michael@0: /*
michael@0:  * Copyright 2014 Google Inc.
michael@0:  *
michael@0:  * Use of this source code is governed by a BSD-style license that can be
michael@0:  * found in the LICENSE file.
michael@0:  */
michael@0: 
michael@0: #include "GrConvexPolyEffect.h"
michael@0: 
michael@0: #include "gl/GrGLEffect.h"
michael@0: #include "gl/GrGLSL.h"
michael@0: #include "GrTBackendEffectFactory.h"
michael@0: 
michael@0: #include "SkPath.h"
michael@0: 
michael@0: //////////////////////////////////////////////////////////////////////////////
michael@0: class GLAARectEffect;
michael@0: 
michael@0: class AARectEffect : public GrEffect {
michael@0: public:
michael@0:     typedef GLAARectEffect GLEffect;
michael@0: 
michael@0:     const SkRect& getRect() const { return fRect; }
michael@0: 
michael@0:     static const char* Name() { return "AARect"; }
michael@0: 
michael@0:     static GrEffectRef* Create(GrEffectEdgeType edgeType, const SkRect& rect) {
michael@0:         return CreateEffectRef(AutoEffectUnref(SkNEW_ARGS(AARectEffect, (edgeType, rect))));
michael@0:     }
michael@0: 
michael@0:     virtual void getConstantColorComponents(GrColor* color,
michael@0:                                             uint32_t* validFlags) const SK_OVERRIDE {
michael@0:         if (fRect.isEmpty()) {
michael@0:             // An empty rect will have no coverage anywhere.
michael@0:             *color = 0x00000000;
michael@0:             *validFlags = kRGBA_GrColorComponentFlags;
michael@0:         } else {
michael@0:             *validFlags = 0;
michael@0:         }
michael@0:     }
michael@0: 
michael@0:     GrEffectEdgeType getEdgeType() const { return fEdgeType; }
michael@0: 
michael@0:     virtual const GrBackendEffectFactory& getFactory() const SK_OVERRIDE;
michael@0: 
michael@0: private:
michael@0:     AARectEffect(GrEffectEdgeType edgeType, const SkRect& rect) : fRect(rect), fEdgeType(edgeType) {
michael@0:         this->setWillReadFragmentPosition();
michael@0:     }
michael@0: 
michael@0:     virtual bool onIsEqual(const GrEffect& other) const SK_OVERRIDE {
michael@0:         const AARectEffect& aare = CastEffect<AARectEffect>(other);
michael@0:         return fRect == aare.fRect;
michael@0:     }
michael@0: 
michael@0:     SkRect fRect;
michael@0:     GrEffectEdgeType fEdgeType;
michael@0: 
michael@0:     typedef GrEffect INHERITED;
michael@0: 
michael@0:     GR_DECLARE_EFFECT_TEST;
michael@0: 
michael@0: };
michael@0: 
michael@0: GR_DEFINE_EFFECT_TEST(AARectEffect);
michael@0: 
michael@0: GrEffectRef* AARectEffect::TestCreate(SkRandom* random,
michael@0:                                       GrContext*,
michael@0:                                       const GrDrawTargetCaps& caps,
michael@0:                                       GrTexture*[]) {
michael@0:     SkRect rect = SkRect::MakeLTRB(random->nextSScalar1(),
michael@0:                                    random->nextSScalar1(),
michael@0:                                    random->nextSScalar1(),
michael@0:                                    random->nextSScalar1());
michael@0:     GrEffectRef* effect;
michael@0:     do {
michael@0:         GrEffectEdgeType edgeType = static_cast<GrEffectEdgeType>(random->nextULessThan(
michael@0:                                                                     kGrEffectEdgeTypeCnt));
michael@0: 
michael@0:         effect = AARectEffect::Create(edgeType, rect);
michael@0:     } while (NULL == effect);
