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Bring back Optimized PCF sampling for shadow maps

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61323f8526
This commit is contained in:
Wojtek Figat
2024-04-09 17:55:29 +02:00
parent ff7c986fb1
commit e7bef5e880
1 changed files with 126 additions and 6 deletions
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132
Source/Shaders/ShadowsSampling.hlsl
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@@ -54,9 +54,7 @@ float2 GetLightShadowAtlasUV(ShadowData shadow, ShadowTileData shadowTile, float
float SampleShadowMap(Texture2D<float> shadowMap, float2 shadowMapUV, float sceneDepth)
{
// Single hardware sample with filtering
float result = SAMPLE_SHADOW_MAP(shadowMap, shadowMapUV, sceneDepth);
#if SHADOWS_QUALITY == 1
result += SAMPLE_SHADOW_MAP_OFFSET(shadowMap, shadowMapUV, int2(-1, 0), sceneDepth);
result += SAMPLE_SHADOW_MAP_OFFSET(shadowMap, shadowMapUV, int2(0, -1), sceneDepth);
@@ -64,7 +62,6 @@ float SampleShadowMap(Texture2D<float> shadowMap, float2 shadowMapUV, float scen
result += SAMPLE_SHADOW_MAP_OFFSET(shadowMap, shadowMapUV, int2(1, 0), sceneDepth);
result = result * (1.0f / 4.0);
#elif SHADOWS_QUALITY == 2 || SHADOWS_QUALITY == 3
// TODO: implement Percentage-Closer Soft Shadows (PCSS) for Ultra quality
result += SAMPLE_SHADOW_MAP_OFFSET(shadowMap, shadowMapUV, int2(-1, -1), sceneDepth);
result += SAMPLE_SHADOW_MAP_OFFSET(shadowMap, shadowMapUV, int2(-1, 0), sceneDepth);
result += SAMPLE_SHADOW_MAP_OFFSET(shadowMap, shadowMapUV, int2(-1, 1), sceneDepth);
@@ -75,10 +72,133 @@ float SampleShadowMap(Texture2D<float> shadowMap, float2 shadowMapUV, float scen
result += SAMPLE_SHADOW_MAP_OFFSET(shadowMap, shadowMapUV, int2(1, 1), sceneDepth);
result = result * (1.0f / 9.0);
#endif
return result;
}
float SampleShadowMapOptimizedPCFHelper(Texture2D<float> shadowMap, float2 baseUV, float u, float v, float2 shadowMapSizeInv, float sceneDepth)
{
float2 uv = baseUV + float2(u, v) * shadowMapSizeInv;
return SAMPLE_SHADOW_MAP(shadowMap, uv, sceneDepth);
}
// [Shadow map sampling method used in The Witness, https://github.com/TheRealMJP/Shadows]
float SampleShadowMapOptimizedPCF(Texture2D<float> shadowMap, float2 shadowMapUV, float sceneDepth)
{
#if SHADOWS_QUALITY != 0
float2 shadowMapSize;
shadowMap.GetDimensions(shadowMapSize.x, shadowMapSize.y);
float2 uv = shadowMapUV.xy * shadowMapSize; // 1 unit - 1 texel
float2 shadowMapSizeInv = 1.0f / shadowMapSize;
float2 baseUV;
baseUV.x = floor(uv.x + 0.5);
baseUV.y = floor(uv.y + 0.5);
float s = (uv.x + 0.5 - baseUV.x);
float t = (uv.y + 0.5 - baseUV.y);
baseUV -= float2(0.5, 0.5);
baseUV *= shadowMapSizeInv;
float sum = 0;
#endif
#if SHADOWS_QUALITY == 0
return SAMPLE_SHADOW_MAP(shadowMap, shadowMapUV, sceneDepth);
#elif SHADOWS_QUALITY == 1
