Reland "Delete the index buffer from middle-out tessellation"
This is a reland of 0d0b1b3b56da6d13506d34756c79a79c4929950f
Original change's description:
> Delete the index buffer from middle-out tessellation
>
> This gives us more flexibility for customizing triangulations in
> future modes. It is also hopefully cheaper than the extra memory
> indirection from indexed draws.
>
> Bug: skia:10419
> Bug: chromium:1202607
> Change-Id: Iba41a35a634edf8f962c3d604c7e035e7a85801d
> Reviewed-on: https://skia-review.googlesource.com/c/skia/+/407296
> Commit-Queue: Chris Dalton <csmartdalton@google.com>
> Reviewed-by: Greg Daniel <egdaniel@google.com>
Bug: skia:10419
Bug: chromium:1202607
Change-Id: I2f5022d2122dee1ca197780b534663b37cd2504f
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/408236
Reviewed-by: Greg Daniel <egdaniel@google.com>
Commit-Queue: Chris Dalton <csmartdalton@google.com>
diff --git a/src/gpu/GrDrawIndirectCommand.h b/src/gpu/GrDrawIndirectCommand.h
index 17cd709..d645223 100644
--- a/src/gpu/GrDrawIndirectCommand.h
+++ b/src/gpu/GrDrawIndirectCommand.h
@@ -52,7 +52,7 @@
bool operator==(const GrDrawIndirectWriter& that) { return fData == that.fData; }
- bool isValid() const { return fData != nullptr; }
+ operator bool() const { return fData != nullptr; }
GrDrawIndirectWriter makeOffset(int drawCount) const { return {fData + drawCount}; }
diff --git a/src/gpu/GrShaderCaps.cpp b/src/gpu/GrShaderCaps.cpp
index 0beba60..22ec760 100644
--- a/src/gpu/GrShaderCaps.cpp
+++ b/src/gpu/GrShaderCaps.cpp
@@ -51,7 +51,7 @@
fSampleMaskSupport = false;
fExternalTextureSupport = false;
fVertexIDSupport = false;
- fFPManipulationSupport = false;
+ fBitManipulationSupport = false;
fFloatIs32Bits = true;
fHalfIs32Bits = false;
fHasLowFragmentPrecision = false;
@@ -135,7 +135,7 @@
writer->appendBool("Sample mask support", fSampleMaskSupport);
writer->appendBool("External texture support", fExternalTextureSupport);
writer->appendBool("sk_VertexID support", fVertexIDSupport);
- writer->appendBool("Floating point manipulation support", fFPManipulationSupport);
+ writer->appendBool("Bit manipulation support", fBitManipulationSupport);
writer->appendBool("float == fp32", fFloatIs32Bits);
writer->appendBool("half == fp32", fHalfIs32Bits);
writer->appendBool("Has poor fragment precision", fHasLowFragmentPrecision);
diff --git a/src/gpu/GrShaderCaps.h b/src/gpu/GrShaderCaps.h
index bf47593..446dc74 100644
--- a/src/gpu/GrShaderCaps.h
+++ b/src/gpu/GrShaderCaps.h
@@ -76,8 +76,8 @@
bool vertexIDSupport() const { return fVertexIDSupport; }
- // frexp, ldexp, etc.
- bool fpManipulationSupport() const { return fFPManipulationSupport; }
+ // frexp, ldexp, findMSB, findLSB.
