/*
* 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 "GrConvexPolyEffect.h"
#include "GrInvariantOutput.h"
#include "SkPathPriv.h"
#include "glsl/GrGLSLFragmentProcessor.h"
#include "glsl/GrGLSLFragmentShaderBuilder.h"
#include "glsl/GrGLSLProgramDataManager.h"
#include "glsl/GrGLSLUniformHandler.h"
//////////////////////////////////////////////////////////////////////////////
class AARectEffect : public GrFragmentProcessor {
public:
const SkRect& getRect() const { return fRect; }
static GrFragmentProcessor* Create(GrPrimitiveEdgeType edgeType, const SkRect& rect) {
return new AARectEffect(edgeType, rect);
}
GrPrimitiveEdgeType getEdgeType() const { return fEdgeType; }
const char* name() const override { return "AARect"; }
void onGetGLSLProcessorKey(const GrGLSLCaps&, GrProcessorKeyBuilder*) const override;
private:
AARectEffect(GrPrimitiveEdgeType edgeType, const SkRect& rect)
: fRect(rect), fEdgeType(edgeType) {
this->initClassID<AARectEffect>();
this->setWillReadFragmentPosition();
}
GrGLSLFragmentProcessor* onCreateGLSLInstance() const override;
bool onIsEqual(const GrFragmentProcessor& other) const override {
const AARectEffect& aare = other.cast<AARectEffect>();
return fRect == aare.fRect;
}
void onComputeInvariantOutput(GrInvariantOutput* inout) const override {
if (fRect.isEmpty()) {
// An empty rect will have no coverage anywhere.
inout->mulByKnownSingleComponent(0);
} else {
inout->mulByUnknownSingleComponent();
}
}
SkRect fRect;
GrPrimitiveEdgeType fEdgeType;
typedef GrFragmentProcessor INHERITED;
GR_DECLARE_FRAGMENT_PROCESSOR_TEST;
};
GR_DEFINE_FRAGMENT_PROCESSOR_TEST(AARectEffect);
const GrFragmentProcessor* AARectEffect::TestCreate(GrProcessorTestData* d) {
SkRect rect = SkRect::MakeLTRB(d->fRandom->nextSScalar1(),
d->fRandom->nextSScalar1(),
d->fRandom->nextSScalar1(),
d->fRandom->nextSScalar1());
GrFragmentProcessor* fp;
do {
GrPrimitiveEdgeType edgeType = static_cast<GrPrimitiveEdgeType>(
d->fRandom->nextULessThan(kGrProcessorEdgeTypeCnt));
fp = AARectEffect::Create(edgeType, rect);
} while (nullptr == fp);
return fp;
}
//////////////////////////////////////////////////////////////////////////////
class GLAARectEffect : public GrGLSLFragmentProcessor {
public:
GLAARectEffect() {
fPrevRect.fLeft = SK_ScalarNaN;
}
void emitCode(EmitArgs&) override;
static inline void GenKey(const GrProcessor&, const GrGLSLCaps&, GrProcessorKeyBuilder*);
protected:
void onSetData(const GrGLSLProgramDataManager&, const GrProcessor&) override;
private:
GrGLSLProgramDataManager::UniformHandle fRectUniform;
SkRect fPrevRect;
typedef GrGLSLFragmentProcessor INHERITED;
};
void GLAARectEffect::emitCode(EmitArgs& args) {
const AARectEffect& aare = args.fFp.cast<AARectEffect>();
const char *rectName;
// The rect uniform's xyzw refer to (left + 0.5, top + 0.5, right - 0.5, bottom - 0.5),
// respectively.
fRectUniform = args.fUniformHandler->addUniform(kFragment_GrShaderFlag,
kVec4f_GrSLType,
kDefault_GrSLPrecision,
"rect",
&rectName);
GrGLSLFPFragmentBuilder* fragBuilder = args.fFragBuilder;
const char* fragmentPos = fragBuilder->fragmentPosition();
if (GrProcessorEdgeTypeIsAA(aare.getEdgeType())) {
// The amount of coverage removed in x and y by the edges is computed as a pair of negative
// numbers, xSub and ySub.
fragBuilder->codeAppend("\t\tfloat xSub, ySub;\n");
fragBuilder->codeAppendf("\t\txSub = min(%s.x - %s.x, 0.0);\n", fragmentPos, rectName);
fragBuilder->codeAppendf("\t\txSub += min(%s.z - %s.x, 0.0);\n", rectName, fragmentPos);
fragBuilder->codeAppendf("\t\tySub = min(%s.y - %s.y, 0.0);\n", fragmentPos, rectName);
fragBuilder->codeAppendf("\t\tySub += min(%s.w - %s.y, 0.0);\n", rectName, fragmentPos);
// Now compute coverage in x and y and multiply them to get the fraction of the pixel
// covered.