float uw0 = (3 - 2 * s);
float uw1 = (1 + 2 * s);
float u0 = (2 - s) / uw0 - 1;
float u1 = s / uw1 + 1;
float vw0 = (3 - 2 * t);
float vw1 = (1 + 2 * t);
float v0 = (2 - t) / vw0 - 1;
float v1 = t / vw1 + 1;
sum += uw0 * vw0 * SampleShadowMapOptimizedPCFHelper(shadowMap, baseUV, u0, v0, shadowMapSizeInv, sceneDepth);
sum += uw1 * vw0 * SampleShadowMapOptimizedPCFHelper(shadowMap, baseUV, u1, v0, shadowMapSizeInv, sceneDepth);
sum += uw0 * vw1 * SampleShadowMapOptimizedPCFHelper(shadowMap, baseUV, u0, v1, shadowMapSizeInv, sceneDepth);
sum += uw1 * vw1 * SampleShadowMapOptimizedPCFHelper(shadowMap, baseUV, u1, v1, shadowMapSizeInv, sceneDepth);
return sum * 1.0f / 16;
#elif SHADOWS_QUALITY == 2
float uw0 = (4 - 3 * s);
float uw1 = 7;
float uw2 = (1 + 3 * s);
float u0 = (3 - 2 * s) / uw0 - 2;
float u1 = (3 + s) / uw1;
float u2 = s / uw2 + 2;
float vw0 = (4 - 3 * t);
float vw1 = 7;
float vw2 = (1 + 3 * t);
float v0 = (3 - 2 * t) / vw0 - 2;
float v1 = (3 + t) / vw1;
float v2 = t / vw2 + 2;
sum += uw0 * vw0 * SampleShadowMapOptimizedPCFHelper(shadowMap, baseUV, u0, v0, shadowMapSizeInv, sceneDepth);
sum += uw1 * vw0 * SampleShadowMapOptimizedPCFHelper(shadowMap, baseUV, u1, v0, shadowMapSizeInv, sceneDepth);
sum += uw2 * vw0 * SampleShadowMapOptimizedPCFHelper(shadowMap, baseUV, u2, v0, shadowMapSizeInv, sceneDepth);
sum += uw0 * vw1 * SampleShadowMapOptimizedPCFHelper(shadowMap, baseUV, u0, v1, shadowMapSizeInv, sceneDepth);
sum += uw1 * vw1 * SampleShadowMapOptimizedPCFHelper(shadowMap, baseUV, u1, v1, shadowMapSizeInv, sceneDepth);
sum += uw2 * vw1 * SampleShadowMapOptimizedPCFHelper(shadowMap, baseUV, u2, v1, shadowMapSizeInv, sceneDepth);
sum += uw0 * vw2 * SampleShadowMapOptimizedPCFHelper(shadowMap, baseUV, u0, v2, shadowMapSizeInv, sceneDepth);
sum += uw1 * vw2 * SampleShadowMapOptimizedPCFHelper(shadowMap, baseUV, u1, v2, shadowMapSizeInv, sceneDepth);
sum += uw2 * vw2 * SampleShadowMapOptimizedPCFHelper(shadowMap, baseUV, u2, v2, shadowMapSizeInv, sceneDepth);
return sum * 1.0f / 144;
#elif SHADOWS_QUALITY == 3
float uw0 = (5 * s - 6);
float uw1 = (11 * s - 28);
float uw2 = -(11 * s + 17);
float uw3 = -(5 * s + 1);
float u0 = (4 * s - 5) / uw0 - 3;
float u1 = (4 * s - 16) / uw1 - 1;
float u2 = -(7 * s + 5) / uw2 + 1;
float u3 = -s / uw3 + 3;
float vw0 = (5 * t - 6);
float vw1 = (11 * t - 28);
float vw2 = -(11 * t + 17);
float vw3 = -(5 * t + 1);
float v0 = (4 * t - 5) / vw0 - 3;
float v1 = (4 * t - 16) / vw1 - 1;
float v2 = -(7 * t + 5) / vw2 + 1;
float v3 = -t / vw3 + 3;
sum += uw0 * vw0 * SampleShadowMapOptimizedPCFHelper(shadowMap, baseUV, u0, v0, shadowMapSizeInv, sceneDepth);
sum += uw1 * vw0 * SampleShadowMapOptimizedPCFHelper(shadowMap, baseUV, u1, v0, shadowMapSizeInv, sceneDepth);
sum += uw2 * vw0 * SampleShadowMapOptimizedPCFHelper(shadowMap, baseUV, u2, v0, shadowMapSizeInv, sceneDepth);