+ bool bitManipulationSupport() const { return fBitManipulationSupport; }
bool floatIs32Bits() const { return fFloatIs32Bits; }
@@ -289,7 +289,7 @@
bool fSampleMaskSupport : 1;
bool fExternalTextureSupport : 1;
bool fVertexIDSupport : 1;
- bool fFPManipulationSupport : 1;
+ bool fBitManipulationSupport : 1;
bool fFloatIs32Bits : 1;
bool fHalfIs32Bits : 1;
bool fHasLowFragmentPrecision : 1;
diff --git a/src/gpu/d3d/GrD3DCaps.cpp b/src/gpu/d3d/GrD3DCaps.cpp
index 9bd72bf..940c7aa 100644
--- a/src/gpu/d3d/GrD3DCaps.cpp
+++ b/src/gpu/d3d/GrD3DCaps.cpp
@@ -241,7 +241,7 @@
shaderCaps->fIntegerSupport = true;
shaderCaps->fVertexIDSupport = true;
- shaderCaps->fFPManipulationSupport = true;
+ shaderCaps->fBitManipulationSupport = true;
shaderCaps->fFloatIs32Bits = true;
shaderCaps->fHalfIs32Bits =
diff --git a/src/gpu/gl/GrGLCaps.cpp b/src/gpu/gl/GrGLCaps.cpp
index e2f43a4..5d4a686 100644
--- a/src/gpu/gl/GrGLCaps.cpp
+++ b/src/gpu/gl/GrGLCaps.cpp
@@ -955,9 +955,9 @@
}
if (GR_IS_GR_GL(standard)) {
- shaderCaps->fFPManipulationSupport = ctxInfo.glslGeneration() >= k400_GrGLSLGeneration;
+ shaderCaps->fBitManipulationSupport = ctxInfo.glslGeneration() >= k400_GrGLSLGeneration;
} else if (GR_IS_GR_GL_ES(standard) || GR_IS_GR_WEBGL(standard)) {
- shaderCaps->fFPManipulationSupport = ctxInfo.glslGeneration() >= k310es_GrGLSLGeneration;
+ shaderCaps->fBitManipulationSupport = ctxInfo.glslGeneration() >= k310es_GrGLSLGeneration;
}
shaderCaps->fFloatIs32Bits = is_float_fp32(ctxInfo, gli, GR_GL_HIGH_FLOAT);
diff --git a/src/gpu/tessellate/GrPathTessellator.cpp b/src/gpu/tessellate/GrPathTessellator.cpp
index 7fe80ae..ce31813 100644
--- a/src/gpu/tessellate/GrPathTessellator.cpp
+++ b/src/gpu/tessellate/GrPathTessellator.cpp
@@ -101,19 +101,13 @@
SkASSERT(count == breadcrumbTriangleList->count());
}
- fIndirectIndexBuffer = GrMiddleOutCubicShader::FindOrMakeMiddleOutIndexBuffer(
- target->resourceProvider());
- if (!fIndirectIndexBuffer) {
- vertexAlloc.unlock(0);
- return;
- }
-
// Allocate space for the GrDrawIndexedIndirectCommand structs. Allocate enough for each
// possible resolve level (kMaxResolveLevel; resolveLevel=0 never has any instances), plus one
// more for the optional inner fan triangles.
int indirectLockCnt = kMaxResolveLevel + 1;
- GrDrawIndexedIndirectWriter indirectWriter = target->makeDrawIndexedIndirectSpace(
- indirectLockCnt, &fIndirectDrawBuffer, &fIndirectDrawOffset);
+ GrDrawIndirectWriter indirectWriter = target->makeDrawIndirectSpace(indirectLockCnt,
+ &fIndirectDrawBuffer,
+ &fIndirectDrawOffset);
if (!indirectWriter) {
SkASSERT(!fIndirectDrawBuffer);
vertexAlloc.unlock(0);
@@ -220,9 +214,9 @@
void GrPathIndirectTessellator::draw(GrOpFlushState* flushState) const {
if (fIndirectDrawCount) {
- flushState->bindBuffers(fIndirectIndexBuffer, fInstanceBuffer, nullptr);
- flushState->drawIndexedIndirect(fIndirectDrawBuffer.get(), fIndirectDrawOffset,
- fIndirectDrawCount);
+ flushState->bindBuffers(nullptr, fInstanceBuffer, nullptr);
+ flushState->drawIndirect(fIndirectDrawBuffer.get(), fIndirectDrawOffset,
+ fIndirectDrawCount);
}
}
diff --git a/src/gpu/tessellate/GrPathTessellator.h b/src/gpu/tessellate/GrPathTessellator.h
index 393ac26..96494c4 100644
--- a/src/gpu/tessellate/GrPathTessellator.h
+++ b/src/gpu/tessellate/GrPathTessellator.h
@@ -71,7 +71,6 @@
sk_sp<const GrBuffer> fIndirectDrawBuffer;
size_t fIndirectDrawOffset = 0;
int fIndirectDrawCount = 0;
- sk_sp<const GrBuffer> fIndirectIndexBuffer;
};
// Base class for GrPathTessellators that draw actual hardware tessellation patches.