michael@0:     return effect;
michael@0: }
michael@0: 
michael@0: //////////////////////////////////////////////////////////////////////////////
michael@0: 
michael@0: class GLAARectEffect : public GrGLEffect {
michael@0: public:
michael@0:     GLAARectEffect(const GrBackendEffectFactory&, const GrDrawEffect&);
michael@0: 
michael@0:     virtual void emitCode(GrGLShaderBuilder* builder,
michael@0:                           const GrDrawEffect& drawEffect,
michael@0:                           EffectKey key,
michael@0:                           const char* outputColor,
michael@0:                           const char* inputColor,
michael@0:                           const TransformedCoordsArray&,
michael@0:                           const TextureSamplerArray&) SK_OVERRIDE;
michael@0: 
michael@0:     static inline EffectKey GenKey(const GrDrawEffect&, const GrGLCaps&);
michael@0: 
michael@0:     virtual void setData(const GrGLUniformManager&, const GrDrawEffect&) SK_OVERRIDE;
michael@0: 
michael@0: private:
michael@0:     GrGLUniformManager::UniformHandle   fRectUniform;
michael@0:     SkRect                              fPrevRect;
michael@0:     typedef GrGLEffect INHERITED;
michael@0: };
michael@0: 
michael@0: GLAARectEffect::GLAARectEffect(const GrBackendEffectFactory& factory,
michael@0:                                const GrDrawEffect& drawEffect)
michael@0:     : INHERITED (factory) {
michael@0:     fPrevRect.fLeft = SK_ScalarNaN;
michael@0: }
michael@0: 
michael@0: void GLAARectEffect::emitCode(GrGLShaderBuilder* builder,
michael@0:                               const GrDrawEffect& drawEffect,
michael@0:                               EffectKey key,
michael@0:                               const char* outputColor,
michael@0:                               const char* inputColor,
michael@0:                               const TransformedCoordsArray&,
michael@0:                               const TextureSamplerArray& samplers) {
michael@0:     const AARectEffect& aare = drawEffect.castEffect<AARectEffect>();
michael@0:     const char *rectName;
michael@0:     // The rect uniform's xyzw refer to (left + 0.5, top + 0.5, right - 0.5, bottom - 0.5),
michael@0:     // respectively.
michael@0:     fRectUniform = builder->addUniform(GrGLShaderBuilder::kFragment_Visibility,
michael@0:                                        kVec4f_GrSLType,
michael@0:                                        "rect",
michael@0:                                        &rectName);
michael@0:     const char* fragmentPos = builder->fragmentPosition();
michael@0:     if (GrEffectEdgeTypeIsAA(aare.getEdgeType())) {
michael@0:         // The amount of coverage removed in x and y by the edges is computed as a pair of negative
michael@0:         // numbers, xSub and ySub.
michael@0:         builder->fsCodeAppend("\t\tfloat xSub, ySub;\n");
michael@0:         builder->fsCodeAppendf("\t\txSub = min(%s.x - %s.x, 0.0);\n", fragmentPos, rectName);
michael@0:         builder->fsCodeAppendf("\t\txSub += min(%s.z - %s.x, 0.0);\n", rectName, fragmentPos);
michael@0:         builder->fsCodeAppendf("\t\tySub = min(%s.y - %s.y, 0.0);\n", fragmentPos, rectName);
michael@0:         builder->fsCodeAppendf("\t\tySub += min(%s.w - %s.y, 0.0);\n", rectName, fragmentPos);
michael@0:         // Now compute coverage in x and y and multiply them to get the fraction of the pixel
michael@0:         // covered.
