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 SkSweepGradient::SkSweepGradient(SkScalar cx, SkScalar cy,
12 const Descriptor& desc, const SkMatrix* localMatrix)
13 : SkGradientShaderBase(desc, localMatrix)
14 , fCenter(SkPoint::Make(cx, cy))
16 fPtsToUnit.setTranslate(-cx, -cy);
18 // overwrite the tilemode to a canonical value (since sweep ignores it)
19 fTileMode = SkShader::kClamp_TileMode;
22 SkShader::BitmapType SkSweepGradient::asABitmap(SkBitmap* bitmap,
23 SkMatrix* matrix, SkShader::TileMode* xy) const {
25 this->getGradientTableBitmap(bitmap);
32 xy[1] = kClamp_TileMode;
34 return kSweep_BitmapType;
37 SkShader::GradientType SkSweepGradient::asAGradient(GradientInfo* info) const {
39 commonAsAGradient(info);
40 info->fPoint[0] = fCenter;
42 return kSweep_GradientType;
45 SkSweepGradient::SkSweepGradient(SkReadBuffer& buffer)
47 fCenter(buffer.readPoint()) {
50 void SkSweepGradient::flatten(SkWriteBuffer& buffer) const {
51 this->INHERITED::flatten(buffer);
52 buffer.writePoint(fCenter);
55 size_t SkSweepGradient::contextSize() const {
56 return sizeof(SweepGradientContext);
59 SkShader::Context* SkSweepGradient::onCreateContext(const ContextRec& rec, void* storage) const {
60 return SkNEW_PLACEMENT_ARGS(storage, SweepGradientContext, (*this, rec));
63 SkSweepGradient::SweepGradientContext::SweepGradientContext(
64 const SkSweepGradient& shader, const ContextRec& rec)
65 : INHERITED(shader, rec) {}
67 // returns angle in a circle [0..2PI) -> [0..255]
68 static unsigned SkATan2_255(float y, float x) {
69 // static const float g255Over2PI = 255 / (2 * SK_ScalarPI);
70 static const float g255Over2PI = 40.584510488433314f;
72 float result = sk_float_atan2(y, x);
74 result += 2 * SK_ScalarPI;
76 SkASSERT(result >= 0);
77 // since our value is always >= 0, we can cast to int, which is faster than
79 int ir = (int)(result * g255Over2PI);
80 SkASSERT(ir >= 0 && ir <= 255);
84 void SkSweepGradient::SweepGradientContext::shadeSpan(int x, int y, SkPMColor* SK_RESTRICT dstC,
86 SkMatrix::MapXYProc proc = fDstToIndexProc;
87 const SkMatrix& matrix = fDstToIndex;
88 const SkPMColor* SK_RESTRICT cache = fCache->getCache32();
89 int toggle = init_dither_toggle(x, y);
92 if (fDstToIndexClass != kPerspective_MatrixClass) {
93 proc(matrix, SkIntToScalar(x) + SK_ScalarHalf,
94 SkIntToScalar(y) + SK_ScalarHalf, &srcPt);
95 SkScalar dx, fx = srcPt.fX;
96 SkScalar dy, fy = srcPt.fY;
98 if (fDstToIndexClass == kFixedStepInX_MatrixClass) {
100 (void)matrix.fixedStepInX(SkIntToScalar(y) + SK_ScalarHalf,
101 &storage[0], &storage[1]);
102 dx = SkFixedToScalar(storage[0]);
103 dy = SkFixedToScalar(storage[1]);
105 SkASSERT(fDstToIndexClass == kLinear_MatrixClass);
106 dx = matrix.getScaleX();
107 dy = matrix.getSkewY();
110 for (; count > 0; --count) {
111 *dstC++ = cache[toggle + SkATan2_255(fy, fx)];
114 toggle = next_dither_toggle(toggle);
116 } else { // perspective case
117 for (int stop = x + count; x < stop; x++) {
118 proc(matrix, SkIntToScalar(x) + SK_ScalarHalf,
119 SkIntToScalar(y) + SK_ScalarHalf, &srcPt);
120 *dstC++ = cache[toggle + SkATan2_255(srcPt.fY, srcPt.fX)];
121 toggle = next_dither_toggle(toggle);
126 void SkSweepGradient::SweepGradientContext::shadeSpan16(int x, int y, uint16_t* SK_RESTRICT dstC,
128 SkMatrix::MapXYProc proc = fDstToIndexProc;
129 const SkMatrix& matrix = fDstToIndex;
130 const uint16_t* SK_RESTRICT cache = fCache->getCache16();
131 int toggle = init_dither_toggle16(x, y);
134 if (fDstToIndexClass != kPerspective_MatrixClass) {
135 proc(matrix, SkIntToScalar(x) + SK_ScalarHalf,
136 SkIntToScalar(y) + SK_ScalarHalf, &srcPt);
137 SkScalar dx, fx = srcPt.fX;
138 SkScalar dy, fy = srcPt.fY;
140 if (fDstToIndexClass == kFixedStepInX_MatrixClass) {
142 (void)matrix.fixedStepInX(SkIntToScalar(y) + SK_ScalarHalf,
143 &storage[0], &storage[1]);
144 dx = SkFixedToScalar(storage[0]);
145 dy = SkFixedToScalar(storage[1]);
147 SkASSERT(fDstToIndexClass == kLinear_MatrixClass);
148 dx = matrix.getScaleX();
149 dy = matrix.getSkewY();
152 for (; count > 0; --count) {
153 int index = SkATan2_255(fy, fx) >> (8 - kCache16Bits);
154 *dstC++ = cache[toggle + index];
