Difference between revisions of "Diffusely convolved cube map"
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| − | = | + | = Introduction = |
| + | A ''diffusely convolved cube map'' is simply a blurred-down version of a regular [[CubeMap|cube map]]. When a [[:Category:Shaders|shader]] adds the cube map to the model's diffuse map the result is similar to global-illumination, except it is extremely efficient performance-wise. | ||
| + | [[image:whatif_nmech_env-alone.jpg|frame|left|The convolved cube map on a normalmapped model. <BR> Image by [http://www.linkedin.com/in/ericchadwick Eric Chadwick] and [http://www.whatif-productions.com/ Whatif Productions LLC].]]<br clear="all"/> | ||
| + | [[image:whatif_nmech_env+lgt.jpg|frame|left|The convolved cube map on a normalmapped model. <BR> Image by [http://www.linkedin.com/in/ericchadwick Eric Chadwick] and [http://www.whatif-productions.com/ Whatif Productions LLC].]]<br clear="all"/> | ||
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| − | + | = AMD Cubemapgen = | |
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| − | + | [http://code.google.com/p/cubemapgen/ Cubemapgen] is great for filtering down cube maps. Sébastien Lagarde made [http://seblagarde.wordpress.com/2012/06/10/amd-cubemapgen-for-physically-based-rendering/ a physically based rendering mod] | |
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| − | [ | + | [[image:Cubemapgen_Tips.jpg|frame|left|Some tips for filtering cubemaps in Cubemapgen. <BR> Image by [http://www.linkedin.com/in/ericchadwick Eric Chadwick].]]<br clear="all"/> |
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| − | + | == Cubemapgen Cube Faces == | |
{| border="1" cellpadding="2" cellspacing="0" | {| border="1" cellpadding="2" cellspacing="0" | ||
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| − | + | == Cubemapgen Custom Meshes == | |
You can load your own geometry in Cubemapgen using the ''Load Object'' button, really helps to see what settings are working well. | You can load your own geometry in Cubemapgen using the ''Load Object'' button, really helps to see what settings are working well. | ||
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* [http://www.ericchadwick.com/examples/files/2005.10.14_DDSformat_and_NormalMapFilter.zip NVIDIA Photoshop Plugins 8.21 beta] | * [http://www.ericchadwick.com/examples/files/2005.10.14_DDSformat_and_NormalMapFilter.zip NVIDIA Photoshop Plugins 8.21 beta] | ||
| − | + | = Links = | |
* [http://zellersamuel.wordpress.com/2010/03/06/cubemaps/ Cubemaps how-to and why] by Zeller Samuel<<BR>>A great introduction to cubemaps. | * [http://zellersamuel.wordpress.com/2010/03/06/cubemaps/ Cubemaps how-to and why] by Zeller Samuel<<BR>>A great introduction to cubemaps. | ||
Revision as of 03:32, 24 November 2014
Contents
Introduction
A diffusely convolved cube map is simply a blurred-down version of a regular cube map. When a shader adds the cube map to the model's diffuse map the result is similar to global-illumination, except it is extremely efficient performance-wise.
AMD Cubemapgen
Cubemapgen is great for filtering down cube maps. Sébastien Lagarde made a physically based rendering mod
Some tips for filtering cubemaps in Cubemapgen.
Image by Eric Chadwick.
Image by Eric Chadwick.
Cubemapgen Cube Faces
| Cubemapgen | 3ds Max | Maya | CryENGINE 3 | Unity |
| +X | _RT | Left -X | ||
| -X | _LF | Right +X | ||
| +Y | _UP | Top +Y | ||
| -Y | _DN | Bottom -Y | ||
| +Z | _BK | Front (+Z) | ||
| -Z | _FR | Back (-Z) |
| Cubemapgen | 3ds Max | Maya | CryENGINE 3 | Unity |
| c00 | Left -X (180°) | |||
| c01 | Right +X (180°) | |||
| c02 | Top +Y | |||
| c03 | Bottom -Y | |||
| c04 | Back -Z (180°) | |||
| c05 | Front +Z (180°) |
Cubemapgen Custom Meshes
You can load your own geometry in Cubemapgen using the Load Object button, really helps to see what settings are working well.
You can also load a bitmap for the model using the Load Basemap button. There's a bug right now that causes your Basemap to be mirrored vertically... to fix it pre-flip the bitmap yourself before loading it in Cubemapgen. An Ambient Occlusion Map map makes a great Basemap, or you can use your DiffuseMap.
| File:DiffuselyConvolvedCubeMap$tmp.320.cubemapgen nmech cube.jpg | File:DiffuselyConvolvedCubeMap$tmp.320.cubemapgen nmech basemap+cube.jpg |
| Custom geometry in Cubemapgen. Actual size< >image byEric Chadwick |
Basemap is modulated (multiplied) with the cube map. Actual size< >image byEric Chadwick |
Editing Cubemaps in Photoshop
If your cube map is in DDS cube format, you'll need the NVIDIA DDS plugin to load and save in Photoshop.
Unfortunately NVIDIA introduced some bugs when they updated the plugin, so now DDS cubes don't load mips properly. If you need to load cube maps with mips, here's an old version that does it right.
Links
- Cubemaps how-to and why by Zeller Samuel<
>A great introduction to cubemaps. - Cubemaps Tutorial by CGTextures.com<
>Tutorial using Nvidia's Photoshop plugin, AMD's CubeMapGen, and Photoshop to convert cubemaps to various layouts. - Cube map<
>Wiki page describing cubemaps.
