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Add option for smooth DDGI cascades blending

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This commit is contained in:
Wojciech Figat
2024-07-18 23:51:03 +02:00
parent 03898a064a
commit 3aa8e67551
7 changed files with 115 additions and 57 deletions
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Source/Engine/Core/Config/GraphicsSettings.h
+6
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@@ -116,6 +116,12 @@ public:
API_FIELD(Attributes="EditorOrder(2120), Limit(50, 1000), EditorDisplay(\"Global Illumination\")")
float GIProbesSpacing = 100;
/// <summary>
/// Enables cascades splits blending for Global Illumination.
/// </summary>
API_FIELD(Attributes="EditorOrder(2125), DefaultValue(false), EditorDisplay(\"Global Illumination\", \"GI Cascades Blending\")")
bool GICascadesBlending = false;
/// <summary>
/// The Global Surface Atlas resolution. Adjust it if atlas `flickers` due to overflow (eg. to 4096).
/// </summary>
Source/Engine/Graphics/Graphics.cpp
+3 -1
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@@ -21,8 +21,9 @@ Quality Graphics::ShadowMapsQuality = Quality::Medium;
bool Graphics::AllowCSMBlending = false;
Quality Graphics::GlobalSDFQuality = Quality::High;
Quality Graphics::GIQuality = Quality::High;
bool Graphics::GICascadesBlending = false;
PostProcessSettings Graphics::PostProcessSettings;
bool Graphics::SpreadWorkload = true;
bool Graphics::SpreadWorkload = false;
#if GRAPHICS_API_NULL
extern GPUDevice* CreateGPUDeviceNull();
@@ -69,6 +70,7 @@ void GraphicsSettings::Apply()
Graphics::ShadowMapsQuality = ShadowMapsQuality;
Graphics::GlobalSDFQuality = GlobalSDFQuality;
Graphics::GIQuality = GIQuality;
Graphics::GICascadesBlending = GICascadesBlending;
Graphics::PostProcessSettings = ::PostProcessSettings();
Graphics::PostProcessSettings.BlendWith(PostProcessSettings, 1.0f);
#if !USE_EDITOR // OptionsModule handles fallback fonts in Editor
Source/Engine/Graphics/Graphics.h
+5
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@@ -64,6 +64,11 @@ public:
/// </summary>
API_FIELD() static Quality GIQuality;
/// <summary>
/// Enables cascades splits blending for Global Illumination.
/// </summary>
API_FIELD() static bool GICascadesBlending;
/// <summary>
/// The default Post Process settings. Can be overriden by PostFxVolume on a level locally, per camera or for a whole map.
/// </summary>
Source/Engine/Renderer/GI/DynamicDiffuseGlobalIllumination.cpp
+13 -7
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@@ -221,12 +221,16 @@ bool DynamicDiffuseGlobalIlluminationPass::setupResources()
_csUpdateProbesDistance = shader->GetCS("CS_UpdateProbes", 1);
auto device = GPUDevice::Instance;
auto psDesc = GPUPipelineState::Description::DefaultFullscreenTriangle;
if (!_psIndirectLighting)
if (!_psIndirectLighting[0])
{
_psIndirectLighting = device->CreatePipelineState();
