetD EnvAvoidWeight 6120 0 End Function Move Set acceleration force Div acceleration mass Add Velocity acceleration Set nVel Velocity Div nVel VelDiv Add Pos Dir Mul Pos nVel Set NextPos Pos Add NextPos Dir Mul NextPos nVel Set ADir Dir End Function CalcDir Mul ADir FlockAvoidWeight Mul CentroidDir CentroidWeight Mul EnvAvoidDir EnvAvoidWeight Set Dir ADir Add Dir CentroidDir Add Dir EnvAvoidDir GetNoiseValue NoiseValue Pos Add Dir NoiseValue Normalize Dir Set the force to be the current Direction so we can calculate the new acceleration in the next iteration Set force Dir CHAPTER 4 FLOCKING End 52 Chapter 5 Agent Render The following chapter highlights the AgentRender module At present the AgentRender has six built in animation cycles to demonstrate the use of the AgentRender these are shown in Figure 2 7 Future versions of the AgentRender module will allow the loading of any obj file with user definable animation loop cycles
46. e Agent calculated from hits with any agents in the current bounding sphere radius This is used with the FlockAvoidDir weight to set the Flock avoid Direction Vector ADir 0 0 0 0 flock avoid dir Vector CentroidDir is the direction to the flock center from the current agent position This is multiplied by the Centroid weight Vector CentroidDir 0 0 0 0 bool HitAgent boolean flag set to indicate that the Agent has hit another Agent bool HitAgent false bool HitEnvObj false GLfloat GPYlevel the ground plane level of the Agent float GPYlevel 20 GLfloat CentroidWeight The weight the CentroidDir vector is multiplied by to calculate the new direction of the Agent so it can flock center float CentroidWeight 72 9 GLfloat FlockAvoidWeight The Weight the FlockAvoidDir vector is multiplied by to calculate the new direction of the Agent when it has hit a member of it s own flock float FlockAvoidWeight 5100 0 float EnvAvoidWeight 6129 0 float Radius 0 6 float Radius2 2 1 float MinCentroidDist 6 0 Vector CentroidDist 0 0 0 0 Vector nVel 0 0 0 0 Vector acceleration 1 1 1 0 Vector force 0 0 0 0 Vector mass 150 150 150 0 Vector EnvAvoidDir 0 0 0 0 Vector Velocity 0 0 0 0 Vector VelDiv 1 1 1 0 float NoiseType 2 0 CHAPTER 4 FLOCKING 49 float NoiseScale 1230 0002 vector NoiseValue 0 0 0 0 InitFunction Randomize Dir 2 0 2 0 2 0 SetGlobalPos Pos Random
47. e stack subtracts them and places the result back on the stack Note if the stack contains 2 and 4 the result will be 2 4 2 2 3 1 6 Fmul The Fmul opcode takes the two top values from the stack and multiplies them and places the product back on the stack 2 3 1 7 Fdiv The Fdiv opcode takes the two top values from the stack and divides them and places the result back on the stack Division by 0 is trapped by changing any 0 value with a 1 and printing a warning to the console in debug mode CHAPTER 2 EBPL LANGUAGE 10 2 3 1 8 Fdup The Fdup opcode takes the top of stack value and duplicates it 2 3 1 9 Fsqrt The Fsqrt opcode takes the top of stack value and places the square root of that value onto the stack 2 3 1 10 Frad2Deg The Frad2deg opcode is a helper function to convert radians to degrees as most C math operations use radians 2 3 1 11 Fatan The Fatan opcode takes the two top values from the stack and calculates the arc tangent The code used is atan2 x y where X is the top of stack value and y is the next value 2 3 1 12 Fsin The Fsin opcode takes the top most value from the stack and puts back the sine of the value 2 3 1 13 Fasin The Fasin opcode takes the top most value from the stack and puts back the arc sine of the value 2 3 1 14 Fcos The Fcos opcode takes the top most value from the stack and puts back the cosine of the value 2 3 1 15 Facos The Facos opcode takes the top most value fr
48. e system and highlight some of the basic principles of the ebpl language 3 1 Simple Particles One of the earliest method of controlling large amounts of objects in a scene is the Particle System intro duced by Reeves Ree83 Ree85 in 1983 When viewed as a whole the particles create the impression of a single dynamic complex object Par02 as shown in Figure 3 1 Figure 3 1 Simple Particle system Created in EBPL For a simple omni directional particle system only a few variables are required as follows e Position the particles current position e NextPosition the position where the particle will be next 24 CHAPTER 3 PROGRAMMABLE PARTICLES e Direction the direction of emission e LifeSpan the life of the particle For each iteration of the system the Direction is added to the current Position to give the particle movement The NextPosition is calculated by setting the current position after this calculation and then adding the Direction again The Life variable is incremented by one each iteration and if it reaches the EndLife value the particle is reset and re emitted For each particle a random life and direction is created and the particles are drawn as lines as shown in the following ebpl script Program 2 Particle bs Simple Particle System Po the Particles Position int Pos 0 0 0 Particles Direction Vector Dir 0 0 0 0 0 0 0 0 The Particles Next Position V
49. eFlag The global collide flags are used to indicate if an Agent has already been hit in a collision detection routine If the global collide flag is set the collision detection will not be executed for the Agent get the flock center Bool TRUE true set glob collide flag SetGlobalCollideFlag TRUE 7 2 5 SetGPYlevel The setgpylevel opcode is used to query the groundplane and set the y value of a tuple data type get the flock center Point Pos 0 0 0 set the y value based on the gp from the agents position GetGPYLevel Pos 7 2 6 PushGPYLevel This opcode pushes the y value of the groundplane onto the float stack No variables are required for this function PushGPYLevel 7 3 Collisions Each time the system is updated the brain s CollideFunction is called this is the only time within an EBPL program that the An Agent can access another Agents data Within the system all agents are contained within a number of bins It is possible to loop through the Agents within the bins and test for collisions This is implemented using the LoopBin and LoobBinEnd EBPL opcodes Whenever the LoopBin structure is encountered the current Agent value is used and the rest of the Agents within the bin are compared with the current Agent For convenience and speed EBPL has two built in collision detection routines however these and others may also be implemented within the EBPL language itself These routines take as parameters v
50. eFunction End draw in all views 31 Chapter 4 Flocking In 1987 Reynolds Rey87 extended the original Reeves Ree83 Ree85 particle system into a sub object system where each particle represented by a point in the Reeves system is replaced by an animated object Each of these objects which Reynolds refers to as Bird oids or Boids are given limited intelligence which when combined into a collective whole produces the flocking behaviour The original Boids have three simple rules 1 Collision Avoidance avoid collisions with nearby flock mates 2 Velocity Matching attempt to match velocity with nearby flock mates 3 Flock Centering attempt to stay close to nearby flock mates Combining these rules produce a simple flocking behaviour as shown in figure 4 3 vw x WK Ser Figure 4 1 A simple Flock Rey87 32 CHAPTER 4 FLOCKING 33 In more recent papers Reynolds has introduced slightly different rules for his flocking behaviours calling them steering behaviours Rey99 The new rules are e Separation steer to avoid crowding local flock mates e Alignment steer towards the average heading of local flock mates e Cohesion steer to move toward the average position of local flock mates Lo Separation Alignment Cohesion Figure 4 2 Steering Flocking rules Rey99 These behaviours are shown in Figure 4 2 and create a different type of flocking to the origin
