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specular_lys [2017/05/15 00:38] adavies |
specular_lys [2017/05/15 21:55] adavies [Reflected Beam] |
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| + | ==== Image Based Lighting Sample Shader ==== | ||
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| + | In the following we describe how to use cube maps generated with Lys in a shader for image based lighting. We also provide a free, complete IBL sample shader & associated source files. | ||
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| + | Please see the [[ibl_sample_shader_lys|Image Based Lighting Sample Shader]] page for more details. | ||
| ==== Computing MIP Levels From Specular Power/Roughness ==== | ==== Computing MIP Levels From Specular Power/Roughness ==== | ||
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| Note that our implementation of BurleyToMip() below differs from the more typical form as cube maps convolved in Lys are based on RdotL and not NdotH. You can find a more detailed description in [[specular_lys#pre-convolved_cube_maps_vs_path_tracers|Pre-convolved Cube Maps vs Path Tracers]]. | Note that our implementation of BurleyToMip() below differs from the more typical form as cube maps convolved in Lys are based on RdotL and not NdotH. You can find a more detailed description in [[specular_lys#pre-convolved_cube_maps_vs_path_tracers|Pre-convolved Cube Maps vs Path Tracers]]. | ||
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| + | Despite the difference in distribution of MIPs the lit specular response resulting from the generated “roughness texture” will be identical to other PBR based game engines and tools. | ||
| <code glsl>float BurleyToMip(float fPerceptualRoughness, int nMips, float NdotR) | <code glsl>float BurleyToMip(float fPerceptualRoughness, int nMips, float NdotR) | ||
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| ==== Reflected Beam ==== | ==== Reflected Beam ==== | ||
| - | [{{https://s3.amazonaws.com/docs.knaldtech.com/docuwiki/reflected_beam_new.png?nolink&1075 |The view direction v reflected by dH will result in dR. Given the existing symmetry the central direction r of dR will result in dV when reflected by dH.}}] | + | [{{https://s3.amazonaws.com/docs.knaldtech.com/docuwiki/reflected_beam_new.png?nolink&1075 |The view direction v reflected by dH will result in dR. Given the existing symmetry the central direction r of dR will result in dV when reflected by dH.}}]\\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ |
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| As an approximation we can correlate size of solid angle with "blur strength"and replace ''h_dot_r'' with ''n_dot_r''. So ultimately what we do is adjust our specular power in the following way: | As an approximation we can correlate size of solid angle with "blur strength"and replace ''h_dot_r'' with ''n_dot_r''. So ultimately what we do is adjust our specular power in the following way: | ||
specular_lys.txt · Last modified: 2017/05/23 03:49 (external edit)
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