sum += uw3 * vw0 * SampleShadowMapOptimizedPCFHelper(shadowMap, baseUV, u3, v0, shadowMapSizeInv, sceneDepth);
sum += uw0 * vw1 * SampleShadowMapOptimizedPCFHelper(shadowMap, baseUV, u0, v1, shadowMapSizeInv, sceneDepth);
sum += uw1 * vw1 * SampleShadowMapOptimizedPCFHelper(shadowMap, baseUV, u1, v1, shadowMapSizeInv, sceneDepth);
sum += uw2 * vw1 * SampleShadowMapOptimizedPCFHelper(shadowMap, baseUV, u2, v1, shadowMapSizeInv, sceneDepth);
sum += uw3 * vw1 * SampleShadowMapOptimizedPCFHelper(shadowMap, baseUV, u3, v1, shadowMapSizeInv, sceneDepth);
sum += uw0 * vw2 * SampleShadowMapOptimizedPCFHelper(shadowMap, baseUV, u0, v2, shadowMapSizeInv, sceneDepth);
sum += uw1 * vw2 * SampleShadowMapOptimizedPCFHelper(shadowMap, baseUV, u1, v2, shadowMapSizeInv, sceneDepth);
sum += uw2 * vw2 * SampleShadowMapOptimizedPCFHelper(shadowMap, baseUV, u2, v2, shadowMapSizeInv, sceneDepth);
sum += uw3 * vw2 * SampleShadowMapOptimizedPCFHelper(shadowMap, baseUV, u3, v2, shadowMapSizeInv, sceneDepth);
sum += uw0 * vw3 * SampleShadowMapOptimizedPCFHelper(shadowMap, baseUV, u0, v3, shadowMapSizeInv, sceneDepth);
sum += uw1 * vw3 * SampleShadowMapOptimizedPCFHelper(shadowMap, baseUV, u1, v3, shadowMapSizeInv, sceneDepth);
sum += uw2 * vw3 * SampleShadowMapOptimizedPCFHelper(shadowMap, baseUV, u2, v3, shadowMapSizeInv, sceneDepth);
sum += uw3 * vw3 * SampleShadowMapOptimizedPCFHelper(shadowMap, baseUV, u3, v3, shadowMapSizeInv, sceneDepth);
return sum * (1.0f / 2704);
#else
return 0.0f;
#endif
}
// Samples the shadow for the given directional light on the material surface (supports subsurface shadowing)
ShadowSample SampleDirectionalLightShadow(LightData light, Buffer<float4> shadowsBuffer, Texture2D<float> shadowMap, GBufferSample gBuffer, float dither = 0.0f)
{
@@ -143,7 +263,7 @@ ShadowSample SampleDirectionalLightShadow(LightData light, Buffer<float4> shadow
float2 shadowMapUV = GetLightShadowAtlasUV(shadow, shadowTile, samplePosition, shadowPosition);
// Sample shadow map
result.SurfaceShadow = SampleShadowMap(shadowMap, shadowMapUV, shadowPosition.z);
result.SurfaceShadow = SampleShadowMapOptimizedPCF(shadowMap, shadowMapUV, shadowPosition.z);
// Increase the sharpness for higher cascades to match the filter radius
//const float SharpnessScale[MaxNumCascades] = { 1.0f, 1.5f, 3.0f, 3.5f };
@@ -207,7 +327,7 @@ ShadowSample SampleLocalLightShadow(LightData light, Buffer<float4> shadowsBuffe
float2 shadowMapUV = GetLightShadowAtlasUV(shadow, shadowTile, samplePosition, shadowPosition);
// Sample shadow map
result.SurfaceShadow = SampleShadowMap(shadowMap, shadowMapUV, shadowPosition.z);
result.SurfaceShadow = SampleShadowMapOptimizedPCF(shadowMap, shadowMapUV, shadowPosition.z);
#if defined(USE_GBUFFER_CUSTOM_DATA)
// Subsurface shadowing