michael@0:         builder->fsCodeAppendf("\t\tfloat alpha = (1.0 + max(xSub, -1.0)) * (1.0 + max(ySub, -1.0));\n");
michael@0:     } else {
michael@0:         builder->fsCodeAppendf("\t\tfloat alpha = 1.0;\n");
michael@0:         builder->fsCodeAppendf("\t\talpha *= (%s.x - %s.x) > -0.5 ? 1.0 : 0.0;\n", fragmentPos, rectName);
michael@0:         builder->fsCodeAppendf("\t\talpha *= (%s.z - %s.x) > -0.5 ? 1.0 : 0.0;\n", rectName, fragmentPos);
michael@0:         builder->fsCodeAppendf("\t\talpha *= (%s.y - %s.y) > -0.5 ? 1.0 : 0.0;\n", fragmentPos, rectName);
michael@0:         builder->fsCodeAppendf("\t\talpha *= (%s.w - %s.y) > -0.5 ? 1.0 : 0.0;\n", rectName, fragmentPos);
michael@0:     }
michael@0: 
michael@0:     if (GrEffectEdgeTypeIsInverseFill(aare.getEdgeType())) {
michael@0:         builder->fsCodeAppend("\t\talpha = 1.0 - alpha;\n");
michael@0:     }
michael@0:     builder->fsCodeAppendf("\t\t%s = %s;\n", outputColor,
michael@0:                            (GrGLSLExpr4(inputColor) * GrGLSLExpr1("alpha")).c_str());
michael@0: }
michael@0: 
michael@0: void GLAARectEffect::setData(const GrGLUniformManager& uman, const GrDrawEffect& drawEffect) {
michael@0:     const AARectEffect& aare = drawEffect.castEffect<AARectEffect>();
michael@0:     const SkRect& rect = aare.getRect();
michael@0:     if (rect != fPrevRect) {
michael@0:         uman.set4f(fRectUniform, rect.fLeft + 0.5f, rect.fTop + 0.5f,
michael@0:                    rect.fRight - 0.5f, rect.fBottom - 0.5f);
michael@0:         fPrevRect = rect;
michael@0:     }
michael@0: }
michael@0: 
michael@0: GrGLEffect::EffectKey GLAARectEffect::GenKey(const GrDrawEffect& drawEffect, const GrGLCaps&) {
michael@0:     const AARectEffect& aare = drawEffect.castEffect<AARectEffect>();
michael@0:     return aare.getEdgeType();
michael@0: }
michael@0: 
michael@0: const GrBackendEffectFactory& AARectEffect::getFactory() const {
michael@0:     return GrTBackendEffectFactory<AARectEffect>::getInstance();
michael@0: }
michael@0: 
michael@0: //////////////////////////////////////////////////////////////////////////////
michael@0: 
michael@0: class GrGLConvexPolyEffect : public GrGLEffect {
michael@0: public:
michael@0:     GrGLConvexPolyEffect(const GrBackendEffectFactory&, const GrDrawEffect&);
michael@0: 
michael@0:     virtual void emitCode(GrGLShaderBuilder* builder,
michael@0:                           const GrDrawEffect& drawEffect,
michael@0:                           EffectKey key,
michael@0:                           const char* outputColor,
michael@0:                           const char* inputColor,
michael@0:                           const TransformedCoordsArray&,
michael@0:                           const TextureSamplerArray&) SK_OVERRIDE;
michael@0: 
michael@0:     static inline EffectKey GenKey(const GrDrawEffect&, const GrGLCaps&);
michael@0: 
michael@0:     virtual void setData(const GrGLUniformManager&, const GrDrawEffect&) SK_OVERRIDE;
michael@0: 
michael@0: private:
michael@0:     GrGLUniformManager::UniformHandle   fEdgeUniform;
michael@0:     SkScalar                            fPrevEdges[3 * GrConvexPolyEffect::kMaxEdges];
michael@0:     typedef GrGLEffect INHERITED;
michael@0: };
michael@0: 
michael@0: GrGLConvexPolyEffect::GrGLConvexPolyEffect(const GrBackendEffectFactory& factory,
michael@0:                                            const GrDrawEffect& drawEffect)
michael@0:     : INHERITED (factory) {
michael@0:     fPrevEdges[0] = SK_ScalarNaN;
michael@0: }
michael@0: 
michael@0: void GrGLConvexPolyEffect::emitCode(GrGLShaderBuilder* builder,
michael@0:                                     const GrDrawEffect& drawEffect,
michael@0:                                     EffectKey key,
michael@0:                                     const char* outputColor,
michael@0:                                     const char* inputColor,
michael@0:                                     const TransformedCoordsArray&,
michael@0:                                     const TextureSamplerArray& samplers) {
michael@0:     const GrConvexPolyEffect& cpe = drawEffect.castEffect<GrConvexPolyEffect>();
michael@0: 
michael@0:     const char *edgeArrayName;
michael@0:     fEdgeUniform = builder->addUniformArray(GrGLShaderBuilder::kFragment_Visibility,
michael@0:                                             kVec3f_GrSLType,
michael@0:                                             "edges",
michael@0:                                             cpe.getEdgeCount(),
michael@0:                                             &edgeArrayName);
michael@0:     builder->fsCodeAppend("\t\tfloat alpha = 1.0;\n");
michael@0:     builder->fsCodeAppend("\t\tfloat edge;\n");
michael@0:     const char* fragmentPos = builder->fragmentPosition();
michael@0:     for (int i = 0; i < cpe.getEdgeCount(); ++i) {
michael@0:         builder->fsCodeAppendf("\t\tedge = dot(%s[%d], vec3(%s.x, %s.y, 1));\n",
michael@0:                                edgeArrayName, i, fragmentPos, fragmentPos);
michael@0:         if (GrEffectEdgeTypeIsAA(cpe.getEdgeType())) {
michael@0:             builder->fsCodeAppend("\t\tedge = clamp(edge, 0.0, 1.0);\n");
michael@0:         } else {
michael@0:             builder->fsCodeAppend("\t\tedge = edge >= 0.5 ? 1.0 : 0.0;\n");
michael@0:         }
michael@0:         builder->fsCodeAppend("\t\talpha *= edge;\n");
michael@0:     }
michael@0: 
michael@0:     // Woe is me. See skbug.com/2149.
