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Merge pull request #2005 from CookiePLMonster/fix-vs-precision 

Improve reverse screenspace transformation precision
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PatrickvL 2020-10-24 23:21:48 +02:00 committed by GitHub
parent 724a1ca684 709a3508ee
commit 23a3bc4b78
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2 changed files with 10 additions and 8 deletions
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8
src/core/hle/D3D8/Direct3D9/CxbxVertexShaderTemplate.hlsl
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@ -261,9 +261,13 @@ float4 reverseScreenspaceTransform(float4 oPos)
// mad oPos.xyz, r12, r1.x, c-37
// where c-37 and c-38 are reserved transform values
// oPos.w and xboxViewportScale.z might be VERY big when a D24 depth buffer is used
// and multiplying oPos.xyz by oPos.w may cause precision issues.
// Pre-divide them to help keep the values reasonably small.
// Test case: Burnout 3
float3 divisor = xboxViewportScale.xyz / oPos.w;
oPos.xyz -= xboxViewportOffset.xyz; // reverse offset
oPos.xyz *= oPos.w; // reverse perspective divide
oPos.xyz /= xboxViewportScale.xyz; // reverse scale
oPos.xyz /= divisor; // reverse scale and perspective divide
return oPos;
}

10
src/core/hle/D3D8/Direct3D9/Direct3D9.cpp
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@ -4032,11 +4032,10 @@ void GetViewPortOffsetAndScale(float (&vOffset)[4], float(&vScale)[4])
void UpdateViewPortOffsetAndScaleConstants()
{
float vOffset[4], vScale[4];
GetViewPortOffsetAndScale(vOffset, vScale);
float vScaleOffset[2][4]; // 0 - scale 1 - offset
GetViewPortOffsetAndScale(vScaleOffset[1], vScaleOffset[0]);
g_pD3DDevice->SetVertexShaderConstantF(CXBX_D3DVS_VIEWPORT_SCALE_MIRROR, vScale, 1);
g_pD3DDevice->SetVertexShaderConstantF(CXBX_D3DVS_VIEWPORT_OFFSET_MIRROR, vOffset, 1);
g_pD3DDevice->SetVertexShaderConstantF(CXBX_D3DVS_VIEWPORT_SCALE_MIRROR, reinterpret_cast<float*>(vScaleOffset), 2);
// Store viewport offset and scale in constant registers 58 (c-38) and
// 59 (c-37) used for screen space transformation.
@ -4044,8 +4043,7 @@ void UpdateViewPortOffsetAndScaleConstants()
// Treat this as a flag
// Test Case: GTA III, Soldier of Fortune II
if (!(g_Xbox_VertexShaderConstantMode & X_D3DSCM_NORESERVEDCONSTANTS)) {
g_pD3DDevice->SetVertexShaderConstantF(X_D3DSCM_RESERVED_CONSTANT_SCALE + X_D3DSCM_CORRECTION, vScale, 1);
g_pD3DDevice->SetVertexShaderConstantF(X_D3DSCM_RESERVED_CONSTANT_OFFSET + X_D3DSCM_CORRECTION, vOffset, 1);
g_pD3DDevice->SetVertexShaderConstantF(X_D3DSCM_RESERVED_CONSTANT_SCALE + X_D3DSCM_CORRECTION, reinterpret_cast<float*>(vScaleOffset), 2);
}
}