Z EXCURSION – GAME ENTRY FOR SWEDISH
Contents
1. 11 3 2 13 pian dece cr 12 3 2 14 O PR 12 3 2 15 LADIES T 13 3 2 16 jiji sais etes 13 3 3 DEVELOPMENT METHOD b ovsss4ssusossossvessatssunspsusskesst ssenss ussnesksnesunessnsssissi sonioptsosbssstansenspais 13 3 4 PRIMITIVE LEVEL EDITOR j ss ssr skesssvpss ssoussnsapsuspossonsnaspoupssnensossnensospssslssposk usoniabesrsnssndas 13 3 5 TEXT FILE REPRESENTING ENEMIES AND PLATFORMS ssscssrsrsverensesconensescenesseseenenso 14 3 6 PHYSICS c TE 15 3 6 1 Equations of ULCUS CO RR 15 3 6 2 Bounding boxes and Collision Detection ss 16 3 6 3 Response to Collision Detection 16 3 7 MODELING PROCESS 5 rere Eee ere Eee eese UE aser eU ee bes evt FEES ev TUE SSR LUE eee RASEN NSD EVER Eee VETE Eee sev 17 3 8 MUSIC AND SOUND EFFECTS eee entente Creuse te aaepe sea ee deteste ni ee tenons eue teste 18 3 8 1 be pe OPER 18 3 8 2 Playing Sounds in XNA sico zioni neeneoneceee 18 3 8 3 Free Sound Effects and Own Sound Effects ssssoocsscssssssssrcrsossrsrorsosssrsreresrssrrsrrrorrssrr 18 3 9 LICENSES mmc ANNE ANAR 19 I Doa BIBLE pcc 21 4 1 INSTALL IPER FRAN NAR 21 4 2 START THE GAME oL 21 4 3 HOW2. Game of the Year 10 000 SEK Best Innovation 5 000 SEK Best Mobile Game 10 000 SEK and an invitation to ARM Cambridge office for private workshop with the Mali GPU engineers Best Serious Game 10 000 SEK Gamers Choice Eternal Glory Table 1 SGA Awards 5 27 2 Methods and Tools 2 1 Methods 2 1 1 What is XNA XNA 2 was used for the development of the game XNA is a collection of tools and a runtime environment that supports development of games and other interactive applications in C XNA Game Studio is an IDE Integrated Development Environment designed for working with XNA It can be used to develop for Xbox 360 or Windows for example XNA Game Studio was first released on December 11 2006 XNA was originally an acronym for Xbox New Architecture but after Xbox 360 was released they changed it to XNA is Not an Acronym The current release 4 0 was announced and released on March 9 2010 To develop for Xbox 360 the VET Compact Framework is used This is based on VET Framework which consists of a CLR Common Language Runtime programs are executed on a virtual machine and an extensive class library Language interoperability is also supported which means that code written in one language can be integrated with code written in another language Furthermore XNA is based on the NET Compact Framework XNA consists of a large class library which have been adjusted particularly for game d
3. xo Forat Xbox qualty xo Compressed xb Fato Loop Notes Rate amp rs Channels Path Men oc PCM mo mum 10s RM 100 01 675 ws N Anm 16 2 ie AGO PCM 100 416640 1 FM 100 E Ux N 42000 16 2 sse ecn 123528 PCM 100 123828 wo PM 100 123528 003 N 2060 16 2 ral wang 179428 POM 100 178428 100 Pom 100 179428 Wu N anm 16 2 mea etalCang02 73262 PCM 100 7268 100 pom 100 7228 Wr N anm 16 2 mea Merano 73335 PM w0 RIE 100 pem 100 72338 0 N 4100 16 2 mG mo 326506 FM 130 326508 xo POM 100 ET Wu N sm 16 2 van a 257252 PCM 100 257252 100 pom 100 257252 Wu N Anm 16 2 m Figure 7 XACT interface lx Ric Vien iniusta Genitus ty iua Help E J1 left 8 b o ee whl ole 6 eee n Eye ES pa E LD ay i DES JE Fi DIE BREES pa a en motos A erties s zen wo d D 020 030 oa ogo ogo 080 100 E 120 ag NET 35 am T TT TR AT tlt o baaki E i SANTE ES vig it ost Project Rato Ho Solocton Star End Longh Audio Postion 44100 srap tor Daama SOON TORRE Figure 8 Audacity interface For the sound effects I did on my own I used FL Studio 14 a Digital Audio Workstation DAW In FL Studio I used a VSTi Virtual Studio Technology Instrument called z3ta For example I created a sound for use when the player jumps I wanted it to sound retro I searched for a proper preset in z3ta then at the b
4. First the world was created then the objects after that movement of objects then collisions between objects and finally response on these collisions Before a new part was implemented the previous part was tested carefully to really see that it worked as planned 3 4 Primitive Level Editor For designing a level I used a bitmap Using a text file for enemies didn t work on Xbox 360 therefore enemies were also added in the bitmap for the Xbox 360 version A disadvantage with this was that all enemies of one type had to be identical because for each color value every argument has to be constant The bitmap was designed in GIMP where different color values represent different objects For example an object with an ice texture has a blue color while a certain enemy type has a red color The levels are designed from the side much like the perspective used in side scrolling games but in the game the perspective is viewed from first person This is shown in Figure 2 13 27 er ee A cet paint te picka con Figure 2 Level design in GIMP 3 5 Text file Representing Enemies and Platforms A text file is used in a way so that it is easy to add remove or alter dynamic objects The syntax of this file can be seen in Figure 3 Two different dynamic objects can be added in the text file an enemy or a platform However the former one is a ba
5. but enough to illuminate A class for handling music and sound effects was created although at this moment only sound effects are used in the game Finally a sky box was defined to the scenery 5 2 General Aims and Objectives and for the Programme After this course I think I have shown that I possess a broad knowledge in the subject I studied I could analyze and define solutions mostly by myself but for some problems I needed to discuss the problem with my instructor to get a clear understanding Regarding methods and theories I was able to mostly find the proper methods by myself For problems where I couldn t find any method I had to be creative and imagine a solution in my mind before starting to implement it This worked a lot of times but for some problems I needed to discuss it with my instructor For planning I think I did a good job during my entire education I have strived to always be a bit ahead so I know I can relax more at the end of a course in case something unexpected should happen During this course I felt stress sometimes but only at a degree which made me focus more on the project It was a pleasant course and the planning turned out very well and approximate Concerning the written and oral exam I think I did a good job with the report itself The oral exam could have been better though it felt as I got the message out and with the help of the slides kept the audience interested Although I wasn t very present my
6. the player loses a life To keep track of how much health the player has left a life bar is displayed at the top left corner of the game interface this is shown in Figure 11 Figure 12 and Figure 13 If the player has lost all his lives the player gets game over and the game is moved to the game over screen Here the player can press the back button to return to the title screen or the start button to try the demo level again If the player gets to the end of the level without getting game over the game is moved to the level clear screen Here the player can press the back button to return to the title screen Figure 11 Start position of the level Figure 12 Riding an elevator 22 27 2 Z Figure 13 Moving blocks 23 27 5 Discussion 5 1 Fulfilled Requirements All the requirements that was listed at the beginning of the course were fulfilled Submission of the game to Swedish Game Awards was made on May 31 consisting of a demo level with about 5 minutes of gameplay A bitmap representing the level and a text file for defining enemies and moving platforms were made early in the development Physics intersection tests and response were the hardest and most time consuming part to implement Enemies and some other objects were crudely modeled in Blender Some models had material properties only and others had textures as well For shading the built in BasicEffect was used decent