51. ebug mode 7 10 5 Fdup The fdup opcode takes the top of stack value and duplicates it 7 10 6 Fsqrt The Fsqrt opcode takes the top of stack value and places the square root of that value onto the stack 7 10 7 Frad2Deg The Frad2deg opcode is a helper function to convert radians to degrees as most C math operations use radians CHAPTER 7 LANGUAGE REFERENCE 82 7 10 8 Fatan The fatan opcode takes the two top values from the stack and calculates the arc tangent The code used is atan2 x y where X is the top of stack value and y is the next value 7 10 9 Fsin The fsin opcode takes the top most value from the stack and puts back the sine of the value 7 10 10 Fasin The fasin opcode takes the top most value from the stack and puts back the arc sine of the value 7 10 11 Fcos The fcos opcode takes the top most value from the stack and puts back the cosine of the value 7 10 12 Facos The facos opcode takes the top most value from the stack and puts back the arc cosine of the value 7 10 13 Fnegate The Fnegate opcode takes the top most value from the stack and puts back the negated value 7 10 14 FStackTrace The FstackTrace opcode prints out the current contents of the stack 7 11 Variable Opcodes Most variables can be accessed directly by the use of opcodes and values can be set and retrieved 7 11 1 Add The Add opcode works on any data type but care must be taken with the mixing of types For example tuple d
52. ector NextPos 0 0 0 0 0 0 0 0 The Lifespan of the particle float Life 0 0 When the particle is to Die float EndLife 10 0 Default init function for the Agent Brain InitFunction Call InitParticle End Initialize the particle Function InitParticle End Create a random direction Randomize Dir 1 0 1 0 1 0 Set the particles life value to 0 SetD Life 0 0 Set the initial position of the particle to 0 0 0 SetD Pos 0 0 0 0 0 0 SetD NextPos 0 0 0 0 0 0 Randomize the particles life span Randomize EndLife 20 just draw the particle as a line from current pos to next pos DrawFunction PushMatrix Translate to the Agents Position Translate Pos Colour 1 0 1 0 1 0 Lines Vertex Pos Vertex NextPos glEnd PopMatrix End update the particles position based on the Dir vector UpdateFunction Add Pos Dir Set NextPos Pos Add NextPos Dir AddD Life 1 0 if we have reached the end of the particle s life reset it if Life gt EndLife CHAPTER 3 PROGRAMMABLE PARTICLES 26 Call InitParticle End No collision detection CollideFunction End 3 2 Cone Emit Particles WY Flock ParamFile ConeEmitParticle fl www dec bournemouth ac uk staff jmacey flock html Press hs x Figure 3 2 Cone Emit Particles The following example Figure 3 2 shows a particle system using a directional cone as
53. ector NoiseValue 0 0 0 0 GetNoiseValue NoiseValue Pos Chapter 8 fi Script reference To run the program type in the console ebpl lt paramfile fl gt where lt paramfile fl gt is the name of the file to load Once the program runs it is best to leave the agents moving in random for a while so the system can reach a suitable chaotic state To run full screen use ebpl lt paramfile fl gt f 8 0 1 Keys Mouse O zero turns the flocking on and off toggles the curve following for the agents Pause simulation Dump agent debug info to console Toggle on screen menu rotates view Left Button x y Right button x z toggle write agent points to file mode ArrowKeys Move Camera PGUP PGDN Zoom Z in and out 1 Toggle Camera follow Centroid Toggle Agent Follow goals mode Pause Simulation Toggle Locked Centroid mode Draw bin lattice structures Toggle draw Environment details Toggle write frames as tiff files will be placed in the directory Frames 88 CHAPTER 8 FL SCRIPT REFERENCE 89 8 1 Flocking System Script File Format The flocking system reads a file to configure the various elements of the system Two initial parameters must be set and after that the parameters may be set in any sequence All variables are assumed floats f except index values which are integer values i and the file name for the Output file s Comments can be added to the file using the standard C comment block also whi
54. ent poly s Polygon Vertexf 0 5 0 2 0 2 Vertexf 0 5 0 2 0 0 Vertexf 0 5 0 2 0 0 Vertexf 0 5 0 2 0 2 Vertexf 0 5 0 2 0 0 Vertexf 0 5 0 2 0 0 glEnd Now draw the Poly s as Lines to give the agent an outline shape LineSize 1 0 Colour 1 0 1 0 1 05 LineLoop Vertexf 0 5 0 2 0 2 Vertexf 0 5 0 2 0 0 Vertexf 0 5 0 2 0 0 Vertexf 0 5 0 2 0 2 Vertexf 0 5 0 2 0 0 Vertexf 0 5 0 2 0 0 glEnd PopMatrix Now Draw Shadows PushMatrix preserve y value Fpush Pos y PushGPYlevel Fpop Pos y Translate Pos RotateX xrot RotateY yrot RotateZ zrot Scale 0 5 0 5 0 5 Colour 0 2 0 2 0 2 Polygon Vertexf 0 5 0 2 0 2 Vertexf 0 5 0 2 0 0 Vertexf 0 5 0 2 0 0 Vertexf 0 5 0 2 0 2 Vertexf 0 5 0 2 0 0 Vertexf 0 5 0 2 0 0 glEnd PopMatrix restore the Y value Fpop Pos y End 2 4 6 AgentRender The AgentRender module allows for a series of key framed Alias wavefront obj Ali03 files to be loaded as separate animation sequences which can be triggered within the system CHAPTER 2 EBPL LANGUAGE 21 Walk Mode 0 Run Mode 1 Neutral Mode 2 Dead Mode 3 Punch Mode 4 Swing Mode 5 Figure 2 7 AgentRender module with 6 animations cycles At present the AgentRender module is hard coded with the six animation cycles shown in Figure 2 7 However in future versions of the system this will be fully scripted within the fl script system Each time the AgentRender module is loaded a s
55. er elements of the script to attach something to the Emitter 8 1 2 1 AgentEmitter The simplest emitter is shown below and is used for most systems AgentEmitter f Pos x f Pos y f Pos z i NumAgents f Width f Height f Depth f Radius i SpeciesTag b EmitType s BrainFile Pos sets the initial position of the emitter NumA gents the number of Agents to Emit Width Height Depth set the size of the agents Radius the bounding sphere radius of the Agent used for collision detection SpeciesTag indicates which species the Agents are EmitType set to 0 for point emitter 1 for random distribution around the world BBox BrainFile The name of the compiled brain for the Agent to use CHAPTER 8 FL SCRIPT REFERENCE 94 8 1 2 2 PathFollow This is used to set a spline curve for the agents to follow at present this is a 4 point Bezier curve PathFollow i Index P1 x f Pl y f Pl z P2 x f P2 y H P2 2 2 P38 7 PS E METER AL Pace EPA Y E PAZ Index which AgentEmitter to attach the curve to P n x P n y P n z the points for the curve 8 1 2 3 PathStep This sets the speed at which the Centroid path step is updated each time default value 0 02 steprate The update speed for the centroid 8 1 2 4 LoadARF This allows for the loading of an AgentResoure file generated from the Layout program LoadARF i Index s Filename Index the index of the AgentEmitter to load Filename The name o
56. eries of OpenGL display lists are created to speed up the execution of the renderer If a non accelerated OpenGL graphics card is used the system will resort back to software rendering which slows down the loading and rendering of Agents When the AgentRender module is created the six animation cycles are created by loading in two obj models and creating a series of frames by the use of linear interpolation Each model loaded in must have the same vertex face and normal layout but the verticies may be in different positions to create the animation Walk Start Frame Walk End Frame Figure 2 8 Sample Agent Render model frames Figure 2 8 shows the two obj models used for generating the walk cycle These are loaded as the start and end frames for the animation cycle then the linear interpolation function shown below is used on each Vertex to calculate the in between frames CHAPTER 2 EBPL LANGUAGE 22 glVertex3f lerp StartObj Verts V x EndObj Verts V lerp StartObj Verts V y EndObj Verts lerp StartObj Verts V z EndObj Verts V V V Where t is the blend function set from 0 the start frame and 1 the end frame The lerp function used is shown below GLfloat lerp GLfloat A GLfloat B GLfloat t GLfloat p p A B A t return p 2 4 6 1 Using the AgentRender To use the AgentRender module both the fl and brainscript files need to have the following instruction added UseAgentRender This tells the environ
57. es For example tuple data types can be added together easily but a tuple to float will cause problems Add Pos Dir add a point to a vector Add yrot zrot add two float variables 2 3 3 2 AddD The AddD opcode adds a value directly to a variable for example AddD yrot 180 0 2 3 3 3 Length The Length opcode returns the length of a Vector or Point Variable onto the stack 2 3 3 4 Normalize The Normalize opcode normalizes the current Vector or Point Variable CHAPTER 2 EBPL LANGUAGE 12 2 3 3 5 Randomize The Randomize opcode sets the variable to a random value within a range based on the seed value passed The RandomizePos opcode only returns positive values Randomize Dir 2 1 0 1 1 1 RandomizePos yrot 4 0 2 3 3 6 Debug The Debug opcode prints to the console the variable argument Debug Pos The DebugOpOn and DebugOpOff enable and disable the printing of the current opcode name to the con sole 2 3 4 Collisions Each time the system is updated the Brain s CollideFunction is called This is the only time within an EBPL program that the an Agent can access another Agent s data Within the ebpl system all Agents are contained within a number of bins see Section for more details It is possible to loop through the Agents within the bins and test for collisions This is implemented using the LoopBin EBPL function Whenever the LoopBin structure is encountered the current Agent value is used and the rest
