GPU-based Techniques for Global Illumination Effects

1. GlobalIlluminationRendering.................................................1 1.1 Materials................................................................6 1.2 Rendering Equation......................................................8 1.3 Local Illumination ......................................................10 1.4 Global Illumination .....................................................13 1.5 Random Walk Solution of the Rendering Equation.........................14 1.5.1 MonteCarloIntegration.........................................17 1.5.2 ImportanceSampling............................................19 1.6 Iteration Solution of the Rendering Equation..............................20 1.7 ApplicationofFormerGIResearchResultsinGPUGI.....................22 2. LocalIlluminationRenderingPipelineofGPUS...............................23 2.1 Evolution of the Fixed-function Rendering Pipeline........................26 2.1.1 RasterOperations................................................27 2.1.2 RasterizationWithLinearInterpolation...........................27 2.1.3 Texturing.......................................................29 2.1.4 Transformation..................................................31 2.1.5 Per-vertexLighting..............................................34 2.2 ProgrammableGPUs....................................................34 2.2.1 Render-to-texture and Multiple Render Targets....................36 2.2.2 TheGeometryShader............................................36 2.3 ArchitectureofProgrammableGPUs.....................................38 2.3.1 Resources.......................................................38 2.3.2 Pipeline Stages and Their Control by Render States.................38 3. ProgrammingandControllingGPUS .........................................42 3.1 IntroductiontoHLSLProgramming.....................................44 3.1.1 VertexShaderProgramming......................................46 3.1.2 GeometryShaderProgramming...................................49 3.1.3 FragmentShaderProgramming...................................49 MOCL002-FM MOBKXXX-Sample.cls April 24, 2008 21:8 viii CONTENTS 3.2 ControllingtheGPUfromtheCPU......................................50 3.2.1 ControllingtheDirect3D9Pipeline...............................51 3.2.2 ControllingthePipelineUsingEffectFiles.........................56 3.2.2.1 ControllingthePipelineFromDirect3D10...............59 3.3 ShadersBeyondtheStandardPipelineOperation..........................60 3.3.1 Are GPUs Good for Global Illumination?..........................60 3.3.2 Basic Techniques for GPU Global Illumination.....................62 4. SimpleImprovementsoftheLocalIlluminationModel.........................66 4.1 ShadowMapping.......................................................68 4.1.1 Shadow Map Generation.........................................70 4.1.2 Rendering With the Shadow Map.................................71 4.1.3 ShadowMapAnti-aliasing.......................................74 4.2 Image-basedLighting...................................................77 4.2.1 MirroredReflectionsandRefractions..............................80 4.2.2 Diffuse and Glossy Reflections Without Self-shadowing.............82 4.2.3 Diffuse and Glossy Reflections With Shadowing....................85 5. RayCastingontheGPU......................................................90 5.1 Ray–TriangleIntersectioninaShader.....................................91 5.2 TheRayEngine........................................................95 5.3 Acceleration Hierarchy Built on Rays .....................................97 5.3.1 ImplementationofRecursiveRay-tracingUsingtheRayEngine.....98 5.3.2 RayCasting....................................................100 5.4 FullRay-TracersontheGPUUsingSpacePartitioning....................102 5.4.1 UniformGrid..................................................102 5.4.2 Octree.........................................................103 5.4.3 HierarchicalBoundingBoxes....................................103 5.4.4 Kd-Tree.......................................................104 5.5 Loosekd-TreeTraversalinaSingleShader...............................107 5.5.1 GPURepresentationoftheLoosekd-tree........................109 5.5.2 GPUTraversaloftheLoosekd-tree..............................111 5.5.3 Performance...................................................115 6. SpecularEffectswithRasterization...........................................116 6.1 Ray-TracingofDistanceMaps..........................................120 6.1.1 ParallaxCorrection.............................................121 6.1.2 LinearSearch..................................................122 6.1.3 RefinementbySecantSearch....................................124 MOCL002-FM MOBKXXX-Sample.cls April 24, 2008 21:8 CONTENTS ix 6.2 SingleLocalizedReflectionsandRefractions..............................126 6.3 Inter-ObjectReflectionsandRefractions.................................130 