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chore(grass): improve sss #2183

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Merged
alandtse merged 7 commits into from
May 2, 2026
Merged

chore(grass): improve sss #2183

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dfe3014
feat(grass): sss/skylighting improvements
doodlum Apr 22, 2026
a2dffde
feat(grass): linearize vertex color; rework subsurface term
doodlum Apr 22, 2026
5f58c12
Merge branch 'feat/grass-skylighting-sss' of https://github.com/doodl…
doodlum Apr 22, 2026
b76cec9
refactor: more cleanup
doodlum Apr 22, 2026
d424229
fix: fix missing normalisation
doodlum Apr 22, 2026
d3d343a
Merge branch 'dev' into feat/grass-skylighting-sss
doodlum May 2, 2026
ed6edaa
Update package/Shaders/RunGrass.hlsl
doodlum May 2, 2026
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22 changes: 7 additions & 15 deletions package/Shaders/RunGrass.hlsl
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Original file line number Diff line number Diff line change
Expand Up @@ -521,14 +521,10 @@ PS_OUTPUT main(PS_INPUT input, bool frontFace : SV_IsFrontFace)
float screenNoise = Random::InterleavedGradientNoise(input.HPosition.xy, SharedData::FrameCount);

// Swaps direction of the backfaces otherwise they seem to get lit from the wrong direction.
if (!(Permutation::ExtraShaderDescriptor & Permutation::ExtraFlags::GrassSphereNormal)) {
if (!(Permutation::ExtraShaderDescriptor & Permutation::ExtraFlags::GrassSphereNormal))
if (!frontFace)
normal = -normal;

normal.z = max(0.0, normal.z);
normal = normalize(float3(normal.xy, max(0, normal.z)));
}

float3x3 tbn = 0;

# if !defined(TRUE_PBR)
Expand Down Expand Up @@ -631,7 +627,7 @@ PS_OUTPUT main(PS_INPUT input, bool frontFace : SV_IsFrontFace)
lightsDiffuseColor += dirLightColor * dirDetailedShadow * saturate(dirLightAngle) * Color::VanillaNormalization();
}

float3 vertexColor = input.VertexColor.xyz;
float3 vertexColor = Color::ColorToLinear(input.VertexColor.xyz);

# if defined(SKYLIGHTING)
# if defined(VR)
Expand All @@ -643,10 +639,9 @@ PS_OUTPUT main(PS_INPUT input, bool frontFace : SV_IsFrontFace)
float skylightingDiffuse = Skylighting::GetVertexSkylightingDiffuse(positionMSSkylight, normal, vertexAO);
# endif // SKYLIGHTING

float3 albedo = max(0, baseColor.xyz * Color::ColorToLinear(vertexColor));
float3 albedo = baseColor.xyz * vertexColor;

float3 subsurfaceColor = lerp(dot(albedo, 1.0 / 3.0), albedo, 2.0) * saturate(input.VertexNormal.w * 10.0);
float3 sss = dirLightColor * dirDetailedShadow * saturate(-dirLightAngle) * Color::VanillaNormalization();
float3 subsurfaceColor = dirLightColor * dirDetailedShadow * saturate(-dirLightAngle) * Color::VanillaNormalization();

if (complex)
lightsSpecularColor += dirDetailedShadow * GrassLighting::GetLightSpecularInput(SharedData::DirLightDirection.xyz, viewDirection, normal, dirLightColor, SharedData::grassLightingSettings.Glossiness) * Color::VanillaNormalization();
Expand Down Expand Up @@ -715,7 +710,7 @@ PS_OUTPUT main(PS_INPUT input, bool frontFace : SV_IsFrontFace)
lightDiffuseColor = lightColor * saturate(lightAngle);
}

sss += lightColor * saturate(-lightAngle);
subsurfaceColor += lightColor * saturate(-lightAngle) * Color::VanillaNormalization();

lightsDiffuseColor += lightDiffuseColor * Color::VanillaNormalization();

Expand Down Expand Up @@ -752,9 +747,8 @@ PS_OUTPUT main(PS_INPUT input, bool frontFace : SV_IsFrontFace)
# endif

diffuseColor += directionalAmbientColor;

diffuseColor += subsurfaceColor * albedo * SharedData::grassLightingSettings.SubsurfaceScatteringAmount;
diffuseColor *= albedo;
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diffuseColor += max(0, sss * subsurfaceColor * SharedData::grassLightingSettings.SubsurfaceScatteringAmount);

directionalAmbientColor *= albedo;

Expand Down Expand Up @@ -902,9 +896,7 @@ PS_OUTPUT main(PS_INPUT input)
float3 ddy = ddy_coarse(input.WorldPosition);
float3 normal = -normalize(cross(ddx, ddy));

normal = normalize(float3(normal.xy, max(0, normal.z)));

float3 vertexColor = input.VertexColor.xyz;
float3 vertexColor = Color::ColorToLinear(input.VertexColor.xyz);

# if defined(SKYLIGHTING)
# if defined(VR)
Expand Down
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