diff -r 000000000000 -r 6474c204b198 gfx/skia/trunk/src/effects/gradients/SkSweepGradient.cpp --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/gfx/skia/trunk/src/effects/gradients/SkSweepGradient.cpp Wed Dec 31 06:09:35 2014 +0100 @@ -0,0 +1,302 @@ + +/* + * 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 "SkSweepGradient.h" + +SkSweepGradient::SkSweepGradient(SkScalar cx, SkScalar cy, + const Descriptor& desc) + : SkGradientShaderBase(desc) + , fCenter(SkPoint::Make(cx, cy)) +{ + fPtsToUnit.setTranslate(-cx, -cy); + + // overwrite the tilemode to a canonical value (since sweep ignores it) + fTileMode = SkShader::kClamp_TileMode; +} + +SkShader::BitmapType SkSweepGradient::asABitmap(SkBitmap* bitmap, + SkMatrix* matrix, SkShader::TileMode* xy) const { + if (bitmap) { + this->getGradientTableBitmap(bitmap); + } + if (matrix) { + *matrix = fPtsToUnit; + } + if (xy) { + xy[0] = fTileMode; + xy[1] = kClamp_TileMode; + } + return kSweep_BitmapType; +} + +SkShader::GradientType SkSweepGradient::asAGradient(GradientInfo* info) const { + if (info) { + commonAsAGradient(info); + info->fPoint[0] = fCenter; + } + return kSweep_GradientType; +} + +SkSweepGradient::SkSweepGradient(SkReadBuffer& buffer) + : INHERITED(buffer), + fCenter(buffer.readPoint()) { +} + +void SkSweepGradient::flatten(SkWriteBuffer& buffer) const { + this->INHERITED::flatten(buffer); + buffer.writePoint(fCenter); +} + +// returns angle in a circle [0..2PI) -> [0..255] +static unsigned SkATan2_255(float y, float x) { + // static const float g255Over2PI = 255 / (2 * SK_ScalarPI); + static const float g255Over2PI = 40.584510488433314f; + + float result = sk_float_atan2(y, x); + if (result < 0) { + result += 2 * SK_ScalarPI; + } + SkASSERT(result >= 0); + // since our value is always >= 0, we can cast to int, which is faster than + // calling floorf() + int ir = (int)(result * g255Over2PI); + SkASSERT(ir >= 0 && ir <= 255); + return ir; +} + +void SkSweepGradient::shadeSpan(int x, int y, SkPMColor* SK_RESTRICT dstC, + int count) { + SkMatrix::MapXYProc proc = fDstToIndexProc; + const SkMatrix& matrix = fDstToIndex; + const SkPMColor* SK_RESTRICT cache = this->getCache32(); + int toggle = init_dither_toggle(x, y); + SkPoint srcPt; + + if (fDstToIndexClass != kPerspective_MatrixClass) { + proc(matrix, SkIntToScalar(x) + SK_ScalarHalf, + SkIntToScalar(y) + SK_ScalarHalf, &srcPt); + SkScalar dx, fx = srcPt.fX; + SkScalar dy, fy = srcPt.fY; + + if (fDstToIndexClass == kFixedStepInX_MatrixClass) { + SkFixed storage[2]; + (void)matrix.fixedStepInX(SkIntToScalar(y) + SK_ScalarHalf, + &storage[0], &storage[1]); + dx = SkFixedToScalar(storage[0]); + dy = SkFixedToScalar(storage[1]); + } else { + SkASSERT(fDstToIndexClass == kLinear_MatrixClass); + dx = matrix.getScaleX(); + dy = matrix.getSkewY(); + } + + for (; count > 0; --count) { + *dstC++ = cache[toggle + SkATan2_255(fy, fx)]; + fx += dx; + fy += dy; + toggle = next_dither_toggle(toggle); + } + } else { // perspective case + for (int stop = x + count; x < stop; x++) { + proc(matrix, SkIntToScalar(x) + SK_ScalarHalf, + SkIntToScalar(y) + SK_ScalarHalf, &srcPt); + *dstC++ = cache[toggle + SkATan2_255(srcPt.fY, srcPt.fX)]; + toggle = next_dither_toggle(toggle); + } + } +} + +void SkSweepGradient::shadeSpan16(int x, int y, uint16_t* SK_RESTRICT dstC, + int count) { + SkMatrix::MapXYProc proc = fDstToIndexProc; + const SkMatrix& matrix = fDstToIndex; + const uint16_t* SK_RESTRICT cache = this->getCache16(); + int toggle = init_dither_toggle16(x, y); + SkPoint srcPt; + + if (fDstToIndexClass != kPerspective_MatrixClass) { + proc(matrix, SkIntToScalar(x) + SK_ScalarHalf, + SkIntToScalar(y) + SK_ScalarHalf, &srcPt); + SkScalar dx, fx = srcPt.fX; + SkScalar dy, fy = srcPt.fY; + + if (fDstToIndexClass == kFixedStepInX_MatrixClass) { + SkFixed storage[2]; + (void)matrix.fixedStepInX(SkIntToScalar(y) + SK_ScalarHalf, + &storage[0], &storage[1]); + dx = SkFixedToScalar(storage[0]); + dy = SkFixedToScalar(storage[1]); + } else { + SkASSERT(fDstToIndexClass == kLinear_MatrixClass); + dx = matrix.getScaleX(); + dy = matrix.getSkewY(); + } + + for (; count > 0; --count) { + int index = SkATan2_255(fy, fx) >> (8 - kCache16Bits); + *dstC++ = cache[toggle + index]; + toggle = next_dither_toggle16(toggle); + fx += dx; + fy += dy; + } + } else { // perspective case + for (int stop = x + count; x < stop; x++) { + proc(matrix, SkIntToScalar(x) + SK_ScalarHalf, + SkIntToScalar(y) + SK_ScalarHalf, &srcPt); + + int index = SkATan2_255(srcPt.fY, srcPt.fX); + index >>= (8 - kCache16Bits); + *dstC++ = cache[toggle + index]; + toggle = next_dither_toggle16(toggle); + } + } +} + +///////////////////////////////////////////////////////////////////// + +#if SK_SUPPORT_GPU + +#include "GrTBackendEffectFactory.h" + +class GrGLSweepGradient : public GrGLGradientEffect { +public: + + GrGLSweepGradient(const GrBackendEffectFactory& factory, + const GrDrawEffect&) : INHERITED (factory) { } + virtual ~GrGLSweepGradient() { } + + virtual void emitCode(GrGLShaderBuilder*, + const GrDrawEffect&, + EffectKey, + const char* outputColor, + const char* inputColor, + const TransformedCoordsArray&, + const TextureSamplerArray&) SK_OVERRIDE; + + static EffectKey GenKey(const GrDrawEffect& drawEffect, const GrGLCaps&) { + return GenBaseGradientKey(drawEffect); + } + +private: + + typedef GrGLGradientEffect INHERITED; + +}; + +///////////////////////////////////////////////////////////////////// + +class GrSweepGradient : public GrGradientEffect { +public: + static GrEffectRef* Create(GrContext* ctx, + const SkSweepGradient& shader, + const SkMatrix& matrix) { + AutoEffectUnref effect(SkNEW_ARGS(GrSweepGradient, (ctx, shader, matrix))); + return CreateEffectRef(effect); + } + virtual ~GrSweepGradient() { } + + static const char* Name() { return "Sweep Gradient"; } + virtual const GrBackendEffectFactory& getFactory() const SK_OVERRIDE { + return GrTBackendEffectFactory::getInstance(); + } + + typedef GrGLSweepGradient GLEffect; + +private: + GrSweepGradient(GrContext* ctx, + const SkSweepGradient& shader, + const SkMatrix& matrix) + : INHERITED(ctx, shader, matrix, SkShader::kClamp_TileMode) { } + GR_DECLARE_EFFECT_TEST; + + typedef GrGradientEffect INHERITED; +}; + +///////////////////////////////////////////////////////////////////// + +GR_DEFINE_EFFECT_TEST(GrSweepGradient); + +GrEffectRef* GrSweepGradient::TestCreate(SkRandom* random, + GrContext* context, + const GrDrawTargetCaps&, + GrTexture**) { + SkPoint center = {random->nextUScalar1(), random->nextUScalar1()}; + + SkColor colors[kMaxRandomGradientColors]; + SkScalar stopsArray[kMaxRandomGradientColors]; + SkScalar* stops = stopsArray; + SkShader::TileMode tmIgnored; + int colorCount = RandomGradientParams(random, colors, &stops, &tmIgnored); + SkAutoTUnref shader(SkGradientShader::CreateSweep(center.fX, center.fY, + colors, stops, colorCount)); + SkPaint paint; + return shader->asNewEffect(context, paint); +} + +///////////////////////////////////////////////////////////////////// + +void GrGLSweepGradient::emitCode(GrGLShaderBuilder* builder, + const GrDrawEffect&, + EffectKey key, + const char* outputColor, + const char* inputColor, + const TransformedCoordsArray& coords, + const TextureSamplerArray& samplers) { + this->emitUniforms(builder, key); + SkString coords2D = builder->ensureFSCoords2D(coords, 0); + const GrGLContextInfo ctxInfo = builder->ctxInfo(); + SkString t; + // 0.1591549430918 is 1/(2*pi), used since atan returns values [-pi, pi] + // On Intel GPU there is an issue where it reads the second arguement to atan "- %s.x" as an int + // thus must us -1.0 * %s.x to work correctly + if (kIntel_GrGLVendor != ctxInfo.vendor()){ + t.printf("atan(- %s.y, - %s.x) * 0.1591549430918 + 0.5", + coords2D.c_str(), coords2D.c_str()); + } else { + t.printf("atan(- %s.y, -1.0 * %s.x) * 0.1591549430918 + 0.5", + coords2D.c_str(), coords2D.c_str()); + } + this->emitColor(builder, t.c_str(), key, + outputColor, inputColor, samplers); +} + +///////////////////////////////////////////////////////////////////// + +GrEffectRef* SkSweepGradient::asNewEffect(GrContext* context, const SkPaint&) const { + SkMatrix matrix; + if (!this->getLocalMatrix().invert(&matrix)) { + return NULL; + } + matrix.postConcat(fPtsToUnit); + return GrSweepGradient::Create(context, *this, matrix); +} + +#else + +GrEffectRef* SkSweepGradient::asNewEffect(GrContext*, const SkPaint&) const { + SkDEBUGFAIL("Should not call in GPU-less build"); + return NULL; +} + +#endif + +#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(")"); +} +#endif