michael@0:     if (kTegra2_GrGLRenderer == builder->ctxInfo().renderer()) {
michael@0:         builder->fsCodeAppend("\t\tif (-1.0 == alpha) {\n\t\t\tdiscard;\n\t\t}\n");
michael@0:     }
michael@0: 
michael@0:     if (GrEffectEdgeTypeIsInverseFill(cpe.getEdgeType())) {
michael@0:         builder->fsCodeAppend("\talpha = 1.0 - alpha;\n");
michael@0:     }
michael@0:     builder->fsCodeAppendf("\t%s = %s;\n", outputColor,
michael@0:                            (GrGLSLExpr4(inputColor) * GrGLSLExpr1("alpha")).c_str());
michael@0: }
michael@0: 
michael@0: void GrGLConvexPolyEffect::setData(const GrGLUniformManager& uman, const GrDrawEffect& drawEffect) {
michael@0:     const GrConvexPolyEffect& cpe = drawEffect.castEffect<GrConvexPolyEffect>();
michael@0:     size_t byteSize = 3 * cpe.getEdgeCount() * sizeof(SkScalar);
michael@0:     if (0 != memcmp(fPrevEdges, cpe.getEdges(), byteSize)) {
michael@0:         uman.set3fv(fEdgeUniform, cpe.getEdgeCount(), cpe.getEdges());
michael@0:         memcpy(fPrevEdges, cpe.getEdges(), byteSize);
michael@0:     }
michael@0: }
michael@0: 
michael@0: GrGLEffect::EffectKey GrGLConvexPolyEffect::GenKey(const GrDrawEffect& drawEffect,
michael@0:                                                    const GrGLCaps&) {
michael@0:     const GrConvexPolyEffect& cpe = drawEffect.castEffect<GrConvexPolyEffect>();
michael@0:     GR_STATIC_ASSERT(kGrEffectEdgeTypeCnt <= 8);
michael@0:     return (cpe.getEdgeCount() << 3) | cpe.getEdgeType();
michael@0: }
michael@0: 
michael@0: //////////////////////////////////////////////////////////////////////////////
michael@0: 
michael@0: GrEffectRef* GrConvexPolyEffect::Create(GrEffectEdgeType type, const SkPath& path, const SkVector* offset) {
michael@0:     if (kHairlineAA_GrEffectEdgeType == type) {
michael@0:         return NULL;
michael@0:     }
michael@0:     if (path.getSegmentMasks() != SkPath::kLine_SegmentMask ||
michael@0:         !path.isConvex()) {
michael@0:         return NULL;
michael@0:     }
michael@0: 
michael@0:     if (path.countPoints() > kMaxEdges) {
michael@0:         return NULL;
michael@0:     }
michael@0: 
michael@0:     SkPoint pts[kMaxEdges];
michael@0:     SkScalar edges[3 * kMaxEdges];
michael@0: 
michael@0:     SkPath::Direction dir;
michael@0:     SkAssertResult(path.cheapComputeDirection(&dir));
michael@0: 
michael@0:     SkVector t;
michael@0:     if (NULL == offset) {
michael@0:         t.set(0, 0);
michael@0:     } else {
michael@0:         t = *offset;
michael@0:     }
michael@0: 
michael@0:     int count = path.getPoints(pts, kMaxEdges);
michael@0:     int n = 0;
michael@0:     for (int lastPt = count - 1, i = 0; i < count; lastPt = i++) {
michael@0:         if (pts[lastPt] != pts[i]) {
michael@0:             SkVector v = pts[i] - pts[lastPt];
michael@0:             v.normalize();
michael@0:             if (SkPath::kCCW_Direction == dir) {
michael@0:                 edges[3 * n] = v.fY;
michael@0:                 edges[3 * n + 1] = -v.fX;
michael@0:             } else {
michael@0:                 edges[3 * n] = -v.fY;
michael@0:                 edges[3 * n + 1] = v.fX;
michael@0:             }
michael@0:             SkPoint p = pts[i] + t;
michael@0:             edges[3 * n + 2] = -(edges[3 * n] * p.fX + edges[3 * n + 1] * p.fY);