_psIndirectLighting[0] = device->CreatePipelineState();
_psIndirectLighting[1] = device->CreatePipelineState();
psDesc.PS = shader->GetPS("PS_IndirectLighting");
psDesc.BlendMode = BlendingMode::Add;
if (_psIndirectLighting->Init(psDesc))
if (_psIndirectLighting[0]->Init(psDesc))
return true;
psDesc.PS = shader->GetPS("PS_IndirectLighting", 1);
if (_psIndirectLighting[1]->Init(psDesc))
return true;
}
@@ -246,7 +250,8 @@ void DynamicDiffuseGlobalIlluminationPass::OnShaderReloading(Asset* obj)
_csTraceRays[3] = nullptr;
_csUpdateProbesIrradiance = nullptr;
_csUpdateProbesDistance = nullptr;
SAFE_DELETE_GPU_RESOURCE(_psIndirectLighting);
SAFE_DELETE_GPU_RESOURCE(_psIndirectLighting[0]);
SAFE_DELETE_GPU_RESOURCE(_psIndirectLighting[1]);
invalidateResources();
}
@@ -260,7 +265,8 @@ void DynamicDiffuseGlobalIlluminationPass::Dispose()
_cb0 = nullptr;
_cb1 = nullptr;
_shader = nullptr;
SAFE_DELETE_GPU_RESOURCE(_psIndirectLighting);
SAFE_DELETE_GPU_RESOURCE(_psIndirectLighting[0]);
SAFE_DELETE_GPU_RESOURCE(_psIndirectLighting[1]);
#if USE_EDITOR
_debugModel = nullptr;
_debugMaterial = nullptr;
@@ -534,7 +540,7 @@ bool DynamicDiffuseGlobalIlluminationPass::RenderInner(RenderContext& renderCont
// Update probes
{
PROFILE_GPU_CPU_NAMED("Probes Update");
uint32 threadGroupsX, threadGroupsY;
uint32 threadGroupsX;
#if DDGI_DEBUG_STATS
uint32 zero[4] = {};
context->ClearUA(ddgiData.StatsWrite, zero);
@@ -732,7 +738,7 @@ bool DynamicDiffuseGlobalIlluminationPass::Render(RenderContext& renderContext,
context->BindSR(6, ddgiData.Result.ProbesIrradiance);
context->SetViewportAndScissors(renderContext.View.ScreenSize.X, renderContext.View.ScreenSize.Y);
context->SetRenderTarget(lightBuffer);
context->SetState(_psIndirectLighting);
context->SetState(_psIndirectLighting[Graphics::GICascadesBlending ? 1 : 0]);
context->DrawFullscreenTriangle();
}
Source/Engine/Renderer/GI/DynamicDiffuseGlobalIllumination.h
+1 -1
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@@ -47,7 +47,7 @@ private:
GPUShaderProgramCS* _csTraceRays[4];
GPUShaderProgramCS* _csUpdateProbesIrradiance;
GPUShaderProgramCS* _csUpdateProbesDistance;
GPUPipelineState* _psIndirectLighting;
GPUPipelineState* _psIndirectLighting[2] = {};
#if USE_EDITOR
AssetReference<Model> _debugModel;
AssetReference<MaterialBase> _debugMaterial;
Source/Shaders/GI/DDGI.hlsl
+85 -48
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@@ -21,6 +21,9 @@
#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
#ifndef DDGI_CASCADE_BLEND_SMOOTH
#define DDGI_CASCADE_BLEND_SMOOTH 0 // Enables smooth cascade blending, otherwise dithering will be used
#endif
#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
@@ -154,37 +157,8 @@ float2 GetDDGIProbeUV(DDGIData data, uint cascadeIndex, uint probeIndex, float2
return uv;
}
// Samples DDGI probes volume at the given world-space position and returns the irradiance.
