/*
* 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 "SkRadialGradient.h"
#include "SkRadialGradient_Table.h"
#include "SkNx.h"
#define kSQRT_TABLE_BITS 11
#define kSQRT_TABLE_SIZE (1 << kSQRT_TABLE_BITS)
SK_COMPILE_ASSERT(sizeof(gSqrt8Table) == kSQRT_TABLE_SIZE, SqrtTableSizesMatch);
#if 0
#include <stdio.h>
void SkRadialGradient_BuildTable() {
// build it 0..127 x 0..127, so we use 2^15 - 1 in the numerator for our "fixed" table
FILE* file = ::fopen("SkRadialGradient_Table.h", "w");
SkASSERT(file);
::fprintf(file, "static const uint8_t gSqrt8Table[] = {\n");
for (int i = 0; i < kSQRT_TABLE_SIZE; i++) {
if ((i & 15) == 0) {
::fprintf(file, "\t");
}
uint8_t value = SkToU8(SkFixedSqrt(i * SK_Fixed1 / kSQRT_TABLE_SIZE) >> 8);
::fprintf(file, "0x%02X", value);
if (i < kSQRT_TABLE_SIZE-1) {
::fprintf(file, ", ");
}
if ((i & 15) == 15) {
::fprintf(file, "\n");
}
}
::fprintf(file, "};\n");
::fclose(file);
}
#endif
namespace {
// GCC doesn't like using static functions as template arguments. So force these to be non-static.
inline SkFixed mirror_tileproc_nonstatic(SkFixed x) {
return mirror_tileproc(x);
}
inline SkFixed repeat_tileproc_nonstatic(SkFixed x) {
return repeat_tileproc(x);
}
SkMatrix rad_to_unit_matrix(const SkPoint& center, SkScalar radius) {
SkScalar inv = SkScalarInvert(radius);
SkMatrix matrix;
matrix.setTranslate(-center.fX, -center.fY);
matrix.postScale(inv, inv);
return matrix;
}
typedef void (* RadialShade16Proc)(SkScalar sfx, SkScalar sdx,
SkScalar sfy, SkScalar sdy,
uint16_t* dstC, const uint16_t* cache,
int toggle, int count);
void shadeSpan16_radial_clamp(SkScalar sfx, SkScalar sdx,
SkScalar sfy, SkScalar sdy,
uint16_t* SK_RESTRICT dstC, const uint16_t* SK_RESTRICT cache,
int toggle, int count) {
const uint8_t* SK_RESTRICT sqrt_table = gSqrt8Table;
/* knock these down so we can pin against +- 0x7FFF, which is an
immediate load, rather than 0xFFFF which is slower. This is a
compromise, since it reduces our precision, but that appears
to be visually OK. If we decide this is OK for all of our cases,
we could (it seems) put this scale-down into fDstToIndex,
to avoid having to do these extra shifts each time.
