/*
* 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, const SkMatrix* localMatrix)
: SkGradientShaderBase(desc, localMatrix)
, 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);
}
size_t SkSweepGradient::contextSize() const {
return sizeof(SweepGradientContext);
}
SkShader::Context* SkSweepGradient::onCreateContext(const ContextRec& rec, void* storage) const {
return SkNEW_PLACEMENT_ARGS(storage, SweepGradientContext, (*this, rec));
}
SkSweepGradient::SweepGradientContext::SweepGradientContext(
const SkSweepGradient& shader, const ContextRec& rec)
: INHERITED(shader, rec) {}
// 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::SweepGradientContext::shadeSpan(int x, int y, SkPMColor* SK_RESTRICT dstC,
int count) {
SkMatrix::MapXYProc proc = fDstToIndexProc;
const SkMatrix& matrix = fDstToIndex;
const SkPMColor* SK_RESTRICT cache = fCache->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::SweepGradientContext::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 = fCache->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"
#include "SkGr.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<GrSweepGradient>::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<SkShader> shader(SkGradientShader::CreateSweep(center.fX, center.fY,
colors, stops, colorCount));
SkPaint paint;
GrEffectRef* effect;
GrColor grColor;
shader->asNewEffect(context, paint, NULL, &grColor, &effect);
return effect;
}
/////////////////////////////////////////////////////////////////////
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);
}
/////////////////////////////////////////////////////////////////////
bool SkSweepGradient::asNewEffect(GrContext* context, const SkPaint& paint,
const SkMatrix* localMatrix, GrColor* grColor,
GrEffectRef** grEffect) const {
SkMatrix matrix;
if (!this->getLocalMatrix().invert(&matrix)) {
return false;
}
if (localMatrix) {
SkMatrix inv;
if (!localMatrix->invert(&inv)) {
return false;
}
matrix.postConcat(inv);
}
matrix.postConcat(fPtsToUnit);
*grEffect = GrSweepGradient::Create(context, *this, matrix);
*grColor = SkColor2GrColorJustAlpha(paint.getColor());
return true;
}
#else
bool SkSweepGradient::asNewEffect(GrContext* context, const SkPaint& paint,
const SkMatrix* localMatrix, GrColor* grColor,
GrEffectRef** grEffect) const {
SkDEBUGFAIL("Should not call in GPU-less build");
return false;
}
#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