| /* |
| * Copyright 2017 Google Inc. |
| * |
| * Use of this source code is governed by a BSD-style license that can be |
| * found in the LICENSE file. |
| */ |
| |
| #include "GrCCCoverageProcessor.h" |
| |
| #include "GrGpuCommandBuffer.h" |
| #include "GrOpFlushState.h" |
| #include "SkMakeUnique.h" |
| #include "ccpr/GrCCCubicShader.h" |
| #include "ccpr/GrCCQuadraticShader.h" |
| #include "glsl/GrGLSLVertexGeoBuilder.h" |
| #include "glsl/GrGLSLFragmentShaderBuilder.h" |
| #include "glsl/GrGLSLVertexGeoBuilder.h" |
| |
| class GrCCCoverageProcessor::TriangleShader : public GrCCCoverageProcessor::Shader { |
| void onEmitVaryings(GrGLSLVaryingHandler* varyingHandler, GrGLSLVarying::Scope scope, |
| SkString* code, const char* position, const char* coverage, |
| const char* cornerCoverage) override { |
| if (!cornerCoverage) { |
| fCoverages.reset(kHalf_GrSLType, scope); |
| varyingHandler->addVarying("coverage", &fCoverages); |
| code->appendf("%s = %s;", OutName(fCoverages), coverage); |
| } else { |
| fCoverages.reset(kHalf3_GrSLType, scope); |
| varyingHandler->addVarying("coverages", &fCoverages); |
| code->appendf("%s = half3(%s, %s);", OutName(fCoverages), coverage, cornerCoverage); |
| } |
| } |
| |
| void onEmitFragmentCode(GrGLSLFPFragmentBuilder* f, const char* outputCoverage) const override { |
| if (kHalf_GrSLType == fCoverages.type()) { |
| f->codeAppendf("%s = %s;", outputCoverage, fCoverages.fsIn()); |
| } else { |
| f->codeAppendf("%s = %s.z * %s.y + %s.x;", |
| outputCoverage, fCoverages.fsIn(), fCoverages.fsIn(), fCoverages.fsIn()); |
| } |
| } |
| |
| GrGLSLVarying fCoverages; |
| }; |
| |
| void GrCCCoverageProcessor::Shader::EmitEdgeDistanceEquation(GrGLSLVertexGeoBuilder* s, |
| const char* leftPt, |
| const char* rightPt, |
| const char* outputDistanceEquation) { |
| s->codeAppendf("float2 n = float2(%s.y - %s.y, %s.x - %s.x);", |
| rightPt, leftPt, leftPt, rightPt); |
| s->codeAppend ("float nwidth = (abs(n.x) + abs(n.y)) * (bloat * 2);"); |
| // When nwidth=0, wind must also be 0 (and coverage * wind = 0). So it doesn't matter what we |
| // come up with here as long as it isn't NaN or Inf. |
| s->codeAppend ("n /= (0 != nwidth) ? nwidth : 1;"); |
| s->codeAppendf("%s = float3(-n, dot(n, %s) - .5);", outputDistanceEquation, leftPt); |
| } |
| |
| void GrCCCoverageProcessor::Shader::CalcEdgeCoverageAtBloatVertex(GrGLSLVertexGeoBuilder* s, |
| const char* leftPt, |
| const char* rightPt, |
| const char* rasterVertexDir, |
| const char* outputCoverage) { |
| // Here we find an edge's coverage at one corner of a conservative raster bloat box whose center |
| // falls on the edge in question. (A bloat box is axis-aligned and the size of one pixel.) We |
| // always set up coverage so it is -1 at the outermost corner, 0 at the innermost, and -.5 at |
| // the center. Interpolated, these coverage values convert jagged conservative raster edges into |
| // smooth antialiased edges. |
| // |
| // d1 == (P + sign(n) * bloat) dot n (Distance at the bloat box vertex whose |
| // == P dot n + (abs(n.x) + abs(n.y)) * bloatSize coverage=-1, where the bloat box is |
| // centered on P.) |
| // |
| // d0 == (P - sign(n) * bloat) dot n (Distance at the bloat box vertex whose |
| // == P dot n - (abs(n.x) + abs(n.y)) * bloatSize coverage=0, where the bloat box is |
| // centered on P.) |
| // |
| // d == (P + rasterVertexDir * bloatSize) dot n (Distance at the bloat box vertex whose |
| // == P dot n + (rasterVertexDir dot n) * bloatSize coverage we wish to calculate.) |
| // |
| // coverage == -(d - d0) / (d1 - d0) (coverage=-1 at d=d1; coverage=0 at d=d0) |
| // |
| // == (rasterVertexDir dot n) / (abs(n.x) + abs(n.y)) * -.5 - .5 |
| // |
| s->codeAppendf("float2 n = float2(%s.y - %s.y, %s.x - %s.x);", |
| rightPt, leftPt, leftPt, rightPt); |
| s->codeAppend ("float nwidth = abs(n.x) + abs(n.y);"); |
| s->codeAppendf("float t = dot(%s, n);", rasterVertexDir); |
| // The below conditional guarantees we get exactly 1 on the divide when nwidth=t (in case the |
| // GPU divides by multiplying by the reciprocal?) It also guards against NaN when nwidth=0. |
| s->codeAppendf("%s = (abs(t) != nwidth ? t / nwidth : sign(t)) * -.5 - .5;", outputCoverage); |
| } |
| |
| void GrCCCoverageProcessor::Shader::CalcEdgeCoveragesAtBloatVertices(GrGLSLVertexGeoBuilder* s, |
| const char* leftPt, |
| const char* rightPt, |
| const char* bloatDir1, |
| const char* bloatDir2, |
| const char* outputCoverages) { |