*/
SkFixed fx = SkScalarToFixed(sfx) >> 1;
SkFixed dx = SkScalarToFixed(sdx) >> 1;
SkFixed fy = SkScalarToFixed(sfy) >> 1;
SkFixed dy = SkScalarToFixed(sdy) >> 1;
// might perform this check for the other modes,
// but the win will be a smaller % of the total
if (dy == 0) {
fy = SkPin32(fy, -0xFFFF >> 1, 0xFFFF >> 1);
fy *= fy;
do {
unsigned xx = SkPin32(fx, -0xFFFF >> 1, 0xFFFF >> 1);
unsigned fi = (xx * xx + fy) >> (14 + 16 - kSQRT_TABLE_BITS);
fi = SkFastMin32(fi, 0xFFFF >> (16 - kSQRT_TABLE_BITS));
fx += dx;
*dstC++ = cache[toggle +
(sqrt_table[fi] >> SkGradientShaderBase::kSqrt16Shift)];
toggle = next_dither_toggle16(toggle);
} while (--count != 0);
} else {
do {
unsigned xx = SkPin32(fx, -0xFFFF >> 1, 0xFFFF >> 1);
unsigned fi = SkPin32(fy, -0xFFFF >> 1, 0xFFFF >> 1);
fi = (xx * xx + fi * fi) >> (14 + 16 - kSQRT_TABLE_BITS);
fi = SkFastMin32(fi, 0xFFFF >> (16 - kSQRT_TABLE_BITS));
fx += dx;
fy += dy;
*dstC++ = cache[toggle +
(sqrt_table[fi] >> SkGradientShaderBase::kSqrt16Shift)];
toggle = next_dither_toggle16(toggle);
} while (--count != 0);
}
}
template <SkFixed (*TileProc)(SkFixed)>
void shadeSpan16_radial(SkScalar fx, SkScalar dx, SkScalar fy, SkScalar dy,
uint16_t* SK_RESTRICT dstC, const uint16_t* SK_RESTRICT cache,
int toggle, int count) {
do {
const SkFixed dist = SkFloatToFixed(sk_float_sqrt(fx*fx + fy*fy));
const unsigned fi = TileProc(dist);
SkASSERT(fi <= 0xFFFF);
*dstC++ = cache[toggle + (fi >> SkGradientShaderBase::kCache16Shift)];
toggle = next_dither_toggle16(toggle);
fx += dx;
fy += dy;
} while (--count != 0);
}
void shadeSpan16_radial_mirror(SkScalar fx, SkScalar dx, SkScalar fy, SkScalar dy,
uint16_t* SK_RESTRICT dstC, const uint16_t* SK_RESTRICT cache,
int toggle, int count) {
shadeSpan16_radial<mirror_tileproc_nonstatic>(fx, dx, fy, dy, dstC, cache, toggle, count);
}
void shadeSpan16_radial_repeat(SkScalar fx, SkScalar dx, SkScalar fy, SkScalar dy,
uint16_t* SK_RESTRICT dstC, const uint16_t* SK_RESTRICT cache,
int toggle, int count) {
shadeSpan16_radial<repeat_tileproc_nonstatic>(fx, dx, fy, dy, dstC, cache, toggle, count);
}
} // namespace
/////////////////////////////////////////////////////////////////////
SkRadialGradient::SkRadialGradient(const SkPoint& center, SkScalar radius, const Descriptor& desc)
: SkGradientShaderBase(desc, rad_to_unit_matrix(center, radius))
, fCenter(center)
, fRadius(radius) {
}
size_t SkRadialGradient::contextSize() const {
return sizeof(RadialGradientContext);
}
SkShader::Context* SkRadialGradient::onCreateContext(const ContextRec& rec, void* storage) const {
return SkNEW_PLACEMENT_ARGS(storage, RadialGradientContext, (*this, rec));
}
SkRadialGradient::RadialGradientContext::RadialGradientContext(
const SkRadialGradient& shader, const ContextRec& rec)
: INHERITED(shader, rec) {}
void SkRadialGradient::RadialGradientContext::shadeSpan16(int x, int y, uint16_t* dstCParam,
int count) {
SkASSERT(count > 0);
const SkRadialGradient& radialGradient = static_cast<const SkRadialGradient&>(fShader);
uint16_t* SK_RESTRICT dstC = dstCParam;
SkPoint srcPt;
SkMatrix::MapXYProc dstProc = fDstToIndexProc;
TileProc proc = radialGradient.fTileProc;
