Game Engines Non-game specific technology Game: Engine Assets (models, animations, sounds, AI, and physics) Code (AI, Scripting, etc.)
Game Engines: Rendering Pipeline Application/Scene Scene database update/traversal Object/Camera Movement/Animation Visibility/LOD/Culling Geometry Transforms: Model/World/View Viewport & Backface Culling Triangles Scan-line conversion Rasterization Shading Texturing/Fog/Alpha Depth
Game Engines: Shading Flat Vertex (Gouraud) Pixel (Phong) Light Maps Programmable (Vertex & Pixel Shaders)
Game Engines: Memory Management Cache Thrashing Group Primitives by Textures? Hardware T&L Compression Card Memory Why isn’t 32 bit color (16.7M) enough? 1280x1024x12 (Front,Back,Z)= 15MB
Game Engines 3D Engine 3D Languages Authoring System Specialized Authoring (first or third person shooters)
Game Engines 3D Engine library of 3D graphics functions. free, $50-$100 up to $250,000 for commercial use. Require programming with an external delevopment system, normally Microsoft Visual C++. maximum of flexibility maximum of experience, work and time required.
Game Engines 3D Languages DirectX/OpenGL interface with a scripting language especially designed for 3D games Simpler than 'real' programming. Many based on Basic easy to learn not very well suited for large or complex games Alternatives: C- or Javascript-based languages.
Game Engines Authoring System 3D engine and a visual very fast 'clicking together' a game prototype. only simple games can be created without any programming. scripting language for programming or customizing the game.
Game Engines Specialized FPS (first or third person shooters) offer no or limited scripting. good alternative if you don't want to script and are not interested in publishing a game commercially.
Engine Considerations Platforms Performance Data Rendering/Features Animation Physics & Environment Scripting Authoring I/O Save/Load
Performance Occlusion Culling LOD Adaptive NURBS/Patches Cell Based: BSP tree, Portal, Octree Other: Potentially Visible Set, HOM LOD Adaptive NURBS/Patches Polygon Reduction Terrain Primitives
Data Import/Export 3D file formats Texture/Image Formats X, 3DS, MDL, MD2, MAP, WAD Texture/Image Formats Models/Animations: Maya, 3D Studio MAX Levels WorldcraftT or MilkshapeT Plugins
Rendering Features OpenGL vs. DirectX Shadow Maps (Lightmaps) Shaders DX6-9 OpenGL1.1-1.5,2.0 Shadow Maps (Lightmaps) Shaders Dynamic Shadows MIP Maps/Multi Maps/ Bump Mapping Effects
Animation Keyframe Bones (Skinning) Facial Animation Vertex Animation Inverse Kinematics (IK) Dynamics High-level Authoring
Physics & Physical Environment Visibility Collision Detection Terrain Following Gravity Physics Rigid & non-rigid bodies
Scripting Scripting languages add logic for controlling actors or objects Languages: Javascript Luo -http://www.lua.org/ Python Basic Custom:UnrealScript, C-Script, etc. Script Compilers for performance
Save/Load System allows the end user to save a complete game state. 'freezes' all running scripts and all objects and variables of the game and writes them into a file Without such a system: a script has to be written which stores the state of every variable and object and the position within every script function
Authoring/Editing Level Editor Model Editor Script Editor Terrain Logic
Sample Engines Specialized Authoring (FPS, 3PS) 3DGM, RF Authoring Quest, Radish, Virtools, Gamestudio/A6, Alice, Adobe Atmosphere, Blender 3D Languages Jamagic, DarkBASIC, Blitz 3D Engines TV3D, Irrlicht, Torque, Nebula, Crystal, Cipher, PR, Jupiter, Quake3, Unreal2 Standards-based Engines & Tools (VRML/X3D) Internet Scene Assembler, Cortona, Blaxxun,OpenWorlds, VizX3D
Game Engine Resources http://www.devmaster.net/engines http://www.pcplus.co.uk/reviews/ (->Software->Development and ->Software->Graphics) http://directory.google.com/Top/Computers/Programming/Games/3D/ http://cg.cs.tu-berlin.de/~ki/engines.html http://fraktali.849pm.com/graphengines.html http://www.flipcode.com/links/