michael@0: 
michael@0: /*
michael@0:  * Copyright 2012 Google Inc.
michael@0:  *
michael@0:  * Use of this source code is governed by a BSD-style license that can be
michael@0:  * found in the LICENSE file.
michael@0:  */
michael@0: 
michael@0: #include "SkSweepGradient.h"
michael@0: 
michael@0: SkSweepGradient::SkSweepGradient(SkScalar cx, SkScalar cy,
michael@0:                                  const Descriptor& desc)
michael@0:     : SkGradientShaderBase(desc)
michael@0:     , fCenter(SkPoint::Make(cx, cy))
michael@0: {
michael@0:     fPtsToUnit.setTranslate(-cx, -cy);
michael@0: 
michael@0:     // overwrite the tilemode to a canonical value (since sweep ignores it)
michael@0:     fTileMode = SkShader::kClamp_TileMode;
michael@0: }
michael@0: 
michael@0: SkShader::BitmapType SkSweepGradient::asABitmap(SkBitmap* bitmap,
michael@0:     SkMatrix* matrix, SkShader::TileMode* xy) const {
michael@0:     if (bitmap) {
michael@0:         this->getGradientTableBitmap(bitmap);
michael@0:     }
michael@0:     if (matrix) {
michael@0:         *matrix = fPtsToUnit;
michael@0:     }
michael@0:     if (xy) {
michael@0:         xy[0] = fTileMode;
michael@0:         xy[1] = kClamp_TileMode;
michael@0:     }
michael@0:     return kSweep_BitmapType;
michael@0: }
michael@0: 
michael@0: SkShader::GradientType SkSweepGradient::asAGradient(GradientInfo* info) const {
michael@0:     if (info) {
michael@0:         commonAsAGradient(info);
michael@0:         info->fPoint[0] = fCenter;
michael@0:     }
michael@0:     return kSweep_GradientType;
michael@0: }
michael@0: 
michael@0: SkSweepGradient::SkSweepGradient(SkReadBuffer& buffer)
michael@0:     : INHERITED(buffer),
michael@0:       fCenter(buffer.readPoint()) {
michael@0: }
michael@0: 
michael@0: void SkSweepGradient::flatten(SkWriteBuffer& buffer) const {
michael@0:     this->INHERITED::flatten(buffer);
michael@0:     buffer.writePoint(fCenter);
michael@0: }
michael@0: 
michael@0: //  returns angle in a circle [0..2PI) -> [0..255]
michael@0: static unsigned SkATan2_255(float y, float x) {
michael@0:     //    static const float g255Over2PI = 255 / (2 * SK_ScalarPI);
michael@0:     static const float g255Over2PI = 40.584510488433314f;
michael@0: 
michael@0:     float result = sk_float_atan2(y, x);
michael@0:     if (result < 0) {
michael@0:         result += 2 * SK_ScalarPI;
michael@0:     }
michael@0:     SkASSERT(result >= 0);
michael@0:     // since our value is always >= 0, we can cast to int, which is faster than
michael@0:     // calling floorf()
michael@0:     int ir = (int)(result * g255Over2PI);
michael@0:     SkASSERT(ir >= 0 && ir <= 255);
michael@0:     return ir;
michael@0: }
michael@0: 
michael@0: void SkSweepGradient::shadeSpan(int x, int y, SkPMColor* SK_RESTRICT dstC,
michael@0:                                int count) {
michael@0:     SkMatrix::MapXYProc proc = fDstToIndexProc;
michael@0:     const SkMatrix&     matrix = fDstToIndex;
michael@0:     const SkPMColor* SK_RESTRICT cache = this->getCache32();
michael@0:     int                 toggle = init_dither_toggle(x, y);
michael@0:     SkPoint             srcPt;
michael@0: 
michael@0:     if (fDstToIndexClass != kPerspective_MatrixClass) {
michael@0:         proc(matrix, SkIntToScalar(x) + SK_ScalarHalf,
michael@0:                      SkIntToScalar(y) + SK_ScalarHalf, &srcPt);
michael@0:         SkScalar dx, fx = srcPt.fX;
michael@0:         SkScalar dy, fy = srcPt.fY;
michael@0: 
michael@0:         if (fDstToIndexClass == kFixedStepInX_MatrixClass) {
michael@0:             SkFixed storage[2];
michael@0:             (void)matrix.fixedStepInX(SkIntToScalar(y) + SK_ScalarHalf,
michael@0:                                       &storage[0], &storage[1]);
michael@0:             dx = SkFixedToScalar(storage[0]);
michael@0:             dy = SkFixedToScalar(storage[1]);
michael@0:         } else {
michael@0:             SkASSERT(fDstToIndexClass == kLinear_MatrixClass);
michael@0:             dx = matrix.getScaleX();
michael@0:             dy = matrix.getSkewY();
michael@0:         }
michael@0: 
michael@0:         for (; count > 0; --count) {
michael@0:             *dstC++ = cache[toggle + SkATan2_255(fy, fx)];
michael@0:             fx += dx;
michael@0:             fy += dy;
michael@0:             toggle = next_dither_toggle(toggle);
michael@0:         }
michael@0:     } else {  // perspective case
michael@0:         for (int stop = x + count; x < stop; x++) {
michael@0:             proc(matrix, SkIntToScalar(x) + SK_ScalarHalf,
michael@0:                          SkIntToScalar(y) + SK_ScalarHalf, &srcPt);
