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Implement non uniform scaled normals for all shader paths
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World matrix is now always normalized in the vertex shader. Without it,
offset bias shadow mapping would malfunction if the object had scaling.

Switch manually multiplying matrices using float4 with explicit
matrices.
Code is eaiser to read and maintain. The CrossPlatform utils make it
easy to work with matrix data types, which didn't exist when the
original code was written.

Affects #373
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@darksylinc
darksylinc committed Dec 31, 2024
1 parent 16a9c7b commit b6f12ea
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Showing 4 changed files with 84 additions and 69 deletions.
2 changes: 2 additions & 0 deletions Samples/Media/Hlms/Common/GLSL/CrossPlatformSettings_piece_all.glsl
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Expand Up @@ -77,6 +77,8 @@

#define buildFloat4x4( row0, row1, row2, row3 ) mat4( row0, row1, row2, row3 )

#define getMatrixRow( mat, idx ) mat[idx]

// Let's explain this madness:
//
// We use the keyword "midf" because "half" is already taken on Metal.
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2 changes: 2 additions & 0 deletions Samples/Media/Hlms/Common/HLSL/CrossPlatformSettings_piece_all.hlsl
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Expand Up @@ -17,6 +17,8 @@

#define buildFloat4x4( row0, row1, row2, row3 ) transpose( float4x4( row0, row1, row2, row3 ) )

#define getMatrixRow( mat, idx ) transpose( mat )[idx]

// See CrossPlatformSettings_piece_all.glsl for an explanation
@property( precision_mode == full32 )
#define _h(x) (x)
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2 changes: 2 additions & 0 deletions Samples/Media/Hlms/Common/Metal/CrossPlatformSettings_piece_all.metal
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Expand Up @@ -50,6 +50,8 @@ inline half3x3 toMatHalf3x3( float3x4 m )

#define buildFloat4x4( row0, row1, row2, row3 ) float4x4( float4( row0 ), float4( row1 ), float4( row2 ), float4( row3 ) )

#define getMatrixRow( mat, idx ) mat[idx]

// See CrossPlatformSettings_piece_all.glsl for an explanation
@property( precision_mode == full32 )
// In Metal 'half' is an actual datatype. It should be OK to override it
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147 changes: 78 additions & 69 deletions Samples/Media/Hlms/Pbs/Any/Main/800.VertexShader_piece_vs.any
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Expand Up @@ -10,6 +10,9 @@

@insertpiece( Common_Matrix_DeclUnpackMatrix4x4 )
@insertpiece( Common_Matrix_DeclUnpackMatrix4x3 )
@property( hlms_skeleton || hlms_pose )
@insertpiece( Common_Matrix_DeclLoadOgreFloat4x3 )
@end
@property( hlms_particle_system )
@insertpiece( DeclQuaternion )
@end
Expand All @@ -33,20 +36,42 @@
@insertpiece( DeclAtmosphereNprSkyFuncs )

@property( accurate_non_uniform_scaled_normals )
midf3x3 adjugate( midf3x3 m )
// Computes transpose( adjugate( m ) )
// See:
// https://x.com/iquilezles/status/1866219178409316362
// https://www.shadertoy.com/view/3s33zj
// https://github.com/graphitemaster/normals_revisited
midf3x3 adjugateForNormals( midf3x3 m )
{
const midf3 r0 = getMatrixRow( m, 0 ).xyz;
const midf3 r1 = getMatrixRow( m, 1 ).xyz;
const midf3 r2 = getMatrixRow( m, 2 ).xyz;
midf3x3 n = buildFloat3x3( cross( r1.xyz, r2.xyz ),
cross( r2.xyz, r0.xyz ),
cross( r0.xyz, r1.xyz ) );
return n;
}

INLINE midf3x3 adjugateForNormalsFrom4x3( ogre_float4x3 m )
{
midf3x3 n;
n[0][0] = m[1][1] * m[2][2] - m[1][2] * m[2][1];
n[0][1] = m[0][2] * m[2][1] - m[0][1] * m[2][2];
n[0][2] = m[0][1] * m[1][2] - m[0][2] * m[1][1];
n[1][0] = m[1][2] * m[2][0] - m[1][0] * m[2][2];
n[1][1] = m[0][0] * m[2][2] - m[0][2] * m[2][0];
n[1][2] = m[0][2] * m[1][0] - m[0][0] * m[1][2];
n[2][0] = m[1][0] * m[2][1] - m[2][0] * m[1][1];
n[2][1] = m[0][1] * m[2][0] - m[0][0] * m[2][1];
n[2][2] = m[0][0] * m[1][1] - m[0][1] * m[1][0];
const midf3 r0 = midf3_c( getMatrixRow( m, 0 ).xyz );
const midf3 r1 = midf3_c( getMatrixRow( m, 1 ).xyz );
const midf3 r2 = midf3_c( getMatrixRow( m, 2 ).xyz );
midf3x3 n = buildFloat3x3( cross( r1.xyz, r2.xyz ),
cross( r2.xyz, r0.xyz ),
cross( r0.xyz, r1.xyz ) );
return n;
}
@else
midf3x3 adjugateForNormals( midf3x3 m )
{
return m;
}

