ccpr: Calculate edge coverage in the coverage processor
Does the opposite-edge coverage calculation for curves in the coverage
processor, rather than the Shader class. This allows the vertex shader
implementation to do it more clean and directly, as well as allowing
the future sample mask implementation to disregard edge coverage
entirely.
Bug: skia:
Change-Id: Idaddfff8b22e3223f2a4e286900941969f975c6a
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/208990
Reviewed-by: Greg Daniel <egdaniel@google.com>
Commit-Queue: Chris Dalton <csmartdalton@google.com>
diff --git a/src/gpu/ccpr/GrCCConicShader.cpp b/src/gpu/ccpr/GrCCConicShader.cpp
index 8b136e9..3d5a6c0 100644
--- a/src/gpu/ccpr/GrCCConicShader.cpp
+++ b/src/gpu/ccpr/GrCCConicShader.cpp
@@ -10,8 +10,8 @@
#include "glsl/GrGLSLFragmentShaderBuilder.h"
#include "glsl/GrGLSLVertexGeoBuilder.h"
-void GrCCConicShader::emitSetupCode(GrGLSLVertexGeoBuilder* s, const char* pts, const char* wind,
- const char** outHull4) const {
+void GrCCConicShader::emitSetupCode(
+ GrGLSLVertexGeoBuilder* s, const char* pts, const char** outHull4) const {
// K is distance from the line P2 -> P0. L is distance from the line P0 -> P1, scaled by 2w.
// M is distance from the line P1 -> P2, scaled by 2w. We do this in a space where P1=0.
s->declareGlobal(fKLMMatrix);
@@ -25,10 +25,11 @@
s->declareGlobal(fControlPoint);
s->codeAppendf("%s = %s[1];", fControlPoint.c_str(), pts);
- // Scale KLM by the inverse Manhattan width of K. This allows K to double as the flat opposite
- // edge AA. kwidth will not be 0 because we cull degenerate conics on the CPU.
- s->codeAppendf("float kwidth = 2*bloat * %s * (abs(%s[0].x) + abs(%s[0].y));",
- wind, fKLMMatrix.c_str(), fKLMMatrix.c_str());
+ // Scale KLM by the inverse Manhattan width of K, and make sure K is positive. This allows K to
+ // double as the flat opposite edge AA. kwidth will not be 0 because we cull degenerate conics
+ // on the CPU.
+ s->codeAppendf("float kwidth = 2*bloat * (abs(%s[0].x) + abs(%s[0].y)) * sign(%s[0].z);",
+ fKLMMatrix.c_str(), fKLMMatrix.c_str(), fKLMMatrix.c_str());
s->codeAppendf("%s *= 1/kwidth;", fKLMMatrix.c_str());
if (outHull4) {
@@ -46,16 +47,15 @@
}
}
-void GrCCConicShader::onEmitVaryings(GrGLSLVaryingHandler* varyingHandler,
- GrGLSLVarying::Scope scope, SkString* code,
- const char* position, const char* coverage,
- const char* cornerCoverage) {
- fKLM_fWind.reset(kFloat4_GrSLType, scope);
- varyingHandler->addVarying("klm_and_wind", &fKLM_fWind);
+void GrCCConicShader::onEmitVaryings(
+ GrGLSLVaryingHandler* varyingHandler, GrGLSLVarying::Scope scope, SkString* code,
+ const char* position, const char* coverage, const char* cornerCoverage, const char* wind) {
code->appendf("float3 klm = float3(%s - %s, 1) * %s;",
position, fControlPoint.c_str(), fKLMMatrix.c_str());
+ fKLM_fWind.reset(kFloat4_GrSLType, scope);
+ varyingHandler->addVarying("klm_and_wind", &fKLM_fWind);
code->appendf("%s.xyz = klm;", OutName(fKLM_fWind));
- code->appendf("%s.w = %s;", OutName(fKLM_fWind), coverage); // coverage == wind.
+ code->appendf("%s.w = %s;", OutName(fKLM_fWind), wind);
fGrad_fCorner.reset(cornerCoverage ? kFloat4_GrSLType : kFloat2_GrSLType, scope);
varyingHandler->addVarying(cornerCoverage ? "grad_and_corner" : "grad", &fGrad_fCorner);
@@ -63,6 +63,7 @@
OutName(fGrad_fCorner), fKLMMatrix.c_str());
if (cornerCoverage) {
+ SkASSERT(coverage);
code->appendf("half hull_coverage;");
this->calcHullCoverage(code, "klm", OutName(fGrad_fCorner), "hull_coverage");
code->appendf("%s.zw = half2(hull_coverage, 1) * %s;",
@@ -74,10 +75,10 @@
const char* outputCoverage) const {
this->calcHullCoverage(&AccessCodeString(f), fKLM_fWind.fsIn(), fGrad_fCorner.fsIn(),
outputCoverage);
- f->codeAppendf("%s *= half(%s.w);", outputCoverage, fKLM_fWind.fsIn()); // Wind.
+ f->codeAppendf("%s *= half(%s.w);", outputCoverage, fKLM_fWind.fsIn()); // Wind.
if (kFloat4_GrSLType == fGrad_fCorner.type()) {
- f->codeAppendf("%s = fma(half(%s.z), half(%s.w), %s);", // Attenuated corner coverage.
+ f->codeAppendf("%s = fma(half(%s.z), half(%s.w), %s);", // Attenuated corner coverage.
outputCoverage, fGrad_fCorner.fsIn(), fGrad_fCorner.fsIn(),
outputCoverage);
}