125 lines
2.9 KiB
Plaintext
125 lines
2.9 KiB
Plaintext
const static float3 vertices[] = {
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// Right
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float3( 1, -1, 1),
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float3( 1, 1, 1),
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float3( 1, -1, -1),
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float3( 1, -1, -1),
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float3( 1, 1, 1),
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float3( 1, 1, -1),
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// Left
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float3(-1, -1, -1),
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float3(-1, 1, -1),
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float3(-1, -1, 1),
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float3(-1, -1, 1),
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float3(-1, 1, -1),
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float3(-1, 1, 1),
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// Bottom
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float3(-1, 1, 1),
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float3(-1, 1, -1),
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float3( 1, 1, 1),
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float3( 1, 1, 1),
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float3(-1, 1, -1),
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float3( 1, 1, -1),
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// Top
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float3(-1, -1, -1),
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float3(-1, -1, 1),
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float3( 1, -1, -1),
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float3( 1, -1, -1),
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float3(-1, -1, 1),
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float3( 1, -1, 1),
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// Back
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float3(-1, -1, 1),
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float3(-1, 1, 1),
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float3( 1, -1, 1),
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float3( 1, -1, 1),
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float3(-1, 1, 1),
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float3( 1, 1, 1),
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// Front
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float3( 1, -1, -1),
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float3( 1, 1, -1),
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float3(-1, -1, -1),
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float3(-1, -1, -1),
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float3( 1, 1, -1),
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float3(-1, 1, -1),
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};
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struct ViewParams
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{
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float4x4 view[6];
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float4x4 projection;
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Texture2D equirectangularMap;
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SamplerState sampler;
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TextureCube cubeMap;
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};
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ParameterBlock<ViewParams> pViewParams;
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struct VertexOutput
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{
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float4 svPos : SV_Position;
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float3 localPos : LOCALPOS;
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};
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[shader("vertex")]
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VertexOutput vertMain(uint vertexIndex : SV_VertexID, uint viewIndex : SV_ViewID)
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{
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VertexOutput output;
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output.localPos = vertices[vertexIndex];
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output.svPos = mul(pViewParams.projection, mul(pViewParams.view[viewIndex], float4(output.localPos, 1)));
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return output;
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}
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const static float2 invAtan = float2(0.1591, 0.3183);
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float2 sampleSphericalMap(float3 v)
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{
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float2 uv = float2(atan2(v.z, v.x), asin(v.y));
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uv *= invAtan;
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uv += 0.5;
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return uv;
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}
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[shader("pixel")]
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float4 computeCubemap(float3 localPos : LOCALPOS) : SV_Target
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{
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float2 uv = sampleSphericalMap(normalize(localPos));
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float3 color = pViewParams.equirectangularMap.Sample(pViewParams.sampler, uv).rgb;
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return float4(color, 1);
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}
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static const float PI = 3.14159265359;
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[shader("pixel")]
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float4 convolveCubemap(float3 localPos : LOCALPOS) : SV_Target
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{
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float3 normal = normalize(localPos);
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float3 irradiance = float3(0);
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float3 up = float3(0, 1, 0);
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float3 right = normalize(cross(up, normal));
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up = normalize(cross(normal, right));
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float sampleDelta = 0.025;
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float nrSamples = 0.0f;
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for(float phi = 0; phi < 2.0 * PI; phi += sampleDelta)
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{
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for(float theta = 0; theta < 0.5 * PI; theta += sampleDelta)
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{
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float3 tangentSample = float3(sin(theta) * cos(phi), sin(theta) * sin(phi), cos(theta));
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float3 sampleVec = tangentSample.x * right + tangentSample.y * up + tangentSample.z * normal;
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irradiance += pViewParams.cubeMap.Sample(pViewParams.sampler, sampleVec).rgb * cos(theta) * sin(theta);
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nrSamples++;
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}
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}
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irradiance = PI * irradiance * (1.0 / nrSamples);
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return float4(irradiance, 1);
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} |