diff --git a/src/gpu/tessellate/GrStencilPathShader.cpp b/src/gpu/tessellate/GrStencilPathShader.cpp
index fb4aee8..b827b6c 100644
--- a/src/gpu/tessellate/GrStencilPathShader.cpp
+++ b/src/gpu/tessellate/GrStencilPathShader.cpp
@@ -302,100 +302,56 @@
return new WedgeImpl;
}
-constexpr static int kMaxResolveLevel = GrTessellationPathRenderer::kMaxResolveLevel;
-
-GR_DECLARE_STATIC_UNIQUE_KEY(gMiddleOutIndexBufferKey);
-
-sk_sp<const GrGpuBuffer> GrMiddleOutCubicShader::FindOrMakeMiddleOutIndexBuffer(
- GrResourceProvider* resourceProvider) {
- GR_DEFINE_STATIC_UNIQUE_KEY(gMiddleOutIndexBufferKey);
- if (auto buffer = resourceProvider->findByUniqueKey<GrGpuBuffer>(gMiddleOutIndexBufferKey)) {
- return std::move(buffer);
- }
-
- // One explicit triangle at index 0, and one middle-out cubic with kMaxResolveLevel line
- // segments beginning at index 3.
- constexpr static int kIndexCount = 3 + NumVerticesAtResolveLevel(kMaxResolveLevel);
- auto buffer = resourceProvider->createBuffer(
- kIndexCount * sizeof(uint16_t), GrGpuBufferType::kIndex, kStatic_GrAccessPattern);
- if (!buffer) {
- return nullptr;
- }
-
- // We shouldn't bin and/or cache static buffers.
- SkASSERT(buffer->size() == kIndexCount * sizeof(uint16_t));
- SkASSERT(!buffer->resourcePriv().getScratchKey().isValid());
- auto indexData = static_cast<uint16_t*>(buffer->map());
- SkAutoTMalloc<uint16_t> stagingBuffer;
- if (!indexData) {
- SkASSERT(!buffer->isMapped());
- indexData = stagingBuffer.reset(kIndexCount);
- }
-
- // Indices 0,1,2 contain special values that emit points P0, P1, and P2 respectively. (When the
- // vertex shader is fed an index value larger than (1 << kMaxResolveLevel), it emits
- // P[index % 4].)
- int i = 0;
- indexData[i++] = (1 << kMaxResolveLevel) + 4; // % 4 == 0
- indexData[i++] = (1 << kMaxResolveLevel) + 5; // % 4 == 1
- indexData[i++] = (1 << kMaxResolveLevel) + 6; // % 4 == 2
-
- // Starting at index 3, we triangulate a cubic with 2^kMaxResolveLevel line segments. Each
- // index value corresponds to parametric value T=(index / 2^kMaxResolveLevel). Since the
- // triangles are arranged in "middle-out" order, we will be able to conveniently control the
- // resolveLevel by changing only the indexCount.
- for (uint16_t advance = 1 << (kMaxResolveLevel - 1); advance; advance >>= 1) {
- uint16_t T = 0;
- do {
- indexData[i++] = T;
- indexData[i++] = (T += advance);
- indexData[i++] = (T += advance);
- } while (T != (1 << kMaxResolveLevel));
- }
- SkASSERT(i == kIndexCount);
-
- if (buffer->isMapped()) {
- buffer->unmap();
- } else {
- buffer->updateData(stagingBuffer, kIndexCount * sizeof(uint16_t));
- }
- buffer->resourcePriv().setUniqueKey(gMiddleOutIndexBufferKey);
- return std::move(buffer);
-}
-
class GrMiddleOutCubicShader::Impl : public GrStencilPathShader::Impl {
void onEmitCode(EmitArgs& args, GrGPArgs* gpArgs) override {
const auto& shader = args.fGeomProc.cast<GrMiddleOutCubicShader>();
args.fVaryingHandler->emitAttributes(shader);
- args.fVertBuilder->defineConstantf("int", "kMaxVertexID", "%i", 1 << kMaxResolveLevel);
- args.fVertBuilder->defineConstantf("float", "kInverseMaxVertexID",
- "(1.0 / float(kMaxVertexID))");
args.fVertBuilder->insertFunction(kUnpackRationalCubicFn);
args.fVertBuilder->insertFunction(kEvalRationalCubicFn);
+ if (args.fShaderCaps->bitManipulationSupport()) {
+ // Determines the T value at which to place the given vertex in a "middle-out" topology.