58. esented as a cube with a bounding sphere When the SphereEn vObjectCollision Opcode is used the parameters passed to the routine are checked against all of the En vObjects contained within the environment Figure 2 4 Agents avoiding an EnvObj CHAPTER 2 EBPL LANGUAGE 14 Detection of collision with EnvObjects is a two stage process first the Agent is tested using Sphere Sphere collision as shown in Section 7 3 0 1 to determine if the Object has been hit Next Sphere Plane collision as shown in Section is used to determine which face of the object has been hit At present the Normal of this face is returned to the Agent and collision avoidance is calculated on this value 2 3 5 2 EnvObject Example EnvObj s are added to the environment using the following fl script EnvObj float Pos x float Pos y float Pos z float Width float Height float Depth float Radius The radius parameter is used to determine the bounding sphere of the object for the collision detection used in the SphereEnvObjCollision opcode The SphereEnvObjCollision opcode takes four parameters as outlined below SphereEnvObjCollision bool Hit Point3 Pos float Radius2 Vector Normal The collision detection is calculated using the Position of the Current Agent and its bounding sphere Radius each EnvObject is tested in turn against the Agent and if a hit is detected the Hit flag is set to true and the Normal to the face hit is returned in the Normal paramete
59. etD EnvAvoidDir 0 0 0 End float dist 0 0 Function UpdateAgainstCentroid GetGlobalCentroid CentroidDir Sub CentroidDir Pos Length CentroidDir fpop dist ifelse dist gt MinCentroidDist Y Y GetGlobalCentroid CentroidDir Sub CentroidDir Pos SetD CentroidDir 0 0 0 End This function calculates the Agents orientation based on the position and the NextPos use these for temp storage in the calc angle function Vector tmpPos 0 0 0 0 Vector tmpPos2 0 0 0 0 Function CalcAngle fist set the vectors to subtract Set tmpPos NextPos Sub tmpPos Pos Fpush tmpPos x Fpush tmpPos z use atan2 to calc the angle fatan this gives us the angle in radians so we convert it Frad2deg finally we align it with the world geometry Fnegate Fpop yrot AddD yrot 180 0 now we align the z rotation Y Pos y NextPos y Set tmpPos NextPos Set tmpPos2 Pos swap the y components Fpush Pos y Fpop tmpPos y Fpush NextPos y Fpop tmpPos2 y now subtract the two Sub tmpPos tmpPos2 zrot asin Y r Length tmpPos Fpush tmpPos y Fdiv asin CHAPTER 4 FLOCKING 51 convert it to degrees frad2deg Fpop zrot End CollideFunction Set HitAgent FALSE Set HitEnvObj FALSE Call CollideAgainstEnvObj LoopBin SphereSphereCollision HitAgent NextPos Radius2 NextPos Radius2 if HitAgent TRUE calc average SetGlobalCollideFlag TRUE GetAgentI ADir Dir A
60. f the ARF file to load Index fl 1 Add 11 25 29 31 37 38 46 48 51 56 59 61 65 70 82 AddD 8 11 25 29 35 38 43 44 50 57 59 61 62 65 66 70 71 76 83 Affine Transforms 15 AgentEmitter 4 38 47 55 64 68 93 AgentRender 15 20 53 55 arf 54 55 57 67 68 atan2 10 BBox 89 bins 12 74 Bool 7 74 bool 6 36 42 48 58 60 61 65 68 70 72 Boolean 8 BrainComp 1 4 bs 1 Call 14 25 26 28 29 31 37 45 46 49 50 59 70 85 CallList 8 70 76 CallListItem 8 69 76 CallLists 8 67 76 Camera 4 38 47 55 64 68 91 CamFollowCentroid 91 Centroid 5 CollideFunction 3 7 12 26 29 31 38 41 45 51 57 59 61 65 70 75 Collisions 12 74 Colour 3 17 20 29 31 36 37 43 49 59 79 comp 1 Cube 17 31 Cylinder 17 79 CylinderCylinderCollision 13 75 Debug 12 86 DebugOpOff 12 86 DebugOpOn 12 86 DefineCallList 8 69 76 DisableLights 31 56 58 70 79 Div 46 51 83 DivD 38 51 84 Dot 41 45 85 95 DrawFunction 3 7 15 25 28 31 36 43 49 56 58 61 65 70 75 Drawing 15 ebpl 1 2 4 88 EnableLights 31 56 58 70 79 End 3 14 20 25 26 28 31 35 38 41 43 46 48 52 55 62 65 66 69 71 86 Environment 5 EnvObj 14 47 89 Facos 10 facos 82 Fadd 9 70 fadd 9 30 31 81 Fasin 10 fasin 35 38 45 50 82 Fatan 10 fatan 35 37 44 50 59 62 66 71 82
61. he orientation of the Agent is calculated using Spherical geometry as shown in Section 4 1 0 1 4 1 0 1 Using spherical geometry to calculate Agent orientation Figure 4 4 Spherical Geometry jr01 Figure 4 4 shows how a point U is defined in spherical coordinates R is the radial distance of U from the origin and is the angle that U makes with the xz plane know as the latitude of the point U 0 is the azimuth of U the angle between the xy plane and the plane through U and the y axis lies in the interval 7 2 lt lt 7 2 and lies in the range 0 lt O lt 277 Using trigonometry we can work out a relationship between spherical coordinates and Cartesian coordi nates Uz Uy Uz for U the equations are Uz Rcos cos 9 uy Rsin and u Rcos sin Using trigonometry we can work out a relationship between Cartesian coordinates and spherical coordi nates as follows R u2 u u2 sin 5 0 arctan uz uz The function arctan is the two argument form of the arctangent defined as atan2 in C CHAPTER 4 FLOCKING 35 tan y x ifx gt 0 _Jowttan y z ifr lt 0 arctan y 7 2 ifx 0andy gt 0 n 2 ifx Oandy lt 0 This may be implemented in C using the following code void Agent CalcAngle void GLfloat X Y Z X NextPos x Pos x Z NextPos z Pos Zz Y Pos y NextPos y using spherical geometry we calculate the rotation based on the New Point yrot atan2 Z X Now con
62. irection When they reach a certain point the animation cycles changes to a run cycle and the Agents speed up as shown in Figure 5 2 CHAPTER 5 AGENT RENDER 55 Figure 5 2 AgentRender Agents with different animation cycles Once the Agents reach the end of the world they are reset to their original position and start the cycle over again The system is configured using the following fl script WorldBBox 0 0 0 80 0 80 0 80 0 2 2 2 120 OutputFile agents out OutFileFrameSkip 1 UpdateRate 1 UseAgentRender GroundPlane 20 0 0 0 2 0 0 1 0 Camera 0 2 100 00001 0 800 660 45 0 1 33 0 1 450 0 AgentEmitter 30 0 0 0 25 0 7 0 3 0 33 0 6 0 0 Agent1 comp PathFollow 0 20 0 0 10 001000 2000 LoadArf 0 AgentLayout arf lockedCentroid 0 0 20 0 The arf file is loaded using the LoadArf fl keyword 5 2 0 6 Setting the Agents original position When the the LoadArf instruction is called the Agent brain InitFunction is called and the Position and Direction variables are loaded as follows InitFunction GetGlobalPos Pos GetGlobalDir Dir Set StartPoint Pos UseAgentRender RandomizePos Frame 8 The GetGlobalPos and GetGlobalDir opcodes are used to access the data from the arf file and store the initial Agent position and Direction Next the system is told to use the AgentRender module and the start frame for the Agent is determined using the RandomizePos opcode CHAPTER 5 AGENT RENDER The full listing of the Example is sh
63. izePos NoiseType 5 Randomize NoiseScale 2000 UseNoise NoiseType NoiseScale End Point Centroid 10 10 0 DrawFunction PushMatrix Translate to the Agents Position Translate Pos Rotate the Agent to the correct orientation RotateX xrot RotateY yrot RotateZ zrot Set the Colour Colour 1 0 0 0 0 0 Polygon Vertexf 0 25 0 1 0 1 Vertexf 0 25 0 1 0 0 Vertexf 0 25 0 1 0 0 Vertexf 0 25 0 1 0 1 Vertexf 0 25 0 1 0 0 Vertexf 0 25 0 1 0 0 glEnd Now draw the Poly s as Lines to give the agent an outline shape LineSize 1 0 Colour 1 0 1 0 1 0 LineLoop Vertexf 0 25 0 1 0 1 Vertexf 0 25 0 1 0 0 Vertexf 0 25 0 1 0 0 Vertexf 0 25 0 1 0 1 Vertexf 0 25 0 1 0 0 Vertexf 0 25 0 1 0 0 glEnd PopMatrix PushMatrix preserve y value Fpush Pos y PushGPYlevel Fpop Pos y Translate Pos RotateX xrot RotateY yrot RotateZ zrot Colour 0 2 0 2 0 2 Polygon Vertexf 0 25 0 1 0 1 Vertexf 0 25 0 1 0 0 Vertexf 0 25 0 1 0 0 Vertexf 0 25 0 1 0 1 Vertexf 0 25 0 1 0 0 Vertexf 0 25 0 1 0 0 glEnd PopMatrix fPop Pos y End float Ylevel 0 0 float gpy 0 0 UpdateFunction SetGlobalCollideFlag FALSE Call UpdateAgainstCentroid CHAPTER 4 FLOCKING Call Move Call CalcDir Call CalcAngle PushGPYlevel fpop gpy fpush Pos y fpop Ylevel if Ylevel lt gpy SetD Dir y 1 SetGlobalPos Pos SetD ADir 0 0 0 SetD CentroidDir 0 0 0 S
