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Improve DDGI cascade transitions to be smoother

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This commit is contained in:
Wojtek Figat
2024-06-18 13:22:10 +02:00
parent 611961cefe
commit 2c4de9878e
2 changed files with 14 additions and 5 deletions
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17
Source/Shaders/GI/DDGI.hlsl
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@@ -18,6 +18,7 @@
#define DDGI_PROBE_STATE_ACTIVE 2
#define DDGI_PROBE_RESOLUTION_IRRADIANCE 6 // Resolution (in texels) for probe irradiance data (excluding 1px padding on each side)
#define DDGI_PROBE_RESOLUTION_DISTANCE 14 // Resolution (in texels) for probe distance data (excluding 1px padding on each side)
#define DDGI_CASCADE_BLEND_SIZE 2.5f // Distance in probes over which cascades blending happens
#define DDGI_SRGB_BLENDING 1 // Enables blending in sRGB color space, otherwise irradiance blending is done in linear space
// DDGI data for a constant buffer
@@ -143,13 +144,21 @@ float3 SampleDDGIIrradiance(DDGIData data, Texture2D<snorm float4> probesData, T
float3 viewDir = normalize(data.ViewPos - worldPosition);
for (; cascadeIndex < data.CascadesCount; cascadeIndex++)
{
// Get cascade data
probesSpacing = data.ProbesOriginAndSpacing[cascadeIndex].w;
probesOrigin = data.ProbesScrollOffsets[cascadeIndex].xyz * probesSpacing + data.ProbesOriginAndSpacing[cascadeIndex].xyz;
probesExtent = (data.ProbesCounts - 1) * (probesSpacing * 0.5f);
biasedWorldPosition = worldPosition + (worldNormal * 0.2f + viewDir * 0.8f) * (0.75f * probesSpacing * bias);
float fadeDistance = probesSpacing * 0.5f;
float cascadeWeight = saturate(Min3(probesExtent - abs(biasedWorldPosition - probesOrigin)) / fadeDistance);
if (cascadeWeight > dither) // Use dither to make transition smoother
// Bias the world-space position to reduce artifacts
float3 surfaceBias = (worldNormal * 0.2f + viewDir * 0.8f) * (0.75f * probesSpacing * bias);
biasedWorldPosition = worldPosition + surfaceBias;
// Calculate cascade blending weight (use input bias to smooth transition)
float cascadeBlendSmooth = frac(max(distance(data.ViewPos, worldPosition) - probesExtent, 0) / probesSpacing) * 0.1f;
float3 cascadeBlendPoint = worldPosition - probesOrigin - cascadeBlendSmooth * probesSpacing;
float fadeDistance = probesSpacing * DDGI_CASCADE_BLEND_SIZE;
float cascadeWeight = saturate(Min3(probesExtent - abs(cascadeBlendPoint)) / fadeDistance);
if (cascadeWeight > dither)
break;
}
if (cascadeIndex == data.CascadesCount)

2
Source/Shaders/GI/DDGI.shader
View File

@@ -102,7 +102,7 @@ void CS_Classify(uint3 DispatchThreadId : SV_DispatchThreadID)
float prevProbesSpacing = DDGI.ProbesOriginAndSpacing[prevCascade].w;
float3 prevProbesOrigin = DDGI.ProbesScrollOffsets[prevCascade].xyz * prevProbesSpacing + DDGI.ProbesOriginAndSpacing[prevCascade].xyz;
float3 prevProbesExtent = (DDGI.ProbesCounts - 1) * (prevProbesSpacing * 0.5f);
prevProbesExtent -= probesSpacing; // Apply safe margin to allow probes on cascade edges
prevProbesExtent -= probesSpacing * ceil(DDGI_CASCADE_BLEND_SIZE); // Apply safe margin to allow probes on cascade edges
float prevCascadeWeight = Min3(prevProbesExtent - abs(probeBasePosition - prevProbesOrigin));
if (prevCascadeWeight > 0.1f)
{