michael@0:             *dstC++ = cache[toggle + SkATan2_255(srcPt.fY, srcPt.fX)];
michael@0:             toggle = next_dither_toggle(toggle);
michael@0:         }
michael@0:     }
michael@0: }
michael@0: 
michael@0: void SkSweepGradient::shadeSpan16(int x, int y, uint16_t* SK_RESTRICT dstC,
michael@0:                                  int count) {
michael@0:     SkMatrix::MapXYProc proc = fDstToIndexProc;
michael@0:     const SkMatrix&     matrix = fDstToIndex;
michael@0:     const uint16_t* SK_RESTRICT cache = this->getCache16();
michael@0:     int                 toggle = init_dither_toggle16(x, y);
michael@0:     SkPoint             srcPt;
michael@0: 
michael@0:     if (fDstToIndexClass != kPerspective_MatrixClass) {
michael@0:         proc(matrix, SkIntToScalar(x) + SK_ScalarHalf,
michael@0:                      SkIntToScalar(y) + SK_ScalarHalf, &srcPt);
michael@0:         SkScalar dx, fx = srcPt.fX;
michael@0:         SkScalar dy, fy = srcPt.fY;
michael@0: 
michael@0:         if (fDstToIndexClass == kFixedStepInX_MatrixClass) {
michael@0:             SkFixed storage[2];
michael@0:             (void)matrix.fixedStepInX(SkIntToScalar(y) + SK_ScalarHalf,
michael@0:                                       &storage[0], &storage[1]);
michael@0:             dx = SkFixedToScalar(storage[0]);
michael@0:             dy = SkFixedToScalar(storage[1]);
michael@0:         } else {
michael@0:             SkASSERT(fDstToIndexClass == kLinear_MatrixClass);
michael@0:             dx = matrix.getScaleX();
michael@0:             dy = matrix.getSkewY();
michael@0:         }
michael@0: 
michael@0:         for (; count > 0; --count) {
michael@0:             int index = SkATan2_255(fy, fx) >> (8 - kCache16Bits);
michael@0:             *dstC++ = cache[toggle + index];
michael@0:             toggle = next_dither_toggle16(toggle);
michael@0:             fx += dx;
michael@0:             fy += dy;
michael@0:         }
michael@0:     } else {  // perspective case
michael@0:         for (int stop = x + count; x < stop; x++) {
michael@0:             proc(matrix, SkIntToScalar(x) + SK_ScalarHalf,
michael@0:                          SkIntToScalar(y) + SK_ScalarHalf, &srcPt);
michael@0: 
michael@0:             int index = SkATan2_255(srcPt.fY, srcPt.fX);
michael@0:             index >>= (8 - kCache16Bits);
michael@0:             *dstC++ = cache[toggle + index];
michael@0:             toggle = next_dither_toggle16(toggle);
michael@0:         }
michael@0:     }
michael@0: }
michael@0: 
michael@0: /////////////////////////////////////////////////////////////////////
michael@0: 
michael@0: #if SK_SUPPORT_GPU
michael@0: 
michael@0: #include "GrTBackendEffectFactory.h"
michael@0: 
michael@0: class GrGLSweepGradient : public GrGLGradientEffect {
michael@0: public:
michael@0: 
michael@0:     GrGLSweepGradient(const GrBackendEffectFactory& factory,
michael@0:                       const GrDrawEffect&) : INHERITED (factory) { }
michael@0:     virtual ~GrGLSweepGradient() { }
michael@0: 
michael@0:     virtual void emitCode(GrGLShaderBuilder*,
michael@0:                           const GrDrawEffect&,
michael@0:                           EffectKey,
michael@0:                           const char* outputColor,
michael@0:                           const char* inputColor,
michael@0:                           const TransformedCoordsArray&,
michael@0:                           const TextureSamplerArray&) SK_OVERRIDE;
michael@0: 
michael@0:     static EffectKey GenKey(const GrDrawEffect& drawEffect, const GrGLCaps&) {
michael@0:         return GenBaseGradientKey(drawEffect);
michael@0:     }
michael@0: 
michael@0: private:
michael@0: 
michael@0:     typedef GrGLGradientEffect INHERITED;
michael@0: 
michael@0: };
michael@0: 
michael@0: /////////////////////////////////////////////////////////////////////
michael@0: 
michael@0: class GrSweepGradient : public GrGradientEffect {
michael@0: public:
michael@0:     static GrEffectRef* Create(GrContext* ctx,
michael@0:                                const SkSweepGradient& shader,
michael@0:                                const SkMatrix& matrix) {
michael@0:         AutoEffectUnref effect(SkNEW_ARGS(GrSweepGradient, (ctx, shader, matrix)));
michael@0:         return CreateEffectRef(effect);
michael@0:     }
michael@0:     virtual ~GrSweepGradient() { }
michael@0: 
michael@0:     static const char* Name() { return "Sweep Gradient"; }
michael@0:     virtual const GrBackendEffectFactory& getFactory() const SK_OVERRIDE {
