PSSM Shadow Fix

fixes the issue with pssm shadows were the softness value makes the shadow cast on the entire cascade.
This commit is contained in:
marauder2k7 2026-03-12 20:47:19 +00:00
parent 058983aa42
commit 6a8d832bd6
3 changed files with 143 additions and 98 deletions

View file

@ -191,6 +191,16 @@ void PSSMLightShadowMap::_roundProjection(const MatrixF& lightMat, const MatrixF
}
void PSSMLightShadowMap::_adjustScaleAndOffset(Box3F& clipAABB, Point3F& scale, Point3F& offset) {
const ShadowMapParams* params = mLight->getExtended<ShadowMapParams>();
F32 padding = params->shadowSoftness * (2.0f / (F32)mTexSize);
clipAABB.minExtents.x -= padding;
clipAABB.minExtents.y -= padding;
clipAABB.maxExtents.x += padding;
clipAABB.maxExtents.y += padding;
scale.x = 2.0f / (clipAABB.maxExtents.x - clipAABB.minExtents.x);
scale.y = 2.0f / (clipAABB.maxExtents.y - clipAABB.minExtents.y);
scale.z = 1.0f;
@ -469,7 +479,7 @@ void PSSMLightShadowMap::setShaderParameters(GFXShaderConstBuffer* params, Light
params->setSafe( lsc->mOverDarkFactorPSSM, p->overDarkFactor);
// The softness is a factor of the texel size.
params->setSafe( lsc->mShadowSoftnessConst, p->shadowSoftness * ( 1.0f / mTexSize ) );
params->setSafe( lsc->mShadowSoftnessConst, p->shadowSoftness * ( 2.0f / mTexSize ) );
}
void PSSMLightShadowMap::_calcPlanesCullForShadowCasters(Vector< Vector<PlaneF> > &out, const Frustum &viewFrustum, const Point3F &_ligthDir)

View file

@ -112,6 +112,18 @@ void ShadowMaterialHook::init( BaseMatInstance *inMat )
mShadowMat[ShadowType_Spot] = newMat;
newMat = new ShadowMatInstance(shadowMat);
newMat->setUserObject(inMat->getUserObject());
newMat->getFeaturesDelegate().bind(&ShadowMaterialHook::_overrideFeatures);
forced.setCullMode(GFXCullCW);
forced.zBias = 1000.0f;
forced.zSlopeBias = 1.0f;
forced.setFillModeSolid();
newMat->addStateBlockDesc(forced);
forced.cullDefined = true;
newMat->init(features, inMat->getVertexFormat());
mShadowMat[ShadowType_PSSM] = newMat;
newMat = new ShadowMatInstance( shadowMat );
newMat->setUserObject( inMat->getUserObject() );
newMat->getFeaturesDelegate().bind( &ShadowMaterialHook::_overrideFeatures );
@ -162,12 +174,6 @@ BaseMatInstance* ShadowMaterialHook::getShadowMat( ShadowType type ) const
{
AssertFatal( type < ShadowType_Count, "ShadowMaterialHook::getShadowMat() - Bad light type!" );
// The cubemap and pssm shadows use the same
// spotlight material for shadows.
if ( type == ShadowType_Spot ||
type == ShadowType_PSSM )
return mShadowMat[ShadowType_Spot];
// Get the specialized shadow material.
return mShadowMat[type];
}