fragBuilder->codeAppendf("\t\tfloat alpha = (1.0 + max(xSub, -1.0)) * (1.0 + max(ySub, -1.0));\n");
} else {
fragBuilder->codeAppendf("\t\tfloat alpha = 1.0;\n");
fragBuilder->codeAppendf("\t\talpha *= (%s.x - %s.x) > -0.5 ? 1.0 : 0.0;\n", fragmentPos, rectName);
fragBuilder->codeAppendf("\t\talpha *= (%s.z - %s.x) > -0.5 ? 1.0 : 0.0;\n", rectName, fragmentPos);
fragBuilder->codeAppendf("\t\talpha *= (%s.y - %s.y) > -0.5 ? 1.0 : 0.0;\n", fragmentPos, rectName);
fragBuilder->codeAppendf("\t\talpha *= (%s.w - %s.y) > -0.5 ? 1.0 : 0.0;\n", rectName, fragmentPos);
}
if (GrProcessorEdgeTypeIsInverseFill(aare.getEdgeType())) {
fragBuilder->codeAppend("\t\talpha = 1.0 - alpha;\n");
}
fragBuilder->codeAppendf("\t\t%s = %s;\n", args.fOutputColor,
(GrGLSLExpr4(args.fInputColor) * GrGLSLExpr1("alpha")).c_str());
}
void GLAARectEffect::onSetData(const GrGLSLProgramDataManager& pdman,
const GrProcessor& processor) {
const AARectEffect& aare = processor.cast<AARectEffect>();
const SkRect& rect = aare.getRect();
if (rect != fPrevRect) {
pdman.set4f(fRectUniform, rect.fLeft + 0.5f, rect.fTop + 0.5f,
rect.fRight - 0.5f, rect.fBottom - 0.5f);
fPrevRect = rect;
}
}
void GLAARectEffect::GenKey(const GrProcessor& processor, const GrGLSLCaps&,
GrProcessorKeyBuilder* b) {
const AARectEffect& aare = processor.cast<AARectEffect>();
b->add32(aare.getEdgeType());
}
void AARectEffect::onGetGLSLProcessorKey(const GrGLSLCaps& caps, GrProcessorKeyBuilder* b) const {
GLAARectEffect::GenKey(*this, caps, b);
}
GrGLSLFragmentProcessor* AARectEffect::onCreateGLSLInstance() const {
return new GLAARectEffect;
}
//////////////////////////////////////////////////////////////////////////////
class GrGLConvexPolyEffect : public GrGLSLFragmentProcessor {
public:
GrGLConvexPolyEffect() {
fPrevEdges[0] = SK_ScalarNaN;
}
void emitCode(EmitArgs&) override;
static inline void GenKey(const GrProcessor&, const GrGLSLCaps&, GrProcessorKeyBuilder*);
protected:
void onSetData(const GrGLSLProgramDataManager&, const GrProcessor&) override;
private:
GrGLSLProgramDataManager::UniformHandle fEdgeUniform;
SkScalar fPrevEdges[3 * GrConvexPolyEffect::kMaxEdges];
typedef GrGLSLFragmentProcessor INHERITED;
};
void GrGLConvexPolyEffect::emitCode(EmitArgs& args) {
const GrConvexPolyEffect& cpe = args.fFp.cast<GrConvexPolyEffect>();
const char *edgeArrayName;
fEdgeUniform = args.fUniformHandler->addUniformArray(kFragment_GrShaderFlag,
kVec3f_GrSLType,
kDefault_GrSLPrecision,
"edges",
cpe.getEdgeCount(),
&edgeArrayName);
GrGLSLFPFragmentBuilder* fragBuilder = args.fFragBuilder;
fragBuilder->codeAppend("\t\tfloat alpha = 1.0;\n");
fragBuilder->codeAppend("\t\tfloat edge;\n");
const char* fragmentPos = fragBuilder->fragmentPosition();
for (int i = 0; i < cpe.getEdgeCount(); ++i) {
fragBuilder->codeAppendf("\t\tedge = dot(%s[%d], vec3(%s.x, %s.y, 1));\n",
edgeArrayName, i, fragmentPos, fragmentPos);
if (GrProcessorEdgeTypeIsAA(cpe.getEdgeType())) {
fragBuilder->codeAppend("\t\tedge = clamp(edge, 0.0, 1.0);\n");
} else {
fragBuilder->codeAppend("\t\tedge = edge >= 0.5 ? 1.0 : 0.0;\n");
}
fragBuilder->codeAppend("\t\talpha *= edge;\n");
}
if (GrProcessorEdgeTypeIsInverseFill(cpe.getEdgeType())) {
fragBuilder->codeAppend("\talpha = 1.0 - alpha;\n");
}
fragBuilder->codeAppendf("\t%s = %s;\n", args.fOutputColor,
(GrGLSLExpr4(args.fInputColor) * GrGLSLExpr1("alpha")).c_str());
}
void GrGLConvexPolyEffect::onSetData(const GrGLSLProgramDataManager& pdman,
const GrProcessor& effect) {
const GrConvexPolyEffect& cpe = effect.cast<GrConvexPolyEffect>();
size_t byteSize = 3 * cpe.getEdgeCount() * sizeof(SkScalar);
if (0 != memcmp(fPrevEdges, cpe.getEdges(), byteSize)) {
pdman.set3fv(fEdgeUniform, cpe.getEdgeCount(), cpe.getEdges());
