| /* |
| * Copyright 2021 Google LLC. |
| * |
| * Use of this source code is governed by a BSD-style license that can be |
| * found in the LICENSE file. |
| */ |
| |
| #include "src/gpu/tessellate/PatchWriter.h" |
| |
| #if SK_GPU_V1 |
| #include "src/gpu/tessellate/PathTessellator.h" |
| #include "src/gpu/tessellate/StrokeTessellator.h" |
| #endif |
| |
| namespace skgpu { |
| |
| SK_ALWAYS_INLINE SkPoint to_skpoint(float2 p) { return skvx::bit_pun<SkPoint>(p); } |
| |
| #if SK_GPU_V1 |
| PatchWriter::PatchWriter(GrMeshDrawTarget* target, |
| PathTessellator* tessellator, |
| int initialPatchAllocCount) |
| : PatchWriter(target, |
| &tessellator->fVertexChunkArray, |
| tessellator->fAttribs, |
| sizeof(SkPoint) * 4 + PatchAttribsStride(tessellator->fAttribs), |
| initialPatchAllocCount) { |
| } |
| |
| PatchWriter::PatchWriter(GrMeshDrawTarget* target, |
| StrokeTessellator* tessellator, |
| int initialPatchAllocCount) |
| : PatchWriter(target, |
| &tessellator->fVertexChunkArray, |
| tessellator->fAttribs, |
| sizeof(SkPoint) * 5 + PatchAttribsStride(tessellator->fAttribs), |
| initialPatchAllocCount) { |
| } |
| #endif |
| |
| void PatchWriter::chopAndWriteQuads(float2 p0, float2 p1, float2 p2, int numPatches) { |
| // If we aren't fanning, we need to fill the space between chops with triangles. |
| bool needsInnerTriangles = !(fAttribs & PatchAttribs::kFanPoint); |
| MiddleOutPolygonTriangulator innerTriangulator(numPatches, to_skpoint(p0)); |
| for (; numPatches >= 3; numPatches -= 2) { |
| // Chop into 3 quads. |
| float4 T = float4(1,1,2,2) / numPatches; |
| float4 ab = mix(p0.xyxy(), p1.xyxy(), T); |
| float4 bc = mix(p1.xyxy(), p2.xyxy(), T); |
| float4 abc = mix(ab, bc, T); |
| // p1 & p2 of the cubic representation of the middle quad. |
| float4 middle = mix(ab, bc, mix(T, T.zwxy(), 2/3.f)); |
| |
| CubicPatch(*this) << QuadToCubic{p0, ab.lo, abc.lo}; // Write the 1st quad. |
| if (needsInnerTriangles) { |
| TrianglePatch(*this) << p0 << abc.lo << abc.hi; |
| } |
| CubicPatch(*this) << abc.lo << middle << abc.hi; // Write the 2nd quad. |
| if (needsInnerTriangles) { |
| *this << innerTriangulator.pushVertex(to_skpoint(abc.hi)); |
| } |
| std::tie(p0, p1) = {abc.hi, bc.hi}; // Save the 3rd quad. |
| } |
| if (numPatches == 2) { |
| // Chop into 2 quads. |
| float2 ab = (p0 + p1) * .5f; |
| float2 bc = (p1 + p2) * .5f; |
| float2 abc = (ab + bc) * .5f; |
| |
| CubicPatch(*this) << QuadToCubic{p0, ab, abc}; // Write the 1st quad. |
| if (needsInnerTriangles) { |
| TrianglePatch(*this) << p0 << abc << p2; |
| } |
| CubicPatch(*this) << QuadToCubic{abc, bc, p2}; // Write the 2nd quad. |
| } else { |
| SkASSERT(numPatches == 1); |
| CubicPatch(*this) << QuadToCubic{p0, p1, p2}; // Write the single quad. |
| } |
| if (needsInnerTriangles) { |
| *this << innerTriangulator.pushVertex(to_skpoint(p2)); |
| *this << innerTriangulator.close(); |
| } |
| } |
| |
| void PatchWriter::chopAndWriteConics(float2 p0, float2 p1, float2 p2, float w, int numPatches) { |
| // If we aren't fanning, we need to fill the space between chops with triangles. |
| bool needsInnerTriangles = !(fAttribs & PatchAttribs::kFanPoint); |
