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Global illumination 49 Procedure For the simulation of global illumination are used in 3D programs, more and more specialized algorithms that can effectively simulate the global illumination. These are, for example, path tracing or photon mapping, under certain conditions, including radiosity. These are always methods to try to solve the rendering equation. The following approaches can be distinguished here: • Inversion: • is not applied in practice • Expansion: • bi-directional approach: Photon mapping + Distributed ray tracing, Bi-directional path tracing, Metropolis light transport • Iteration: • Radiosity In Light path notation global lighting the paths of the type L (D | S) corresponds * E. Image-based lighting Another way to simulate real global illumination, is the use of High dynamic range images (HDRIs), also known as environment maps, which encircle the scene, and they illuminate. This process is known as image-based lighting. External links • SSRT [1] – C++ source code for a Monte-carlo pathtracer (supporting GI) - written with ease of understanding in mind. • Video demonstrating global illumination and the ambient color effect [2] • Real-time GI demos [3] – survey of practical real-time GI techniques as a list of executable demos • kuleuven [4] - This page contains the Global Illumination Compendium, an effort to bring together most of the useful formulas and equations for global illumination algorithms in computer graphics. • GI Tutorial [5] - Video tutorial on faking global illumination within 3D Studio Max by Jason Donati References [1] http:/ / www. nirenstein. com/ e107/ page. php?11 [2] http:/ / www. archive. org/ details/ MarcC_AoI-Global_Illumination [3] http:/ / realtimeradiosity. com/ demos [4] http:/ / www. cs. kuleuven. be/ ~phil/ GI/ [5] http:/ / www. youtube. com/ watch?v=K5a-FqHz3o0
Gouraud shading 50 Gouraud shading Gouraud shading, named after Henri Gouraud, is an interpolation method used in computer graphics to produce continuous shading of surfaces represented by polygon meshes. In practice, Gouraud shading is most often used to achieve continuous lighting on triangle surfaces by computing the lighting at the corners of each triangle and linearly interpolating the resulting colours for each pixel covered by the triangle. Gouraud first published the [1] [2] [3] technique in 1971. Description Gouraud-shaded triangle mesh using the Phong reflection model Gouraud shading works as follows: An estimate to the surface normal of each vertex in a polygonal 3D model is either specified for each vertex or found by averaging the surface normals of the polygons that meet at each vertex. Using these estimates, lighting computations based on a reflection model, e.g. the Phong reflection model, are then performed to produce colour intensities at the vertices. For each screen pixel that is covered by the polygonal mesh, colour intensities can then be interpolated from the colour values calculated at the vertices. Comparison with other shading techniques Gouraud shading is considered superior to flat shading, which requires significantly less processing than Gouraud shading, but usually results in a faceted look. In comparison to Phong shading, Gouraud shading's strength and weakness lies in its interpolation. If a mesh covers more pixels in screen space than it has vertices, interpolating colour values from samples of expensive lighting calculations at vertices is less processor intensive than performing the Comparison of flat shading and Gouraud shading. lighting calculation for each pixel as in Phong shading. However, highly localized lighting effects (such as specular highlights, e.g. the glint of reflected light on the surface of an apple) will not be rendered correctly, and if a highlight lies in the middle of a polygon, but does not spread to the polygon's vertex, it will not be apparent in a Gouraud rendering; conversely, if a highlight occurs at the vertex of a polygon, it will be rendered correctly at this vertex (as this is where the lighting model is applied), but will be spread unnaturally across all neighboring polygons via the interpolation method. The problem is easily spotted in a rendering which ought to have a specular highlight moving smoothly across the surface of a model as it rotates. Gouraud shading will instead produce a highlight continuously fading in and out across neighboring portions of the model, peaking in intensity when the intended specular highlight passes over a vertex of the model. (This can be improved by increasing the density of vertices in the object, or alternatively an adaptive tessellation scheme might be used to increase the density only near the highlight.)
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3D Rendering PDF generated using th
Page 3 and 4: Image-based lighting 64 Image plane
Page 5 and 6: References Article Sources and Cont
Page 7 and 8: 3D rendering 2 Non real-time Animat
Page 9 and 10: 3D rendering 4 The shaded three-dim
Page 11 and 12: Ambient occlusion 6 ambient occlusi
Page 13 and 14: Ambient occlusion 8 • ShadeVis (h
Page 15 and 16: Anisotropic filtering 10 will only
Page 17 and 18: Beam tracing 12 Beam tracing Beam t
Page 19 and 20: Bilinear filtering 14 Are all true.
Page 21 and 22: Binary space partitioning 16 togeth
Page 23 and 24: Binary space partitioning 18 Other
Page 25 and 26: Binary space partitioning 20 [1] Bi
Page 27 and 28: Bounding interval hierarchy 22 Prop
Page 29 and 30: Bounding volume 24 bounding boxes b
Page 31 and 32: Bump mapping 26 Bump mapping Bump m
Page 33 and 34: CatmullClark subdivision surface 28
Page 35 and 36: CatmullClark subdivision surface 30
Page 37 and 38: Conversion between quaternions and
Page 39 and 40: Cube mapping 34 Advantages Cube map
Page 41 and 42: Cube mapping 36 Related A large set
Page 43 and 44: Diffuse reflection 38 2), or, of co
Page 45 and 46: Displacement mapping 40 Meaning of
Page 47 and 48: DooSabin subdivision surface 42 Ext
Page 49 and 50: False radiosity 44 False radiosity
Page 51 and 52: Geometry pipelines 46 Geometry pipe
Page 53: Global illumination 48 Rendering wi
Page 57 and 58: Graphics pipeline 52 Graphics pipel
Page 59 and 60: Graphics pipeline 54 References 1.