64. lt in functions are shown in Table 7 1 and are called for every Agent in the system for each iteration of the environment User defined functions are generated by the Function keyword and can be called from within any of the main built in functions 2 2 5 Call Lists Call lists are a way of creating switchable function calls depending upon an ordinal variable value similar to the C C switch case construct The creation of a call list is a two stage process as follows DefineCallList TestList CallListItem TestList foo CallListItem TestList bar First a call list name is defined to make storage for the Function pointers to be allocated to the list Next list items may be added to the list To use a CallList within a Function the following code is used float ListValue 0 function foo called CallList TestList ListValue AddD ListValue 1 Function bar called CallList TestList ListValue 2 3 EBPL language structure The EBPL language is split into four distinct parts these are e Stack Based Operations e Variable Operations e Collisions e Drawing 2 3 1 Stack Operations Each stack has a series of opcodes which can access the stack data The operations are based upon the stack data type and results from the operations are always placed back upon the stack All stack operations are prefixed with the stack type name as shown in Table 2 3 Operator Prefix Description F Float stack operator pre fix FZ Fuz
65. main areas e Affine Transforms e Drawing 2 4 2 Affine Transforms The following Opcodes are responsible for transforms within the environment all transforms are based on a transformation matrix which can be preserved for each drawing routine CHAPTER 2 EBPL LANGUAGE 16 2 4 2 1 PushMatrix PopMatrix The PushMatrix and PopMatrix opcodes preserve the affine transformation stack an operate in a similar way to the OpenGL matrix stack Care must be taken when using these operations and PushMatrix PopMatrix opcodes must be matched else the outcome is undefined create an empty transform stack PushMatrix draw stuff restore the transform stack PopMatrix 2 4 2 2 Rotations The rotation opcode set the current rotation in the X Y and Z axis all drawable objects called after a rotation opcode will be rotated by the amount of degrees specified The Rotate opcodes are defined as follows RotateX float Degrees RotateY float Degrees RotateZ float Degrees At present the Rotate opcode only accepts a Float variable and not a direct floating value 2 4 2 3 Scale The Scale opcode scales in the X Y and Z axis any drawable objects specified after the Scale is used At present the Scale opcode only accepts direct floating point values and not variables as shown in the example below scale in X y and Z Scale 5 0 6 0 55 2 4 2 4 Translate The Translate opcode translates the current drawing position from the cu
66. ment and the Brain that the AgentRender is being used If this is not present in the scripts and any other AgentRender calls are made the system will crash In the brain script this call is generally placed in the InitFunction as it only needs to be set once There are four Opcodes used for configuring the AgentRender as follows Value Meaning SetAnimCycle sets the animation cycle to be drawn as indicated by the Mode values in Figure 2 7 RenderFrame Selects which frame of the AgentRender sequence to draw RenderA gent Draws the Agent configured by the above two opcodes RenderMaterial Set the current material for the Agent see Table 7 3 Table 2 5 AgentRender Opcodes All these opcodes can take either Float variables or direct float values as shown in the example below set to agent walk cycle float DrawMode 0 float Frame 4 SetAnimCycle DrawMode set material to chrome RenderMaterial 3 render the 3rd frame of the cycle RenderFrame Frame The material types currently used in EBPL are shown in Table 7 3 CHAPTER 2 EBPL LANGUAGE 23 Material Number Material Type BLACKPLASTIC BRASS BRONZE CHROME COPPER GOLD PEWTER SILVER POLISHEDSILVER Oo DUB 0NO Table 2 6 Material Types Chapter 3 Programmable Particles As well as emergent behaviour ebpl can generate user programmable particles for simple simulations This chapter presents a number of example ebpl brain scripts for generating a simple particl
67. nction CalcAngle fist set the vectors to subtract Set tmpPos NextPos Sub tmpPos Pos Fpush tmpPos x Fpush tmpPos z use atan2 to calc the angle fatan this gives us the angle in radians so we convert it Frad2deg finally we align it with the world geometry Fnegate Fpop yrot AddD yrot 90 0 End Chapter 7 Language Reference The following Chapter describes the syntax of the EBPL programming language 7 1 Variable syntax 7 1 1 Float A floating point variable may be defined as shown below it must be defined in the script before it used float xrot 0 0 7 1 2 Point The Point data type is used to represent a 3D point for drawing it must be defined in the script before it is used The point is defined as a 3 tuple with x y and z components Point Pos 0 0 0 7 1 3 Vector The Vector data type is used to represent a 4D mathematical vector it must be defined in the script before it is used The point is defined as a 4 tuple with x y z and w components Vector Dir 0 0 0 2 0 1 0 0 7 1 4 Bool The Bool data type is used to represent true and false values it must be defined in the script before it is used bool HitAgent false 72 CHAPTER 7 LANGUAGE REFERENCE 73 7 1 5 Fuzzy The Fuzzy data type represents a class of fuzzy object It is defined as a floating point value usually clamped between 0 0 1 0 and is capable of having fuzzy set operations applied to it 1t must
68. nd primitives it can take either a Point data type using the x y and z tuple values for Red Green and Blue or direct Float values as shown in the following examples set colour to red Point ColourValue 1 0 0 Colour ColourValue set colour to white Colour 1 1 1 CHAPTER 2 EBPL LANGUAGE 18 2 4 4 2 Line and Point Size The current line and point size can be set using the PointSize and LineSize opcodes these only take direct float values and are valid until another call to PointSize and LineSize The default value for both is 1 0 set the pointsize to 5 0 PointSize 5 0 set the linesize to 2 0 LineSize 2 0 2 4 4 3 Drawing Styles MiniGL supports five line drawing style as shown in Table 2 4 Value Meaning Points individual points Lines pairs of verticies interpreted as individual line segments LineLoop same as above with a segment added between last and first verticies Polygon boundary of a simple convex polygon Quads quadruples of verticies interpreted as four sided polygons Table 2 4 Line Drawing styles MW99 These are shown in Figure 2 5 ee de ey v2 A vO vO y3 ys vie e3 A vie evz v6 v5 y1 v2 Points Lines Polygon Quads Figure 2 5 MiniGL Line Drawing types Each of these opcodes are called to specify the line drawing style for the verticies which follow each of the drawing styles must be ended by the use of the glEnd opcode as shown in the following example Draw using poin
69. ned within the environment Detection of collision is a two stage process first the Agent is tested using Sphere Sphere to determine if the Object has been hit Next Sphere Plane collision is used to determine which face of the object has been hit At present the Normal of this face is returned to the Agent and collision avoidance is calculated on this value The SphereEnvObjCollision opcode takes four parameters as outlined below SphereEnvObjCollision bool Hit Point3 Pos float Radius2 Vector Normal The collision detection is calculated using the Position of the Current Agent and its bounding sphere radius each EnvObject is tested in turn against the Agent and if a hit is detected the Hit flag is set to true and the Normal to the face hit is returned in the Normal parameter 7 4 Functions EBPL has two types of functions there are 4 default built in functions which must be present in every EBPL script and user defined functions which act as procedure calls Built In Functions Description InitFunction Called when the Agent brain is created and used to initialize variables etc UpdateFunction Called every iteration of the system to update the Agents position DrawFunction Called every iteration of the system to Draw the Agent Collide Function Called every iteration to do collision detection Table 7 1 EBPL variable types CHAPTER 7 LANGUAGE REFERENCE 76 The built in functions are shown in Table 7 1 and are called for every
