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/*
* Copyright 2012 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#include "SkColorSpaceXformer.h"
#include "SkSweepGradient.h"
#include "SkPM4fPriv.h"
#include "SkRasterPipeline.h"
static SkMatrix translate(SkScalar dx, SkScalar dy) {
SkMatrix matrix;
matrix.setTranslate(dx, dy);
return matrix;
}
SkSweepGradient::SkSweepGradient(SkScalar cx, SkScalar cy, const Descriptor& desc)
: SkGradientShaderBase(desc, translate(-cx, -cy))
, fCenter(SkPoint::Make(cx, cy))
{
// overwrite the tilemode to a canonical value (since sweep ignores it)
fTileMode = SkShader::kClamp_TileMode;
}
SkShader::GradientType SkSweepGradient::asAGradient(GradientInfo* info) const {
if (info) {
commonAsAGradient(info);
info->fPoint[0] = fCenter;
}
return kSweep_GradientType;
}
sk_sp<SkFlattenable> SkSweepGradient::CreateProc(SkReadBuffer& buffer) {
DescriptorScope desc;
if (!desc.unflatten(buffer)) {
return nullptr;
}
const SkPoint center = buffer.readPoint();
return SkGradientShader::MakeSweep(center.x(), center.y(), desc.fColors,
std::move(desc.fColorSpace), desc.fPos, desc.fCount,
desc.fGradFlags, desc.fLocalMatrix);
}
void SkSweepGradient::flatten(SkWriteBuffer& buffer) const {
this->INHERITED::flatten(buffer);
buffer.writePoint(fCenter);
}
/////////////////////////////////////////////////////////////////////
#if SK_SUPPORT_GPU
#include "SkGr.h"
#include "GrShaderCaps.h"
#include "gl/GrGLContext.h"
#include "glsl/GrGLSLFragmentShaderBuilder.h"
class GrSweepGradient : public GrGradientEffect {
public:
class GLSLSweepProcessor;
static sk_sp<GrFragmentProcessor> Make(const CreateArgs& args) {
auto processor = sk_sp<GrSweepGradient>(new GrSweepGradient(args));
return processor->isValid() ? std::move(processor) : nullptr;
}
~GrSweepGradient() override {}
const char* name() const override { return "Sweep Gradient"; }
private:
GrSweepGradient(const CreateArgs& args) : INHERITED(args, args.fShader->colorsAreOpaque()) {
this->initClassID<GrSweepGradient>();
}
GrGLSLFragmentProcessor* onCreateGLSLInstance() const override;
virtual void onGetGLSLProcessorKey(const GrShaderCaps& caps,
GrProcessorKeyBuilder* b) const override;
GR_DECLARE_FRAGMENT_PROCESSOR_TEST
typedef GrGradientEffect INHERITED;
};
/////////////////////////////////////////////////////////////////////
class GrSweepGradient::GLSLSweepProcessor : public GrGradientEffect::GLSLProcessor {
public:
GLSLSweepProcessor(const GrProcessor&) {}
~GLSLSweepProcessor() override {}
virtual void emitCode(EmitArgs&) override;
static void GenKey(const GrProcessor& processor, const GrShaderCaps&, GrProcessorKeyBuilder* b) {
b->add32(GenBaseGradientKey(processor));
}
private:
typedef GrGradientEffect::GLSLProcessor INHERITED;
};
/////////////////////////////////////////////////////////////////////
GrGLSLFragmentProcessor* GrSweepGradient::onCreateGLSLInstance() const {
return new GrSweepGradient::GLSLSweepProcessor(*this);
}
void GrSweepGradient::onGetGLSLProcessorKey(const GrShaderCaps& caps,
GrProcessorKeyBuilder* b) const {
GrSweepGradient::GLSLSweepProcessor::GenKey(*this, caps, b);
}
/////////////////////////////////////////////////////////////////////
GR_DEFINE_FRAGMENT_PROCESSOR_TEST(GrSweepGradient);
#if GR_TEST_UTILS
sk_sp<GrFragmentProcessor> GrSweepGradient::TestCreate(GrProcessorTestData* d) {
SkPoint center = {d->fRandom->nextUScalar1(), d->fRandom->nextUScalar1()};
RandomGradientParams params(d->fRandom);
auto shader = params.fUseColors4f ?
