2 * Copyright 2012 Google Inc.
4 * Use of this source code is governed by a BSD-style license that can be
5 * found in the LICENSE file.
8 #include "SkSweepGradient.h"
10 static SkMatrix translate(SkScalar dx, SkScalar dy) {
12 matrix.setTranslate(dx, dy);
16 SkSweepGradient::SkSweepGradient(SkScalar cx, SkScalar cy, const Descriptor& desc)
17 : SkGradientShaderBase(desc, translate(-cx, -cy))
18 , fCenter(SkPoint::Make(cx, cy))
20 // overwrite the tilemode to a canonical value (since sweep ignores it)
21 fTileMode = SkShader::kClamp_TileMode;
24 SkShader::GradientType SkSweepGradient::asAGradient(GradientInfo* info) const {
26 commonAsAGradient(info);
27 info->fPoint[0] = fCenter;
29 return kSweep_GradientType;
32 sk_sp<SkFlattenable> SkSweepGradient::CreateProc(SkReadBuffer& buffer) {
34 if (!desc.unflatten(buffer)) {
37 const SkPoint center = buffer.readPoint();
38 return SkGradientShader::MakeSweep(center.x(), center.y(), desc.fColors, desc.fPos,
39 desc.fCount, desc.fGradFlags, desc.fLocalMatrix);
42 void SkSweepGradient::flatten(SkWriteBuffer& buffer) const {
43 this->INHERITED::flatten(buffer);
44 buffer.writePoint(fCenter);
47 size_t SkSweepGradient::onContextSize(const ContextRec&) const {
48 return sizeof(SweepGradientContext);
51 SkShader::Context* SkSweepGradient::onCreateContext(const ContextRec& rec, void* storage) const {
52 return new (storage) SweepGradientContext(*this, rec);
55 SkSweepGradient::SweepGradientContext::SweepGradientContext(
56 const SkSweepGradient& shader, const ContextRec& rec)
57 : INHERITED(shader, rec) {}
59 // returns angle in a circle [0..2PI) -> [0..255]
60 static unsigned SkATan2_255(float y, float x) {
61 // static const float g255Over2PI = 255 / (2 * SK_ScalarPI);
62 static const float g255Over2PI = 40.584510488433314f;
64 float result = sk_float_atan2(y, x);
65 if (!SkScalarIsFinite(result)) {
69 result += 2 * SK_ScalarPI;
71 SkASSERT(result >= 0);
72 // since our value is always >= 0, we can cast to int, which is faster than
74 int ir = (int)(result * g255Over2PI);
75 SkASSERT(ir >= 0 && ir <= 255);
79 void SkSweepGradient::SweepGradientContext::shadeSpan(int x, int y, SkPMColor* SK_RESTRICT dstC,
81 SkMatrix::MapXYProc proc = fDstToIndexProc;
82 const SkMatrix& matrix = fDstToIndex;
83 const SkPMColor* SK_RESTRICT cache = fCache->getCache32();
84 int toggle = init_dither_toggle(x, y);
87 if (fDstToIndexClass != kPerspective_MatrixClass) {
88 proc(matrix, SkIntToScalar(x) + SK_ScalarHalf,
89 SkIntToScalar(y) + SK_ScalarHalf, &srcPt);
90 SkScalar dx, fx = srcPt.fX;
91 SkScalar dy, fy = srcPt.fY;
93 if (fDstToIndexClass == kFixedStepInX_MatrixClass) {
94 const auto step = matrix.fixedStepInX(SkIntToScalar(y) + SK_ScalarHalf);
98 SkASSERT(fDstToIndexClass == kLinear_MatrixClass);
99 dx = matrix.getScaleX();
100 dy = matrix.getSkewY();
103 for (; count > 0; --count) {
104 *dstC++ = cache[toggle + SkATan2_255(fy, fx)];
107 toggle = next_dither_toggle(toggle);
109 } else { // perspective case
110 for (int stop = x + count; x < stop; x++) {
111 proc(matrix, SkIntToScalar(x) + SK_ScalarHalf,
112 SkIntToScalar(y) + SK_ScalarHalf, &srcPt);
113 *dstC++ = cache[toggle + SkATan2_255(srcPt.fY, srcPt.fX)];
114 toggle = next_dither_toggle(toggle);
119 /////////////////////////////////////////////////////////////////////
124 #include "gl/GrGLContext.h"
125 #include "glsl/GrGLSLCaps.h"
126 #include "glsl/GrGLSLFragmentShaderBuilder.h"
128 class GrGLSweepGradient : public GrGLGradientEffect {
131 GrGLSweepGradient(const GrProcessor&) {}
132 virtual ~GrGLSweepGradient() { }
134 virtual void emitCode(EmitArgs&) override;
