52 lines
1.6 KiB
HLSL
52 lines
1.6 KiB
HLSL
#include "ibl_common.hlsli"
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struct Block
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{
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uint SkyboxHandle;
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uint OutputTextureHandle;
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int CubeSide;
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};
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[[vk::push_constant]]
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Block pcb;
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/*
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| Axis | Layer | Up |
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|:----:|:-----:|:--:|
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| +x | 0 | -y |
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| -x | 1 | -y |
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| +y | 2 | +z |
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| -y | 3 | -z |
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| -z | 4 | -y |
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| +z | 5 | -y |
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*/
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[numthreads(16, 16, 1)]
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void main(uint3 GlobalInvocationID : SV_DispatchThreadID)
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{
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float3 Forward, Up, Right;
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Forward = GetCubeDir(GlobalInvocationID, pcb.CubeSide);
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Up = abs(Forward.y) < 1.0f ? float3(0.0f, 1.0f, 0.0f) : float3(1.0f, 0.0f, 0.0f); // 0.01f offset to
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Right = normalize(cross(Up, Forward));
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Up = normalize(cross(Forward, Right));
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float3 Irradiance = 0.0f.xxx;
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float3 IrrDirr = 0.0f.xxx;
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float SampleStep = 0.005f;
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float SampleCount = 0.0f;
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for (float Azimuth = 0.0f; Azimuth < TAU; Azimuth += SampleStep)
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{
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for (float Zenith = 0.0f; Zenith < HALF_PI; Zenith += SampleStep)
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{
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float3 DirectionTanSpace = float3(sin(Zenith) * cos(Azimuth), sin(Zenith) * sin(Azimuth), cos(Zenith));
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float3 DirectionWorld = DirectionTanSpace.x * Right + DirectionTanSpace.y * Up + DirectionTanSpace.z * Forward;
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Irradiance += TextureCubes[pcb.SkyboxHandle].SampleLevel(ImmutableSamplers[pcb.SkyboxHandle], DirectionWorld, 0).xyz * (cos(Zenith) * sin(Zenith));
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SampleCount++;
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}
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}
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StorageTextureArrays[pcb.OutputTextureHandle][GlobalInvocationID.xyz] = PI * float4(Irradiance * (1.0f / SampleCount), 1.0f);
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} |