3 * Copyright 2012 Google Inc.
5 * Use of this source code is governed by a BSD-style license that can be
6 * found in the LICENSE file.
9 #include "SkSweepGradient.h"
11 static SkMatrix translate(SkScalar dx, SkScalar dy) {
13 matrix.setTranslate(dx, dy);
17 SkSweepGradient::SkSweepGradient(SkScalar cx, SkScalar cy, const Descriptor& desc)
18 : SkGradientShaderBase(desc, translate(-cx, -cy))
19 , fCenter(SkPoint::Make(cx, cy))
21 // overwrite the tilemode to a canonical value (since sweep ignores it)
22 fTileMode = SkShader::kClamp_TileMode;
25 SkShader::GradientType SkSweepGradient::asAGradient(GradientInfo* info) const {
27 commonAsAGradient(info);
28 info->fPoint[0] = fCenter;
30 return kSweep_GradientType;
33 SkFlattenable* SkSweepGradient::CreateProc(SkReadBuffer& buffer) {
35 if (!desc.unflatten(buffer)) {
38 const SkPoint center = buffer.readPoint();
39 return SkGradientShader::CreateSweep(center.x(), center.y(), desc.fColors, desc.fPos,
40 desc.fCount, desc.fGradFlags, desc.fLocalMatrix);
43 void SkSweepGradient::flatten(SkWriteBuffer& buffer) const {
44 this->INHERITED::flatten(buffer);
45 buffer.writePoint(fCenter);
48 size_t SkSweepGradient::contextSize() const {
49 return sizeof(SweepGradientContext);
52 SkShader::Context* SkSweepGradient::onCreateContext(const ContextRec& rec, void* storage) const {
53 return new (storage) SweepGradientContext(*this, rec);
56 SkSweepGradient::SweepGradientContext::SweepGradientContext(
57 const SkSweepGradient& shader, const ContextRec& rec)
58 : INHERITED(shader, rec) {}
60 // returns angle in a circle [0..2PI) -> [0..255]
61 static unsigned SkATan2_255(float y, float x) {
62 // static const float g255Over2PI = 255 / (2 * SK_ScalarPI);
63 static const float g255Over2PI = 40.584510488433314f;
65 float result = sk_float_atan2(y, x);
67 result += 2 * SK_ScalarPI;
69 SkASSERT(result >= 0);
70 // since our value is always >= 0, we can cast to int, which is faster than
72 int ir = (int)(result * g255Over2PI);
73 SkASSERT(ir >= 0 && ir <= 255);
77 void SkSweepGradient::SweepGradientContext::shadeSpan(int x, int y, SkPMColor* SK_RESTRICT dstC,
79 SkMatrix::MapXYProc proc = fDstToIndexProc;
80 const SkMatrix& matrix = fDstToIndex;
81 const SkPMColor* SK_RESTRICT cache = fCache->getCache32();
82 int toggle = init_dither_toggle(x, y);
85 if (fDstToIndexClass != kPerspective_MatrixClass) {
86 proc(matrix, SkIntToScalar(x) + SK_ScalarHalf,
87 SkIntToScalar(y) + SK_ScalarHalf, &srcPt);
88 SkScalar dx, fx = srcPt.fX;
89 SkScalar dy, fy = srcPt.fY;
91 if (fDstToIndexClass == kFixedStepInX_MatrixClass) {
93 (void)matrix.fixedStepInX(SkIntToScalar(y) + SK_ScalarHalf,
94 &storage[0], &storage[1]);
95 dx = SkFixedToScalar(storage[0]);
96 dy = SkFixedToScalar(storage[1]);
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 void SkSweepGradient::SweepGradientContext::shadeSpan16(int x, int y, uint16_t* SK_RESTRICT dstC,
121 SkMatrix::MapXYProc proc = fDstToIndexProc;
122 const SkMatrix& matrix = fDstToIndex;
123 const uint16_t* SK_RESTRICT cache = fCache->getCache16();
124 int toggle = init_dither_toggle16(x, y);
127 if (fDstToIndexClass != kPerspective_MatrixClass) {
128 proc(matrix, SkIntToScalar(x) + SK_ScalarHalf,
129 SkIntToScalar(y) + SK_ScalarHalf, &srcPt);
130 SkScalar dx, fx = srcPt.fX;
131 SkScalar dy, fy = srcPt.fY;
133 if (fDstToIndexClass == kFixedStepInX_MatrixClass) {
135 (void)matrix.fixedStepInX(SkIntToScalar(y) + SK_ScalarHalf,
136 &storage[0], &storage[1]);
137 dx = SkFixedToScalar(storage[0]);
138 dy = SkFixedToScalar(storage[1]);
140 SkASSERT(fDstToIndexClass == kLinear_MatrixClass);
141 dx = matrix.getScaleX();
142 dy = matrix.getSkewY();
145 for (; count > 0; --count) {
146 int index = SkATan2_255(fy, fx) >> (8 - kCache16Bits);
147 *dstC++ = cache[toggle + index];
148 toggle = next_dither_toggle16(toggle);
152 } else { // perspective case
153 for (int stop = x + count; x < stop; x++) {
154 proc(matrix, SkIntToScalar(x) + SK_ScalarHalf,
155 SkIntToScalar(y) + SK_ScalarHalf, &srcPt);
157 int index = SkATan2_255(srcPt.fY, srcPt.fX);