7. TO PLAY civici carene Nere etae eret eese rete dee metiers rennes des Sev vU ES ae ee eU ANS SRK Sae ee VPE eser vU Eee eed 21 DIS CUSSION RE 24 5 1 FULFILLED REQUIREMENTS s d rvss vsssrsst sutss eosnt ss ser dsassssssns sontepu ssidsss nounsss nsissss ssnnssnns 24 5 2 GENERAL AIMS AND OBJECTIVES AND FOR THE PROGRAMME ccccoscscssssscssccccscssssees 24 5 3 FUTURE IMPROVEMENTS 5 sssssccscsdecsessssvacesesessovesdssacedssssoncesssveccessss EE TR E PEE RR SEE PU Ha ae SE br esee bn 25 REFERENCES i A nn ed re RER savante ben A tonne cese vet ee ooo eee er cea sel Pob area l ee odd 26 3 27 1 Introduction 1 1 Background I have done a game developed in XNA for use with Xbox 360 and Windows The genre of the game is a platformer viewed from a first person perspective A platformer is a game where the focus is on jumping on and between platforms and also for avoiding obstacles Platform games exist in both 2D and 3D The 2D platformers are usually viewed from the side and are referred to as side scrollers one example of a 2D platformer is Super Mario Bros NES 3D platformers are often viewed from a third person perspective and the player has more freedom than in the 2D counterparts Super Mario 64 Nintendo 64 an example of a 3D platformer revolutionized the way platformers were played Many 3D platformes have taken inspiration from Super Mario 64 since then Not least a later installment in the Mario series called Su
8. URL http wiki blender org index php Doc 2 6 Manual XNA Game Studio Connect Retrieved 2012 04 08 URL http msdn microsoft com en us library bb975643 aspx Skybox Tutorial Retrieved 2012 05 09 URL http sidvind com wiki Skybox_tutorial Reed Aaron Learning XNA 4 0 Farnham UK O Reilly 2011 ISBN 10 1449394620 ISBN 13 978 1449394622 XNA 4 0 First Person Camera Demo Retrieved 2012 05 09 URL http www dhpoware com demos xnaFirstPersonCamera html Buckland Mat Programming Game AI by Example Plano Tex Wordware 2004 ISBN 10 1556220782 ISBN 13 978 1556220784 Equations of Motion Retrieved 2012 05 10 URL http physics info motion equations XACT Retrieved 2012 05 16 URL http msdn microsoft com en us library ff827590 aspx Audacity Retrieved 2012 05 14 URL http audacity sourceforge net 26 27 14 FL Studio 10 Retrieved 2012 05 16 URL http www image line com documents flstudio html 15 Attribution 3 0 Retrieved 2012 05 16 URL http creativecommons org licenses by 3 0 16 Creative Commons Retrieved 2012 05 16 URL http creativecommons org about 27 27
9. functionality but enough to illuminate the environment 8 27 World EZ Object Y Resources F2 Class Class FR Class Game Object Audio Tickable Input Y Class Class Class Object E SkyBox x Animated Class L ty Class Animated Tickable Interactive E Class Animated Static Y Dynamic amp Class Class Interactive Interactive Map Platform Y Enemy amp Player x Bullet EZ Class Class Class Class Class gt Static Dynamic Dynamic Dynamic Dynamic MovingBlock Y Spike amp RobotEnemy EZ Rocket E Class Class Class Class Enemy Enemy Enemy Enemy Figure 1 Class diagram It also contains instances of the pre defined Model class For example a model representing a particular enemy that was created in Blender is imported into the project trough the content pipeline and stored in an instance of the Model class Every time an instance of this enemy is drawn it uses the instance of the Model class to draw it In this way if a model is instantiated more than once it still only has to be imported once The Resources class also sets up a projection matrix and view matrix Since the game is viewed from a first person perspective the latter one changes depending on the player s position and orientation 3 2 3 Tickable This class contains a static list with all objects that depend on time It has a static method for inserting objects into the list The first time this method
10. game programming experience before this project it was hard to know exactly how to structure things in a good way Meetings with the instructor occurred once a week throughout the whole project Actually the meetings began two weeks before the project officially started At those two meetings we started to sketch on a class structure The concept we had in mind was that it in the end should be easy to add new elements to the game and that a lot of code should be reusable At these two meetings we also formed a plan for things that should be implemented each week throughout the project Overall the development method consisted of that we first met early in the weeks usually Mondays and discussed problems that had occurred the previous week and discussed more in depth about what should be implemented the current week The meetings was also a good place to get feedback on things that had been accomplished so far During the implementation itself the experience from the meetings were useful mostly it meant that the implementation was going on well For some parts though particularly the response for collisions some trial and error had to been forced The collision response was scratched two times before a good and efficient method was found It should also be mentioned that the collision response method isn t perfect there is still room for improvement To summarize the implementation method mostly it was about implementing things in a logical order
11. hard On the opposite I was surprised how much I could achieve on my own during these 10 weeks only A lot of the other participants worked in teams and had worked on their game for more than 10 weeks If I had had just 10 weeks more I think I could have had a better chance 4 1 Install 1 Start XNA Game Studio Connect on your Xbox 360 make sure your computer is properly connected to your Xbox 360 2 Double click the Z Excursion ccgame file on your computer 3 XNA Game Studio Package Utility starts a make sure the platform to unpack to is your Xbox 360 b Click on unpack 4 2 Start the Game 1 On your Xbox 360 select games and press A 2 Select My Games and press A 3 Select Z Excursion and press X to launch 4 3 How to Play When the level has started you can move forward and backward while tilting the left thumbstick up and down To aim with the arm cannon the right thumbstick is tilted in any direction however it is only possible to aim in a certain range To jump the left bumper button is pressed and to shoot the right bumper button is pressed For rotating 180 degrees the right trigger is pressed The control scheme is also illustrated in Figure 10 Rotate Move Aim Figure 10 Control scheme 21 27 The purpose of the demo level is to get to the end of the level The player starts with 5 lives Every time a player loses all its health or falling down a pit or stepping on a spike