memcpy(fPrevEdges, cpe.getEdges(), byteSize);
}
}
void GrGLConvexPolyEffect::GenKey(const GrProcessor& processor, const GrGLSLCaps&,
GrProcessorKeyBuilder* b) {
const GrConvexPolyEffect& cpe = processor.cast<GrConvexPolyEffect>();
GR_STATIC_ASSERT(kGrProcessorEdgeTypeCnt <= 8);
uint32_t key = (cpe.getEdgeCount() << 3) | cpe.getEdgeType();
b->add32(key);
}
//////////////////////////////////////////////////////////////////////////////
GrFragmentProcessor* GrConvexPolyEffect::Create(GrPrimitiveEdgeType type, const SkPath& path,
const SkVector* offset) {
if (kHairlineAA_GrProcessorEdgeType == type) {
return nullptr;
}
if (path.getSegmentMasks() != SkPath::kLine_SegmentMask ||
!path.isConvex()) {
return nullptr;
}
if (path.countPoints() > kMaxEdges) {
return nullptr;
}
SkPoint pts[kMaxEdges];
SkScalar edges[3 * kMaxEdges];
SkPathPriv::FirstDirection dir;
SkAssertResult(SkPathPriv::CheapComputeFirstDirection(path, &dir));
SkVector t;
if (nullptr == offset) {
t.set(0, 0);
} else {
t = *offset;
}
int count = path.getPoints(pts, kMaxEdges);
int n = 0;
for (int lastPt = count - 1, i = 0; i < count; lastPt = i++) {
if (pts[lastPt] != pts[i]) {
SkVector v = pts[i] - pts[lastPt];
v.normalize();
if (SkPathPriv::kCCW_FirstDirection == dir) {
edges[3 * n] = v.fY;
edges[3 * n + 1] = -v.fX;
} else {
edges[3 * n] = -v.fY;
edges[3 * n + 1] = v.fX;
}
SkPoint p = pts[i] + t;
edges[3 * n + 2] = -(edges[3 * n] * p.fX + edges[3 * n + 1] * p.fY);
++n;
}
}
if (path.isInverseFillType()) {
type = GrInvertProcessorEdgeType(type);
}
return Create(type, n, edges);
}
GrFragmentProcessor* GrConvexPolyEffect::Create(GrPrimitiveEdgeType edgeType, const SkRect& rect) {
if (kHairlineAA_GrProcessorEdgeType == edgeType){
return nullptr;
}
return AARectEffect::Create(edgeType, rect);
}
GrConvexPolyEffect::~GrConvexPolyEffect() {}
void GrConvexPolyEffect::onComputeInvariantOutput(GrInvariantOutput* inout) const {
inout->mulByUnknownSingleComponent();
}
void GrConvexPolyEffect::onGetGLSLProcessorKey(const GrGLSLCaps& caps,
GrProcessorKeyBuilder* b) const {
GrGLConvexPolyEffect::GenKey(*this, caps, b);
}
GrGLSLFragmentProcessor* GrConvexPolyEffect::onCreateGLSLInstance() const {
return new GrGLConvexPolyEffect;
}
GrConvexPolyEffect::GrConvexPolyEffect(GrPrimitiveEdgeType edgeType, int n, const SkScalar edges[])
: fEdgeType(edgeType)
, fEdgeCount(n) {
this->initClassID<GrConvexPolyEffect>();
// Factory function should have already ensured this.
SkASSERT(n <= kMaxEdges);
memcpy(fEdges, edges, 3 * n * sizeof(SkScalar));
// Outset the edges by 0.5 so that a pixel with center on an edge is 50% covered in the AA case
// and 100% covered in the non-AA case.
for (int i = 0; i < n; ++i) {
fEdges[3 * i + 2] += SK_ScalarHalf;
}
this->setWillReadFragmentPosition();
}
bool GrConvexPolyEffect::onIsEqual(const GrFragmentProcessor& other) const {
const GrConvexPolyEffect& cpe = other.cast<GrConvexPolyEffect>();
// ignore the fact that 0 == -0 and just use memcmp.
return (cpe.fEdgeType == fEdgeType && cpe.fEdgeCount == fEdgeCount &&
0 == memcmp(cpe.fEdges, fEdges, 3 * fEdgeCount * sizeof(SkScalar)));
}
//////////////////////////////////////////////////////////////////////////////
GR_DEFINE_FRAGMENT_PROCESSOR_TEST(GrConvexPolyEffect);
const GrFragmentProcessor* GrConvexPolyEffect::TestCreate(GrProcessorTestData* d) {
int count = d->fRandom->nextULessThan(kMaxEdges) + 1;
SkScalar edges[kMaxEdges * 3];
for (int i = 0; i < 3 * count; ++i) {
edges[i] = d->fRandom->nextSScalar1();
}
GrFragmentProcessor* fp;
do {
GrPrimitiveEdgeType edgeType = static_cast<GrPrimitiveEdgeType>(
d->fRandom->nextULessThan(kGrProcessorEdgeTypeCnt));
fp = GrConvexPolyEffect::Create(edgeType, count, edges);
} while (nullptr == fp);
return fp;
}