70. oat WALK 0 0 float RUN 1 0 float DrawMode 0 0 float Frame 0 0 Point StartPoint 0 0 0 CHAPTER 5 AGENT RENDER bool HitAgent false float Radius 1 5 float ZposEnd 40 0 float CurrZpos 0 0 float NewSpeed 1 5 float MaxFrame 15 0 float StartWalk 30 0 Vector NormalSpeed 0 0 0 6 0 InitFunction GetGlobalPos Pos GetGlobalDir Dir Set StartPoint Pos UseAgentRender RandomizePos Frame 15 End DrawFunction PushMatrix Translate to the Agents Position Translate Pos Scale 5 0 5 0 5 0 RotateY yrot RenderMaterial 3 SetAnimCycle DrawMode RenderFrame Frame RenderAgent PopMat rix End UpdateFunction SetGlobalPos Pos Add Pos Dir Set NextPos Pos Add NextPos Dir fpush Pos z fpop CurrZpos if CurrZpos lt ZposEnd Set Pos StartPoint Set DrawMode WALK Set Dir NormalSpeed AddD Frame 1 if Frame gt MaxFrame SetD Frame 0 Call CalcAngle End Point AiPos 0 0 0 CollideFunction Set HitAgent FALSE LoopBin SphereSphereCollision HitAgent Pos Radius NextPos Radius if we have hit if HitAgent TRUE get the position GetAgentI AiPos Pos if were in front move faster ifelse AiPos lt Pos SetD Dir 0 0 1 7 SetAgentI Dir Dir CHAPTER 5 AGENT RENDER End SetD Dir 0 0 0 2 otherwise slow down SetD Dir 0 0 0 2 SetAgentI Dir Dir SetD Dir 0 0 1 7 SetAgentI HitAgent HitAgent LoopBinEnd r Vector tmpPo
71. oat Ypos 20 0 InitFunction get the target point from the arf file GetGlobalPos TargetPoint cal random position Randomize Pos 40 1 40 UseAgentRender SetGlobalPos Pos lock to the groundplane fpush Ypos fpop Ypos y RandomizePos Frame 15 End function to reset the Agent Function ResetFunc SetD Time 0 Set Resting FALSE Randomize Pos 40 1 40 End DrawFunction turn on lights EnableLights PushMatrix draw the target spheres Translate TargetPoint SolidSphere 0 2 12 12 PopMatrix draw the Agent PushMatrix Translate Pos PushMatrix Scale 5 0 5 0 5 0 RotateY yrot SetAnimCycle DrawMode RenderMaterial 3 RenderFrame Frame RenderAgent PopMat rix PopMat rix DisableLights draw the path line for the Agent 58 CHAPTER 5 AGENT RENDER PushMatrix Lines Colour 1 1 1 Vertex TargetPoint Vertex Pos glEnd PopMatrix End UpdateFunction AddD Time 1 0 AddD Frame 1 0 if were at the max frame set frame to 0 if Frame gt MaxFrame SetD Frame 0 0 if the simulation has run too long reset if Time gt EndTime Call ResetFunc if were not at point continue to move ifelse Resting TRUE fpush Ypos fpop Pos y Call UpdateAgainstTargetPoint Call CalcDir Call CalcAngle Add Pos Dir else align the agent the right way SetD yrot 180 End CollideFunction End Vector tmpPos 0 0 0 0 Vector tmpPos2 0 0 0 0 calculate the
72. ode WALK Set Dir NormalSpeed incriment the frame for animation cycle AddD Frame 1 if Frame gt MaxFrame SetD Frame 0 End no collisions CollideFunction End 5 3 Using arf to set Agent target points In the following example the arf file is used to configure target points for each of the Agents as show in Figure 5 3 These points are loaded in from the arf file and the Agents are assigned a random starting point Agents Lined up Figure 5 3 Agents moving to position set in arf file When the simulation starts the Agents move to find their start point and then stop on the spot The simula tion then resets to a new random start position and starts again This is shown in the following ebpl program Program 10 Agent2 bs Using arf to set Agent Target Positions the Agents position CHAPTER 5 AGENT RENDER Point Pos 30 0 0 the Agent direction Vector Dir 0 0 0 0 0 0 0 0 where to line up Point TargetPoint 0 0 0 the direction to the target Vector TDir 0 0 0 0 bool TRUE true bool FALSE false flag to say were resting bool Resting false frames float MaxFrame 15 0 float EndTime 75 0 float MinDist 1 0 float dist 0 0 zero vector to stop agent moveing Vector ZERO 0 0 0 0 The rotation of the Agent in the X plane float yrot 180 0 The rotation of the Agent in the Z plane float WALK 0 0 float RUN 1 0 float DrawMode 0 0 float Time 0 0 float Frame 0 0 fl
73. om the stack and puts back the arc cosine of the value 2 3 1 16 Fnegate The Fnegate opcode takes the top most value from the stack and puts back the negated value 2 3 1 17 FStackTrace The FStackTrace opcode prints out the current contents of the stack CHAPTER 2 EBPL LANGUAGE 11 2 3 2 Variable Operations All variables within EBPL have global scope and can be accessed within any Function They can be set directly or assigned a value based upon another variable The setting of individual tuple values can only be accomplished via the float stack as outlined in Section 2 3 1 Variables may also be used in comparison if and ifelse operations These may only be carried out with variables of the same type and relies upon the overloaded comparison operators of Point and Vector classes As the comparison of the operators gt gt lt lt is ambiguous for Points and Vectors they have be defined to work for all tuple values for example the Point gt operator is defined as bool Point3 operator gt Point3 amp v if x gt v x amp amp y gt v y amp amp Z gt V Z return true else return false 2 3 3 Variable Opcodes Most variables can be accessed directly by the use of opcodes and values can be set and retrieved The following section show the basics full examples of all opcodes are shown in Section 7 11 2 3 3 1 Add The Add opcode works on any data type but care must be taken with the mixing of typ
74. on of the Agent in the Z plane float zrot 0 0 Vector ADir is the Average direction of the Agent calculated from hits with any agents in the current bounding sphere radius This is used with the FlockAvoidDir weight to set the Flock avoid Direction Vector ADir 0 0 0 0 flock avoid dir Vector CentroidDir is the direction to the flock center from the current agent position This is multiplied by the Centroid weight Vector CentroidDir 0 0 0 0 bool HitAgent boolean flag set to indicate that the Agent has hit another Agent bool HitAgent false GLfloat GPYlevel the ground plane level of the Agent float GPYlevel 18 GLfloat CentroidWeight The weight the CentroidDir vector is multiplied by to calculate the new direction of the Agent so it can flock center float CentroidWeight 20 0 GLfloat FlockAvoidWeight The Weight the FlockAvoidDir vector is multiplied by to calculate the new direction of the Agent when it has hit a member of it s own flock float FlockAvoidWeight 99 0 float Radius 4 1 GLfloat Hunger will be used to make Agent hunt for food when hungry float MinCentroidDist 10 0 Vector CentroidDist 0 0 0 0 Point Centroid 0 0 0 InitFunction Randomize Dir 2 0 2 0 2 0 SetGlobalPos Pos RandomizePos MinCentroidDist 28 End DrawFunction PushMatrix Translate to the Agents Position Translate Pos Rotate the Agent to the correct orientation RotateX xrot RotateY yrot RotateZ zrot
75. os Pos2 7 11 6 AddD The AddD opcode adds a value directly to a variable for example using a float AddD yrot 180 0 using a point AddD Pos 0 1 0 CHAPTER 7 LANGUAGE REFERENCE 84 7 11 7 SubD The SubD opcode subtracts a value directly from a variable for example using a float SubD yrot 180 0 using a point SubD Pos 0 1 0 7 11 8 MulD The MulD opcode multiplies a value directly from a variable for example using a float MulD yrot 180 0 using a point MulD Pos 0 1 0 7 11 9 DivD The DivD opcode divides a value directly from a variable If the divisor is zero the value will be set to 1 for example using a float DivD yrot 180 0 using a point DivD Pos 0 1 0 7 11 10 SetD The SetD opcode assigns a direct value to a variable as follows using a float SetD yrot 180 0 using a point SetD Pos 0 1 0 7 11 11 Length The Length opcode returns the length of a Vector or Point Variable onto the stack Vector Dir 1 0 2 0 Length Dir 7 11 12 Normalize The Normalize opcode set the variable to unit size Vector Dir 1 0 2 0 Normalize Dir CHAPTER 7 LANGUAGE REFERENCE 85 7 11 13 Dot The Dot opcode returns the dot product of two Point or Vector data types these types may be mixed but the return type is always a float It is used as follows Float DotResult 0 0 Vector Dir 1 0 2 0 Vector Dir2 1 0 1 0 return the result DotResult Dir e