+ args.fVertBuilder->insertFunction(R"(
+ float find_middle_out_T() {
+ int totalTriangleIdx = sk_VertexID/3 + 1;
+ int depth = findMSB(totalTriangleIdx);
+ int firstTriangleAtDepth = (1 << depth);
+ int triangleIdxWithinDepth = totalTriangleIdx - firstTriangleAtDepth;
+ int vertexIdxWithinDepth = triangleIdxWithinDepth * 2 + sk_VertexID % 3;
+ return ldexp(float(vertexIdxWithinDepth), -1 - depth);
+ })");
+ } else {
+ // Determines the T value at which to place the given vertex in a "middle-out" topology.
+ args.fVertBuilder->insertFunction(R"(
+ float find_middle_out_T() {
+ float totalTriangleIdx = float(sk_VertexID/3) + 1;
+ float depth = floor(log2(totalTriangleIdx));
+ float firstTriangleAtDepth = exp2(depth);
+ float triangleIdxWithinDepth = totalTriangleIdx - firstTriangleAtDepth;
+ float vertexIdxWithinDepth = triangleIdxWithinDepth * 2 + float(sk_VertexID % 3);
+ return vertexIdxWithinDepth * exp2(-1 - depth);
+ })");
+ }
args.fVertBuilder->codeAppend(R"(
float2 pos;
if (isinf(inputPoints_2_3.z)) {
// A conic with w=Inf is an exact triangle.
- pos = (sk_VertexID == 0) ? inputPoints_0_1.xy :
- (sk_VertexID != kMaxVertexID) ? inputPoints_0_1.zw : inputPoints_2_3.xy;
+ pos = (sk_VertexID < 1) ? inputPoints_0_1.xy
+ : (sk_VertexID == 1) ? inputPoints_0_1.zw
+ : inputPoints_2_3.xy;
} else {
- // Evaluate the cubic at T = (sk_VertexID / 2^kMaxResolveLevel).
- float T = float(sk_VertexID) * kInverseMaxVertexID;
float4x3 P = unpack_rational_cubic(inputPoints_0_1.xy, inputPoints_0_1.zw,
inputPoints_2_3.xy, inputPoints_2_3.zw);
+ float T = find_middle_out_T();
pos = eval_rational_cubic(P, T);
})");
-
- GrShaderVar vertexPos("pos", kFloat2_GrSLType);
if (!shader.viewMatrix().isIdentity()) {
const char* viewMatrix;
fViewMatrixUniform = args.fUniformHandler->addUniform(
nullptr, kVertex_GrShaderFlag, kFloat3x3_GrSLType, "view_matrix", &viewMatrix);
args.fVertBuilder->codeAppendf(R"(
- float2 transformedPoint = (%s * float3(pos, 1)).xy;)", viewMatrix);
- vertexPos.set(kFloat2_GrSLType, "transformedPoint");
+ pos = (%s * float3(pos, 1)).xy;)", viewMatrix);
}
- gpArgs->fPositionVar = vertexPos;
+ gpArgs->fPositionVar.set(kFloat2_GrSLType, "pos");
// No fragment shader.
}
};
diff --git a/src/gpu/tessellate/GrStencilPathShader.h b/src/gpu/tessellate/GrStencilPathShader.h
index 203a184..ea12276 100644
--- a/src/gpu/tessellate/GrStencilPathShader.h
+++ b/src/gpu/tessellate/GrStencilPathShader.h
@@ -133,10 +133,17 @@
GrGLSLGeometryProcessor* createGLSLInstance(const GrShaderCaps&) const override;
};
-// Uses indirect (instanced) draws to triangulate standalone closed cubics with a "middle-out"
-// topology. The caller must compute each cubic's resolveLevel on the CPU (i.e., the log2 number of
-// line segments it will be divided into; see GrWangsFormula::cubic_log2/quadratic_log2), and then
-// sort the instance buffer by resolveLevel for efficient batching of indirect draws.
+// Uses instanced draws to triangulate standalone closed curves with a "middle-out" topology.