// bias - scales the bias vector to the initial sample point to reduce self-shading artifacts
// dither - randomized per-pixel value in range 0-1, used to smooth dithering for cascades blending
float3 SampleDDGIIrradiance(DDGIData data, Texture2D<snorm float4> probesData, Texture2D<float4> probesDistance, Texture2D<float4> probesIrradiance, float3 worldPosition, float3 worldNormal, float bias = 0.2f, float dither = 0.0f)
float3 SampleDDGIIrradianceCascade(DDGIData data, Texture2D<snorm float4> probesData, Texture2D<float4> probesDistance, Texture2D<float4> probesIrradiance, float3 worldPosition, float3 worldNormal, uint cascadeIndex, float3 probesOrigin, float3 probesExtent, float probesSpacing, float3 biasedWorldPosition)
{
// Select the highest cascade that contains the sample location
uint cascadeIndex = 0;
float probesSpacing = 0;
float3 probesOrigin = (float3)0, probesExtent = (float3)0, biasedWorldPosition = (float3)0;
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);
// 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.x, 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)
return data.FallbackIrradiance;
uint3 probeCoordsEnd = data.ProbesCounts - uint3(1, 1, 1);
uint3 baseProbeCoords = clamp(uint3((worldPosition - probesOrigin + probesExtent) / probesSpacing), uint3(0, 0, 0), probeCoordsEnd);
@@ -208,25 +182,26 @@ float3 SampleDDGIIrradiance(DDGIData data, Texture2D<snorm float4> probesData, T
{
// Search nearby probes to find any nearby GI sample
for (int searchDistance = 1; searchDistance < 3 && probeState == DDGI_PROBE_STATE_INACTIVE; searchDistance++)
for (uint searchAxis = 0; searchAxis < 3; searchAxis++)
{
int searchAxisDir = probeCoordsOffset[searchAxis] ? 1 : -1;
int3 searchCoordsOffset = SearchAxisMasks[searchAxis] * searchAxisDir * searchDistance;
uint3 searchCoords = clamp((int3)probeCoords + searchCoordsOffset, int3(0, 0, 0), (int3)probeCoordsEnd);
uint searchIndex = GetDDGIScrollingProbeIndex(data, cascadeIndex, searchCoords);
float4 searchData = LoadDDGIProbeData(data, probesData, cascadeIndex, searchIndex);
uint searchState = DecodeDDGIProbeState(searchData);
if (searchState != DDGI_PROBE_STATE_INACTIVE)
for (uint searchAxis = 0; searchAxis < 3; searchAxis++)
{
// Use nearby probe as a fallback (visibility test might ignore it but with smooth gradient)
probeCoords = searchCoords;
probeIndex = searchIndex;
probeData = searchData;
probeState = searchState;
break;
int searchAxisDir = probeCoordsOffset[searchAxis] ? 1 : -1;
int3 searchCoordsOffset = SearchAxisMasks[searchAxis] * searchAxisDir * searchDistance;
uint3 searchCoords = clamp((int3)probeCoords + searchCoordsOffset, int3(0, 0, 0), (int3)probeCoordsEnd);
uint searchIndex = GetDDGIScrollingProbeIndex(data, cascadeIndex, searchCoords);
float4 searchData = LoadDDGIProbeData(data, probesData, cascadeIndex, searchIndex);
uint searchState = DecodeDDGIProbeState(searchData);
if (searchState != DDGI_PROBE_STATE_INACTIVE)
{
// Use nearby probe as a fallback (visibility test might ignore it but with smooth gradient)
probeCoords = searchCoords;
probeIndex = searchIndex;
probeData = searchData;
probeState = searchState;
break;
}
}
}
if (probeState == DDGI_PROBE_STATE_INACTIVE) continue;
if (probeState == DDGI_PROBE_STATE_INACTIVE)
continue;
}
float3 probeBasePosition = baseProbeWorldPosition + ((probeCoords - baseProbeCoords) * probesSpacing);
float3 probePosition = probeBasePosition + probeData.xyz * probesSpacing; // Probe offset is [-1;1] within probes spacing
@@ -257,7 +232,8 @@ float3 SampleDDGIIrradiance(DDGIData data, Texture2D<snorm float4> probesData, T
// Adjust weight curve to inject a small portion of light
const float minWeightThreshold = 0.2f;
if (weight < minWeightThreshold) weight *= Square(weight) / Square(minWeightThreshold);
if (weight < minWeightThreshold)
weight *= Square(weight) / Square(minWeightThreshold);
// Calculate trilinear weights based on the distance to each probe to smoothly transition between grid of 8 probes
float3 trilinear = lerp(1.0f - biasAlpha, biasAlpha, (float3)probeCoordsOffset);
@@ -301,3 +277,64 @@ float3 SampleDDGIIrradiance(DDGIData data, Texture2D<snorm float4> probesData, T
}
return irradiance.rgb;
}
float3 GetDDGISurfaceBias(float3 viewDir, float probesSpacing, float3 worldNormal, float bias)
{
// Bias the world-space position to reduce artifacts
return (worldNormal * 0.2f + viewDir * 0.8f) * (0.75f * probesSpacing * bias);
}
// Samples DDGI probes volume at the given world-space position and returns the irradiance.