76. os Wind Set NextPos Pos Add NextPos EmitDir AddD Life 1 0 set the global pos so the particles get draw in all views SetGlobalPos Pos are we dead yet if Life gt EndLife create a new particle Call InitParticle End CollideFunction End 29 3 3 Projectile Motion Particles Figure 3 4 shows a series of spheres using the equations for projectile motion outlined in Algorithm 3 Y Flock ParamFile ProjectileParticles fl_www dec bournemouth ac uk staff jmacey flock html Press h_ Xx Figure 3 4 Projectile particles CHAPTER 3 PROGRAMMABLE PARTICLES 30 Algorithm 3 Projectile Motion modified from Len01 The position P t of a projectile having initial position I and initial velocity voat time t 0 is given by x t I vot 5gt where gravity g 0 g 0 assuming the Y axis is upward and g 9 8m s From the above equation values for the x y and f components of x may be calculated at any time t by the following expressions a t Ix vxt y t I vyt 38 z t I vat This can be implemented using the following ebpl code pre calculate 1 2 G for speed float Gravity 4 09 Function CalcProjectileMotion calc x fpush Pos x fpush Velocity x fpush Time fadd fadd fpop Pos x calc z fpush Pos z fpush Velocity z fpush Time fadd fadd fpop Pos z do t 2 fpush Time fdup fmul fpush Gravity fmul fpush Time fpush Pos y fmul fsub f
77. own below Program 9 Agentl bs Using Agent Render the Agents position Point Pos 30 0 0 The Agents direction Vector Dir 0 0 0 0 0 0 0 0 Where the agent start from set from arf Point StartPoint 0 0 0 Agent Render Modes float WALK 0 0 float RUN 1 0 float DrawMode 0 0 float Frame 0 0 float Zpos 12 0 float ZposEnd 40 0 float CurrZpos 0 0 float NewSpeed 1 5 float MaxFrame 8 0 float StartWalk 30 0 float Yrot 180 The Agents normal speed Vector NormalSpeed 0 0 0 6 0 InitFunction get the values from the Agent class GetGlobalPos Pos GetGlobalDir Dir Set StartPoint Pos use the agent render UseAgentRender set a start frame for the animation cycle RandomizePos Frame 8 End DrawFunction PushMatrix Translate to the Agents Position Translate Pos make the Agent bigger Scala 570 530 5 0 turn on lights EnableLights set material to silver RenderMaterial 8 vender the Agent SetAnimCycle DrawMode RenderFrame Frame RotateY Yrot RenderAgent DisableLights PopMat rix End UpdateFunction calculate the new position SetGlobalPos Pos Add Pos Dir fpush Pos z fpop CurrZpos if we have reach the run point set agent to if CurrZpos lt Zpos fpush NewSpeed fpop Dir z CHAPTER 5 AGENT RENDER 57 Set DrawMode RUN if we have reached the end set agent back to start if CurrZpos lt ZposEnd Set Pos StartPoint Set DrawM
78. pop Pos y End And the full program listing is as follows Program 5 ProjectileParticle bs Projectile particles the particles position Point Pos 0 0 0 wind vector to add to the particle Vector Wind 0 0 0 0 0 0 float Time 1 0 float EndTime 0 4 Vector Velocity 0 0 0 0 initialise the particle InitFunction Call InitParticle End Function InitParticle set initial position to 0 SetD Pos 0 0 0 CHAPTER 3 PROGRAMMABLE PARTICLES SetGlobalPos Pos RandomizePos Time 1 0 Randomize Wind 1 1 1 Randomize Velocity 1 1 1 End DrawFunction PushMatrix Colour 1 1 1 Cube 2 0 draw a line from the origin to the particle Lines Vertex Pos Vertexf 0 0 0 glEnd Translate to the Agents Position Translate Pos EnableLights Colour 1 0 1 0 0 0 Sphere 0 4 12 12 DisableLights PopMatrix End half gravity float Gravity 4 65 Function CalcProjectileMotion fpush Pos x fpush Velocity x fpush Time fadd fadd fpop Pos x fpush Pos z fpush Velocity z fpush Time fadd fadd fpop Pos z calculate y do t 2 fpush Time fdup fmul fpush Gravity fmul fpush Time fpush Pos y fmul fsub fpop Pos y End UpdateFunction move the particle SubD Time 0 01 Call CalcProjectileMotion Add Pos Wind set the global pos so the particles get SetGlobalPos Pos are we dead yet if Time lt EndTime Call InitParticle End Collid
79. r 2 3 6 Structure Opcodes The structure opcodes are used to define and call functions and make decisions 2 3 6 1 Function The Function Opcode defines the beginning of a function block It must be terminated by use of an End opcode as shown below Function CalcAngle Fpush yrot Fpop yrot End 2 3 6 2 Call The Call opcode will call a function within the script Call CalcAngle CHAPTER 2 EBPL LANGUAGE 15 2 3 6 3 If The if structure can be used on all data types and is constructed as shown below if dist gt MinCentroidDist do something All if statements must use the open and closed braces however if statements may be nested 2 3 6 4 ifelse The ifelse structure can be used on all data type and is constructed as shown below ifelse dist gt MinCentroidDist do something else do something else All ifelse statements must use the open and closed braces At present the ifelse statement may not be nested however if statements may be placed within an ifelse structure If multiple ifelse type structures are required use the CallList mechanism as outlined in Section 7 5 2 4 Drawing The EBPL DrawFunction is a built in function to allow the rendering of Agents for previewing of the simulation The system has two main methods for drawing either using a cut down version of OpenGL or a built in AgentRender system 2 4 1 MiniGL Opcodes The MiniGL Opcodes are split into 2
80. r The main function of the Brain is to execute the opcodes and produce output The basic structure of the brain is shown in Figure 2 2 CHAPTER 2 EBPL LANGUAGE 6 OUTPUT M ain Flocking Program Co mp il eff Co 1 1 is io Gl o bal V ar iabl es BOOL Fu zzy roat Vector Float Fuzzy vzcro R PO INT Figure 2 2 Agent Brain Structure 2 2 1 Brain Stacks The Agent Brain has four built in stacks as follows A floating point stack A stack for operation on the Vector class A boolean stack A stack for operation on the Fuzzy object class Unlike most interpretive languages EBPL operations are not entirely dependent upon the stack architecture Most data types can be accessed queried and modified directly however some operation such as access to tuple data types still rely upon the stack These stack operations are outlined in Section 2 3 1 CHAPTER 2 EBPL LANGUAGE 7 2 2 2 Global Variables When the Brain is loaded the variables defined in the brain script file are loaded in the form of a Variable list Each element of this list is a class called a VarObj as shown in Figure 2 3 VarObj Var Ob j Type VAR TYPE Figure 2 3 VarObj Class diagram This object can assume any of the data type shown in Table 2 1 and has built in methods for specialist OpenGL functions such as Vertex Normal and Translate These OpenGL operations only execute for the Vector and Point classes 2 2 3 Va
81. rator used CHAPTER 8 FL SCRIPT REFERENCE 92 8 1 1 13 VectObj Vector objects are objects in the environment which act like winds Each vector Obj has a bounding sphere which will become active if the Agents collide with them VectObj f Pos x f Pos y f Pos z f Width f Height f Depth f Radius X f Y 2 Pos the position of the Vector Object Width Height Depth The width height and depth of the object Radius The radius of the Objects bounding sphere for agent collision detection X Y Z The vector direction for the Vector object 8 1 1 14 GroundPlane The ground plane is the default ground level for the Agents in the Environment GroundPlane f Level f Red f Green f Blue f Alpha Level The ground plane level Red The red colour component for the gp Green The green colour component for the gp Blue The blue colour component for the gp Alpha The transparency for the gp 1 1 15 ImageGroundPlane This allows the groundplane to be loaded from an image file The extents of the ground plane are calculated from the WorldBBox size and the number of triangle strips used are dependent upon the size the image loaded ImageGroundPlane f Ylevel s Filename bmp f Ydivisor Ylevel The level of the groundplane Filename bmp The name of the bmp file to load Ydivisor The value to scale the heightmap by 8 1 1 16 GroundPlaneTex This allows the groundplane to be loaded from an image file The extents of
82. ressed to terminate the program This error is usually due to a misplaced in the source file 1 3 ebpl program The ebpl program loads in an ebpl fl script and runs the simulation The fl script is responsible for configuring the environment and the placement of the Agents within the environment CHAPTER 1 INTRODUCTION 2 The environment is responsible for containing all the Objects within the scene as well as calling all of the Agent s brain routines as shown in Figure 1 1 compiled Cua Is Agent Ge Tl hide Fume s tren Figure 1 1 EBPL environment flow chart 1 4 Getting started The following section shows a simple ebpl program to place and render 50 random spheres in the environ ment as shown in Figure 1 2 CHAPTER 1 INTRODUCTION 3 WY Flock ParamFile GettingStarted fl_www dec bournemouth ac uk staff jmacey flock html Press h for Xx I Figure 1 2 Getting Started 50 Random Spheres The Agent brain for this simulation is shown in Program 1 When the nitFunction is called on the creation of the Agents brain the position of each of the Agents is calculated as a random number seeded with the value 20 10 20 for the x y and z position The Agent is drawn using the Sphere opcode by first setting the colour using the Colour opcode then translating it to the random position using the Translate command Program 1 GettingStarted bs 50 Random Spheres the Agents position Point Pos