12. moment a story doesn t exist However for the design retro graphics was intended already from the beginning The goal with the game is to go from point A to point B in a level and finishing a boss at the end Perhaps there will be an option for choosing in which order these levels should be played Regarding rewards there will be checkpoints on the levels and some form of artifact to retrieve after a finished level Also something to collect throughout the levels thus motivating the player to collect these to get a better ending The player can move forward and backward and also change direction The player can jump and is affected by gravity The player will fall if no solid ground is beneath The player has an arm cannon attached to its arm This arm cannon fires a small cannon ball and it has infinite ammo In the level there are platforms that are either stationary or moving There also exists an enemy type depicting a robot There are two variants of the robot In the first one the robot can walk fire and turn at walls However if it walks out of an edge it will fall down The second variant though turns at edges as well There is another type of enemy a spike which is stationary if the player touches one of these the player will lose a live immediately The final enemy in the level is a block of ice it moves vertically between two platforms This enemy can t fire When it touches a platform above or below it rests there for a while
13. s using a similar approach internally This method takes one parameter in the form of another bounding box and returns true if this instance s bounding box and the parameter s bounding box has collided 3 6 3 Response to Collision Detection After a collision has been detected between two objects correct logic must be chosen for how these two objects should respond There are two different main objects in the game static and dynamic objects Static objects are stationary while dynamic objects can move If a dynamic object collides with a static object only the dynamic object needs to respond On the other hand if two dynamic objects collide with each other both have to respond mostly Because there exists both static and dynamic objects the dynamic objects needs to have two separate functions one for handling response to the world i e static objects and one for handling response to other dynamic objects These methods are defined as virtual methods in the Dynamic class these are then overridden in each of Dynamic s sub classes thus making response logic individual for each different dynamic object type Perhaps the most trivial response logic is between a bullet and an enemy If these two dynamic objects collide the bullet is removed from the game and the enemy loses a certain amount of health BoundingBox bb1 bb2 Vector3 min Max bb1 min bb2 min Vector3 max Min bb1 max bb2 max if min x lt max x min y lt ma
14. Computer Engineering Degree Project Advanced Course 15 higher education credits Z EXCURSION GAME ENTRY FOR SWEDISH GAME AWARDS Tobias Nylin Programme in Simulation and Computer Games Technology 180 higher education credits Orebro Sweden Spring 2012 Examiner Lars Karlsson Z EXCURSION SPEL BIDRAG TILL SWEDISH GAME AWARDS Orebro universitet Institutionen f r naturvetenskap och teknik 701 82 Orebro Orebro University School of Science and Technology SE 701 82 Orebro Sweden Abstract This report describes my degree project For my degree project I made a demo for a game idea that I ve developed and implemented for use with Xbox 360 The idea was about converting the feeling and gameplay of old 2D side scrolling platform games into 3D viewed from a first person perspective The Xbox 360 version of the demo was also submitted for the game competition Swedish Game Awards In the report I explain this idea more extensive what software I used to implement it and how I implemented it Finally at the end I clarify the results and discuss fulfilled tasks and future improvements I m very pleased with my progress so far and I will continue to work on this on my own until it feels like a finished product that can be distributed Sammanfattning Den h r rapporten beskriver mitt examensarbete F r mitt examensarbete s gjorde jag en demoversion av en spelid som jag utvecklat och som implementerades f r anv ndnin
15. Image Manipulation Program It is a free and open source raster graphics editor under the General Public License GPL which means users have access to and can alter the source code GIMP is mainly used for retouching photos image composition how to make a photo more attractive to the eye and construction of images It was the latter one I used for creating the textures The maps of the levels are also textures The textures were then imported in my project trough XNAs content pipeline 2 2 2 3D Modeling in Blender For the modeling part I used Blender 5 which is a 3D computer graphics software free and open source under the General Public License GPL In Blender it is possible to make animated films special effects for movies and even entire video games For this purpose I only used it to create primitive models with materials and exported them to the DirectX file format with the extension x These were then imported trough XNAs content pipeline 2 3 Other Resources For debugging the game on Xbox 360 it was required to own an Xbox Live Gold Membership and that XNA Game Studio Connect was installed on the console 6 7 27 3 Design amp Implementation 3 1 Game Concept The concept of the game was to do something creative with the old genre of side scrolling platformers Since this degree project was focusing more on programming most time was spent on that Less time was spent on developing a story and designing At this
16. and then starts to move again but in the opposite direction Finally there is a checkpoint during the level and at the end there is a cube defining the goal 3 2 Class Structure The idea behind the particular class structure chosen was to focus on that it should be easy to extend and to reuse In this section I will go trough the class structure in a top down approach A class diagram of this structure is illustrated in Figure 1 3 2 1 Object This is the base class for all other classes in the program Right now it doesn t contain anything of interest except a print method and a type property that is accessed trough all its sub classes The type property returns the class name as a string of the instance calling it 3 2 2 Resources This is a singleton class A singleton is a class that can only have one instance it is used for storing commonly used information that can be accessed by other objects in the system Resources is a sub class to Object The main purpose of this class is to have a container where textures models and audio are imported and stored And also for the playback of the audio and for drawing textures and models It contains one instance of the following The ContentManager which is the pipeline for loading textures models etc The SpriteBatch that is used for drawing 2D graphics on the screen A GraphicsDevice for handling the drawing of polygons The BasicEffect which is a default shader in XNA with restricted
17. avity After that a modified version of Eq 2 was used which is defined in Eq 4 the difference is that the acceleration part of the equation is removed because the velocity had already been updated by Eq 3 The reason why it was divided into two equations was because a threshold was used for the velocity so when the velocity reaches a pre defined max value it will stay on that velocity until the velocity starts to change in the opposite direction Eq 3 Vy Voy gAt Eq 4 y yo v At Eq 5 x xXo v At If the player decides to jump the velocity is set to a constant positive scalar representing the initial jumping velocity The player starts to jump with this velocity but for every frame gravity affects this velocity after some time the velocity becomes less than zero and the player starts falling down again The player continues to fall until it has collided with any static object or moving platform in the world The horizontal velocity is constant so it doesn t need any acceleration at all Eq 5 Although when playing with an Xbox 360 controller the left thumbstick is used for moving forward or backward By pressing up on the stick the player moves forward and by pressing down it moves backward The thumbstick returns a decimal fraction value between 1 and 1 depending on the direction or how much the player has tilted it This value is multiplied with the horizontal velocity of the player before the new position is stored T
