| /* |
| * 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 "src/gpu/ccpr/GrCCCoverageProcessor.h" |
| |
| #include "src/core/SkMakeUnique.h" |
| #include "src/gpu/GrOpFlushState.h" |
| #include "src/gpu/GrOpsRenderPass.h" |
| #include "src/gpu/GrProgramInfo.h" |
| #include "src/gpu/ccpr/GrCCConicShader.h" |
| #include "src/gpu/ccpr/GrCCCubicShader.h" |
| #include "src/gpu/ccpr/GrCCQuadraticShader.h" |
| #include "src/gpu/glsl/GrGLSLFragmentShaderBuilder.h" |
| #include "src/gpu/glsl/GrGLSLVertexGeoBuilder.h" |
| #include "src/gpu/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, |
| const char* /*wind*/) 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 emitFragmentCoverageCode( |
| 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()); |
| } |
| } |
| |
| void emitSampleMaskCode(GrGLSLFPFragmentBuilder*) const override { return; } |
| |
| GrGLSLVarying fCoverages; |
| }; |
| |
| void GrCCCoverageProcessor::Shader::CalcWind(const GrCCCoverageProcessor& proc, |
| GrGLSLVertexGeoBuilder* s, const char* pts, |
| const char* outputWind) { |
| if (3 == proc.numInputPoints()) { |
| s->codeAppendf("float2 a = %s[0] - %s[1], " |
| "b = %s[0] - %s[2];", pts, pts, pts, pts); |
| } else { |
| // All inputs are convex, so it's sufficient to just average the middle two input points. |
| SkASSERT(4 == proc.numInputPoints()); |
| s->codeAppendf("float2 p12 = (%s[1] + %s[2]) * .5;", pts, pts); |
| s->codeAppendf("float2 a = %s[0] - p12, " |
| "b = %s[0] - %s[3];", pts, pts, pts); |
| } |
| |
| s->codeAppend ("float area_x2 = determinant(float2x2(a, b));"); |
| if (proc.isTriangles()) { |
| // We cull extremely thin triangles by zeroing wind. When a triangle gets too thin it's |
| // possible for FP round-off error to actually give us the wrong winding direction, causing |
| // rendering artifacts. The criteria we choose is "height <~ 1/1024". So we drop a triangle |
| // if the max effect it can have on any single pixel is <~ 1/1024, or 1/4 of a bit in 8888. |
| s->codeAppend ("float2 bbox_size = max(abs(a), abs(b));"); |
| s->codeAppend ("float basewidth = max(bbox_size.x + bbox_size.y, 1);"); |
| s->codeAppendf("%s = (abs(area_x2 * 1024) > basewidth) ? sign(half(area_x2)) : 0;", |
| outputWind); |
| } else { |
| // We already converted nearly-flat curves to lines on the CPU, so no need to worry about |
| // thin curve hulls at this point. |
| s->codeAppendf("%s = sign(half(area_x2));", outputWind); |
| } |
| } |
| |
| 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 = half(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] = half(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 |
| // |
| // NOTE: leftDir and rightDir are normalized and point in the same direction the path was |
| // defined with, i.e., leftDir points into the corner and rightDir points away from the corner. |
| s->codeAppendf("half obtuseness = max(half(dot(%s, %s)), 0);", leftDir, rightDir); |
| |
| // axis_alignedness = 1 - tan(angle_to_nearest_axis_from_corner_bisector) |
| // (i.e., 1 when the corner bisector is aligned with the x- or y-axis |
| // 0 when the corner bisector falls on a 45 degree angle |
| // 0..1 when the corner bisector falls somewhere in between |
| s->codeAppendf("half2 abs_bisect_maybe_transpose = abs((0 == obtuseness) ? half2(%s - %s) : " |
| "half2(%s + %s));", |
| leftDir, rightDir, leftDir, rightDir); |
| s->codeAppend ("half axis_alignedness = " |
| "1 - min(abs_bisect_maybe_transpose.y, abs_bisect_maybe_transpose.x) / " |
| "max(abs_bisect_maybe_transpose.x, abs_bisect_maybe_transpose.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); |
| } |
| |
| 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; |
| case PrimitiveType::kConics: |
| shader = skstd::make_unique<GrCCConicShader>(); |
| break; |
| } |
| return this->onCreateGLSLInstance(std::move(shader)); |
| } |
| |
| void GrCCCoverageProcessor::draw( |
| GrOpFlushState* flushState, const GrPipeline& pipeline, const SkIRect scissorRects[], |
| const GrMesh meshes[], int meshCount, const SkRect& drawBounds) const { |
| GrPipeline::DynamicStateArrays dynamicStateArrays; |
| dynamicStateArrays.fScissorRects = scissorRects; |
| GrOpsRenderPass* renderPass = flushState->opsRenderPass(); |
| |
| GrProgramInfo programInfo(flushState->drawOpArgs().numSamples(), |
| flushState->drawOpArgs().origin(), |
| pipeline, |
| *this, |
| nullptr, |
| &dynamicStateArrays, 0); |
| |
| |
| renderPass->draw(programInfo, meshes, meshCount, drawBounds); |
| } |