INLINE midf3x3 adjugateForNormalsFrom4x3( ogre_float4x3 m )
{
return toMidf3x3( m );
}
@end
@end

Expand All @@ -63,60 +88,43 @@
@property( hlms_skeleton )
@piece( SkeletonTransform )
uint _idx = (inVs_blendIndices[0] << 1u) + inVs_blendIndices[0]; //inVs_blendIndices[0] * 3u; a 32-bit int multiply is 4 cycles on GCN! (and mul24 is not exposed to GLSL...)
uint matStart = worldMaterialIdx[inVs_drawId].x >> 9u;
float4 worldMat[3];
worldMat[0] = readOnlyFetch( worldMatBuf, int(matStart + _idx + 0u) );
worldMat[1] = readOnlyFetch( worldMatBuf, int(matStart + _idx + 1u) );
worldMat[2] = readOnlyFetch( worldMatBuf, int(matStart + _idx + 2u) );
const uint matStart = worldMaterialIdx[inVs_drawId].x >> 9u;
ogre_float4x3 worldMat;
worldMat = makeOgreFloat4x3( readOnlyFetch( worldMatBuf, int( matStart + _idx + 0u ) ),
readOnlyFetch( worldMatBuf, int( matStart + _idx + 1u ) ),
readOnlyFetch( worldMatBuf, int( matStart + _idx + 2u ) ) );
float4 worldPos;
worldPos.x = dot( worldMat[0], inputPos );
worldPos.y = dot( worldMat[1], inputPos );
worldPos.z = dot( worldMat[2], inputPos );
worldPos.xyz *= inVs_blendWeights[0];
@property( hlms_normal || hlms_qtangent )
worldPos.xyz = mul( inputPos, worldMat ) * inVs_blendWeights[0];
@property( hlms_normal || hlms_qtangent )
midf3x3 normalAdjMat = adjugateForNormalsFrom4x3( worldMat );

midf3 worldNorm;
worldNorm.x = dot( midf3_c( worldMat[0].xyz ), inputNormal );
worldNorm.y = dot( midf3_c( worldMat[1].xyz ), inputNormal );
worldNorm.z = dot( midf3_c( worldMat[2].xyz ), inputNormal );
worldNorm *= midf_c( inVs_blendWeights[0] );
worldNorm = mul( inputNormal, normalAdjMat ) * midf_c( inVs_blendWeights[0] );
@end
@property( normal_map )
midf3 worldTang;
worldTang.x = dot( midf3_c( worldMat[0].xyz ), inputTangent );
worldTang.y = dot( midf3_c( worldMat[1].xyz ), inputTangent );
worldTang.z = dot( midf3_c( worldMat[2].xyz ), inputTangent );
worldTang *= midf_c( inVs_blendWeights[0] );
worldTang = mul( inputTangent, normalAdjMat ) * midf_c( inVs_blendWeights[0] );
@end

@psub( NeedsMoreThan1BonePerVertex, hlms_bones_per_vertex, 1 )
@property( NeedsMoreThan1BonePerVertex )
float4 tmp4;
tmp4.w = 1.0;
midf3 tmp3;
@end //!NeedsMoreThan1BonePerVertex
@foreach( hlms_bones_per_vertex, n, 1 )
_idx = (inVs_blendIndices[@n] << 1u) + inVs_blendIndices[@n]; //inVs_blendIndices[@n] * 3; a 32-bit int multiply is 4 cycles on GCN! (and mul24 is not exposed to GLSL...)
worldMat[0] = readOnlyFetch( worldMatBuf, int(matStart + _idx + 0u) );
worldMat[1] = readOnlyFetch( worldMatBuf, int(matStart + _idx + 1u) );
worldMat[2] = readOnlyFetch( worldMatBuf, int(matStart + _idx + 2u) );
tmp4.x = dot( worldMat[0], inputPos );
tmp4.y = dot( worldMat[1], inputPos );
tmp4.z = dot( worldMat[2], inputPos );
worldPos.xyz += (tmp4 * inVs_blendWeights[@n]).xyz;
_idx = (inVs_blendIndices[@n] << 1u) + inVs_blendIndices[@n]; //inVs_blendIndices[@n] * 3; a 32-bit int multiply is 4 cycles on GCN! (and mul24 is not exposed to GLSL...).
worldMat = makeOgreFloat4x3( readOnlyFetch( worldMatBuf, int( matStart + _idx + 0u ) ),
readOnlyFetch( worldMatBuf, int( matStart + _idx + 1u ) ),
readOnlyFetch( worldMatBuf, int( matStart + _idx + 2u ) ) );
worldPos.xyz += mul( inputPos, worldMat ) * inVs_blendWeights[@n];
@property( hlms_normal || hlms_qtangent )
tmp3.x = dot( midf3_c( worldMat[0].xyz ), inputNormal );
tmp3.y = dot( midf3_c( worldMat[1].xyz ), inputNormal );
tmp3.z = dot( midf3_c( worldMat[2].xyz ), inputNormal );
worldNorm += tmp3.xyz * midf_c( inVs_blendWeights[@n] );
normalAdjMat = adjugateForNormalsFrom4x3( worldMat );
worldNorm += mul( inputNormal, normalAdjMat ) * midf_c( inVs_blendWeights[@n] );
@end
@property( normal_map )
tmp3.x = dot( midf3_c( worldMat[0].xyz ), inputTangent );
tmp3.y = dot( midf3_c( worldMat[1].xyz ), inputTangent );
tmp3.z = dot( midf3_c( worldMat[2].xyz ), inputTangent );
worldTang += tmp3.xyz * midf_c( inVs_blendWeights[@n] );
worldNorm += mul( inputTangent, normalAdjMat ) * midf_c( inVs_blendWeights[@n] );
@end
@end