18. can be applied to one face each of a cube But for a skybox the textures should be drawn on the inside of the cube This can be fixed by temporarily changing the cull mode to clockwise instead of counter clockwise The skybox is then translated to the player s position and scaled Every time the player moves the skybox will retrieve the player s new position this means that no matter where the player is the skybox will always look as if it is at a constant distance thus creating the illusion that it is very far away The skybox is the object that is drawn first by all objects It needs to be drawn with the depth buffer turned off and therefore it will always be behind all other objects in the scene even though there might be other objects behind it since it is not sorted depending on z value 7 3 2 6 Interactive This is a sub class to Animated The purpose of this class is to distinguish between animated objects that are just animated or that also interacts with the environment For example an explosion might be an animated object that doesn t need to interact with the other objects in the world it could just be used for a nice effect when an enemy dies On the other hand an enemy is definitely an interactive object that needs to know what it collides with and how to respond This class contains a bounding box and a vector for the relative bounding box position A bounding box contains a min and max vector defining it s extremes The min a
19. e Linux Mac OS X Nintendo DS PlayStation 3 PlayStation Portable Solaris Wii Windows Windows Phone and Xbox 360 The first event during this years SGA was the SGA Tour It already started in December 2011 and ended in February 2012 On January 18 the SGA Tour visited Orebro University for a short briefing which I attended The second event was the SGA Conference held at KTH in Stockholm Participants from all over the country gathered here to talk to each other and to attend lectures from people inside the business A similar event was also held in Malm The deadline for submitting the game was at May 31 To enter the competition a submission form was submitted at SGAs webpage Also the game itself along with a trailer and 3 screenshots were uploaded to an FTP server The final event at June 20 was the grand finale held at the Central Station in Stockholm and an award ceremony at KTH 1 4 Requirements response among these Enemies as models Sky box Submission to Swedish Game Awards One playable level at least 5 minutes of gameplay Bitmap representing a level for easy alterations of the level Text file representing a list of enemies with type position and possible other attributes Simple physics movement of player enemies platforms and collision detection and Textures or procedural textures for platforms Artistic shading technique rather than state of the art Infrastructure for music and sound effects
20. e texture if abs this min y cube max y range y amp amp this vel y 0 do this y epsilon this vel y while this Intersects cube Figure 5 Pseudo code for collision response 17 27 WE je deling in Blender CE s comm D GED eng Figure 6 Mo 3 8 Music and Sound Effects 3 8 4 XACT Importing sound effects and music isn t done in the same way trough the content pipeline like models and textures Instead an external program called Microsoft Cross Platform Audio Creation Tool is used or for short XACT 12 A screenshot of the XACTS interface is shown in Figure 7 To use XACT a new project is first defined Then a Wave Bank and Sound Bank is created in the project In the Wave Bank wave files are imported The Sound Bank consists of sounds and cues By dragging a wave file from the Wave Bank and drop it in the Cue section of the Sound Bank XACT automatically create a sound name and cue name for the wave file Trough the sound name it is possible to modify the sound e g altering volume and pitch enabling looping and applying filters In this way the sound could be altered without having to open it in an external audio editing software The cue names are used for playing the sound from XNA 3 8 2 Playing Sounds in XNA First the project created in XACT is loaded into XNA trough the content pipeline Then for being able to play sounds an instance each of AudioEngine WaveBank So
21. een inspired by video game music especially from older games when hardware was an issue and the composers were forced to create more melodic tunes rather than atmospheric music I ve been composing and producing music for about 10 years now and I would say I get better all the time not a professional but enough to compose music that people like By creating music for us in the game will add a new dimension for composing music for me I think Right now the only way to make a level in the game is trough a bitmap it s a fast and easy way to create or edit a level but not so efficient when more and more objects and textures are added to the game Because one color value must be used for each different texture and object Therefore I will create a level editor where it is easy to assign the texture to use for a certain cube and also for adding enemies platforms and other objects 25 27 6 References 1 2 3 4 5 6 7 8 9 10 11 12 13 Swedish Game Awards Retrieved 2012 02 22 http gameawards se XNA Reference Retrieved 2012 04 09 URL http msdn microsoft com en us library bb200104 aspx App Hub FAQ Retrieved 2012 04 16 URL http create msdn com en US home faq xbox_live_indie_games xboxfaq registration GNU Image Manipulation Program User Manual Retrieved 2012 05 10 URL http docs gimp org 2 6 en Blender User Manual Retrieved 2012 05 10
22. eginning of the sound I pitched it up and at the middle of the sound I pitch it down again thus creating a sound that sounds similar to old platform games The interface of FL Studio is shown in Figure 9 3 9 Licenses I have strived to use content in the game that I either have a license to use or that are free for commercial use I ve used GIMP for texture creation and level design and Blender for modeling For sound effects I ve created on my own I ve only used software which I have licenses for Moreover for sound effects I ve downloaded I used sounds that are licensed under the Attribution 3 0 license 15 Sounds under this license are free for commercial use and to share and to edit Although a certain sound that is used in a work needs to be attributed if the author requires that Attribution 3 0 is a license under Creative Commons 16 on their webpage they state their mission like this Our vision is nothing less than realizing the full potential of the Internet universal access to research and education full participation in culture to drive a new era of development growth and productivity 19 27 Figure 9 FL Studio interface 20 27 4 Result The result of this project is a demo level of about 5 minutes of gameplay The demo is played on Xbox 360 Windows was mostly used for debugging The game was submitted for Swedish Game Awards but wasn t nominated in any category Although I wasn t taking that so