83. riables At present five variable types are supported in EBPL as shown in Table 2 1 Variable Type Description Example Float A signed floating point value Float CentroidWeight 50 0 Bool A boolean value Bool HitAgent false Vector A four tuple vector class x y z w Vector Dir 0 1 0 0 Point A three tuple Cartesian point class x y z Point Pos 0 0 0 Fuzzy A full fuzzy logic class with fuzzy operators Fuzzy NearAgent 0 2 Table 2 1 EBPL variable types The syntax of the variable definitions is tightly specified as shown in the Examples column of Table 2 1 All variables must be initialized when declared and all have global scope to the Brain This means that all variables are available to all functions in the source file as well as accessible by other Agents 2 2 4 Functions EBPL has two types of Function these are built in and user defined There are 4 default built in functions which must be present in every EBPL script The user may additionally create any number of Functions within the program which act as procedure calls Built In Functions Description InitFunction Called when the Agent brain is created and used to initialize variables etc UpdateFunction Called every iteration of the system to update the Agents position DrawFunction Called every iteration of the system to Draw the Agent Collide Function Called every iteration to do collision detection Table 2 2 EBPL variable types CHAPTER 2 EBPL LANGUAGE 8 The bui
84. rrent point of the transformation matrix to a new point specified by either a Vector or Point variable as shown below Translate Point NewPos Translate Vector NewPos 2 4 3 Drawing Primitives EBPL has three geometric drawing primitives these are Sphere Cube and Cylinder CHAPTER 2 EBPL LANGUAGE 17 2 4 3 1 Sphere The Sphere and SolidSphere opcodes draw a sphere using the current Colour The syntax for these opcodes are as follows Sphere Float Radius Float slices Float Stacks SolidSphere Float Radius Float slices Float Stacks The Radius value may be either a EBPL variable or a direct floating point value as shown in the following examples Float Radius 2 0 Sphere Radius 12 12 SolidSphere 10 12 12 2 4 3 2 Cube The Cube opcode will draw a wire frame cube of width height and depth d where d is either a Float variable or a direct float value as shown in the following examples float Width 1 0 Cube Width Cube 4 3 2 4 3 3 Cylinder The Cylinder opcode draws a wire frame cylinder of Radius r and Height h where r and h are either a Float variable or a direct float value as shown in the following examples float Width 1 0 float Height 0 5 Cylinder Width Height Cylinder 4 3 2 5 2 4 4 Line Drawing The line drawing elements of the MiniGL opcodes allow for the setting of line style colour and the drawing of verticies 2 4 4 1 Colour The Colour opcode sets the current drawing colour for lines a
85. s 0 0 0 0 Vector tmpPos2 0 0 0 0 Function CalcAngle End fist set the vectors to subtract Set tmpPos NextPos Sub tmpPos Pos Fpush tmpPos x Fpush tmpPos z use atan2 to calc the angle fatan this gives us the angle in radians so we convert it Frad2deg finally we align it with the world geometry Fnegate Fpop yrot AddD yrot 90 0 now we align the z rotation 62 Chapter 6 Terrain Interaction Figure 6 1 shows Agents interacting with a terrain model loaded from an Alias Wavefront obj file Figure 6 1 Agents Interacting with the Terrain To calculate the current Y height value of the Agent within the terrain the GetHeight method is used This is based on calculating the point normal for each of the faces in the obj file and determining if the point passed is withing the triangle The method used is modified from jr01 as shown in Algorithm 6 63 CHAPTER 6 TERRAIN INTERACTION 64 Algorithm 6 Calculating if a point is within a triangle Given each Triangle within the obj file extract the Points To T1 T and construct the Lines b1 ba b3 by subtracting the the Triangle Points as follows by T To be h T and bs To To The point Normal of each line is constructed by negating the y value and swapping it for the x so PN biy biz 0 PN2 bay bee 0 and PN3 b3y d3a 0 Next the Point to be tested P is subtracted from each of the original tri
86. se Material gt ZERO SetD Material 1 0 fNegate fpop Dir z SetD Material 4 0 fpop Dir z SetD DrawCallListindex 0 0 RandomizePos Life 10 0 End DrawFunction SetGPYlevel Pos PushMatrix EnableLights Translate to the Agents Position Translate Pos Scale 10 0 10 0 10 0 RotateY yrot CallList DrawFunctions DrawCallListindex DisableLights PopMat rix End UpdateFunction Set HitAgent FALSE Add Pos Dir Set NextPos Pos Add NextPos Dir AddD Frame 2 0 if Frame gt EndFrame SetD Frame 0 End float EL 100 0 bool AgentILifeFlag false CollideFunction if ALIVE TRUE LoopBin SphereSphereCollision HitAgent NextPos Radius NextPos Radius if HitAgent TRUE SetD Dir 0 0 0 SetAgentI Dir Dir RandomizePos Choice 100 0 SubD Life 4 0 GetAgentI AgentILife Life if AgentILife ZERO CHAPTER 6 TERRAIN INTERACTION if Choice gt ChoiceVal SetD DrawCallListindex 1 0 if Choice lt ChoiceVal SetD DrawCallListindex 2 0 if Life lt ZERO Set ALIVE FALSE SetD DrawCallListindex 4 0 SetAgentI Life EL SetGlobalCollideFlag TRUE LoopBinEnd if AgentILife ZERO SetD Life 10 SetD DrawCallListindex 3 0 SetD Frame 0 End This function calculates the Agents orientation based on the poistion and the NextPos use these for temp storage in the calc angle function Vector tmpPos 0 0 0 0 Vector tmpPos2 0 0 0 0 Fu
87. t RotateZ zrot Set the Colour Now draw the agent poly s Colour 1 0 0 0 0 03 Polygon Vertexf 0 25 0 1 0 1 Vertexf 0 25 0 1 0 0 Vertexf 0 25 0 1 0 0 Vertexf 0 25 0 1 0 1 Vertexf 0 25 0 1 0 0 Vertexf 0 25 0 1 0 0 glEnd Now draw the Poly s as Lines to give the agent an outline shape LineSize 1 0 Colour 1 0 1 0 1 03 LineLoop Vertexf 0 25 0 1 0 1 Vertexf 0 25 0 1 0 0 Vertexf 0 25 0 1 0 0 Vertexf 0 25 0 1 0 1 Vertexf 0 25 0 1 0 0 Vertexf 0 25 0 1 0 0 CHAPTER 4 FLOCKING glEnd PopMatrix PushMatrix preserve y value Fpush Pos y PushGPYlevel Fpop Pos y Translate Pos RotateX xrot RotateY yrot RotateZ zrot Scale 0 5 0 5 0 5 Colour 0 2 0 2 0 2 Polygon Vertexf 0 25 0 1 0 1 Vertexf 0 25 0 1 0 0 Vertexf 0 25 0 1 0 0 Vertexf 0 25 0 1 0 1 Vertexf 0 25 0 1 0 0 Vertexf 0 25 0 1 0 0 glEnd PopMatrix fPop Pos y End Function UpdateAgainstCentroid GetGlobalCentroid Centroid Set CentroidDist Centroid Sub CentroidDist Pos Length CentroidDist fpop dist ifelse dist gt MinCentroidDist GetGlobalCentroid CentroidDir Sub CentroidDir Pos SetD CentroidDir 0 0 0 End This function calculates the Agents orientation based on the and use Vector Vector the NextPos these for temp storage in the calc angle function tmpPos 0 0 0 0 tmpPos2 0 0 0 0
88. tRender is being used If this is not present in the scripts and any other AgentRender calls are made the system will crash In the brain script this call is generally placed in the InitFunction as it only needs to be set once CHAPTER 7 LANGUAGE REFERENCE 80 There are four Opcodes used for configuring the AgentRender as follows Value Meaning SetAnimCycle sets the animation cycle to be drawn as indicated by the Mode values in Figure 2 7 RenderFrame Selects which frame of the AgentRender sequence to draw RenderAgent Draws the Agent configured by the above two opcodes RenderMaterial Set the current material for the Agent see Table 7 3 Table 7 2 AgentRender Opcodes All these opcodes can take either floating point variables or direct float values as shown in the example below set to agent walk cycle float DrawMode 0 float Frame 4 SetAnimCycle DrawMode set material to chrome RenderMaterial 3 render the 3rd frame of the cycle RenderFrame Frame The material types currently used in EBPL are shown in Table 7 3 Material Number Material Type BLACKPLASTIC BRASS BRONZE CHROME COPPER GOLD PEWTER SILVER POLISHEDSILVER CDADNMNAPWNK OC Table 7 3 Material Types 7 9 Float Stack Opcodes The floating point stack operates in a First in Last Out principle any operations on the stack use reverse polish notation for example 2 3 will be executed in the script by push 3 push 2 fadd which will result in 5
