Pica/Rasterizer: Make orient2d a free function and rename it to SignedArea.
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1 changed files with 39 additions and 32 deletions
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@ -55,10 +55,6 @@ static void SetDepth(int x, int y, u16 value) {
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*(depth_buffer + x + y * registers.framebuffer.GetWidth()) = value;
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*(depth_buffer + x + y * registers.framebuffer.GetWidth()) = value;
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}
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}
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void ProcessTriangle(const VertexShader::OutputVertex& v0,
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const VertexShader::OutputVertex& v1,
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const VertexShader::OutputVertex& v2)
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{
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// NOTE: Assuming that rasterizer coordinates are 12.4 fixed-point values
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// NOTE: Assuming that rasterizer coordinates are 12.4 fixed-point values
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struct Fix12P4 {
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struct Fix12P4 {
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Fix12P4() {}
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Fix12P4() {}
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@ -79,14 +75,13 @@ void ProcessTriangle(const VertexShader::OutputVertex& v0,
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u16 val;
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u16 val;
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};
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};
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// vertex positions in rasterizer coordinates
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/**
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auto FloatToFix = [](float24 flt) {
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* Calculate signed area of the triangle spanned by the three argument vertices.
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return Fix12P4(static_cast<unsigned short>(flt.ToFloat32() * 16.0f));
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* The sign denotes an orientation.
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};
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*
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auto ScreenToRasterizerCoordinates = [FloatToFix](const Math::Vec3<float24> vec) {
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* @todo define orientation concretely.
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return Math::Vec3<Fix12P4>{FloatToFix(vec.x), FloatToFix(vec.y), FloatToFix(vec.z)};
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*/
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};
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static int SignedArea (const Math::Vec2<Fix12P4>& vtx1,
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static auto orient2d = [](const Math::Vec2<Fix12P4>& vtx1,
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const Math::Vec2<Fix12P4>& vtx2,
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const Math::Vec2<Fix12P4>& vtx2,
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const Math::Vec2<Fix12P4>& vtx3) {
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const Math::Vec2<Fix12P4>& vtx3) {
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const auto vec1 = Math::MakeVec(vtx2 - vtx1, 0);
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const auto vec1 = Math::MakeVec(vtx2 - vtx1, 0);
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@ -95,6 +90,18 @@ void ProcessTriangle(const VertexShader::OutputVertex& v0,
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return Math::Cross(vec1, vec2).z;
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return Math::Cross(vec1, vec2).z;
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};
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};
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void ProcessTriangle(const VertexShader::OutputVertex& v0,
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const VertexShader::OutputVertex& v1,
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const VertexShader::OutputVertex& v2)
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{
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// vertex positions in rasterizer coordinates
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auto FloatToFix = [](float24 flt) {
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return Fix12P4(static_cast<unsigned short>(flt.ToFloat32() * 16.0f));
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};
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auto ScreenToRasterizerCoordinates = [FloatToFix](const Math::Vec3<float24> vec) {
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return Math::Vec3<Fix12P4>{FloatToFix(vec.x), FloatToFix(vec.y), FloatToFix(vec.z)};
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};
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Math::Vec3<Fix12P4> vtxpos[3]{ ScreenToRasterizerCoordinates(v0.screenpos),
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Math::Vec3<Fix12P4> vtxpos[3]{ ScreenToRasterizerCoordinates(v0.screenpos),
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ScreenToRasterizerCoordinates(v1.screenpos),
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ScreenToRasterizerCoordinates(v1.screenpos),
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ScreenToRasterizerCoordinates(v2.screenpos) };
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ScreenToRasterizerCoordinates(v2.screenpos) };
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@ -107,7 +114,7 @@ void ProcessTriangle(const VertexShader::OutputVertex& v0,
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if (registers.cull_mode != Regs::CullMode::KeepAll) {
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if (registers.cull_mode != Regs::CullMode::KeepAll) {
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// Cull away triangles which are wound clockwise.
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// Cull away triangles which are wound clockwise.
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// TODO: A check for degenerate triangles ("== 0") should be considered for CullMode::KeepAll
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// TODO: A check for degenerate triangles ("== 0") should be considered for CullMode::KeepAll
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if (orient2d(vtxpos[0].xy(), vtxpos[1].xy(), vtxpos[2].xy()) <= 0)
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if (SignedArea(vtxpos[0].xy(), vtxpos[1].xy(), vtxpos[2].xy()) <= 0)
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return;
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return;
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}
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}
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@ -153,9 +160,9 @@ void ProcessTriangle(const VertexShader::OutputVertex& v0,
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for (u16 x = min_x; x < max_x; x += 0x10) {
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for (u16 x = min_x; x < max_x; x += 0x10) {
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// Calculate the barycentric coordinates w0, w1 and w2
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// Calculate the barycentric coordinates w0, w1 and w2
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int w0 = bias0 + orient2d(vtxpos[1].xy(), vtxpos[2].xy(), {x, y});
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int w0 = bias0 + SignedArea(vtxpos[1].xy(), vtxpos[2].xy(), {x, y});
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int w1 = bias1 + orient2d(vtxpos[2].xy(), vtxpos[0].xy(), {x, y});
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int w1 = bias1 + SignedArea(vtxpos[2].xy(), vtxpos[0].xy(), {x, y});
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int w2 = bias2 + orient2d(vtxpos[0].xy(), vtxpos[1].xy(), {x, y});
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int w2 = bias2 + SignedArea(vtxpos[0].xy(), vtxpos[1].xy(), {x, y});
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int wsum = w0 + w1 + w2;
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int wsum = w0 + w1 + w2;
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// If current pixel is not covered by the current primitive
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// If current pixel is not covered by the current primitive
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