23. es between extremes and depending on the direction of the velocity different responses are chosen They also use an for moving the player s position back 3 7 Modeling Process The focus in this project was not to make elegant models therefore much time wasn t spent on designing models But as an easy and quick compromise a model of a robot consisting of only cubes was created Even the eyes of the robot are cubes they are translated a tiny fraction so that they appear in front of the head This model only has basic materials A screenshot of the Blender interface and the Robot model is shown in Figure 6 Another model illustrating a spike uses textures This model is represented by a square pyramid meaning that it has four sides Each of these sides is a triangle to apply a square texture to these the correct UV coordinates had to be given UV coordinates are used to define the part of a texture that should be applied to a face U is the horizontal coordinate of the texture while V is the vertical UV coordinates are usually defined in the range from 0 to 1 For defining the part of the texture I wanted to use for a face of my pyramid I had to give three UV coordinates One at the bottom left of the texture one at the bottom right and finally one at the middle at the top thus forming a triangle in the texture The model and its associated texture where then imported in XNA and linked correctly so the model knew the relative path to th
24. evelopment A reason for this is to increase code reuse so the game developers can focus more on the design rather than to build the entire engine from scratch The library consists of namespaces The framework audio content graphics and input namespaces were the ones that were frequently used in this project The framework namespace can be thought of as the main namespace every other namespace in XNA is derived from this one Three important classes in this namespace is Game GameTime and GraphicsDeviceManager The Game class is the main class of any XNA game It consists of five important methods The first one Initialize performs initialization of content that aren t graphics related before the game starts to run The second one is LoadContent in this method textures models audio etc should be loaded and objects that depend on these should be initialized The third one UnLoadContent is the opposite here content should be unloaded The fourth one is Update this is an important method where code for updating objects should be placed this method is called once every frame The final one is Draw also important and called once per frame in this method code for objects that shall be drawn should be placed The GameTime class of the framework namespace is used for retrieving how much time that has passed since the last frame by using the time retrieved it is possible to do calculations based on variable time step which means that object
25. g p Xbox 360 Id n bestod av att verf ra k nslan och spelmekaniken fr n gamla tv dimensionella sidoskrollande plattformsspel till 3D sett ur ett f rstapersonsperspektiv Demoversionen f r Xbox 360 skickades ocks in som ett bidrag till spelt vlingen Swedish Game Awards I rapporten s f rklarar jag id n mer utf rligt vad f r mjukvara jag anv nde f r att implementera den och hur jag implementerade den I slutet av rapporten s klarg r jag resultaten och diskuterar m l som har uppfyllts samt id er f r att vidareutveckla spelet Jag r n jd med det jag stadkommit hitintills och jag kommer att forts tta arbeta p spelet sj lv tills det k nns som en f rdig produkt som kan distribueras 1 27 Preface I would like to thank my instructor Mathias Broxvall for devoting about one to two hours per week for appointments with me He was very enthusiastic in this task and clarified a lot of doubts for me 2 27 Contents 1 2 3 6 INTRODUCTION PEE 4 1 1 BACKGROUND 5i eere reas eot E Nee EEU P Mtas eU Nae NR R 4 1 2 PROTECT ni AAE ATEA 4 1 3 OBJECTIV Ess d r CL E 4 1 4 REQUIRE MEN SEO ELE 5 METHODS AND TOOLS s cd cssosves osssoss vssesv sesoooks ss cvs ssesons nssesvsonsesonsosssevst sieesns ebessrastesossssen 6 2 1 METHODS oraire 6 2 1 1 What isXNA onda i D 6 2 2 A NE DO ES E EE sasanide 7 2 2 1 Textures and LevelDesig sssesesssssoso
26. gine spinning yourself around To translate and rotate the arm cannon correctly a side vector perpendicular from the heading and up vector is created This is done by using the cross product The side vector is then normalized The player s position is then stored in a vector defining the basis for the arm cannon s position Next each component of this vector is transformed with the heading up and side vector All these three vectors are normalized Yet another vector though constant is used for defining the relative offset for the arm cannon By multiplying the heading vector with the x component of the offset vector the up vector with the y component of the offset vector and the side vector with the z component of the offset vector and adding these three to the player s position the correct relative position of the arm cannon is retrieved Since the heading up and side vectors are normalized the relative distance from the player s position will always be the same Finally the arm cannon s transformation matrix is defined by first translating the arm cannon to the newly calculated position and rotating it with the yaw and respectively the pitch angle and lastly scaling it 9 3 2 13 Enemy This class serves as a base class for all different enemy types in the game It is also a sub class to Dynamic It contains some protected methods for different behaviors e g walking falling and shooting These can all be accessed in sub classes t
27. he result of this is that the player will move slower the less the player has tilted the thumbstick 15 27 The equations of motion are also used for moving enemies and platforms Enemies motion is a similar to the player s motion except that they cannot jump They only move vertically and fall due to gravity Platforms aren t affected by gravity they either move vertically or horizontally 3 6 2 Bounding boxes and Collision Detection The Interactive class has a bounding box member which can be accessed by all sub classes to it Every sub class can add a bounding box representing the boundaries for the particular model that is used for that class For defining a bounding box the built in XNA structure BoundingBox was used This structure contains two vectors The first one Min defines the minimum coordinates of the bounding box the second one Max defines the maximum coordinates One way for checking if a collision has occurred is by creating a union by the two bounding boxes min and max vectors To get the min union vector the method Max is used this method returns the maximum value of each component pair in the vectors For the max union vector it is similar but the method Min is used instead After this these two union vectors are used to check if a collision has occurred this is given in Figure 4 Although I m not using this approach since there is a method called ntersects in the BoundingBox structure but I m guessing it
28. ice it is used for displaying 2D graphics on the screen The SpriteFont is used for loading external fonts and are drawn by using a SpriteBatch The Texture2D class is used for loading textures and by assigning texture coordinates for objects vertices textures can be mapped to them Finally different vertex formats can be used for telling the graphics card how to draw objects The most basic one just contains position and color data The one that is used in this project contains a position normal and texture coordinate The last frequently used namespace mentioned is the input namespace This is used for checking if the player has pushed any buttons on a gamepad or on the keyboard or clicked a button on the mouse or moved it If any input is detected a different logic is executed depending on which button was pressed XNA is available for Windows XP Windows Vista Windows 7 Windows Phone 7 and Xbox 360 XNA supports easy portability across these platforms if a game is developed on a computer with Windows it can easily be ported to e g Xbox 360 For distributing your game commercially to Xbox 360 a membership on App Hub is needed the annual fee is 99 3 2 2 Tools For the entire development process I used Windows but for running the demo I used Xbox 360 as well For the programming I used Visual Studio and XNA 2 2 1 Textures and Level Design For creating textures and designing levels I used GIMP 4 which is an acronym for GNU