const uint16_t* SK_RESTRICT cache = fCache->getCache16();
int toggle = init_dither_toggle16(x, y);
if (fDstToIndexClass != kPerspective_MatrixClass) {
dstProc(fDstToIndex, SkIntToScalar(x) + SK_ScalarHalf,
SkIntToScalar(y) + SK_ScalarHalf, &srcPt);
SkScalar sdx = fDstToIndex.getScaleX();
SkScalar sdy = fDstToIndex.getSkewY();
if (fDstToIndexClass == kFixedStepInX_MatrixClass) {
SkFixed storage[2];
(void)fDstToIndex.fixedStepInX(SkIntToScalar(y),
&storage[0], &storage[1]);
sdx = SkFixedToScalar(storage[0]);
sdy = SkFixedToScalar(storage[1]);
} else {
SkASSERT(fDstToIndexClass == kLinear_MatrixClass);
}
RadialShade16Proc shadeProc = shadeSpan16_radial_repeat;
if (SkShader::kClamp_TileMode == radialGradient.fTileMode) {
shadeProc = shadeSpan16_radial_clamp;
} else if (SkShader::kMirror_TileMode == radialGradient.fTileMode) {
shadeProc = shadeSpan16_radial_mirror;
} else {
SkASSERT(SkShader::kRepeat_TileMode == radialGradient.fTileMode);
}
(*shadeProc)(srcPt.fX, sdx, srcPt.fY, sdy, dstC,
cache, toggle, count);
} else { // perspective case
SkScalar dstX = SkIntToScalar(x);
SkScalar dstY = SkIntToScalar(y);
do {
dstProc(fDstToIndex, dstX, dstY, &srcPt);
unsigned fi = proc(SkScalarToFixed(srcPt.length()));
SkASSERT(fi <= 0xFFFF);
int index = fi >> (16 - kCache16Bits);
*dstC++ = cache[toggle + index];
toggle = next_dither_toggle16(toggle);
dstX += SK_Scalar1;
} while (--count != 0);
}
}
SkShader::BitmapType SkRadialGradient::asABitmap(SkBitmap* bitmap,
SkMatrix* matrix, SkShader::TileMode* xy) const {
if (bitmap) {
this->getGradientTableBitmap(bitmap);
}
if (matrix) {
matrix->setScale(SkIntToScalar(kCache32Count),
SkIntToScalar(kCache32Count));
matrix->preConcat(fPtsToUnit);
}
if (xy) {
xy[0] = fTileMode;
xy[1] = kClamp_TileMode;
}
return kRadial_BitmapType;
}
SkShader::GradientType SkRadialGradient::asAGradient(GradientInfo* info) const {
if (info) {
commonAsAGradient(info);
info->fPoint[0] = fCenter;
info->fRadius[0] = fRadius;
}
return kRadial_GradientType;
}
SkFlattenable* SkRadialGradient::CreateProc(SkReadBuffer& buffer) {
DescriptorScope desc;
if (!desc.unflatten(buffer)) {
return NULL;
}
const SkPoint center = buffer.readPoint();
const SkScalar radius = buffer.readScalar();
return SkGradientShader::CreateRadial(center, radius, desc.fColors, desc.fPos, desc.fCount,
desc.fTileMode, desc.fGradFlags, desc.fLocalMatrix);
}
void SkRadialGradient::flatten(SkWriteBuffer& buffer) const {
this->INHERITED::flatten(buffer);
buffer.writePoint(fCenter);
buffer.writeScalar(fRadius);
}
namespace {
inline bool radial_completely_pinned(SkScalar fx, SkScalar dx, SkScalar fy, SkScalar dy) {
// fast, overly-conservative test: checks unit square instead of unit circle
bool xClamped = (fx >= 1 && dx >= 0) || (fx <= -1 && dx <= 0);
bool yClamped = (fy >= 1 && dy >= 0) || (fy <= -1 && dy <= 0);
return xClamped || yClamped;
}
typedef void (* RadialShadeProc)(SkScalar sfx, SkScalar sdx,
SkScalar sfy, SkScalar sdy,
SkPMColor* dstC, const SkPMColor* cache,
int count, int toggle);
static inline Sk4f fast_sqrt(const Sk4f& R) {
// R * R.rsqrt0() is much faster, but it's non-monotonic, which isn't so pretty for gradients.