136 static void GenKey(const GrProcessor& processor, const GrGLSLCaps&, GrProcessorKeyBuilder* b) {
137 b->add32(GenBaseGradientKey(processor));
142 typedef GrGLGradientEffect INHERITED;
146 /////////////////////////////////////////////////////////////////////
148 class GrSweepGradient : public GrGradientEffect {
150 static GrFragmentProcessor* Create(GrContext* ctx, const SkSweepGradient& shader,
152 return new GrSweepGradient(ctx, shader, m);
154 virtual ~GrSweepGradient() { }
156 const char* name() const override { return "Sweep Gradient"; }
159 GrSweepGradient(GrContext* ctx,
160 const SkSweepGradient& shader,
161 const SkMatrix& matrix)
162 : INHERITED(ctx, shader, matrix, SkShader::kClamp_TileMode) {
163 this->initClassID<GrSweepGradient>();
166 GrGLSLFragmentProcessor* onCreateGLSLInstance() const override {
167 return new GrGLSweepGradient(*this);
170 virtual void onGetGLSLProcessorKey(const GrGLSLCaps& caps,
171 GrProcessorKeyBuilder* b) const override {
172 GrGLSweepGradient::GenKey(*this, caps, b);
175 GR_DECLARE_FRAGMENT_PROCESSOR_TEST;
177 typedef GrGradientEffect INHERITED;
180 /////////////////////////////////////////////////////////////////////
182 GR_DEFINE_FRAGMENT_PROCESSOR_TEST(GrSweepGradient);
184 const GrFragmentProcessor* GrSweepGradient::TestCreate(GrProcessorTestData* d) {
185 SkPoint center = {d->fRandom->nextUScalar1(), d->fRandom->nextUScalar1()};
187 SkColor colors[kMaxRandomGradientColors];
188 SkScalar stopsArray[kMaxRandomGradientColors];
189 SkScalar* stops = stopsArray;
190 SkShader::TileMode tmIgnored;
191 int colorCount = RandomGradientParams(d->fRandom, colors, &stops, &tmIgnored);
192 sk_sp<SkShader> shader(SkGradientShader::MakeSweep(center.fX, center.fY, colors, stops,
194 const GrFragmentProcessor* fp = shader->asFragmentProcessor(d->fContext,
195 GrTest::TestMatrix(d->fRandom),
196 NULL, kNone_SkFilterQuality,
197 SkSourceGammaTreatment::kRespect);
202 /////////////////////////////////////////////////////////////////////
204 void GrGLSweepGradient::emitCode(EmitArgs& args) {
205 const GrSweepGradient& ge = args.fFp.cast<GrSweepGradient>();
206 this->emitUniforms(args.fUniformHandler, ge);
207 SkString coords2D = args.fFragBuilder->ensureFSCoords2D(args.fCoords, 0);
209 // 0.1591549430918 is 1/(2*pi), used since atan returns values [-pi, pi]
210 // On Intel GPU there is an issue where it reads the second arguement to atan "- %s.x" as an int
211 // thus must us -1.0 * %s.x to work correctly
212 if (args.fGLSLCaps->mustForceNegatedAtanParamToFloat()){
213 t.printf("atan(- %s.y, -1.0 * %s.x) * 0.1591549430918 + 0.5",
214 coords2D.c_str(), coords2D.c_str());
216 t.printf("atan(- %s.y, - %s.x) * 0.1591549430918 + 0.5",
217 coords2D.c_str(), coords2D.c_str());
219 this->emitColor(args.fFragBuilder,
220 args.fUniformHandler,
228 /////////////////////////////////////////////////////////////////////
230 const GrFragmentProcessor* SkSweepGradient::asFragmentProcessor(
232 const SkMatrix& viewM,
233 const SkMatrix* localMatrix,
235 SkSourceGammaTreatment) const {
238 if (!this->getLocalMatrix().invert(&matrix)) {
243 if (!localMatrix->invert(&inv)) {
246 matrix.postConcat(inv);
248 matrix.postConcat(fPtsToUnit);
250 SkAutoTUnref<const GrFragmentProcessor> inner(
251 GrSweepGradient::Create(context, *this, matrix));
252 return GrFragmentProcessor::MulOutputByInputAlpha(inner);
257 #ifndef SK_IGNORE_TO_STRING
258 void SkSweepGradient::toString(SkString* str) const {
259 str->append("SkSweepGradient: (");
261 str->append("center: (");
262 str->appendScalar(fCenter.fX);
264 str->appendScalar(fCenter.fY);
267 this->INHERITED::toString(str);