| // See comments in CalcEdgeCoverageAtBloatVertex. |
| s->codeAppendf("float2 n = float2(%s.y - %s.y, %s.x - %s.x);", |
| rightPt, leftPt, leftPt, rightPt); |
| s->codeAppend ("float nwidth = abs(n.x) + abs(n.y);"); |
| s->codeAppendf("float2 t = n * float2x2(%s, %s);", bloatDir1, bloatDir2); |
| s->codeAppendf("for (int i = 0; i < 2; ++i) {"); |
| s->codeAppendf( "%s[i] = (abs(t[i]) != nwidth ? t[i] / nwidth : sign(t[i])) * -.5 - .5;", |
| outputCoverages); |
| s->codeAppendf("}"); |
| } |
| |
| void GrCCCoverageProcessor::Shader::CalcCornerAttenuation(GrGLSLVertexGeoBuilder* s, |
| const char* leftDir, const char* rightDir, |
| const char* outputAttenuation) { |
| // obtuseness = cos(corner_angle) if corner_angle > 90 degrees |
| // 0 if corner_angle <= 90 degrees |
| s->codeAppendf("half obtuseness = max(dot(%s, %s), 0);", leftDir, rightDir); |
| |
| // axis_alignedness = 1 when the leftDir/rightDir bisector is aligned with the x- or y-axis |
| // 0 when the bisector falls on a 45 degree angle |
| // (i.e. 1 - tan(angle_to_nearest_axis)) |
| s->codeAppendf("half2 abs_bisect = abs(%s - %s);", leftDir, rightDir); |
| s->codeAppend ("half axis_alignedness = 1 - min(abs_bisect.y, abs_bisect.x) / " |
| "max(abs_bisect.x, abs_bisect.y);"); |
| |
| // ninety_degreesness = sin^2(corner_angle) |
| // sin^2 just because... it's always positive and the results looked better than plain sine... ? |
| s->codeAppendf("half ninety_degreesness = determinant(half2x2(%s, %s));", leftDir, rightDir); |
| s->codeAppend ("ninety_degreesness = ninety_degreesness * ninety_degreesness;"); |
| |
| // The below formula is not smart. It was just arrived at by considering the following |
| // observations: |
| // |
| // 1. 90-degree, axis-aligned corners have full attenuation along the bisector. |
| // (i.e. coverage = 1 - distance_to_corner^2) |
| // (i.e. outputAttenuation = 0) |
| // |
| // 2. 180-degree corners always have zero attenuation. |
| // (i.e. coverage = 1 - distance_to_corner) |
| // (i.e. outputAttenuation = 1) |
| // |
| // 3. 90-degree corners whose bisector falls on a 45 degree angle also do not attenuate. |
| // (i.e. outputAttenuation = 1) |
| s->codeAppendf("%s = max(obtuseness, axis_alignedness * ninety_degreesness);", |
| outputAttenuation); |
| } |
| |
| void GrCCCoverageProcessor::getGLSLProcessorKey(const GrShaderCaps&, |
| GrProcessorKeyBuilder* b) const { |
| int key = (int)fPrimitiveType << 2; |
| if (GSSubpass::kCorners == fGSSubpass) { |
| key |= 2; |
| } |
| if (Impl::kVertexShader == fImpl) { |
| key |= 1; |
| } |
| #ifdef SK_DEBUG |
| uint32_t bloatBits; |
| memcpy(&bloatBits, &fDebugBloat, 4); |
| b->add32(bloatBits); |
| #endif |
| b->add32(key); |
| } |
| |
| GrGLSLPrimitiveProcessor* GrCCCoverageProcessor::createGLSLInstance(const GrShaderCaps&) const { |
| std::unique_ptr<Shader> shader; |
| switch (fPrimitiveType) { |
| case PrimitiveType::kTriangles: |
| case PrimitiveType::kWeightedTriangles: |
| shader = skstd::make_unique<TriangleShader>(); |
| break; |
| case PrimitiveType::kQuadratics: |
| shader = skstd::make_unique<GrCCQuadraticShader>(); |
| break; |
| case PrimitiveType::kCubics: |
| shader = skstd::make_unique<GrCCCubicShader>(); |
| break; |
| } |
| return Impl::kGeometryShader == fImpl ? this->createGSImpl(std::move(shader)) |
| : this->createVSImpl(std::move(shader)); |
| } |
| |
| void GrCCCoverageProcessor::Shader::emitFragmentCode(const GrCCCoverageProcessor& proc, |
| GrGLSLFPFragmentBuilder* f, |
| const char* skOutputColor, |
| const char* skOutputCoverage) const { |
| f->codeAppendf("half coverage = 0;"); |
| this->onEmitFragmentCode(f, "coverage"); |
| f->codeAppendf("%s.a = coverage;", skOutputColor); |
| f->codeAppendf("%s = half4(1);", skOutputCoverage); |
| } |
| |
| void GrCCCoverageProcessor::draw(GrOpFlushState* flushState, const GrPipeline& pipeline, |
| const GrMesh meshes[], |
| const GrPipeline::DynamicState dynamicStates[], int meshCount, |
| const SkRect& drawBounds) const { |
| GrGpuRTCommandBuffer* cmdBuff = flushState->rtCommandBuffer(); |
| cmdBuff->draw(pipeline, *this, meshes, dynamicStates, meshCount, drawBounds); |
| |
| // Geometry shader backend draws primitives in two subpasses. |
| if (Impl::kGeometryShader == fImpl) { |
| SkASSERT(GSSubpass::kHulls == fGSSubpass); |
| GrCCCoverageProcessor cornerProc(*this, GSSubpass::kCorners); |
| cmdBuff->draw(pipeline, cornerProc, meshes, dynamicStates, meshCount, drawBounds); |
| } |
| } |
