GeometryShader: Transform the projection within the geometry shader.

Reduces the amount of data transferred through uniforms.
The shearing transformation is reduced to a single multiplication/addition for optimization.
This commit is contained in:
Jules Blok 2014-10-30 02:08:15 +01:00
parent 4fd943aedd
commit 6cacfad010
4 changed files with 14 additions and 24 deletions

View file

@ -43,6 +43,6 @@ struct VertexShaderConstants
float4 normalmatrices[32];
float4 posttransformmatrices[64];
float4 depthparams;
float4 stereoprojection[8];
float4 stereooffset;
};

View file

@ -70,16 +70,18 @@ static inline void GenerateGeometryShader(T& out, u32 components, API_TYPE ApiTy
out.Write("flat out int layer;\n");
out.Write("void main()\n{\n");
if (!g_ActiveConfig.backend_info.bSupportsGSInstancing)
if (g_ActiveConfig.backend_info.bSupportsGSInstancing)
out.Write("\tlayer = gl_InvocationID;\n");
else
out.Write("\tfor (layer = 0; layer < %d; ++layer) {\n", g_ActiveConfig.bStereo ? 2 : 1);
out.Write("\tgl_Layer = layer;\n");
out.Write("\tvec4 stereoproj = "I_PROJECTION"[0];\n");
out.Write("\tstereoproj[2] += "I_STEREOOFFSET"[layer] * stereoproj[0];\n");
out.Write("\tfor (int i = 0; i < gl_in.length(); ++i) {\n");
out.Write("\t\to = v[i];\n");
if (g_ActiveConfig.backend_info.bSupportsGSInstancing)
out.Write("\t\tlayer = gl_InvocationID;\n");
if (g_ActiveConfig.bStereo)
out.Write("\t\to.pos = float4(dot(" I_STEREOPROJECTION"[layer * 4 + 0], v[i].rawpos), dot(" I_STEREOPROJECTION"[layer * 4 + 1], v[i].rawpos), dot(" I_STEREOPROJECTION"[layer * 4 + 2], v[i].rawpos), dot(" I_STEREOPROJECTION"[layer * 4 + 3], v[i].rawpos)); \n");
out.Write("\t\to.pos = float4(dot(stereoproj, v[i].rawpos), dot(" I_PROJECTION"[1], v[i].rawpos), dot(" I_PROJECTION"[2], v[i].rawpos), dot(" I_PROJECTION"[3], v[i].rawpos)); \n");
out.Write("\t\tgl_Position = o.pos;\n");
out.Write("\t\tgl_Layer = layer;\n");
out.Write("\t\tEmitVertex();\n");
out.Write("\t}\n");
out.Write("\tEndPrimitive();\n");

View file

@ -239,7 +239,7 @@ private:
#define I_NORMALMATRICES "cnmtx"
#define I_POSTTRANSFORMMATRICES "cpostmtx"
#define I_DEPTHPARAMS "cDepth" // farZ, zRange
#define I_STEREOPROJECTION "csproj"
#define I_STEREOOFFSET "csoffset"
static const char s_shader_uniforms[] =
"\tfloat4 " I_POSNORMALMATRIX"[6];\n"
@ -251,4 +251,4 @@ static const char s_shader_uniforms[] =
"\tfloat4 " I_NORMALMATRICES"[32];\n"
"\tfloat4 " I_POSTTRANSFORMMATRICES"[64];\n"
"\tfloat4 " I_DEPTHPARAMS";\n"
"\tfloat4 " I_STEREOPROJECTION"[8];\n";
"\tfloat4 " I_STEREOOFFSET";\n";

View file

@ -515,25 +515,13 @@ void VertexShaderManager::SetConstants()
if (g_ActiveConfig.bStereo && xfmem.projection.type == GX_PERSPECTIVE)
{
Matrix44 projMtx;
Matrix44::Set(projMtx, g_fProjectionMatrix);
Matrix44 leftShearMtx, rightShearMtx;
Matrix44::Shear(leftShearMtx, g_ActiveConfig.iStereoSeparation / (200.0f * g_ActiveConfig.iStereoFocalLength));
Matrix44::Shear(rightShearMtx, -g_ActiveConfig.iStereoSeparation / (200.0f * g_ActiveConfig.iStereoFocalLength));
Matrix44 leftProjMtx, rightProjMtx, leftCorrectedMtx, rightCorrectedMtx;
Matrix44::Multiply(projMtx, leftShearMtx, leftProjMtx);
Matrix44::Multiply(s_viewportCorrection, leftProjMtx, leftCorrectedMtx);
Matrix44::Multiply(projMtx, rightShearMtx, rightProjMtx);
Matrix44::Multiply(s_viewportCorrection, rightProjMtx, rightCorrectedMtx);
memcpy(constants.stereoprojection, leftCorrectedMtx.data, 4*16);
memcpy(constants.stereoprojection + 4, rightCorrectedMtx.data, 4*16);
float offset = g_ActiveConfig.iStereoSeparation / (200.0f * g_ActiveConfig.iStereoFocalLength);
constants.stereooffset[0] = offset;
constants.stereooffset[1] = -offset;
}
else
{
memcpy(constants.stereoprojection, constants.projection, 4 * 16);
memcpy(constants.stereoprojection + 4, constants.projection, 4 * 16);
constants.stereooffset[0] = constants.stereooffset[1] = 0;
}
dirty = true;