6.4 SpecularReflectionswithSearchingontheReflector......................130 6.5 SpecularReflectionswithGeometryorImageTransformation..............131 6.6 SelfReflectionsandRefractions.........................................132 6.6.1 Simplified Methods for Multiple Reflections and Refractions .......136 6.7 Caustics...............................................................136 6.7.1 LightPass.....................................................137 6.7.2 PhotonHitFilteringandLightProjection........................139 6.8 CombiningDifferentSpecularEffects...................................144 7. DiffuseandGlossyIndirectIllumination.....................................146 7.1 RadiosityontheGPU..................................................148 7.1.1 RandomTexelSelection........................................151 7.1.2 UpdateoftheRadianceTexture..................................153 7.2 Pre-ComputedRadiosity...............................................157 7.3 DiffuseandGlossyFinalGatheringwithDistanceMaps...................159 8. Pre-computationAidedGlobalIllumination..................................169 8.1 Sampling..............................................................171 8.2 Finite-element Method.................................................171 8.2.1 CompressionofTransferCoefficients.............................173 8.3 Pre-computedRadianceTransfer........................................175 8.3.1 Direct3D Support of the Diffuse Pre-computed Radiance Transfer..179 8.4 LightPathMap.......................................................182 8.4.1 Implementation................................................184 9. ParticipatingMediaRendering ..............................................195 9.1 PhaseFunctions.......................................................197 9.2 ParticleSystemModel..................................................197 9.3 Billboard Rendering....................................................198 9.3.1 Spherical Billboards.............................................199 9.3.1.1 GouraudShadingofParticles...........................201 9.3.1.2 GPU Implementation of Spherical Billboards.............202 9.4 Illuminating Participating Media........................................204 9.5 Rendering Explosions and Fire..........................................205 9.5.1 DustandSmoke................................................205 9.5.2 Fire...........................................................206 9.5.3 LayerComposition.............................................209 MOCL002-FM MOBKXXX-Sample.cls April 24, 2008 21:8 xCONTENTS 9.6 Participating Media Illumination Networks...............................210 9.6.1 Iteration Solution of the Volumetric Rendering Equation...........211 9.6.2 Building the Illumination Network...............................212 9.6.3 Iterating the Illumination Network...............................213 10. FakeGlobalIllumination....................................................218 10.1 TheScalarObscurancesMethod........................................220 10.2 TheSpectralObscurancesMethod.......................................221 10.3 ConstructionoftheObscurancesMap...................................223 10.4 Depth Peeling.........................................................225 11. PostprocessingEffects.......................................................229 11.1 ImageFiltering........................................................229 11.1.1 SeparationofDimensions.......................................231 11.1.2 ExploitationoftheBi-linearFilteringHardware...................232 11.1.3 ImportanceSampling...........................................234 11.2 Glow.................................................................236 11.3 ToneMapping.........................................................236 11.3.1 LocalToneMapping...........................................238 11.3.2 GlowIntegrationIntoToneMapping............................239 11.3.3 TemporalLuminanceAdaptation................................239 11.3.4 ScotopicVision.................................................240 11.3.5 Implementation................................................241 11.4 DepthofField.........................................................242 11.4.1 CameraModelsandDepthofField..............................243 11.4.2 DepthofFieldWiththeSimulationofCircleofConfusion.........244 12. IntegratingGIEffectsinGamesandVirtualRealitySystems...................248 12.1 GameEnginesandSceneGraphManagers...............................249 12.2 Combining Different Rendering Algorithms..............................253 12.3 CaseStudies...........................................................256 12.3.1 Moria.........................................................257 12.3.2 RTCar........................................................259 12.3.3 SpaceStation...................................................263 Bibliography................................................................265