Page 61 and 62: Hidden surface determination 56 imp
Page 63 and 64: High dynamic range rendering 58 Hig
Page 65 and 66: High dynamic range rendering 60 Ton
Page 67 and 68: High dynamic range rendering 62 Fro
Page 69 and 70: High dynamic range rendering 64 •
Page 71 and 72: Irregular Z-buffer 66 Applications
Page 73 and 74: Lambert's cosine law 68 than would
Page 75 and 76: Lambertian reflectance 70 Lambertia
Page 77 and 78: Level of detail 72 Well known appro
Page 79 and 80: Level of detail 74 Hierarchical LOD
Page 81 and 82: Newell's algorithm 76 Newell's algo
Page 83 and 84: Non-uniform rational B-spline 78 Us
Page 85 and 86: Non-uniform rational B-spline 80 of
Page 87 and 88: Non-uniform rational B-spline 82 ar
Page 89 and 90: Non-uniform rational B-spline 84 Ex
Page 91 and 92: Normal mapping 86 How it works To c
Page 93 and 94: OrenNayar reflectance model 88 Oren
Page 95 and 96: OrenNayar reflectance model 90 , ,
Page 97 and 98: Painter's algorithm 92 The algorith
Page 99 and 100: Parallax mapping 94 • Parallax Ma
Page 101 and 102: Particle system 96 A cube emitting
Page 103 and 104: Path tracing 98 History Further inf
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Path tracing 100 Scattering distrib
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Phong reflection model 102 Visual i
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Phong reflection model 104 Because
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Phong shading 106 Visual illustrati
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Photon mapping 108 Rendering (2nd p
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Photon tracing 110 Advantages and d
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Potentially visible set 112 • Can
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Potentially visible set 114 Externa
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Procedural generation 116 increases
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Procedural generation 118 • Softi
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Procedural generation 120 Reference
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Procedural texture 122 Self-organiz
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Procedural texture 124 References [
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3D projection 126 The distance of t
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Quaternions and spatial rotation 12
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Radiosity 140 Overview of the radio
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Radiosity 142 This is sometimes kno
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Radiosity 144 References [1] " Mode
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Ray casting 146 the light will reac
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Ray tracing 148 Typically, each ray
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Ray tracing 150 independence of eac
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Ray tracing 152 On June 12, 2008 In
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Reflection 154 Reflection Reflectio
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Reflection 156 Glossy Reflection Fu
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Reflection mapping 158 Cube mapping
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Render Output unit 160 Render Outpu
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Rendering 162 • indirect illumina
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Rendering 164 Ray tracing Ray traci
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Rendering 166 Academic core The imp
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Rendering 168 • 1984 Distributed
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Retained mode 170 Retained mode In
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Scanline rendering 172 Comparison w
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Screen Space Ambient Occlusion 174
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Screen Space Ambient Occlusion 176
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Shadow mapping 178 Algorithm overvi
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Shadow mapping 180 Drawing the scen
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Shadow mapping 182 Further reading
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Shadow volume 184 There is also a p
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Shadow volume 186 The depth fail me
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Silhouette edge 188 Silhouette edge
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Specular highlight 190 Specular hig
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Specular highlight 192 normalized o
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Sphere mapping 194 Sphere mapping I
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Stencil codes 196 Stencil codes Ste
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Stencil codes 198 Stencils The shap
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Stencil codes 200 [7] Wellein, G et
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Subdivision surface 202 used a four
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Subsurface scattering 204 Subsurfac
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Subsurface scattering 206 External
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Surface normal 208 If a (possibly n
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Surface normal 210 Normal in geomet
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Texture filtering 212 Texture filte
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Texture mapping 214 Texture mapping
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Texture mapping 216 constant distan
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Texture synthesis 218 • Structure
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Texture synthesis 220 Pattern-based
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Texture synthesis 222 • Micro-tex
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UV mapping 224 A UV map can either
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Vertex 226 Polytope vertices are re
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Vertex Buffer Object 228 //Make the
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Vertex Buffer Object 230 GLuint sha
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Vertex Buffer Object 232 vertexes *
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Virtual actor 234 Virtual actor A v
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Virtual actor 236 exercises, and ev
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Volume rendering 238 Volume ray cas
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Volume rendering 240 Maximum intens
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Volume rendering 242 Image-based me
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Volumetric lighting 244 References
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Voxel 246 • Outcast, a game made
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Z-buffering 248 Z-buffering In comp
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Z-buffering 250 } } display COLOR a
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Z-fighting 252 Z-fighting Z-fightin
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Appendix 3D computer graphics softw
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3D computer graphics software 256
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3D computer graphics software 258
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3D computer graphics software 260 2
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Article Sources and Contributors 26
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Article Sources and Contributors 26
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Image Sources, Licenses and Contrib
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Image Sources, Licenses and Contrib
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