29. irection the player is looking and the up 11 27 vector is the positive y axis since the player cannot rotate freely it is enough to have the positive y axis as the up vector Furthermore to define the target vector another vector called heading is used This is a normalized vector meaning the length of its components is always 1 The heading vector defines the direction in which the player is facing right now If the player rotates a matrix is created with the current angle and is used to transform the heading vector Finally to get the final target vector the player s position and heading vector are summed 8 The biggest method in the player class is the update method The first thing that is checked here is if the player has done any input That is pushed any buttons or moved the thumbsticks on the Xbox 360 controller or pressed any keys or moved the mouse Depending on the input different actions are performed Mainly the actions are based on movement and rotation and also if the player has triggered its weapon While the player itself isn t a model it has a model picturing an arm cannon weapon this model is placed relative to the player s position so when the player moves the arm cannon moves indirectly It is also rotated based on the player s pitch and yaw angle A pitch rotation defines a rotation vertically imagine an airplane that ascends or descends A yaw angle on the other hand defines a rotation that is horizontal ima
30. is called it initializes the list It also contains a virtual method for updating the objects this method is overridden in the sub classes so that the correct update method is called for each sub class Tickable is a sub class to Object 3 2 4 Animated Animated is a base class for all classes that have objects that shall be drawn to the screen There are three different type of objects that can be drawn One type of object that can be drawn is just used for scenery and doesn t interact with other objects in the world The second type are objects that can move and interact with other objects The final type are objects that are stationary which the objects that can move can interact with 9 27 This class contains a vector for the position of objects which defines the point in space where the object shall be drawn from Animated is a sub class to Tickable 3 2 5 SkyBox This class is a sub class to Animated and it contains a cube map that is used for the skybox A cube map is a bitmap with six textures inside it they are ordered like a flag with a cross another way to see it is as an array with 3 rows and 4 columns The middle row has 4 textures that lie next to each other they could be labeled as left right back and front texture The top row has one texture representing the top of the cube and the bottom also has one but representing the bottom of the cube By assigning the correct texture coordinates each of these 6 textures
31. latform that moves in the vertical or horizontal direction this is done using an enumeration It s starting direction and how far it should travel before it changes direction should also be determined For example if a vertical platform with starting direction up and range 80 units is initialized it moves 80 units up in the vertical direction than changes direction to down and moves 80 units down and then changes to up again and so on 3 2 11 Bullet A sub class to Dynamic An instance of this class is only created if the player or an enemy has fired its weapon Then an instance is created relative to the trigger s weapon If the player is the trigger it also needs to know in which direction the player s weapon is facing since the player can move the weapon for aiming An instance is removed if it has collided with any dynamic or static object or if it has left the game area 3 2 12 Player This class is the most extensive class It contains all the logic for the movement of the player It is a sub class to Dynamic Unlike other objects in the world the player itself isn t a model the player views the world from a first person perspective this is the same as the camera s position which is defined by the view matrix Based on the player s movement and rotation the view matrix is updated For defining a view matrix a position target and up vector is required In this case position is the position of the player the target is in which d
32. n max vectors of the bounding box are calculated with this relative vector based on the current position of the object 3 2 7 Static This class is a sub class to Interactive It works as a base class for classes that contain objects that don t move i e they are static For example the cubes that the world is built by The dynamic objects needs to know the cubes boundaries so they can know when they have collided with a cube and how to respond to that 3 2 8 Map This is a sub class to Static The purpose of this class is to create cubes for each pixel s color value in the bitmap representing the level that has been stated A bounding box is also created for each cube If two or more bounding boxes are adjacent horizontally they are combined into a single bounding box The reason for this is that when the player falls down due to gravity the player collides with a cube s bounding box If several cubes bounding boxes hasn t been merged the player will 10 27 collide with the cube but not knowing how to respond e g should the player move back up or should the player move left This problem occurs because of the order how collisions are checked First I check if the player has collided with the right face of a cube then with a left face then with a top face and finally a bottom face Since I check the horizontal faces first it means that the player will think it has collided with a horizontal face and thus moves back or forward i
33. n the x direction though it should move up in the y direction Therefore I merged all bounding boxes that are adjacent horizontally When the entire bitmap has been iterated the vertices for all found cubes are stored in a vertex buffer It is then used to draw all the cubes to the scene 3 2 9 Dynamic This class works as a base class for classes that contain objects that can move i e dynamic It is in turn a sub class to Interactive It contains a vector representing velocity that is used for moving the object based on variable time step which means the final velocity is retrieved by multiplying the velocity by the time that has elapsed since the last frame The reason for this is so that the objects will move proportionally against the time that has elapsed each frame Every dynamic instance has an ID and the class also has a static variable that keeps track of the next available ID When a new dynamic object is initialized it gets a unique ID The class also has a variable for hit points health It has two virtual methods for how an instance should respond one for other dynamic objects and one for how to respond to the world These methods are overridden in Dynamic s sub classes It also has a function that updates the bounding boxes if necessary 3 2 10 Platform A dynamic class and thus a sub class to Dynamic This class represents platforms that can move When calling this class constructor you can determine if it should be a p