michael@0:         return GrTBackendEffectFactory<GrSweepGradient>::getInstance();
michael@0:     }
michael@0: 
michael@0:     typedef GrGLSweepGradient GLEffect;
michael@0: 
michael@0: private:
michael@0:     GrSweepGradient(GrContext* ctx,
michael@0:                     const SkSweepGradient& shader,
michael@0:                     const SkMatrix& matrix)
michael@0:     : INHERITED(ctx, shader, matrix, SkShader::kClamp_TileMode) { }
michael@0:     GR_DECLARE_EFFECT_TEST;
michael@0: 
michael@0:     typedef GrGradientEffect INHERITED;
michael@0: };
michael@0: 
michael@0: /////////////////////////////////////////////////////////////////////
michael@0: 
michael@0: GR_DEFINE_EFFECT_TEST(GrSweepGradient);
michael@0: 
michael@0: GrEffectRef* GrSweepGradient::TestCreate(SkRandom* random,
michael@0:                                          GrContext* context,
michael@0:                                          const GrDrawTargetCaps&,
michael@0:                                          GrTexture**) {
michael@0:     SkPoint center = {random->nextUScalar1(), random->nextUScalar1()};
michael@0: 
michael@0:     SkColor colors[kMaxRandomGradientColors];
michael@0:     SkScalar stopsArray[kMaxRandomGradientColors];
michael@0:     SkScalar* stops = stopsArray;
michael@0:     SkShader::TileMode tmIgnored;
michael@0:     int colorCount = RandomGradientParams(random, colors, &stops, &tmIgnored);
michael@0:     SkAutoTUnref<SkShader> shader(SkGradientShader::CreateSweep(center.fX, center.fY,
michael@0:                                                                 colors, stops, colorCount));
michael@0:     SkPaint paint;
michael@0:     return shader->asNewEffect(context, paint);
michael@0: }
michael@0: 
michael@0: /////////////////////////////////////////////////////////////////////
michael@0: 
michael@0: void GrGLSweepGradient::emitCode(GrGLShaderBuilder* builder,
michael@0:                                  const GrDrawEffect&,
michael@0:                                  EffectKey key,
michael@0:                                  const char* outputColor,
michael@0:                                  const char* inputColor,
michael@0:                                  const TransformedCoordsArray& coords,
michael@0:                                  const TextureSamplerArray& samplers) {
michael@0:     this->emitUniforms(builder, key);
michael@0:     SkString coords2D = builder->ensureFSCoords2D(coords, 0);
michael@0:     const GrGLContextInfo ctxInfo = builder->ctxInfo();
michael@0:     SkString t;
michael@0:     // 0.1591549430918 is 1/(2*pi), used since atan returns values [-pi, pi]
michael@0:     // On Intel GPU there is an issue where it reads the second arguement to atan "- %s.x" as an int
michael@0:     // thus must us -1.0 * %s.x to work correctly
michael@0:     if (kIntel_GrGLVendor != ctxInfo.vendor()){
michael@0:         t.printf("atan(- %s.y, - %s.x) * 0.1591549430918 + 0.5",
michael@0:                  coords2D.c_str(), coords2D.c_str());
michael@0:     } else {
michael@0:         t.printf("atan(- %s.y, -1.0 * %s.x) * 0.1591549430918 + 0.5",
michael@0:                  coords2D.c_str(), coords2D.c_str());
michael@0:     }
michael@0:     this->emitColor(builder, t.c_str(), key,
michael@0:                           outputColor, inputColor, samplers);
michael@0: }
michael@0: 
michael@0: /////////////////////////////////////////////////////////////////////
michael@0: 
michael@0: GrEffectRef* SkSweepGradient::asNewEffect(GrContext* context, const SkPaint&) const {
michael@0:     SkMatrix matrix;
michael@0:     if (!this->getLocalMatrix().invert(&matrix)) {
michael@0:         return NULL;
michael@0:     }
michael@0:     matrix.postConcat(fPtsToUnit);
michael@0:     return GrSweepGradient::Create(context, *this, matrix);
michael@0: }
michael@0: 
michael@0: #else
michael@0: 
michael@0: GrEffectRef* SkSweepGradient::asNewEffect(GrContext*, const SkPaint&) const {
michael@0:     SkDEBUGFAIL("Should not call in GPU-less build");
michael@0:     return NULL;
michael@0: }
michael@0: 
michael@0: #endif
michael@0: 
michael@0: #ifndef SK_IGNORE_TO_STRING
michael@0: void SkSweepGradient::toString(SkString* str) const {
michael@0:     str->append("SkSweepGradient: (");
michael@0: 
michael@0:     str->append("center: (");
michael@0:     str->appendScalar(fCenter.fX);
michael@0:     str->append(", ");
michael@0:     str->appendScalar(fCenter.fY);
michael@0:     str->append(") ");
michael@0: 
michael@0:     this->INHERITED::toString(str);
michael@0: 
michael@0:     str->append(")");
michael@0: }
michael@0: #endif