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/*
* Copyright 2013 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#include "GrEllipseEdgeEffect.h"
#include "gl/GrGLEffect.h"
#include "gl/GrGLSL.h"
#include "GrTBackendEffectFactory.h"
class GrGLEllipseEdgeEffect : public GrGLEffect {
public:
GrGLEllipseEdgeEffect(const GrBackendEffectFactory& factory, const GrDrawEffect&)
: INHERITED (factory) {}
virtual void emitCode(GrGLShaderBuilder* builder,
const GrDrawEffect& drawEffect,
EffectKey key,
const char* outputColor,
const char* inputColor,
const TextureSamplerArray& samplers) SK_OVERRIDE {
const GrEllipseEdgeEffect& ellipseEffect = drawEffect.castEffect<GrEllipseEdgeEffect>();
const char *vsCenterName, *fsCenterName;
const char *vsEdgeName, *fsEdgeName;
builder->addVarying(kVec2f_GrSLType, "EllipseCenter", &vsCenterName, &fsCenterName);
const SkString* attr0Name =
builder->getEffectAttributeName(drawEffect.getVertexAttribIndices()[0]);
builder->vsCodeAppendf("\t%s = %s;\n", vsCenterName, attr0Name->c_str());
builder->addVarying(kVec4f_GrSLType, "EllipseEdge", &vsEdgeName, &fsEdgeName);
const SkString* attr1Name =
builder->getEffectAttributeName(drawEffect.getVertexAttribIndices()[1]);
builder->vsCodeAppendf("\t%s = %s;\n", vsEdgeName, attr1Name->c_str());
// translate to origin
builder->fsCodeAppendf("\tvec2 outerOffset = (%s.xy - %s.xy);\n",
builder->fragmentPosition(), fsCenterName);
builder->fsCodeAppend("\tvec2 innerOffset = outerOffset;\n");
// scale y by xRadius/yRadius
builder->fsCodeAppendf("\touterOffset.y *= %s.y;\n", fsEdgeName);
builder->fsCodeAppend("\tfloat dOuter = length(outerOffset);\n");
// compare outer lengths against xOuterRadius
builder->fsCodeAppendf("\tfloat edgeAlpha = clamp(%s.x-dOuter, 0.0, 1.0);\n", fsEdgeName);
if (ellipseEffect.isStroked()) {
builder->fsCodeAppendf("\tinnerOffset.y *= %s.w;\n", fsEdgeName);
builder->fsCodeAppend("\tfloat dInner = length(innerOffset);\n");
// compare inner lengths against xInnerRadius
builder->fsCodeAppendf("\tfloat innerAlpha = clamp(dInner-%s.z, 0.0, 1.0);\n", fsEdgeName);
builder->fsCodeAppend("\tedgeAlpha *= innerAlpha;\n");
}
SkString modulate;
GrGLSLModulate4f(&modulate, inputColor, "edgeAlpha");
builder->fsCodeAppendf("\t%s = %s;\n", outputColor, modulate.c_str());
}
static inline EffectKey GenKey(const GrDrawEffect& drawEffect, const GrGLCaps&) {
const GrEllipseEdgeEffect& ellipseEffect = drawEffect.castEffect<GrEllipseEdgeEffect>();
return ellipseEffect.isStroked() ? 0x1 : 0x0;
}
virtual void setData(const GrGLUniformManager&, const GrDrawEffect&) SK_OVERRIDE {
}
private:
typedef GrGLEffect INHERITED;
};
///////////////////////////////////////////////////////////////////////////////
GrEllipseEdgeEffect::GrEllipseEdgeEffect(bool stroke) : GrEffect() {
this->addVertexAttrib(kVec2f_GrSLType);
this->addVertexAttrib(kVec4f_GrSLType);
fStroke = stroke;
}
void GrEllipseEdgeEffect::getConstantColorComponents(GrColor* color, uint32_t* validFlags) const {
*validFlags = 0;
}
const GrBackendEffectFactory& GrEllipseEdgeEffect::getFactory() const {
return GrTBackendEffectFactory<GrEllipseEdgeEffect>::getInstance();
}
///////////////////////////////////////////////////////////////////////////////
GR_DEFINE_EFFECT_TEST(GrEllipseEdgeEffect);
GrEffectRef* GrEllipseEdgeEffect::TestCreate(SkMWCRandom* random,
GrContext* context,
const GrDrawTargetCaps&,
GrTexture* textures[]) {
return GrEllipseEdgeEffect::Create(random->nextBool());
}
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