158 index >>= (8 - kCache16Bits);
159 *dstC++ = cache[toggle + index];
160 toggle = next_dither_toggle16(toggle);
165 /////////////////////////////////////////////////////////////////////
170 #include "gl/GrGLContext.h"
171 #include "gl/builders/GrGLProgramBuilder.h"
173 class GrGLSweepGradient : public GrGLGradientEffect {
176 GrGLSweepGradient(const GrProcessor&) {}
177 virtual ~GrGLSweepGradient() { }
179 virtual void emitCode(EmitArgs&) override;
181 static void GenKey(const GrProcessor& processor, const GrGLSLCaps&, GrProcessorKeyBuilder* b) {
182 b->add32(GenBaseGradientKey(processor));
187 typedef GrGLGradientEffect INHERITED;
191 /////////////////////////////////////////////////////////////////////
193 class GrSweepGradient : public GrGradientEffect {
195 static GrFragmentProcessor* Create(GrContext* ctx, const SkSweepGradient& shader,
197 return new GrSweepGradient(ctx, shader, m);
199 virtual ~GrSweepGradient() { }
201 const char* name() const override { return "Sweep Gradient"; }
204 GrSweepGradient(GrContext* ctx,
205 const SkSweepGradient& shader,
206 const SkMatrix& matrix)
207 : INHERITED(ctx, shader, matrix, SkShader::kClamp_TileMode) {
208 this->initClassID<GrSweepGradient>();
211 GrGLSLFragmentProcessor* onCreateGLSLInstance() const override {
212 return new GrGLSweepGradient(*this);
215 virtual void onGetGLSLProcessorKey(const GrGLSLCaps& caps,
216 GrProcessorKeyBuilder* b) const override {
217 GrGLSweepGradient::GenKey(*this, caps, b);
220 GR_DECLARE_FRAGMENT_PROCESSOR_TEST;
222 typedef GrGradientEffect INHERITED;
225 /////////////////////////////////////////////////////////////////////
227 GR_DEFINE_FRAGMENT_PROCESSOR_TEST(GrSweepGradient);
229 const GrFragmentProcessor* GrSweepGradient::TestCreate(GrProcessorTestData* d) {
230 SkPoint center = {d->fRandom->nextUScalar1(), d->fRandom->nextUScalar1()};
232 SkColor colors[kMaxRandomGradientColors];
233 SkScalar stopsArray[kMaxRandomGradientColors];
234 SkScalar* stops = stopsArray;
235 SkShader::TileMode tmIgnored;
236 int colorCount = RandomGradientParams(d->fRandom, colors, &stops, &tmIgnored);
237 SkAutoTUnref<SkShader> shader(SkGradientShader::CreateSweep(center.fX, center.fY,
238 colors, stops, colorCount));
239 const GrFragmentProcessor* fp = shader->asFragmentProcessor(d->fContext,
240 GrTest::TestMatrix(d->fRandom),
241 NULL, kNone_SkFilterQuality);
246 /////////////////////////////////////////////////////////////////////
248 void GrGLSweepGradient::emitCode(EmitArgs& args) {
249 const GrSweepGradient& ge = args.fFp.cast<GrSweepGradient>();
250 this->emitUniforms(args.fBuilder, ge);
251 SkString coords2D = args.fFragBuilder->ensureFSCoords2D(args.fCoords, 0);
253 // 0.1591549430918 is 1/(2*pi), used since atan returns values [-pi, pi]
254 // On Intel GPU there is an issue where it reads the second arguement to atan "- %s.x" as an int
255 // thus must us -1.0 * %s.x to work correctly
256 if (args.fGLSLCaps->mustForceNegatedAtanParamToFloat()){
257 t.printf("atan(- %s.y, -1.0 * %s.x) * 0.1591549430918 + 0.5",
258 coords2D.c_str(), coords2D.c_str());
260 t.printf("atan(- %s.y, - %s.x) * 0.1591549430918 + 0.5",
261 coords2D.c_str(), coords2D.c_str());
263 this->emitColor(args.fBuilder,
272 /////////////////////////////////////////////////////////////////////
274 const GrFragmentProcessor* SkSweepGradient::asFragmentProcessor(
276 const SkMatrix& viewM,
277 const SkMatrix* localMatrix,
278 SkFilterQuality) const {
281 if (!this->getLocalMatrix().invert(&matrix)) {
286 if (!localMatrix->invert(&inv)) {
289 matrix.postConcat(inv);
291 matrix.postConcat(fPtsToUnit);
293 SkAutoTUnref<const GrFragmentProcessor> inner(
294 GrSweepGradient::Create(context, *this, matrix));
295 return GrFragmentProcessor::MulOutputByInputAlpha(inner);
300 #ifndef SK_IGNORE_TO_STRING
301 void SkSweepGradient::toString(SkString* str) const {
302 str->append("SkSweepGradient: (");
304 str->append("center: (");
305 str->appendScalar(fCenter.fX);
307 str->appendScalar(fCenter.fY);
310 this->INHERITED::toString(str);