3D graphics eBook - Course Materials Repository
3D graphics eBook - Course Materials Repository 3D graphics eBook - Course Materials Repository
Photon mapping 109 This can produce sharper images. • Image space photon mapping [1] achieves real-time performance by computing the first and last scattering using a GPU rasterizer. Variations • Although photon mapping was designed to work primarily with ray tracers, it can also be extended for use with scanline renderers. External links • Global Illumination using Photon Maps [2] • Realistic Image Synthesis Using Photon Mapping [3] ISBN 1-56881-147-0 • Photon mapping introduction [4] from Worcester Polytechnic Institute • Bias in Rendering [5] • Siggraph Paper [6] References [1] http:/ / research. nvidia. com/ publication/ hardware-accelerated-global-illumination-image-space-photon-mapping [2] http:/ / graphics. ucsd. edu/ ~henrik/ papers/ photon_map/ global_illumination_using_photon_maps_egwr96. pdf [3] http:/ / graphics. ucsd. edu/ ~henrik/ papers/ book/ [4] http:/ / www. cs. wpi. edu/ ~emmanuel/ courses/ cs563/ write_ups/ zackw/ photon_mapping/ PhotonMapping. html [5] http:/ / www. cgafaq. info/ wiki/ Bias_in_rendering [6] http:/ / www. cs. princeton. edu/ courses/ archive/ fall02/ cs526/ papers/ course43sig02. pdf Photon tracing Photon tracing is a rendering method similar to ray tracing and photon mapping for creating ultra high realism images. Rendering Method The method aims to simulate realistic photon behavior by using an adapted ray tracing method similar to photon mapping, by sending rays from the light source. However, unlike photon mapping, each ray keeps bouncing around until one of three things occurs: 1. it is absorbed by any material. 2. it leaves the rendering scene. 3. it hits a special photo sensitive plane, similar to the film in cameras.
Photon tracing 110 Advantages and disadvantages This method has a number of advantages compared to other methods. • Global illumination and radiosity are automatic and nearly free. • Sub-surface scattering is simple and cheap. • True caustics are free. • There are no rendering artifacts if done right. • Fairly simple to code and implement using a regular ray tracer. • Simple to parallelize, even across multiple computers. Even though the image quality is superior this method has one major drawback: render times. One of the first simulations in 1991, programmed in C by Richard Keene, it took 100 Sun 1 computers operating at 1 MHz a month to render a single image. With modern computers it can take up to one day to compute a crude result using even the simplest scene. Shading methods Because the rendering method differs from both ray tracing and scan line rendering, photon tracing needs its own set of shaders. • Surface shader - dictates how the photon rays reflect or refract. • Absorption shader - tells the ray if the photon should be absorbed or not. • Emission shader - when called it emits a photon ray Renderers • [1] - A light simulation renderer similar to the experiment performed by Keene. Future With newer ray tracing hardware large rendering farms may be possible that can render images on a commercial level. Eventually even home computers will be able to render images using this method without any problem. External links • www.cpjava.net [1] References [1] http:/ / www. cpjava. net/ photonproj. html
- 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
- Page 105 and 106: Path tracing 100 Scattering distrib
- Page 107 and 108: Phong reflection model 102 Visual i
- Page 109 and 110: Phong reflection model 104 Because
- Page 111 and 112: Phong shading 106 Visual illustrati
- Page 113: Photon mapping 108 Rendering (2nd p
- Page 117 and 118: Potentially visible set 112 • Can
- Page 119 and 120: Potentially visible set 114 Externa
- Page 121 and 122: Procedural generation 116 increases
- Page 123 and 124: Procedural generation 118 • Softi
- Page 125 and 126: Procedural generation 120 Reference
- Page 127 and 128: Procedural texture 122 Self-organiz
- Page 129 and 130: Procedural texture 124 References [
- Page 131 and 132: 3D projection 126 The distance of t
- Page 133 and 134: Quaternions and spatial rotation 12
- Page 135 and 136: Quaternions and spatial rotation 13
- Page 137 and 138: Quaternions and spatial rotation 13
- Page 139 and 140: Quaternions and spatial rotation 13
- Page 141 and 142: Quaternions and spatial rotation 13
- Page 143 and 144: Quaternions and spatial rotation 13
- Page 145 and 146: Radiosity 140 Overview of the radio
- Page 147 and 148: Radiosity 142 This is sometimes kno
- Page 149 and 150: Radiosity 144 References [1] " Mode
- Page 151 and 152: Ray casting 146 the light will reac
- Page 153 and 154: Ray tracing 148 Typically, each ray
- Page 155 and 156: Ray tracing 150 independence of eac
- Page 157 and 158: Ray tracing 152 On June 12, 2008 In
- Page 159 and 160: Reflection 154 Reflection Reflectio
- Page 161 and 162: Reflection 156 Glossy Reflection Fu
- Page 163 and 164: Reflection mapping 158 Cube mapping
Photon mapping 109<br />
This can produce sharper images.<br />
• Image space photon mapping [1] achieves real-time performance by computing the first and last scattering using a<br />
GPU rasterizer.<br />
Variations<br />
• Although photon mapping was designed to work primarily with ray tracers, it can also be extended for use with<br />
scanline renderers.<br />
External links<br />
• Global Illumination using Photon Maps [2]<br />
• Realistic Image Synthesis Using Photon Mapping [3] ISBN 1-56881-147-0<br />
• Photon mapping introduction [4] from Worcester Polytechnic Institute<br />
• Bias in Rendering [5]<br />
• Siggraph Paper [6]<br />
References<br />
[1] http:/ / research. nvidia. com/ publication/ hardware-accelerated-global-illumination-image-space-photon-mapping<br />
[2] http:/ / <strong>graphics</strong>. ucsd. edu/ ~henrik/ papers/ photon_map/ global_illumination_using_photon_maps_egwr96. pdf<br />
[3] http:/ / <strong>graphics</strong>. ucsd. edu/ ~henrik/ papers/ book/<br />
[4] http:/ / www. cs. wpi. edu/ ~emmanuel/ courses/ cs563/ write_ups/ zackw/ photon_mapping/ PhotonMapping. html<br />
[5] http:/ / www. cgafaq. info/ wiki/ Bias_in_rendering<br />
[6] http:/ / www. cs. princeton. edu/ courses/ archive/ fall02/ cs526/ papers/ course43sig02. pdf<br />
Photon tracing<br />
Photon tracing is a rendering method similar to ray tracing and photon mapping for creating ultra high realism<br />
images.<br />
Rendering Method<br />
The method aims to simulate realistic photon behavior by using an adapted ray tracing method similar to photon<br />
mapping, by sending rays from the light source. However, unlike photon mapping, each ray keeps bouncing around<br />
until one of three things occurs:<br />
1. it is absorbed by any material.<br />
2. it leaves the rendering scene.<br />
3. it hits a special photo sensitive plane, similar to the film in cameras.
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