1234567891011121314151617181920212223242526272829303132333435363738394041424344454647484950515253545556575859606162636465666768697071727374757677787980818283848586878889909192939495 |
- /*
- * 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/GrCCQuadraticShader.h"
- #include "src/gpu/glsl/GrGLSLFragmentShaderBuilder.h"
- #include "src/gpu/glsl/GrGLSLVertexGeoBuilder.h"
- void GrCCQuadraticShader::emitSetupCode(
- GrGLSLVertexGeoBuilder* s, const char* pts, const char** outHull4) const {
- s->declareGlobal(fQCoordMatrix);
- s->codeAppendf("%s = float2x2(1, 1, .5, 0) * inverse(float2x2(%s[2] - %s[0], %s[1] - %s[0]));",
- fQCoordMatrix.c_str(), pts, pts, pts, pts);
- s->declareGlobal(fQCoord0);
- s->codeAppendf("%s = %s[0];", fQCoord0.c_str(), pts);
- if (outHull4) {
- // Clip the bezier triangle by the tangent line at maximum height. Quadratics have the nice
- // property that maximum height always occurs at T=.5. This is a simple application for
- // De Casteljau's algorithm.
- s->codeAppend ("float2 quadratic_hull[4];");
- s->codeAppendf("quadratic_hull[0] = %s[0];", pts);
- s->codeAppendf("quadratic_hull[1] = (%s[0] + %s[1]) * .5;", pts, pts);
- s->codeAppendf("quadratic_hull[2] = (%s[1] + %s[2]) * .5;", pts, pts);
- s->codeAppendf("quadratic_hull[3] = %s[2];", pts);
- *outHull4 = "quadratic_hull";
- }
- }
- void GrCCQuadraticShader::onEmitVaryings(
- GrGLSLVaryingHandler* varyingHandler, GrGLSLVarying::Scope scope, SkString* code,
- const char* position, const char* coverage, const char* cornerCoverage, const char* wind) {
- fCoord_fGrad.reset(kFloat4_GrSLType, scope);
- varyingHandler->addVarying("coord_and_grad", &fCoord_fGrad);
- code->appendf("%s.xy = %s * (%s - %s);", // Quadratic coords.
- OutName(fCoord_fGrad), fQCoordMatrix.c_str(), position, fQCoord0.c_str());
- code->appendf("%s.zw = 2*bloat * float2(2 * %s.x, -1) * %s;", // Gradient.
- OutName(fCoord_fGrad), OutName(fCoord_fGrad), fQCoordMatrix.c_str());
- if (coverage) {
- // Coverages need full precision since distance to the opposite edge can be large.
- fEdge_fWind_fCorner.reset((cornerCoverage) ? kFloat4_GrSLType : kFloat2_GrSLType, scope);
- varyingHandler->addVarying((cornerCoverage) ? "edge_and_wind_and_corner" : "edge_and_wind",
- &fEdge_fWind_fCorner);
- code->appendf("%s.x = %s;", OutName(fEdge_fWind_fCorner), coverage);
- code->appendf("%s.y = %s;", OutName(fEdge_fWind_fCorner), wind);
- }
- if (cornerCoverage) {
- SkASSERT(coverage);
- code->appendf("half hull_coverage;");
- this->calcHullCoverage(code, OutName(fCoord_fGrad), coverage, "hull_coverage");
- code->appendf("%s.zw = half2(hull_coverage, 1) * %s;",
- OutName(fEdge_fWind_fCorner), cornerCoverage);
- }
- }
- void GrCCQuadraticShader::emitFragmentCoverageCode(
- GrGLSLFPFragmentBuilder* f, const char* outputCoverage) const {
- this->calcHullCoverage(&AccessCodeString(f), fCoord_fGrad.fsIn(),
- SkStringPrintf("%s.x", fEdge_fWind_fCorner.fsIn()).c_str(),
- outputCoverage);
- f->codeAppendf("%s *= half(%s.y);", outputCoverage, fEdge_fWind_fCorner.fsIn()); // Wind.
- if (kFloat4_GrSLType == fEdge_fWind_fCorner.type()) {
- f->codeAppendf("%s = half(%s.z * %s.w) + %s;", // Attenuated corner coverage.
- outputCoverage, fEdge_fWind_fCorner.fsIn(), fEdge_fWind_fCorner.fsIn(),
- outputCoverage);
- }
- }
- void GrCCQuadraticShader::calcHullCoverage(SkString* code, const char* coordAndGrad,
- const char* edge, const char* outputCoverage) const {
- code->appendf("float x = %s.x, y = %s.y;", coordAndGrad, coordAndGrad);
- code->appendf("float2 grad = %s.zw;", coordAndGrad);
- code->append ("float f = x*x - y;");
- code->append ("float fwidth = abs(grad.x) + abs(grad.y);");
- code->appendf("float curve_coverage = min(0.5 - f/fwidth, 1);");
- // Flat edge opposite the curve.
- code->appendf("float edge_coverage = min(%s, 0);", edge);
- // Total hull coverage.
- code->appendf("%s = max(half(curve_coverage + edge_coverage), 0);", outputCoverage);
- }
- void GrCCQuadraticShader::emitSampleMaskCode(GrGLSLFPFragmentBuilder* f) const {
- f->codeAppendf("float x = %s.x, y = %s.y;", fCoord_fGrad.fsIn(), fCoord_fGrad.fsIn());
- f->codeAppendf("float f = x*x - y;");
- f->codeAppendf("float2 grad = %s.zw;", fCoord_fGrad.fsIn());
- f->applyFnToMultisampleMask("f", "grad", GrGLSLFPFragmentBuilder::ScopeFlags::kTopLevel);
- }
|