+// Middle-out draws a triangle with vertices at T=[0, 1/2, 1] and then recurses breadth first:
+//
+// depth=0: T=[0, 1/2, 1]
+// depth=1: T=[0, 1/4, 2/4], T=[2/4, 3/4, 1]
+// depth=2: T=[0, 1/8, 2/8], T=[2/8, 3/8, 4/8], T=[4/8, 5/8, 6/8], T=[6/8, 7/8, 1]
+// ...
+//
+// The caller may compute each cubic's resolveLevel on the CPU (i.e., the log2 number of line
+// segments it will be divided into; see GrWangsFormula::cubic_log2/quadratic_log2/conic_log2), and
+// then sort the instance buffer by resolveLevel for efficient batching of indirect draws.
class GrMiddleOutCubicShader : public GrStencilPathShader {
public:
// How many vertices do we need to draw in order to triangulate a cubic with 2^resolveLevel
@@ -152,21 +159,16 @@
// Configures an indirect draw to render cubic instances with 2^resolveLevel evenly-spaced (in
// the parametric sense) line segments.
- static void WriteDrawIndirectCmd(GrDrawIndexedIndirectWriter* indirectWriter, int resolveLevel,
+ static void WriteDrawIndirectCmd(GrDrawIndirectWriter* indirectWriter, int resolveLevel,
uint32_t instanceCount, uint32_t baseInstance) {
SkASSERT(resolveLevel > 0 && resolveLevel <= GrTessellationPathRenderer::kMaxResolveLevel);
- // Starting at baseIndex=3, the index buffer triangulates a cubic with 2^kMaxResolveLevel
- // line segments. Each index value corresponds to a parametric T value on the curve. Since
- // the triangles are arranged in "middle-out" order, we can conveniently control the
- // resolveLevel by changing only the indexCount.
- uint32_t indexCount = NumVerticesAtResolveLevel(resolveLevel);
- indirectWriter->writeIndexed(indexCount, 3, instanceCount, baseInstance, 0);
+ // The vertex shader determines the T value at which to draw each vertex. Since the
+ // triangles are arranged in "middle-out" order, we can conveniently control the
+ // resolveLevel by changing only the vertexCount.
+ uint32_t vertexCount = NumVerticesAtResolveLevel(resolveLevel);
+ indirectWriter->write(instanceCount, baseInstance, vertexCount, 0);
}
- // Returns the index buffer that should be bound when drawing with this shader.
- // (Our vertex shader uses raw index values directly, so there is no vertex buffer.)
- static sk_sp<const GrGpuBuffer> FindOrMakeMiddleOutIndexBuffer(GrResourceProvider*);
-
GrMiddleOutCubicShader(const SkMatrix& viewMatrix)
: GrStencilPathShader(kTessellate_GrMiddleOutCubicShader_ClassID, viewMatrix,
GrPrimitiveType::kTriangles) {
diff --git a/src/gpu/tessellate/GrStrokeIndirectTessellator.cpp b/src/gpu/tessellate/GrStrokeIndirectTessellator.cpp
index 593b38f..5fdf450 100644
--- a/src/gpu/tessellate/GrStrokeIndirectTessellator.cpp
+++ b/src/gpu/tessellate/GrStrokeIndirectTessellator.cpp
@@ -758,7 +758,7 @@
GrDrawIndirectWriter indirectWriter = target->makeDrawIndirectSpace(fChainedDrawIndirectCount,
&fDrawIndirectBuffer,
&fDrawIndirectOffset);
- if (!indirectWriter.isValid()) {
+ if (!indirectWriter) {
SkASSERT(!fDrawIndirectBuffer);
return;
}
diff --git a/src/gpu/vk/GrVkCaps.cpp b/src/gpu/vk/GrVkCaps.cpp
index 223b361..563b3df 100644
--- a/src/gpu/vk/GrVkCaps.cpp
+++ b/src/gpu/vk/GrVkCaps.cpp
@@ -716,7 +716,7 @@
shaderCaps->fIntegerSupport = true;
shaderCaps->fNonsquareMatrixSupport = true;
shaderCaps->fVertexIDSupport = true;
- shaderCaps->fFPManipulationSupport = true;
+ shaderCaps->fBitManipulationSupport = true;
// Assume the minimum precisions mandated by the SPIR-V spec.
shaderCaps->fFloatIs32Bits = true;