View file

@ -64,109 +64,138 @@ uniform float4 scaleY;
uniform float4 offsetX;
uniform float4 offsetY;
float4 AL_VectorLightShadowCast( TORQUE_SAMPLER2D(sourceShadowMap),
float2 texCoord,
float4x4 worldToLightProj,
float3 worldPos,
float4 scaleX,
float4 scaleY,
float4 offsetX,
float4 offsetY,
float4 farPlaneScalePSSM,
float dotNL)
float ComputeESMFactor(float cascadeNear, float cascadeFar, int shadowMapResolution, float targetShadow = 0.1)
{
// Compute shadow map coordinate
float4 pxlPosLightProj = mul(worldToLightProj, float4(worldPos,1));
float2 baseShadowCoord = pxlPosLightProj.xy / pxlPosLightProj.w;
float delta = (cascadeFar - cascadeNear) / shadowMapResolution;
float esmFactor = -log(targetShadow) / delta;
return esmFactor;
}
// Distance to light, in shadowmap space
float distToLight = pxlPosLightProj.z / pxlPosLightProj.w;
// Figure out which split to sample from. Basically, we compute the shadowmap sample coord
// for all of the splits and then check if its valid.
float4 shadowCoordX = baseShadowCoord.xxxx;
float4 shadowCoordY = baseShadowCoord.yyyy;
float4 farPlaneDists = distToLight.xxxx;
shadowCoordX *= scaleX;
shadowCoordY *= scaleY;
shadowCoordX += offsetX;
shadowCoordY += offsetY;
farPlaneDists *= farPlaneScalePSSM;
// If the shadow sample is within -1..1 and the distance
// to the light for this pixel is less than the far plane
// of the split, use it.
float4 finalMask;
if ( shadowCoordX.x > -0.99 && shadowCoordX.x < 0.99 &&
shadowCoordY.x > -0.99 && shadowCoordY.x < 0.99 &&
farPlaneDists.x < 1.0 )
finalMask = float4(1, 0, 0, 0);
float4 AL_VectorLightShadowCast(
TORQUE_SAMPLER2D(sourceShadowMap),
float2 texCoord,
float4x4 worldToLightProj,
float3 worldPos,
float4 scaleX,
float4 scaleY,
float4 offsetX,
float4 offsetY,
float4 farPlaneScalePSSM,
float dotNL)
{
// Compute shadow map coordinate
float4 pxlPosLightProj = mul(worldToLightProj, float4(worldPos,1));
float2 baseShadowCoord = pxlPosLightProj.xy / pxlPosLightProj.w;
float distToLight = pxlPosLightProj.z / pxlPosLightProj.w;
else if ( shadowCoordX.y > -0.99 && shadowCoordX.y < 0.99 &&
shadowCoordY.y > -0.99 && shadowCoordY.y < 0.99 &&
farPlaneDists.y < 1.0 )
finalMask = float4(0, 1, 0, 0);
// PSSM split handling
float4 shadowCoordX = baseShadowCoord.xxxx;
float4 shadowCoordY = baseShadowCoord.yyyy;
float4 farPlaneDists = distToLight.xxxx;
shadowCoordX *= scaleX;
shadowCoordY *= scaleY;
shadowCoordX += offsetX;
shadowCoordY += offsetY;
farPlaneDists *= farPlaneScalePSSM;
else if ( shadowCoordX.z > -0.99 && shadowCoordX.z < 0.99 &&
shadowCoordY.z > -0.99 && shadowCoordY.z < 0.99 &&
farPlaneDists.z < 1.0 )
finalMask = float4(0, 0, 1, 0);
else
finalMask = float4(0, 0, 0, 1);
float3 debugColor = float3(0,0,0);
#ifdef NO_SHADOW
debugColor = float3(1.0,1.0,1.0);
#endif
#ifdef PSSM_DEBUG_RENDER
if ( finalMask.x > 0 )
debugColor += float3( 1, 0, 0 );
else if ( finalMask.y > 0 )
debugColor += float3( 0, 1, 0 );
else if ( finalMask.z > 0 )
debugColor += float3( 0, 0, 1 );
else if ( finalMask.w > 0 )
debugColor += float3( 1, 1, 0 );
#endif
const float cascadeBorder = 0.02;
float4 insideX = step(-1.0 + cascadeBorder, shadowCoordX) * step(shadowCoordX, 1.0 - cascadeBorder);
float4 insideY = step(-1.0 + cascadeBorder, shadowCoordY) * step(shadowCoordY, 1.0 - cascadeBorder);
float4 insideZ = step(farPlaneDists, 1.0);
// Here we know what split we're sampling from, so recompute the texcoord location