michael@0:             ++n;
michael@0:         }
michael@0:     }
michael@0:     if (path.isInverseFillType()) {
michael@0:         type = GrInvertEffectEdgeType(type);
michael@0:     }
michael@0:     return Create(type, n, edges);
michael@0: }
michael@0: 
michael@0: GrEffectRef* GrConvexPolyEffect::Create(GrEffectEdgeType edgeType, const SkRect& rect) {
michael@0:     if (kHairlineAA_GrEffectEdgeType == edgeType){
michael@0:         return NULL;
michael@0:     }
michael@0:     return AARectEffect::Create(edgeType, rect);
michael@0: }
michael@0: 
michael@0: GrConvexPolyEffect::~GrConvexPolyEffect() {}
michael@0: 
michael@0: void GrConvexPolyEffect::getConstantColorComponents(GrColor* color, uint32_t* validFlags) const {
michael@0:     *validFlags = 0;
michael@0: }
michael@0: 
michael@0: const GrBackendEffectFactory& GrConvexPolyEffect::getFactory() const {
michael@0:     return GrTBackendEffectFactory<GrConvexPolyEffect>::getInstance();
michael@0: }
michael@0: 
michael@0: GrConvexPolyEffect::GrConvexPolyEffect(GrEffectEdgeType edgeType, int n, const SkScalar edges[])
michael@0:     : fEdgeType(edgeType)
michael@0:     , fEdgeCount(n) {
michael@0:     // Factory function should have already ensured this.
michael@0:     SkASSERT(n <= kMaxEdges);
michael@0:     memcpy(fEdges, edges, 3 * n * sizeof(SkScalar));
michael@0:     // Outset the edges by 0.5 so that a pixel with center on an edge is 50% covered in the AA case
michael@0:     // and 100% covered in the non-AA case.
michael@0:     for (int i = 0; i < n; ++i) {
michael@0:         fEdges[3 * i + 2] += SK_ScalarHalf;
michael@0:     }
michael@0:     this->setWillReadFragmentPosition();
michael@0: }
michael@0: 
michael@0: bool GrConvexPolyEffect::onIsEqual(const GrEffect& other) const {
michael@0:     const GrConvexPolyEffect& cpe = CastEffect<GrConvexPolyEffect>(other);
michael@0:     // ignore the fact that 0 == -0 and just use memcmp.
michael@0:     return (cpe.fEdgeType == fEdgeType && cpe.fEdgeCount == fEdgeCount &&
michael@0:             0 == memcmp(cpe.fEdges, fEdges, 3 * fEdgeCount * sizeof(SkScalar)));
michael@0: }
michael@0: 
michael@0: //////////////////////////////////////////////////////////////////////////////
michael@0: 
michael@0: GR_DEFINE_EFFECT_TEST(GrConvexPolyEffect);
michael@0: 
michael@0: GrEffectRef* GrConvexPolyEffect::TestCreate(SkRandom* random,
michael@0:                                             GrContext*,
michael@0:                                             const GrDrawTargetCaps& caps,
michael@0:                                             GrTexture*[]) {
michael@0:     int count = random->nextULessThan(kMaxEdges) + 1;
michael@0:     SkScalar edges[kMaxEdges * 3];
michael@0:     for (int i = 0; i < 3 * count; ++i) {
michael@0:         edges[i] = random->nextSScalar1();
michael@0:     }
michael@0: 
michael@0:     GrEffectRef* effect;
michael@0:     do {
michael@0:         GrEffectEdgeType edgeType = static_cast<GrEffectEdgeType>(
michael@0:                                         random->nextULessThan(kGrEffectEdgeTypeCnt));
michael@0:         effect = GrConvexPolyEffect::Create(edgeType, count, edges);
michael@0:     } while (NULL == effect);
michael@0:     return effect;
michael@0: }