SkGradientShader::MakeSweep(center.fX, center.fY, params.fColors4f, params.fColorSpace,
params.fStops, params.fColorCount) :
SkGradientShader::MakeSweep(center.fX, center.fY, params.fColors,
params.fStops, params.fColorCount);
GrTest::TestAsFPArgs asFPArgs(d);
sk_sp<GrFragmentProcessor> fp = as_SB(shader)->asFragmentProcessor(asFPArgs.args());
GrAlwaysAssert(fp);
return fp;
}
#endif
/////////////////////////////////////////////////////////////////////
void GrSweepGradient::GLSLSweepProcessor::emitCode(EmitArgs& args) {
const GrSweepGradient& ge = args.fFp.cast<GrSweepGradient>();
this->emitUniforms(args.fUniformHandler, ge);
SkString coords2D = args.fFragBuilder->ensureCoords2D(args.fTransformedCoords[0]);
SkString t;
// 0.1591549430918 is 1/(2*pi), used since atan returns values [-pi, pi]
if (args.fShaderCaps->atan2ImplementedAsAtanYOverX()) {
// On some devices they incorrectly implement atan2(y,x) as atan(y/x). In actuality it is
// atan2(y,x) = 2 * atan(y / (sqrt(x^2 + y^2) + x)). So to work around this we pass in
// (sqrt(x^2 + y^2) + x) as the second parameter to atan2 in these cases. We let the device
// handle the undefined behavior of the second paramenter being 0 instead of doing the
// divide ourselves and using atan instead.
t.printf("(2.0 * atan(- %s.y, length(%s) - %s.x) * 0.1591549430918 + 0.5)",
coords2D.c_str(), coords2D.c_str(), coords2D.c_str());
} else {
t.printf("(atan(- %s.y, - %s.x) * 0.1591549430918 + 0.5)",
coords2D.c_str(), coords2D.c_str());
}
this->emitColor(args.fFragBuilder,
args.fUniformHandler,
args.fShaderCaps,
ge, t.c_str(),
args.fOutputColor,
args.fInputColor,
args.fTexSamplers);
}
/////////////////////////////////////////////////////////////////////
sk_sp<GrFragmentProcessor> SkSweepGradient::asFragmentProcessor(const AsFPArgs& args) const {
SkMatrix matrix;
if (!this->getLocalMatrix().invert(&matrix)) {
return nullptr;
}
if (args.fLocalMatrix) {
SkMatrix inv;
if (!args.fLocalMatrix->invert(&inv)) {
return nullptr;
}
matrix.postConcat(inv);
}
matrix.postConcat(fPtsToUnit);
sk_sp<GrColorSpaceXform> colorSpaceXform = GrColorSpaceXform::Make(fColorSpace.get(),
args.fDstColorSpace);
sk_sp<GrFragmentProcessor> inner(GrSweepGradient::Make(
GrGradientEffect::CreateArgs(args.fContext, this, &matrix, SkShader::kClamp_TileMode,
std::move(colorSpaceXform), SkToBool(args.fDstColorSpace))));
if (!inner) {
return nullptr;
}
return GrFragmentProcessor::MulOutputByInputAlpha(std::move(inner));
}
#endif
sk_sp<SkShader> SkSweepGradient::onMakeColorSpace(SkColorSpaceXformer* xformer) const {
SkSTArray<8, SkColor> xformedColors(fColorCount);
xformer->apply(xformedColors.begin(), fOrigColors, fColorCount);
return SkGradientShader::MakeSweep(fCenter.fX, fCenter.fY, xformedColors.begin(), fOrigPos,
fColorCount, fGradFlags, &this->getLocalMatrix());
}
#ifndef SK_IGNORE_TO_STRING
void SkSweepGradient::toString(SkString* str) const {
str->append("SkSweepGradient: (");
str->append("center: (");
str->appendScalar(fCenter.fX);
str->append(", ");
str->appendScalar(fCenter.fY);
str->append(") ");
this->INHERITED::toString(str);
str->append(")");
}
bool SkSweepGradient::adjustMatrixAndAppendStages(SkArenaAlloc* alloc,
SkMatrix* matrix,
SkRasterPipeline* p,
SkRasterPipeline*) const {
#ifdef SK_SUPPORT_LEGACY_GRADIENT_MATRIX_MATH
matrix->postTranslate(-fCenter.fX, -fCenter.fY);
#else
matrix->postConcat(fPtsToUnit);
#endif
p->append(SkRasterPipeline::xy_to_unit_angle);
return true;
}
#endif
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