| MiddleOutPolygonTriangulator innerTriangulator(numPatches, to_skpoint(p0)); |
| // Load the conic in 3d homogeneous (unprojected) space. |
| float4 h0 = float4(p0,1,1); |
| float4 h1 = float4(p1,1,1) * w; |
| float4 h2 = float4(p2,1,1); |
| for (; numPatches >= 2; --numPatches) { |
| // Chop in homogeneous space. |
| float T = 1.f/numPatches; |
| float4 ab = mix(h0, h1, T); |
| float4 bc = mix(h1, h2, T); |
| float4 abc = mix(ab, bc, T); |
| |
| // Project and write the 1st conic. |
| float2 midpoint = abc.xy() / abc.w(); |
| ConicPatch(*this) << (h0.xy() / h0.w()) |
| << (ab.xy() / ab.w()) |
| << midpoint |
| << (ab.w() / sqrtf(h0.w() * abc.w())); |
| if (needsInnerTriangles) { |
| *this << innerTriangulator.pushVertex(to_skpoint(midpoint)); |
| } |
| std::tie(h0, h1) = {abc, bc}; // Save the 2nd conic (in homogeneous space). |
| } |
| // Project and write the remaining conic. |
| SkASSERT(numPatches == 1); |
| ConicPatch(*this) << (h0.xy() / h0.w()) |
| << (h1.xy() / h1.w()) |
| << h2.xy() // h2.w == 1 |
| << (h1.w() / sqrtf(h0.w())); |
| if (needsInnerTriangles) { |
| *this << innerTriangulator.pushVertex(to_skpoint(h2.xy())); |
| *this << innerTriangulator.close(); |
| } |
| } |
| |
| void PatchWriter::chopAndWriteCubics(float2 p0, float2 p1, float2 p2, float2 p3, int numPatches) { |
| // If we aren't fanning, we need to fill the space between chops with triangles. |
| bool needsInnerTriangles = !(fAttribs & PatchAttribs::kFanPoint); |
| MiddleOutPolygonTriangulator innerTriangulator(numPatches, to_skpoint(p0)); |
| for (; numPatches >= 3; numPatches -= 2) { |
| // Chop into 3 cubics. |
| float4 T = float4(1,1,2,2) / numPatches; |
| float4 ab = mix(p0.xyxy(), p1.xyxy(), T); |
| float4 bc = mix(p1.xyxy(), p2.xyxy(), T); |
| float4 cd = mix(p2.xyxy(), p3.xyxy(), T); |
| float4 abc = mix(ab, bc, T); |
| float4 bcd = mix(bc, cd, T); |
| float4 abcd = mix(abc, bcd, T); |
| float4 middle = mix(abc, bcd, T.zwxy()); // p1 & p2 of the middle cubic. |
| |
| CubicPatch(*this) << p0 << ab.lo << abc.lo << abcd.lo; // Write the 1st cubic. |
| if (needsInnerTriangles) { |
| TrianglePatch(*this) << p0 << abcd.lo << abcd.hi; |
| } |
| CubicPatch(*this) << abcd.lo << middle << abcd.hi; // Write the 2nd cubic. |
| if (needsInnerTriangles) { |
| *this << innerTriangulator.pushVertex(to_skpoint(abcd.hi)); |
| } |
| std::tie(p0, p1, p2) = {abcd.hi, bcd.hi, cd.hi}; // Save the 3rd cubic. |
| } |
| if (numPatches == 2) { |
| // Chop into 2 cubics. |
| float2 ab = (p0 + p1) * .5f; |
| float2 bc = (p1 + p2) * .5f; |
| float2 cd = (p2 + p3) * .5f; |
| float2 abc = (ab + bc) * .5f; |
| float2 bcd = (bc + cd) * .5f; |
| float2 abcd = (abc + bcd) * .5f; |
| |
| CubicPatch(*this) << p0 << ab << abc << abcd; // Write the 1st cubic. |
| if (needsInnerTriangles) { |
| TrianglePatch(*this) << p0 << abcd << p3; |
| } |
| CubicPatch(*this) << abcd << bcd << cd << p3; // Write the 2nd cubic. |
| } else { |
| SkASSERT(numPatches == 1); |
| CubicPatch(*this) << p0 << p1 << p2 << p3; // Write the single cubic. |
| } |
| if (needsInnerTriangles) { |
| *this << innerTriangulator.pushVertex(to_skpoint(p3)); |
| *this << innerTriangulator.close(); |
| } |
| } |
| |
| } // namespace skgpu |