/*
* 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 "SkPathPriv.h"
#include "effects/GrAARectEffect.h"
#include "effects/GrConstColorProcessor.h"
#include "glsl/GrGLSLFragmentProcessor.h"
#include "glsl/GrGLSLFragmentShaderBuilder.h"
#include "glsl/GrGLSLProgramDataManager.h"
#include "glsl/GrGLSLUniformHandler.h"
#include "../private/GrGLSL.h"
//////////////////////////////////////////////////////////////////////////////
class GrGLConvexPolyEffect : public GrGLSLFragmentProcessor {
public:
GrGLConvexPolyEffect() {
for (size_t i = 0; i < SK_ARRAY_COUNT(fPrevEdges); ++i) {
fPrevEdges[i] = SK_ScalarNaN;
}
}
void emitCode(EmitArgs&) override;
static inline void GenKey(const GrProcessor&, const GrShaderCaps&, GrProcessorKeyBuilder*);
protected:
void onSetData(const GrGLSLProgramDataManager&, const GrFragmentProcessor&) 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,
kHalf3_GrSLType,
"edges",
cpe.getEdgeCount(),
&edgeArrayName);
GrGLSLFPFragmentBuilder* fragBuilder = args.fFragBuilder;
fragBuilder->codeAppend("\t\thalf alpha = 1.0;\n");
fragBuilder->codeAppend("\t\thalf edge;\n");
for (int i = 0; i < cpe.getEdgeCount(); ++i) {
fragBuilder->codeAppendf("\t\tedge = dot(%s[%d], half3(sk_FragCoord.x, sk_FragCoord.y, "
"1));\n",
edgeArrayName, i);
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 * alpha;\n", args.fOutputColor, args.fInputColor);
}
void GrGLConvexPolyEffect::onSetData(const GrGLSLProgramDataManager& pdman,
const GrFragmentProcessor& 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 GrShaderCaps&,
GrProcessorKeyBuilder* b) {
const GrConvexPolyEffect& cpe = processor.cast<GrConvexPolyEffect>();
GR_STATIC_ASSERT(kGrClipEdgeTypeCnt <= 8);
uint32_t key = (cpe.getEdgeCount() << 3) | (int) cpe.getEdgeType();
b->add32(key);
}
//////////////////////////////////////////////////////////////////////////////
std::unique_ptr<GrFragmentProcessor> GrConvexPolyEffect::Make(GrClipEdgeType type,
const SkPath& path) {
if (GrClipEdgeType::kHairlineAA == type) {
return nullptr;
}
if (path.getSegmentMasks() != SkPath::kLine_SegmentMask ||
!path.isConvex()) {
return nullptr;
}
SkPathPriv::FirstDirection dir;
// The only way this should fail is if the clip is effectively a infinitely thin line. In that
// case nothing is inside the clip. It'd be nice to detect this at a higher level and either
// skip the draw or omit the clip element.
if (!SkPathPriv::CheapComputeFirstDirection(path, &dir)) {
if (GrProcessorEdgeTypeIsInverseFill(type)) {
return GrConstColorProcessor::Make(GrColor4f::OpaqueWhite(),
GrConstColorProcessor::InputMode::kModulateRGBA);
}
// This could use kIgnore instead of kModulateRGBA but it would trigger a debug print
// about a coverage processor not being compatible with the alpha-as-coverage optimization.
// We don't really care about this unlikely case so we just use kModulateRGBA to suppress
// the print.
return GrConstColorProcessor::Make(GrColor4f::TransparentBlack(),
GrConstColorProcessor::InputMode::kModulateRGBA);
}
SkScalar edges[3 * kMaxEdges];
SkPoint pts[4];
SkPath::Verb verb;
SkPath::Iter iter(path, true);
// SkPath considers itself convex so long as there is a convex contour within it,
// regardless of any degenerate contours such as a string of moveTos before it.
// Iterate here to consume any degenerate contours and only process the points
// on the actual convex contour.
int n = 0;
while ((verb = iter.next(pts, true, true)) != SkPath::kDone_Verb) {
switch (verb) {
case SkPath::kMove_Verb:
SkASSERT(n == 0);
case SkPath::kClose_Verb:
break;
case SkPath::kLine_Verb: {
if (n >= kMaxEdges) {
return nullptr;
}
SkVector v = pts[1] - pts[0];
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;
}
edges[3 * n + 2] = -(edges[3 * n] * pts[1].fX + edges[3 * n + 1] * pts[1].fY);
++n;
break;
}
default:
return nullptr;
}
}
if (path.isInverseFillType()) {
type = GrInvertProcessorEdgeType(type);
}
return Make(type, n, edges);
}
std::unique_ptr<GrFragmentProcessor> GrConvexPolyEffect::Make(GrClipEdgeType edgeType,
const SkRect& rect) {
if (GrClipEdgeType::kHairlineAA == edgeType){
return nullptr;
}
return GrAARectEffect::Make(edgeType, rect);
}
GrConvexPolyEffect::~GrConvexPolyEffect() {}
void GrConvexPolyEffect::onGetGLSLProcessorKey(const GrShaderCaps& caps,
GrProcessorKeyBuilder* b) const {
GrGLConvexPolyEffect::GenKey(*this, caps, b);
}
GrGLSLFragmentProcessor* GrConvexPolyEffect::onCreateGLSLInstance() const {
return new GrGLConvexPolyEffect;
}
GrConvexPolyEffect::GrConvexPolyEffect(GrClipEdgeType edgeType, int n, const SkScalar edges[])
: INHERITED(kGrConvexPolyEffect_ClassID, kCompatibleWithCoverageAsAlpha_OptimizationFlag)
, fEdgeType(edgeType)
, fEdgeCount(n) {
// 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;
}
}
GrConvexPolyEffect::GrConvexPolyEffect(const GrConvexPolyEffect& that)
: INHERITED(kGrConvexPolyEffect_ClassID, kCompatibleWithCoverageAsAlpha_OptimizationFlag)
, fEdgeType(that.fEdgeType)
, fEdgeCount(that.fEdgeCount) {
memcpy(fEdges, that.fEdges, 3 * that.fEdgeCount * sizeof(SkScalar));
}
std::unique_ptr<GrFragmentProcessor> GrConvexPolyEffect::clone() const {
return std::unique_ptr<GrFragmentProcessor>(new GrConvexPolyEffect(*this));
}
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);
#if GR_TEST_UTILS
std::unique_ptr<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();
}
std::unique_ptr<GrFragmentProcessor> fp;
do {
GrClipEdgeType edgeType = static_cast<GrClipEdgeType>(
d->fRandom->nextULessThan(kGrClipEdgeTypeCnt));
fp = GrConvexPolyEffect::Make(edgeType, count, edges);
} while (nullptr == fp);
return fp;
}
#endif