// Yes, we could just use the result from above, but doing it this way actually saves
// shader instructions.
float2 finalScale;
finalScale.x = dot(finalMask, scaleX);
finalScale.y = dot(finalMask, scaleY);
float4 cascadeValid = insideX * insideY * insideZ;
float2 finalOffset;
finalOffset.x = dot(finalMask, offsetX);
finalOffset.y = dot(finalMask, offsetY);
float4 finalMask;
float2 shadowCoord;
shadowCoord = baseShadowCoord * finalScale;
shadowCoord += finalOffset;
finalMask.x = cascadeValid.x;
finalMask.y = (1 - finalMask.x) * cascadeValid.y;
finalMask.z = (1 - finalMask.x - finalMask.y) * cascadeValid.z;
finalMask.w = 1 - finalMask.x - finalMask.y - finalMask.z;
// Convert to texcoord space
shadowCoord = 0.5 * shadowCoord + float2(0.5, 0.5);
shadowCoord.y = 1.0f - shadowCoord.y;
float3 debugColor = float3(0,0,0);
// Move around inside of atlas
float2 aOffset;
aOffset.x = dot(finalMask, atlasXOffset);
aOffset.y = dot(finalMask, atlasYOffset);
#ifdef NO_SHADOW
debugColor = float3(1.0,1.0,1.0);
#endif
shadowCoord *= atlasScale;
shadowCoord += aOffset;
// Each split has a different far plane, take this into account.
float farPlaneScale = dot( farPlaneScalePSSM, finalMask );
distToLight *= farPlaneScale;
#ifdef PSSM_DEBUG_RENDER
if ( finalMask.x > 0 )
debugColor += float3( 1, 0, 0 );
else if ( finalMask.y > 0 )
debugColor += float3( 0, 1, 0 );
else if ( finalMask.z > 0 )
debugColor += float3( 0, 0, 1 );
else if ( finalMask.w > 0 )
debugColor += float3( 1, 1, 0 );
#endif
return float4(debugColor, softShadow_filter( TORQUE_SAMPLER2D_MAKEARG(sourceShadowMap), texCoord, shadowCoord, farPlaneScale * shadowSoftness,
distToLight, dotNL, dot( finalMask, overDarkPSSM ) ) );
};
// Compute final scale & offset for PSSM atlas
float2 finalScale;
finalScale.x = dot(finalMask, scaleX);
finalScale.y = dot(finalMask, scaleY);
float2 finalOffset;
finalOffset.x = dot(finalMask, offsetX);
finalOffset.y = dot(finalMask, offsetY);
float2 shadowCoord = baseShadowCoord * finalScale + finalOffset;
// Convert to texcoord space and atlas
shadowCoord = 0.5 *shadowCoord + 0.5;
shadowCoord.y = 1.0 - shadowCoord.y;
float2 aOffset;
aOffset.x = dot(finalMask, atlasXOffset);
aOffset.y = dot(finalMask, atlasYOffset);
shadowCoord = shadowCoord * atlasScale + aOffset;
// Compute atlas tile bounds
float2 tileMin = aOffset;
float2 tileMax = aOffset + atlasScale;
// Convert filter radius to atlas UV space
float2 filterRadiusUV = shadowSoftness * atlasScale;
// Adjust for PSSM far plane
float farPlaneScale = dot(farPlaneScalePSSM, finalMask);
distToLight *= farPlaneScale;
// Shadow map resolution per cascade
int shadowRes = 1024;
float cascadeTexel = 1.0 / shadowRes;
float4 depthBiasPSSM = float4(
0.2 * cascadeTexel,
0.3 * cascadeTexel,
0.7 * cascadeTexel,
1.5 * cascadeTexel
);
float shadow_bias = dot(finalMask, depthBiasPSSM);
distToLight += shadow_bias;
distToLight = saturate(distToLight);
// Example cascade ranges
float cascadeNear[4] = { 0.0, 0.2, 0.5, 0.75 };
float cascadeFar[4] = { 0.2, 0.5, 0.75, 1.0 };
float4 overDarkPSSM;
for(int i=0;i<4;i++)
{
overDarkPSSM[i] = ComputeESMFactor(cascadeNear[i], cascadeFar[i], shadowRes, 0.1);
}
return float4(
debugColor,
softShadow_filter(
TORQUE_SAMPLER2D_MAKEARG(sourceShadowMap),
texCoord,
shadowCoord,
shadowSoftness,
distToLight,
dotNL,
dot(finalMask, overDarkPSSM) // replace this with shadowBias for pcf.
)
);
}
float4 main(FarFrustumQuadConnectP IN) : SV_TARGET
{