xref: /aosp_15_r20/external/skia/src/gpu/ganesh/tessellate/VertexChunkPatchAllocator.h (revision c8dee2aa9b3f27cf6c858bd81872bdeb2c07ed17)
1 /*
2  * Copyright 2022 Google LLC
3  *
4  * Use of this source code is governed by a BSD-style license that can be
5  * found in the LICENSE file.
6  */
7 
8 #ifndef VertexChunkPatchAllocator_DEFINED
9 #define VertexChunkPatchAllocator_DEFINED
10 
11 #include "src/gpu/BufferWriter.h"
12 #include "src/gpu/ganesh/GrVertexChunkArray.h"
13 #include "src/gpu/tessellate/LinearTolerances.h"
14 
15 #include <cstddef>
16 
17 class GrMeshDrawTarget;
18 
19 namespace skgpu::ganesh {
20 
21 // An adapter around GrVertexChunkBuilder that fits the API requirements of
22 // skgpu::tess::PatchWriter's PatchAllocator template parameter.
23 class VertexChunkPatchAllocator {
24 public:
25     // 'stride' is provided by PatchWriter.
26     // 'worstCaseTolerances' is used to accumulate the LinearTolerances from each append().
27     // 'target', 'chunks', and 'minVerticesPerChunk' are forwarded from the PatchWriter's ctor and
28     // are used to construct a GrVertexChunkBuilder matching the PatchWriter's stride.
VertexChunkPatchAllocator(size_t stride,tess::LinearTolerances * worstCaseTolerances,GrMeshDrawTarget * target,GrVertexChunkArray * chunks,int minVerticesPerChunk)29     VertexChunkPatchAllocator(size_t stride,
30                               tess::LinearTolerances* worstCaseTolerances,
31                               GrMeshDrawTarget* target,
32                               GrVertexChunkArray* chunks,
33                               int minVerticesPerChunk)
34             : fWorstCaseTolerances(worstCaseTolerances)
35             , fBuilder(target, chunks, stride, minVerticesPerChunk) {}
36 
append(const tess::LinearTolerances & tolerances)37     VertexWriter append(const tess::LinearTolerances& tolerances) {
38         fWorstCaseTolerances->accumulate(tolerances);
39         return fBuilder.appendVertices(1);
40     }
41 
42 private:
43     tess::LinearTolerances* fWorstCaseTolerances;
44     GrVertexChunkBuilder    fBuilder;
45 };
46 
47 }  // namespace skgpu::ganesh
48 
49 #endif // VertexChunkPatchAllocator_DEFINED
50