Difference between revisions of "Radiosity normal map"

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* [[Polycount|Main Page]] > [[Category:Texturing]] > Radiosity Normal Map
 
 
= Radiosity Normal Map =
 
 
Lighting can be baked as a set of three light maps, storing the lighting vectors instead of just the brightness/color. This allows the surface normal maps to receive directional lighting so the bumps/recesses are lit more accurately by the baked lighting information.  
 
Lighting can be baked as a set of three light maps, storing the lighting vectors instead of just the brightness/color. This allows the surface normal maps to receive directional lighting so the bumps/recesses are lit more accurately by the baked lighting information.  
  
 
Valve used this method extensively in Half-Life 2, which they called "Radiosity Normal Mapping" in their GDC 2004 paper ''[http://www.decew.net/OSS/References/D3DTutorial10_Half-Life2_Shading.pdf Half-Life®2 / Valve Source™ Shading]''.  
 
Valve used this method extensively in Half-Life 2, which they called "Radiosity Normal Mapping" in their GDC 2004 paper ''[http://www.decew.net/OSS/References/D3DTutorial10_Half-Life2_Shading.pdf Half-Life®2 / Valve Source™ Shading]''.  
  
{| border="1" cellpadding="2" cellspacing="0"
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[[image:Valve_RadiosityNormalMapping_Lightmaps.jpg|frame|left|Three light maps are used for radiosity normal mapping. Here they're shown projected on geometry. Image by [http://www.valvesoftware.com Valve Software].]]<br clear="all"/>
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A further optimization of this technique was used by Insomniac Games for their game ''Resistance: Fall of Man''. The directions of the light rays were combined into a single RGB bitmap, using a kind of normal map, where each color channel was used to store one of the three directional components.  
 
A further optimization of this technique was used by Insomniac Games for their game ''Resistance: Fall of Man''. The directions of the light rays were combined into a single RGB bitmap, using a kind of normal map, where each color channel was used to store one of the three directional components.  
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All three RGB channels are used to store the light vectors, so the light maps could not also store the colors of the lights. Apparently they used vertex color to store the light colors.
 
All three RGB channels are used to store the light vectors, so the light maps could not also store the colors of the lights. Apparently they used vertex color to store the light colors.
  
{| border="1" cellpadding="2" cellspacing="0"
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[[image:ResistanceFallOfMan_Lightmap.jpg|frame|left|A directional light map used in ''Resistance: Fall of Man'', from the article [http://www.cybergooch.com/tutorials/pages/lighting_rfom1.htm Creating the Lighting for Resistance: Fall of Man]. Image by [http://www.cybergooch.com Eric Gooch].]]<br clear="all"/>
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* See the Polycount thread [http://boards.polycount.net/showthread.php?t=71538 How to ? Directional lightmaps with 3dsMax/Vray].
 
* See the Polycount thread [http://boards.polycount.net/showthread.php?t=71538 How to ? Directional lightmaps with 3dsMax/Vray].
 
* More reading at [http://www.decew.net/OSS/references.php Jeffrey DeCew's site].
 
* More reading at [http://www.decew.net/OSS/references.php Jeffrey DeCew's site].
* For info about traditional light mapping see [[Light Map]].
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* For info about traditional light mapping see [[Light map]].
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== Related Pages ==
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* [[Curvature map]]
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* [[DuDv map]]
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* [[Flow map]]
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* [[Normal map]]
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* [[Radiosity normal map]]
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* [[Vector displacement map]]
  
<<BR>>
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* [[Polycount|Main Page]] > [[Category:Texturing]] > Radiosity Normal Map
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[[Category:Texturing]] [[Category:TextureTypes]] [[Category:Bump map]] [[Category:Light map]]

Latest revision as of 12:14, 24 November 2018

Lighting can be baked as a set of three light maps, storing the lighting vectors instead of just the brightness/color. This allows the surface normal maps to receive directional lighting so the bumps/recesses are lit more accurately by the baked lighting information.

Valve used this method extensively in Half-Life 2, which they called "Radiosity Normal Mapping" in their GDC 2004 paper Half-Life®2 / Valve Source™ Shading.

Three light maps are used for radiosity normal mapping. Here they're shown projected on geometry. Image by Valve Software.

A further optimization of this technique was used by Insomniac Games for their game Resistance: Fall of Man. The directions of the light rays were combined into a single RGB bitmap, using a kind of normal map, where each color channel was used to store one of the three directional components.

All three RGB channels are used to store the light vectors, so the light maps could not also store the colors of the lights. Apparently they used vertex color to store the light colors.

A directional light map used in Resistance: Fall of Man, from the article Creating the Lighting for Resistance: Fall of Man. Image by Eric Gooch.

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