ccpr: Pack wind into existing varyings
Bug: skia:
Change-Id: I189a22a6779af5d3fa7671992da50ede36eaaa8f
Reviewed-on: https://skia-review.googlesource.com/102067
Reviewed-by: Greg Daniel <egdaniel@google.com>
Commit-Queue: Chris Dalton <csmartdalton@google.com>
diff --git a/src/gpu/ccpr/GrCCCubicShader.cpp b/src/gpu/ccpr/GrCCCubicShader.cpp
index 295de0c..fbaf7d9 100644
--- a/src/gpu/ccpr/GrCCCubicShader.cpp
+++ b/src/gpu/ccpr/GrCCCubicShader.cpp
@@ -58,12 +58,14 @@
// Evaluate the cubic at T=.5 for a mid-ish point.
s->codeAppendf("float2 midpoint = %s * float4(.125, .375, .375, .125);", pts);
- // Orient the KLM matrix so we fill the correct side of the curve.
+ // Orient the KLM matrix so L & M have matching signs on the side of the curve we wish to fill.
+ // We give L & M both the same sign as wind, in order to pass this value to the fragment shader.
+ // (Cubics are pre-chopped such that L & M do not change sign within any individual segment).
s->codeAppendf("float2 orientation = sign(float3(midpoint, 1) * float2x3(%s[1], %s[2]));",
fKLMMatrix.c_str(), fKLMMatrix.c_str());
s->codeAppendf("%s *= float3x3(orientation[0] * orientation[1], 0, 0, "
- "0, orientation[0], 0, "
- "0, 0, orientation[1]);", fKLMMatrix.c_str());
+ "0, orientation[0] * %s, 0, "
+ "0, 0, orientation[1] * %s);", fKLMMatrix.c_str(), wind, wind);
// Determine the amount of additional coverage to subtract out for the flat edge (P3 -> P0).
s->declareGlobal(fEdgeDistanceEquation);
@@ -75,11 +77,11 @@
this->onEmitSetupCode(s, pts, repetitionID, vars);
}
-Shader::WindHandling GrCCCubicShader::onEmitVaryings(GrGLSLVaryingHandler* varyingHandler,
- GrGLSLVarying::Scope scope,
- SkString* code, const char* position,
- const char* coverage, const char* /*wind*/) {
- SkASSERT(!coverage);
+void GrCCCubicShader::onEmitVaryings(GrGLSLVaryingHandler* varyingHandler,
+ GrGLSLVarying::Scope scope, SkString* code,
+ const char* position, const char* inputCoverage,
+ const char* /*wind*/) {
+ SkASSERT(!inputCoverage);
fKLMD.reset(kFloat4_GrSLType, scope);
varyingHandler->addVarying("klmd", &fKLMD);
@@ -88,7 +90,20 @@
code->appendf("%s = float4(klm, d);", OutName(fKLMD));
this->onEmitVaryings(varyingHandler, scope, code);
- return WindHandling::kNotHandled;
+}
+
+void GrCCCubicShader::onEmitFragmentCode(GrGLSLPPFragmentBuilder* f,
+ const char* outputCoverage) const {
+ f->codeAppendf("float k = %s.x, l = %s.y, m = %s.z, d = %s.w;",
+ fKLMD.fsIn(), fKLMD.fsIn(), fKLMD.fsIn(), fKLMD.fsIn());
+
+ this->emitCoverage(f, outputCoverage);
+
+ // Wind is the sign of both L and/or M. Take the sign of whichever has the larger magnitude.
+ // (In reality, either would be fine because we chop cubics with more than a half pixel of
+ // padding around the L & M lines, so neither should approach zero.)
+ f->codeAppend ("half wind = sign(l + m);");
+ f->codeAppendf("%s *= wind;", outputCoverage);
}
void GrCCCubicHullShader::onEmitVaryings(GrGLSLVaryingHandler* varyingHandler,
@@ -101,14 +116,13 @@
OutName(fGradMatrix), fKLMMatrix.c_str(), fKLMMatrix.c_str());
}
-void GrCCCubicHullShader::onEmitFragmentCode(GrGLSLPPFragmentBuilder* f,
- const char* outputCoverage) const {
- f->codeAppendf("float k = %s.x, l = %s.y, m = %s.z, d = %s.w;",
- fKLMD.fsIn(), fKLMD.fsIn(), fKLMD.fsIn(), fKLMD.fsIn());
+void GrCCCubicHullShader::emitCoverage(GrGLSLPPFragmentBuilder* f,
+ const char* outputCoverage) const {
+ // k,l,m,d are defined by the base class.
f->codeAppend ("float f = k*k*k - l*m;");
f->codeAppendf("float2 grad_f = %s * float2(k, 1);", fGradMatrix.fsIn());
f->codeAppendf("%s = clamp(0.5 - f * inversesqrt(dot(grad_f, grad_f)), 0, 1);", outputCoverage);
- f->codeAppendf("%s += min(d, 0);", outputCoverage); // Flat closing edge.
+ f->codeAppendf("%s += min(d, 0);", outputCoverage); // Flat edge opposite the curve.
}
void GrCCCubicCornerShader::onEmitSetupCode(GrGLSLVertexGeoBuilder* s, const char* pts,
@@ -132,14 +146,13 @@
fKLMMatrix.c_str(), fEdgeDistanceEquation.c_str());
}
-void GrCCCubicCornerShader::onEmitFragmentCode(GrGLSLPPFragmentBuilder* f,
- const char* outputCoverage) const {
+void GrCCCubicCornerShader::emitCoverage(GrGLSLPPFragmentBuilder* f,
+ const char* outputCoverage) const {
f->codeAppendf("float2x4 grad_klmd = float2x4(%s, %s);", fdKLMDdx.fsIn(), fdKLMDdy.fsIn());
// Erase what the previous hull shader wrote. We don't worry about the two corners falling on
// the same pixel because those cases should have been weeded out by this point.
- f->codeAppendf("float k = %s.x, l = %s.y, m = %s.z, d = %s.w;",
- fKLMD.fsIn(), fKLMD.fsIn(), fKLMD.fsIn(), fKLMD.fsIn());
+ // k,l,m,d are defined by the base class.
f->codeAppend ("float f = k*k*k - l*m;");
f->codeAppend ("float2 grad_f = float3(3*k*k, -m, -l) * float2x3(grad_klmd);");
f->codeAppendf("%s = -clamp(0.5 - f * inversesqrt(dot(grad_f, grad_f)), 0, 1);",