155 toggle = next_dither_toggle16(toggle);
159 } else { // perspective case
160 for (int stop = x + count; x < stop; x++) {
161 proc(matrix, SkIntToScalar(x) + SK_ScalarHalf,
162 SkIntToScalar(y) + SK_ScalarHalf, &srcPt);
164 int index = SkATan2_255(srcPt.fY, srcPt.fX);
165 index >>= (8 - kCache16Bits);
166 *dstC++ = cache[toggle + index];
167 toggle = next_dither_toggle16(toggle);
172 /////////////////////////////////////////////////////////////////////
176 #include "GrTBackendEffectFactory.h"
178 class GrGLSweepGradient : public GrGLGradientEffect {
181 GrGLSweepGradient(const GrBackendEffectFactory& factory,
182 const GrDrawEffect&) : INHERITED (factory) { }
183 virtual ~GrGLSweepGradient() { }
185 virtual void emitCode(GrGLShaderBuilder*,
188 const char* outputColor,
189 const char* inputColor,
190 const TransformedCoordsArray&,
191 const TextureSamplerArray&) SK_OVERRIDE;
193 static EffectKey GenKey(const GrDrawEffect& drawEffect, const GrGLCaps&) {
194 return GenBaseGradientKey(drawEffect);
199 typedef GrGLGradientEffect INHERITED;
203 /////////////////////////////////////////////////////////////////////
205 class GrSweepGradient : public GrGradientEffect {
207 static GrEffectRef* Create(GrContext* ctx,
208 const SkSweepGradient& shader,
209 const SkMatrix& matrix) {
210 AutoEffectUnref effect(SkNEW_ARGS(GrSweepGradient, (ctx, shader, matrix)));
211 return CreateEffectRef(effect);
213 virtual ~GrSweepGradient() { }
215 static const char* Name() { return "Sweep Gradient"; }
216 virtual const GrBackendEffectFactory& getFactory() const SK_OVERRIDE {
217 return GrTBackendEffectFactory<GrSweepGradient>::getInstance();
220 typedef GrGLSweepGradient GLEffect;
223 GrSweepGradient(GrContext* ctx,
224 const SkSweepGradient& shader,
225 const SkMatrix& matrix)
226 : INHERITED(ctx, shader, matrix, SkShader::kClamp_TileMode) { }
227 GR_DECLARE_EFFECT_TEST;
229 typedef GrGradientEffect INHERITED;
232 /////////////////////////////////////////////////////////////////////
234 GR_DEFINE_EFFECT_TEST(GrSweepGradient);
236 GrEffectRef* GrSweepGradient::TestCreate(SkRandom* random,
238 const GrDrawTargetCaps&,
240 SkPoint center = {random->nextUScalar1(), random->nextUScalar1()};
242 SkColor colors[kMaxRandomGradientColors];
243 SkScalar stopsArray[kMaxRandomGradientColors];
244 SkScalar* stops = stopsArray;
245 SkShader::TileMode tmIgnored;
246 int colorCount = RandomGradientParams(random, colors, &stops, &tmIgnored);
247 SkAutoTUnref<SkShader> shader(SkGradientShader::CreateSweep(center.fX, center.fY,
248 colors, stops, colorCount));
250 return shader->asNewEffect(context, paint);
253 /////////////////////////////////////////////////////////////////////
255 void GrGLSweepGradient::emitCode(GrGLShaderBuilder* builder,
258 const char* outputColor,
259 const char* inputColor,
260 const TransformedCoordsArray& coords,
261 const TextureSamplerArray& samplers) {
262 this->emitUniforms(builder, key);
263 SkString coords2D = builder->ensureFSCoords2D(coords, 0);
264 const GrGLContextInfo ctxInfo = builder->ctxInfo();
266 // 0.1591549430918 is 1/(2*pi), used since atan returns values [-pi, pi]
267 // On Intel GPU there is an issue where it reads the second arguement to atan "- %s.x" as an int
268 // thus must us -1.0 * %s.x to work correctly
269 if (kIntel_GrGLVendor != ctxInfo.vendor()){
270 t.printf("atan(- %s.y, - %s.x) * 0.1591549430918 + 0.5",
271 coords2D.c_str(), coords2D.c_str());
273 t.printf("atan(- %s.y, -1.0 * %s.x) * 0.1591549430918 + 0.5",
274 coords2D.c_str(), coords2D.c_str());
276 this->emitColor(builder, t.c_str(), key,
277 outputColor, inputColor, samplers);
280 /////////////////////////////////////////////////////////////////////
282 GrEffectRef* SkSweepGradient::asNewEffect(GrContext* context, const SkPaint&) const {
284 if (!this->getLocalMatrix().invert(&matrix)) {
287 matrix.postConcat(fPtsToUnit);
288 return GrSweepGradient::Create(context, *this, matrix);
293 GrEffectRef* SkSweepGradient::asNewEffect(GrContext*, const SkPaint&) const {
294 SkDEBUGFAIL("Should not call in GPU-less build");
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);