@property( hlms_normal || hlms_qtangent )
worldNorm = normalize( worldNorm );
@end

worldPos.w = 1.0;
@end // SkeletonTransform
@end // !hlms_skeleton
Expand Down Expand Up @@ -185,14 +193,13 @@
// If hlms_skeleton is defined the transforms will be provided by bones.
// If hlms_pose is not combined with hlms_skeleton the object's worldMat and worldView have to be set.
@property( !hlms_skeleton )
float4 worldMat[3];
worldMat[0] = readOnlyFetch( worldMatBuf, int( poseDataStart + @value(NumPoseWeightVectors)u + 1u ) );
worldMat[1] = readOnlyFetch( worldMatBuf, int( poseDataStart + @value(NumPoseWeightVectors)u + 2u ) );
worldMat[2] = readOnlyFetch( worldMatBuf, int( poseDataStart + @value(NumPoseWeightVectors)u + 3u ) );
ogre_float4x3 worldMat;
worldMat = makeOgreFloat4x3(
readOnlyFetch( worldMatBuf, int( poseDataStart + @value( NumPoseWeightVectors )u + 1u ) ),
readOnlyFetch( worldMatBuf, int( poseDataStart + @value( NumPoseWeightVectors )u + 2u ) ),
readOnlyFetch( worldMatBuf, int( poseDataStart + @value( NumPoseWeightVectors )u + 3u ) ) );
float4 worldPos;
worldPos.x = dot( worldMat[0], inputPos );
worldPos.y = dot( worldMat[1], inputPos );
worldPos.z = dot( worldMat[2], inputPos );
worldPos.xyz = mul( inputPos, worldMat );
worldPos.w = 1.0;

@property( hlms_normal || hlms_qtangent )
Expand All @@ -213,11 +220,12 @@
@property( hlms_normal || hlms_qtangent ) outVs.pos = @insertpiece( CalculatePsPos );@end
@property( hlms_normal || hlms_qtangent )
midf3x3 worldMat3x3 = toMidf3x3( worldViewMat );
@property( accurate_non_uniform_scaled_normals )
midf3x3 normalMat = transpose( adjugate( worldMat3x3 ) );
outVs.normal = normalize( mul( @insertpiece(local_normal), normalMat ) );
@else
@property( hlms_skeleton )
// worldViewMat is actually passBuf.view so we don't need the adjugate. We've already done that.
outVs.normal = mul( @insertpiece(local_normal), worldMat3x3 );
@else
midf3x3 normalMat = adjugateForNormals( worldMat3x3 );
outVs.normal = mul( @insertpiece(local_normal), normalMat );
@end
@end
@property( normal_map ) outVs.tangent = mul( @insertpiece(local_tangent), toMidf3x3( worldViewMat ) );@end
Expand Down Expand Up @@ -290,19 +298,20 @@

float4 worldPos = float4( mul(inVs_vertex, worldMat).xyz, 1.0f );
@property( ( hlms_normal || hlms_qtangent) && hlms_num_shadow_map_lights )
// We need worldNorm for normal offset bias
midf3 worldNorm = mul( inputNormal, toMidf3x3( worldMat ) ).xyz;
const midf3x3 normalAdjMat = adjugateForNormalsFrom4x3( worldMat );

// We need worldNorm for normal offset bias.
midf3 worldNorm = normalize( mul( inputNormal, normalAdjMat ).xyz );
@end
@end

@insertpiece( PoseTransform )

@property( !hlms_skeleton && hlms_pose && ( hlms_normal || hlms_qtangent) && hlms_num_shadow_map_lights )
// We need worldNorm for normal offset bias, special path when using poses
midf3 worldNorm;
worldNorm.x = dot( midf3_c( worldMat[0].xyz ), inputNormal );
worldNorm.y = dot( midf3_c( worldMat[1].xyz ), inputNormal );
worldNorm.z = dot( midf3_c( worldMat[2].xyz ), inputNormal );
const midf3x3 normalAdjMat = adjugateForNormalsFrom4x3( worldMat );

// We need worldNorm for normal offset bias, special path when using poses.
midf3 worldNorm = normalize( mul( inputNormal, normalAdjMat ).xyz );
@end

@insertpiece( SkeletonTransform )
Expand Down

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