| /* |
| * Copyright 2014 Google Inc. |
| * |
| * Use of this source code is governed by a BSD-style license that can be |
| * found in the LICENSE file. |
| */ |
| |
| #include "GrRRectEffect.h" |
| |
| #include "gl/GrGLEffect.h" |
| #include "gl/GrGLSL.h" |
| #include "GrTBackendEffectFactory.h" |
| |
| #include "SkPath.h" |
| |
| // This effect only supports circular corner rrects where all corners have the same radius |
| // which must be <= kRadiusMin. |
| static const SkScalar kRadiusMin = 0.5; |
| |
| ////////////////////////////////////////////////////////////////////////////// |
| class GrGLRRectEffect : public GrGLEffect { |
| public: |
| GrGLRRectEffect(const GrBackendEffectFactory&, const GrDrawEffect&); |
| |
| virtual void emitCode(GrGLShaderBuilder* builder, |
| const GrDrawEffect& drawEffect, |
| EffectKey key, |
| const char* outputColor, |
| const char* inputColor, |
| const TransformedCoordsArray&, |
| const TextureSamplerArray&) SK_OVERRIDE; |
| |
| static inline EffectKey GenKey(const GrDrawEffect&, const GrGLCaps&) { return 0; } |
| |
| virtual void setData(const GrGLUniformManager&, const GrDrawEffect&) SK_OVERRIDE; |
| |
| private: |
| GrGLUniformManager::UniformHandle fInnerRectUniform; |
| GrGLUniformManager::UniformHandle fRadiusPlusHalfUniform; |
| SkRRect fPrevRRect; |
| typedef GrGLEffect INHERITED; |
| }; |
| |
| GrGLRRectEffect::GrGLRRectEffect(const GrBackendEffectFactory& factory, |
| const GrDrawEffect& drawEffect) |
| : INHERITED (factory) { |
| fPrevRRect.setEmpty(); |
| } |
| |
| void GrGLRRectEffect::emitCode(GrGLShaderBuilder* builder, |
| const GrDrawEffect& drawEffect, |
| EffectKey key, |
| const char* outputColor, |
| const char* inputColor, |
| const TransformedCoordsArray&, |
| const TextureSamplerArray& samplers) { |
| const char *rectName; |
| const char *radiusPlusHalfName; |
| // The inner rect is the rrect bounds inset by the radius. Its top, left, right, and bottom |
| // edges correspond to components x, y, z, and w, respectively. |
| fInnerRectUniform = builder->addUniform(GrGLShaderBuilder::kFragment_Visibility, |
| kVec4f_GrSLType, |
| "innerRect", |
| &rectName); |
| fRadiusPlusHalfUniform = builder->addUniform(GrGLShaderBuilder::kFragment_Visibility, |
| kFloat_GrSLType, |
| "radiusPlusHalf", |
| &radiusPlusHalfName); |
| const char* fragmentPos = builder->fragmentPosition(); |
| // At each quarter-circle corner we compute a vector that is the offset of the fragment position |
| // from the circle center. The vector is pinned in x and y to be in the quarter-plane relevant |
| // to that corner. This means that points near the interior near the rrect top edge will have |
| // a vector that points straight up for both the TL left and TR corners. Computing an |
| // alpha from this vector at either the TR or TL corner will give the correct result. Similarly, |
| // fragments near the other three edges will get the correct AA. Fragments in the interior of |
| // the rrect will have a (0,0) vector at all four corners. So long as the radius > 0.5 they will |
| // correctly produce an alpha value of 1 at all four corners. We take the min of all the alphas. |
| // The code below is a simplified version of the above that performs maxs on the vector |
| // components before computing distances and alpha values so that only one distance computation |
| // need be computed to determine the min alpha. |
| builder->fsCodeAppendf("\t\tvec2 dxy0 = %s.xy - %s.xy;\n", rectName, fragmentPos); |
| builder->fsCodeAppendf("\t\tvec2 dxy1 = %s.xy - %s.zw;\n", fragmentPos, rectName); |
| builder->fsCodeAppend("\t\tvec2 dxy = max(max(dxy0, dxy1), 0.0);\n"); |
| builder->fsCodeAppendf("\t\tfloat alpha = clamp(%s - length(dxy), 0.0, 1.0);\n", |
| radiusPlusHalfName); |
| |
| builder->fsCodeAppendf("\t\t%s = %s;\n", outputColor, |
| (GrGLSLExpr4(inputColor) * GrGLSLExpr1("alpha")).c_str()); |
| } |
| |
| void GrGLRRectEffect::setData(const GrGLUniformManager& uman, const GrDrawEffect& drawEffect) { |
| const GrRRectEffect& rre = drawEffect.castEffect<GrRRectEffect>(); |
| const SkRRect& rrect = rre.getRRect(); |
| if (rrect != fPrevRRect) { |
| SkASSERT(rrect.isSimpleCircular()); |
| SkRect rect = rrect.getBounds(); |
| SkScalar radius = rrect.getSimpleRadii().fX; |
| SkASSERT(radius >= kRadiusMin); |
| rect.inset(radius, radius); |
| uman.set4f(fInnerRectUniform, rect.fLeft, rect.fTop, rect.fRight, rect.fBottom); |
| uman.set1f(fRadiusPlusHalfUniform, radius + 0.5f); |
| fPrevRRect = rrect; |
| } |
| } |
| |
| ////////////////////////////////////////////////////////////////////////////// |
| |
| GrEffectRef* GrRRectEffect::Create(const SkRRect& rrect) { |
| if (!rrect.isSimpleCircular()) { |
| return NULL; |
| } |
| if (rrect.getSimpleRadii().fX < kRadiusMin) { |
| return NULL; |
| } |
| return CreateEffectRef(AutoEffectUnref(SkNEW_ARGS(GrRRectEffect, (rrect)))); |
| } |
| |
| GrRRectEffect::~GrRRectEffect() {} |
| |
| void GrRRectEffect::getConstantColorComponents(GrColor* color, uint32_t* validFlags) const { |
| *validFlags = 0; |
| } |
| |
| const GrBackendEffectFactory& GrRRectEffect::getFactory() const { |
| return GrTBackendEffectFactory<GrRRectEffect>::getInstance(); |
| } |
| |
| GrRRectEffect::GrRRectEffect(const SkRRect& rrect) |
| : fRRect(rrect) { |
| SkASSERT(rrect.isSimpleCircular()); |
| SkASSERT(rrect.getSimpleRadii().fX >= kRadiusMin); |
| this->setWillReadFragmentPosition(); |
| } |
| |
| bool GrRRectEffect::onIsEqual(const GrEffect& other) const { |
| const GrRRectEffect& rre = CastEffect<GrRRectEffect>(other); |
| return fRRect == rre.fRRect; |
| } |
| |
| ////////////////////////////////////////////////////////////////////////////// |
| |
| GR_DEFINE_EFFECT_TEST(GrRRectEffect); |
| |
| GrEffectRef* GrRRectEffect::TestCreate(SkRandom* random, |
| GrContext*, |
| const GrDrawTargetCaps& caps, |
| GrTexture*[]) { |
| SkScalar w = random->nextRangeScalar(20.f, 1000.f); |
| SkScalar h = random->nextRangeScalar(20.f, 1000.f); |
| SkScalar r = random->nextRangeF(kRadiusMin, 9.f); |
| SkRRect rrect; |
| rrect.setRectXY(SkRect::MakeWH(w, h), r, r); |
| |
| return GrRRectEffect::Create(rrect); |
| } |