34. o Enemy so for example for every enemy type that shall walk they can just call the base class walk method from their update method and they will walk Every sub class to Enemy can contain their own specific data that is not general for all enemy types 10 3 2 14 World This is the main class of the game this is where all the objects are instantiated updated and drawn In this class update method all objects are first updated and after that they are checked against each other if they have collided The objects that have collided performs corresponding response depending on the object they ve collided with If some objects have been marked for removal these objects are removed at the end of this method 12 27 3 2 15 Audio This class handles the playback of audio in the game It has methods for playing pausing and stopping sounds To start playing a sound the name of the sound to play is given to the play method The class also has an update method The instance of this class is a member of the Resources instance and therefore it is accessible throughout the system 3 2 16 Input This class is a standalone class and checks for input particularly from the gamepad but also from the keyboard and the mouse Built in structures in XNA are defined for checking events among these input devices There is only one instance of the Input class which is accessible throughout the system 3 3 Development Method Because of the lack of
35. on of objects I used the equations of motion 11 These are only working with constant acceleration and when the motion is along a straight line Constant acceleration means that the rate of change in velocity is uniform Also when acceleration is constant changes in velocity is proportional to time In addition the displacement is proportional to both velocity and time The motion of an object depends on three kinematic variables velocity displacement and time In total there are 4 different equations of motion one for calculating the new velocity Eq 1 one for calculating the new displacement Eq 2 these were the only two that were used The remaining two equations of motion are both combinations of the two which were used Eq 1 v vo alt Eq 2 x Xo vot a Af The only acceleration that was used is the acceleration due to gravity which is a constant acceleration for real this is approximately 9 81 m s on Earth Although it is not a number that worked well in the game a gravity of 3 00 units per second squared was chosen instead The gravity is negative because the negative y axis goes in the direction beneath the world For updating the position vertically Eq 2 wasn t used right away Instead the velocity was calculated using Eq 3 which in theory is the same as Eq 1 the apparent difference is that it is specified for vertical velocity and that the acceleration has been replaced by a g which stands for gr
36. onse to work correctly and had added some sound effects the game started to feel like a game I will continue to develop this game on my own after graduation Unfortunately I can t do that all the time since I need to study or work to get money But I will devote a lot of spare time for the development of the game In the end I want a product that feels professional and flawless and try to submit it to Xbox Live Indie Games 3 With everything implemented so far there are a lot of things that could be improved For example the textures of objects and better looking models I m going to learn Blender better and create more detailed models that are also animated Also particle systems could be used for visual effects e g snow Terrain in the background and around the level could be used for more variation in the environment There are also a lot of code that can be optimized An example of this is the bounding boxes for the cubes these are now only merged horizontally but can also be merged vertically for reducing the number of bounding boxes created Another thing that I will learn but haven t used yet is HLSL High Level Shader Language Right now I m using the BasicEffect class a default shader in XNA With HLSL it is possible to render the environment more freely and it is more flexibly to separate the code for the shading from the rest of the code Of course there must be music in the game as well Throughout my life I ve always b
37. per Mario Galaxy Wii An early example of a 3D platformer viewed from a first person perspective is Jumping Flash PlayStation There also exists a sub genre called 2 5D that merges the visuals and gameplay of 2D and 3D platformers 2 5D uses the gameplay and perspective of 2D side scrollers but is rendered in full 3D As early as the mid 90 s 2 5D games started to show up but they have appeared more frequently during the last decade An example of a 2 5D game is LittleBigPlanet PS3 The idea for the game developed as my degree project was to convert the gameplay and feeling of 2D side scrollers viewed from a first person perspective Meaning taking the concept of 2D levels and traversing them from a first person perspective I also wrote a concept and design document about this idea at another course called Game Design at Orebro University in 2008 1 2 Project The game consists of linear levels where the player can walk forward backward up and down The latter two is mostly through jumping or falling by gravity You can also aim at a certain degree with the right thumbstick on the Xbox 360 controller or with the mouse on Windows This enables the player to get more variation when shooting at enemies To turn around quickly there is a button for rotating the character 180 This simplifies the gameplay since there isn t anything to interact with on the sides of the player just in front and behind and also to enhance the feeling of
38. s are updated consistent each frame no matter how much time has passed Trough the GraphicsDeviceManager it is possible to change the resolution of the game or to switch to full screen mode The framework namespace also contains some important structures BoundingBox is a structure that is used for determining collisions between objects this structure is explained more in section 3 6 2 Matrix and Vectors structures are frequently used for performing transformations of objects The audio namespace contains classes for how audio should be handled this is explained more in section 3 8 The content namespace includes the class ContentManager which is used for loading textures models and audio etc The graphics namespace is an extensive namespace that is used for handling how to draw and for drawing objects It contains the BasicEffect which is an alternative for using shaders Instead of using external shader files 6 27 the code for illuminating the environment is defined directly in the C files The GraphicsDevice is mostly used for drawing primitives this can be achieved by using a vertex buffer and or an index buffer these two buffers are also declared in this namespace The possible primitive types that can be drawn are triangle list triangle strip line list or line strip Another class called Model is used for loading an external model file and for displaying it on the screen The SpriteBatch is a 2D counterpart for the GraphicsDev