// bias - scales the bias vector to the initial sample point to reduce self-shading artifacts
// dither - randomized per-pixel value in range 0-1, used to smooth dithering for cascades blending
float3 SampleDDGIIrradiance(DDGIData data, Texture2D<snorm float4> probesData, Texture2D<float4> probesDistance, Texture2D<float4> probesIrradiance, float3 worldPosition, float3 worldNormal, float bias = 0.2f, float dither = 0.0f)
{
// Select the highest cascade that contains the sample location
uint cascadeIndex = 0;
float probesSpacing = 0, cascadeWeight = 0;
float3 probesOrigin = (float3)0, probesExtent = (float3)0, biasedWorldPosition = (float3)0;
float3 viewDir = normalize(data.ViewPos - worldPosition);
#if DDGI_CASCADE_BLEND_SMOOTH
dither = 0.0f;
#endif
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 + GetDDGISurfaceBias(viewDir, probesSpacing, worldNormal, bias);
// Calculate cascade blending weight (use input bias to smooth transition)
float cascadeBlendSmooth = frac(max(distance(data.ViewPos, worldPosition) - probesExtent.x, 0) / probesSpacing) * 0.1f;
float3 cascadeBlendPoint = worldPosition - probesOrigin - cascadeBlendSmooth * probesSpacing;
float fadeDistance = probesSpacing * DDGI_CASCADE_BLEND_SIZE;
#if DDGI_CASCADE_BLEND_SMOOTH
fadeDistance *= 2.0f; // Make it even smoother when using linear blending
#endif
cascadeWeight = saturate(Min3(probesExtent - abs(cascadeBlendPoint)) / fadeDistance);
if (cascadeWeight > dither)
break;
}
if (cascadeIndex == data.CascadesCount)
return data.FallbackIrradiance;
// Sample cascade
float3 result = SampleDDGIIrradianceCascade(data, probesData, probesDistance, probesIrradiance, worldPosition, worldNormal, cascadeIndex, probesOrigin, probesExtent, probesSpacing, biasedWorldPosition);
#if DDGI_CASCADE_BLEND_SMOOTH
// Blend with the next cascade
cascadeIndex++;
if (cascadeIndex < data.CascadesCount && cascadeWeight < 0.99f)
{
probesSpacing = data.ProbesOriginAndSpacing[cascadeIndex].w;
probesOrigin = data.ProbesScrollOffsets[cascadeIndex].xyz * probesSpacing + data.ProbesOriginAndSpacing[cascadeIndex].xyz;
probesExtent = (data.ProbesCounts - 1) * (probesSpacing * 0.5f);
biasedWorldPosition = worldPosition + GetDDGISurfaceBias(viewDir, probesSpacing, worldNormal, bias);
float3 resultNext = SampleDDGIIrradianceCascade(data, probesData, probesDistance, probesIrradiance, worldPosition, worldNormal, cascadeIndex, probesOrigin, probesExtent, probesSpacing, biasedWorldPosition);
result = lerp(resultNext, result, cascadeWeight);
}
#endif
return result;
}
Source/Shaders/GI/DDGI.shader
+2
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@@ -768,6 +768,8 @@ Texture2D<float4> ProbesIrradiance : register(t6);
// Pixel shader for drawing indirect lighting in fullscreen
META_PS(true, FEATURE_LEVEL_SM5)
META_PERMUTATION_1(DDGI_CASCADE_BLEND_SMOOTH=0)
META_PERMUTATION_1(DDGI_CASCADE_BLEND_SMOOTH=1)
void PS_IndirectLighting(Quad_VS2PS input, out float4 output : SV_Target0)
{
output = 0;