89. te space on lines is also ignored All keywords are case insensitive and capitalizations are only used for ease of reading the script 8 1 1 Environment Parameters The Environment parameters are used to set up the initial parameters for the world 8 1 1 1 BBox The first script element of the file must be a BBox which sets up the world bounding box WorldBBox f Pos x f Pos y f Pos z f Width f Height f Depth i Xdiv i Ydiv i Zdiv i BinSize Pos sets the initial position of the bounding box center Width Height Depth the extents of the box calculated from the center as Width 2 etc Xdiv Y div Zdiv The subdivision of the Lattice bin structure for agent containments BinSize the max size of bins this is usually set to be the number of Agents in the system 8 1 1 2 EnvObj Any number of EnvObj can be added to the Environment they are added sequentially from 0 and any subsequent operations of these objects refer to the index EnvObj f Pos x f Pos y f Pos z f Width f Height f Depth f Radius Pos sets the central position of the Object Width Height Depth set the extents of the Object Radius the radius of the object used for collision detection it is best to set it slightly larger than the biggest extent of the object 8 1 1 3 RotateObj This is used to rotate an object around it s own axis in x y or Zz RotateObj i Index f angle f xAxis f yAxis f zAxis CHAPTER 8 FL SCRIPT REFERENCE 9
90. the ground plane are calculated from the WorldBBox size and the number of triangle strips used are dependent upon the size the image loaded The second filename is the name of the texture to use CHAPTER 8 FL SCRIPT REFERENCE 93 GroundPlaneTex f Ylevel s Filename bmp s TextureName bmp Ydivisor Ylevel The level of the groundplane Filename bmp The name of the bmp file to load TextureName bmp The name of the file to use as a texture for the groundplane Y divisor The value to scale the heightmap by 1 1 17 ObjTerrain This allows the groundplane to be loaded from an obj file with textured support from a bitmap file ObjTerrain f Ylevel s Filename obj s TextureName bmp f AgentHeightOffset f Scale X f ScaleY f Scalez Ylevel The level of the groundplane Filename obj The name of the obj file to load TextureName bmp The name of the file to use as a texture for the groundplane AgentHeightOffset The value to add to the Agents Y value Scale X Y Z The scale in X Y and Z for the obj file This pre scales the obj file before loading 8 1 2 Emitters The Environment can have any number of AgentEmitter These are the source for each of the agents and are responsible for all the agent collision detection updates and rendering There must be at least one AgentEmitter in the file and this is set to index 0 each subsequent one is then incremented by one These numeric values are then referred to by the oth
91. ts Points Vertexf 0 0 0 Vertexf 0 10 0 glEnd CHAPTER 2 EBPL LANGUAGE 19 2 4 4 4 Vertex Commands The drawing of individual verticies is carried out using the Vertex and Vertexf opcodes The Vertex opcode takes a Point or Vector variable as the argument whereas the Vertexf takes a direct floating point value for the x y and z values These are shown in the following examples Draw a triangle using direct values LineLoop Vertexf 0 0 0 Vertexf 1 0 0 Vertexf 1 1 0 glEnd Draw a triangle using variables Point P1 0 0 0 Point P2 1 0 0 Point P3 1 1 0 LineLoop Vertex Pl Vertex P2 Vertex P3 glEnd 2 4 4 5 Lighting The current OpenGL lighting may be turned on and off using the LightingOn and LightingOff opcodes At present only the default OpenGL light GL_LIGHTO see MW99 for more details is enabled in the system Later version will allow for the full scripting of all available OpenGL lights 2 4 5 MiniGL Example Figure 2 6 Mini GL drawing Figure 2 6 shows MiniGL in action rendering both the Boid type Agents and the ground shadows with the ebpl code shown in Algorithm 1 CHAPTER 2 EBPL LANGUAGE 20 Algorithm 1 MiniGL Drawing Example Reynolds Boids Rey87 DrawFunction PushMatrix Translate to the Agents Position Translate Pos Rotate the Agent to the correct orientation RotateX xrot RotateY yrot RotateZ zrot Set the Colour Colour 1 0 0 0 0 0 Now draw the ag
92. ur 7 7 1 RotateX The RotateX opcode calls g Rotatef d 1 0 0 and rotates the current transformation matrix by degrees in the X axis It takes as its argument either a direct floating point value or a Floating point variable RotateX xrot using a variable RotateX 90 0 using a direct value CHAPTER 7 LANGUAGE REFERENCE 77 7 7 2 RotateY The RotateY opcode calls g Rotatef d 0 1 0 and rotates the current transformation matrix by degrees in the Y axis It takes as its argument either a direct floating point value or a Floating point variable RotateY yrot using a variable RotateY 90 0 using a direct value 7 7 3 RotateZ The RotateZ opcode calls glRotatef d 0 0 1 and rotates the current transformation matrix by degrees in the Z axis It takes as its argument either a direct floating point value or a Floating point variable RotateZ zrot using a variable RotateZ 90 0 using a direct value 7 7 4 PushMatrix The PushMatrix opcode calls g PushMatrix to store the state of the current OpenGL transformation matrix 7 7 5 PopMatrix The PopMatrix opcode calls glPopMatrix to re store the state of the current OpenGL transformation matrix 7 7 6 Translate Translate calls g Translate3f x y z where the x y and z values come from either a Point or Vector data type It is used as shown below Translate Pos where Pos is a point Translate Dir where dir is a vector 7 7 7 Polygon The Polygon op
93. vert from radians to deg yrot yrot TWO_P1 360 0f now align the geometry to our world yrot 180 Now for the zrot GLfloat r sqrt X X Y Y Z Z zrot asin Y r convert from radians to deg zrot zrot TWO_PI 360 0f The following code does the same using the ebpl language Vector tmpPos 0 0 0 0 Vector tmpPos2 0 0 0 0 Function CalcAngle fist set the vectors to subtract Set tmpPos NextPos Sub tmpPos Pos Fpush tmpPos x Fpush tmpPos z use atan2 to calc the angle fatan this gives us the angle in radians so we convert it Frad2deg finally we align it with the world geometry Fnegate Fpop yrot AddD yrot 180 0 now we align the z rotation Y Pos y NextPos y Set tmpPos NextPos Set tmpPos2 Pos swap the y components Fpush Pos y Fpop tmpPos y Fpush NextPos y Fpop tmpPos2 y now subtract the two Sub tmpPos tmpPos2 zrot asin Y r Length tmpPos Fpush tmpPos y Fdiv fasin convert it to degrees frad2deg Fpop zrot End CHAPTER 4 FLOCKING 36 4 1 0 2 Simple Flock program using ebpl The following code is used to control the Agent for the simple flock example Program 6 SimpleFlock bs Simple flocking system the Agents position Point Pos 0 0 0 Vector Dir 0 0 0 2 0 1 0 0 Point NextPos 0 0 0 bool TRUE true bool FALSE false The rotation of the Agent in the X plane float xrot 0 0 float yrot 0 0 The rotati
94. zy stack operator pre fix B Boolean stack operator pre fix V Vector stack operator pre fix Table 2 3 Stack Operation Prefix For example to push an element of a vector onto the floating point stack the following code would be used CHAPTER 2 EBPL LANGUAGE 9 Vector Dir 0 1 0 01 Fpush Dir y 2 3 1 1 Float Stack Opcodes The floating point stack operates in a First in Last Out principle any operations on the stack use Reverse Polish Notation RPN For example 2 3 will be executed in the script by Fpushd 3 Fpushd 2 Fadd which will result in 5 being placed onto the top of the stack 2 3 1 2 Fpush The Fpush opcode pushes a floating value onto the stack Any variable type may be pushed onto the stack however with tuple data types the element of the tuple to be pushed must be specified as shown in the following example Fpush Pos x pushes the x component of the Point pos Fpush yrot pushes the float variable yrot Fpushd 10 places 10 directly onto the stack 2 3 1 3 Fpop The Fpop opcode takes the value from the top of the stack and places it into the variable if a tuple data type is used the x y or z destination must be specified Fpop ypos places the tos value into ypos Fpop tempPos y places the tos value into tempPos y 2 3 1 4 Fadd The Fadd opcode takes the top two values from the stack adds them and places the sum back onto the stack 2 3 1 5 Fsub The Fsub opcode takes the top two value from th

E.B.P.L. USER GUIDE AND LANGUAGE

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