39. se class for all enemy types so it is possible to create several types of enemies in the text file The text file were only used on the Windows version since the Xbox 360 couldn t find and handle it The text file is read when the game executes by the use of a StreamReader instance The StreamReader class reads text files From the stream one line is read at the time and each word or number is inserted into an array This is done by telling the stream reader to group characters together as long as no space sign is encountered Depending on the data collected it selects the proper class to create an instance and insert it into the list of dynamic objects Syntax for enemies class name x y z speed start direction Syntax for platforms class name x y z speed range start direction type Legend class name the name of the class that should be instantiated x grid position on the x axis Ly grid position on the y axis z grid position on the z axis speed the speed in which an object will travel at range the distance a platform will travel before changing direction given in units not grid position type defines if a platform should move horizontally or vertically Example RobotEnemy 4 3 0 4 Forward Platform 12 3 0 4 80 Forward Horizontal Figure 3 Syntax for creating enemies or platforms in a text file 14 27 3 6 Physics 3 6 1 Equations of Motion For the moti
40. self But it was a good experience to being able to perform an oral exam for 30 minutes and I managed to get the presentation time for the slides very close to 20 minutes which was recommended I had gone trough the slides with the instructor before and got a lot of good feedback how to adjust the tempo of the presentation to retrieve a time that wasn t to short nor too long In the future if I m going to have a similar oral exam I think I will find it easier to achieve more eye contact with the audience During the entire education I feel that I have gained a better ability to derive solutions with relevance to a particular problem I m very aware that I still lack a lot of experience I noticed this already some weeks into this project at the beginning of the course I thought I was ready However I gained a lot of experience just during these 10 weeks Besides studying the courses throughout this programme I have spent a lot of free time learning how to make games that experience gained me a lot during this degree project Without it I m not sure I ve could have finished this at all This is just the beginning if I look relative on problems that have occurred previously during my education a lot of them seems trivial now In a couple of years I think I can call myself a fulfilled game programmer maybe even designer 24 27 5 3 Future Improvements I m pretty pleased with what I have accomplished so far After I got the intersection resp
41. ssovsstovssssssssrsessossosss sesssrsssosiovsnsessts ssoneosseersssssssenssessesssssen 7 2 2 2 3D Modeling in Blender s ssssssvsvsssvssaoss vssv vsovsssenessrsvssosssssrssenssesssssorssesesessassenssrsesssserssdesilereerese 7 2 3 OTHER RESOURCES oerte eoe isis erst tie nent sn nn tiens tn se en nsne ii sera een tit 7 DESIGN amp IMPLEMENTATION si ssicisecetsicceascevesscsastcccsseceesecbaracseosscsesccdestuctoaestesssoestsseeseccesesese 8 3 1 GAME CONCEPT sins oc tenir SANS BANKS des SANASEN EKRAR Iaia iris 8 3 2 CEASS STRUCTURE nant Uu Ee eee edu e ew an ene ee NuUa a Waa ten 8 3 2 1 nom IAA 8 3 2 2 RESOUN CES NER 8 3 2 3 Tickable 5 AR rere vede ien cort tu aes e EE tese bn ten aan eode Teva done des Ses EROR Eee dina 9 3 2 4 Animated seio navita Le hy ve M met Sateen mesi te basen et be veo SEAS 9 3 2 5 NqIDQ C use 10 3 2 6 Interactive snai tete E A Lv e Sa OST Oasis aS Oh o ovde UN se eee i 10 32 7 SE LE LEA sQ 10 3 2 8 MAD e M 10 3 2 9 DYNAMIC 50555 v ssossss ss v ssasnss re bss ste Et 11 3 2 10 jad EDOS i 11 DE EE TIL 11 3 2 11 BUM AEE E REE EEEE ETE AA TAA EEA dea AE E EEEN 11 32 12 PIAYEL sn
42. the initial idea 1 3 Objective The purpose of the project was to create something that feels unique not entirely with focus on the technical part but rather something that is pleasing to play and is esthetic The demo of the game was submitted to Swedish Game Awards SGA 1 which is a competition in game development for students resided in Sweden SGA started in 2002 as the KTH Game Awards KTH is the Royal Institute of Technology based in Stockholm SGA is a part of Excitera which is a student driven entrepreneurship association at KTH Already at the beginning prominent companies like Microsoft and DICE supported the competition The second year the competition was held another competition Excitera Mobile Awards was created targeting mobile platforms Though the following year KTH Game Awards and Excitera Mobile Awards were merged into one competition namingly SGA This competition was aimed at both PC and mobile platforms In 2005 the SGA Tour was arranged for the first time where the organizers travels to institutes all around Sweden to inform about the competition 4 27 In the 2011 2012 edition of the competition the edition in which this game participated the following awards were listed Game of the Year Best Innovation Best Mobile Game Best Serious Game educational and Gamers Choice The awards with prizes are also listed in Table 1 The available platforms for developing for was Android arcade Flash iPad iPhon
43. undBank and Cue is needed The AudioEngine instance is the instance where the project from XACT is loaded into The WaveBank and SoundBank instance are then linked to the Wave Bank and Sound Bank that were created in XACT correspondingly In this way it is not needed to write code every time a sound should be added or removed This is done in XACT by dragging or removing sounds Finally for playing sounds the Cue instance is used It could also be used for pausing or stopping sounds 3 8 3 Free Sound Effects and Own Sound Effects I have used sound effects that I ve downloaded from the Internet and also some that I have made on my own When downloading sound effects I had to think about that they need to be free for commercial use Right now the game isn t in a state for going commercial but it might be a good habit to have sound effects that are properly licensed Some of these sound effects was edited with Audacity 13 which is a free and open source sound editing software The interface of Audacity is shown in Figure 6 18 27 File Edit View WaveBonks SoundBanks Global Settings Audition Window Help CCONE DEGLEGECCECECCOOEG Options Notes DI E ADI RPC Free EG DSP Bec Path Presets Gal AQ Compression Presets A Session Windows Gl Wave Bank Wave Bank Name Sze PCrema PC Quai PC Compressed PC Ratio
44. x y min z lt max z return true else return false Figure 4 Pseudo code for collision detection 16 27 A more complex response logic is between the player and the world The player can approach four faces of a cuboid Depending on which face the player has collided with different logic needs to be used For example if the player has collided with the top the ground of a cuboid the player needs to move back in the vertical direction so it appears as the player is standing on the ground To really know that the player has collided with the top of a cuboid the distance between the min vector s y component of the player s bounding box and the max vector s y component of the cuboid s bounding box is calculated Then the absolute value of this distance is checked if it is smaller than a certain range which defines the top of the cuboid If this is true and the player is also falling down i e it s vertical velocity is below zero it means that this is the face the player has collided with To move the player back so it doesn t collide a small number is used e this number is multiplied with the vertical velocity and added to the position of the player then it checks if there still is a collision if it is is used again until the player isn t colliding with the cuboid anymore This is given in Figure 5 The remaining three faces of a cuboid that the player can collide with uses a similar response it check differenc
Download Pdf Manuals
Related Search