return R * R.rsqrt1();
}
static inline Sk4f sum_squares(const Sk4f& a, const Sk4f& b) {
return a * a + b * b;
}
void shadeSpan_radial_clamp2(SkScalar sfx, SkScalar sdx, SkScalar sfy, SkScalar sdy,
SkPMColor* SK_RESTRICT dstC, const SkPMColor* SK_RESTRICT cache,
int count, int toggle) {
if (radial_completely_pinned(sfx, sdx, sfy, sdy)) {
unsigned fi = SkGradientShaderBase::kCache32Count - 1;
sk_memset32_dither(dstC,
cache[toggle + fi],
cache[next_dither_toggle(toggle) + fi],
count);
} else {
const Sk4f max(255);
const float scale = 255;
sfx *= scale;
sfy *= scale;
sdx *= scale;
sdy *= scale;
const Sk4f fx4(sfx, sfx + sdx, sfx + 2*sdx, sfx + 3*sdx);
const Sk4f fy4(sfy, sfy + sdy, sfy + 2*sdy, sfy + 3*sdy);
const Sk4f dx4(sdx * 4);
const Sk4f dy4(sdy * 4);
Sk4f tmpxy = fx4 * dx4 + fy4 * dy4;
Sk4f tmpdxdy = sum_squares(dx4, dy4);
Sk4f R = sum_squares(fx4, fy4);
Sk4f dR = tmpxy + tmpxy + tmpdxdy;
const Sk4f ddR = tmpdxdy + tmpdxdy;
for (int i = 0; i < (count >> 2); ++i) {
Sk4f dist = Sk4f::Min(fast_sqrt(R), max);
R += dR;
dR += ddR;
int fi[4];
dist.castTrunc().store(fi);
for (int i = 0; i < 4; i++) {
*dstC++ = cache[toggle + fi[i]];
toggle = next_dither_toggle(toggle);
}
}
count &= 3;
if (count) {
Sk4f dist = Sk4f::Min(fast_sqrt(R), max);
int fi[4];
dist.castTrunc().store(fi);
for (int i = 0; i < count; i++) {
*dstC++ = cache[toggle + fi[i]];
toggle = next_dither_toggle(toggle);
}
}
}
}
// Unrolling this loop doesn't seem to help (when float); we're stalling to
// get the results of the sqrt (?), and don't have enough extra registers to
// have many in flight.
template <SkFixed (*TileProc)(SkFixed)>
void shadeSpan_radial(SkScalar fx, SkScalar dx, SkScalar fy, SkScalar dy,
SkPMColor* SK_RESTRICT dstC, const SkPMColor* SK_RESTRICT cache,
int count, int toggle) {
do {
const SkFixed dist = SkFloatToFixed(sk_float_sqrt(fx*fx + fy*fy));
const unsigned fi = TileProc(dist);
SkASSERT(fi <= 0xFFFF);
*dstC++ = cache[toggle + (fi >> SkGradientShaderBase::kCache32Shift)];
toggle = next_dither_toggle(toggle);
fx += dx;
fy += dy;
} while (--count != 0);
}
void shadeSpan_radial_mirror(SkScalar fx, SkScalar dx, SkScalar fy, SkScalar dy,
SkPMColor* SK_RESTRICT dstC, const SkPMColor* SK_RESTRICT cache,
int count, int toggle) {
shadeSpan_radial<mirror_tileproc_nonstatic>(fx, dx, fy, dy, dstC, cache, count, toggle);
}
void shadeSpan_radial_repeat(SkScalar fx, SkScalar dx, SkScalar fy, SkScalar dy,
SkPMColor* SK_RESTRICT dstC, const SkPMColor* SK_RESTRICT cache,
int count, int toggle) {
shadeSpan_radial<repeat_tileproc_nonstatic>(fx, dx, fy, dy, dstC, cache, count, toggle);
}
} // namespace
void SkRadialGradient::RadialGradientContext::shadeSpan(int x, int y,
SkPMColor* SK_RESTRICT dstC, int count) {
SkASSERT(count > 0);
const SkRadialGradient& radialGradient = static_cast<const SkRadialGradient&>(fShader);
SkPoint srcPt;
SkMatrix::MapXYProc dstProc = fDstToIndexProc;
TileProc proc = radialGradient.fTileProc;
const SkPMColor* SK_RESTRICT cache = fCache->getCache32();
int toggle = init_dither_toggle(x, y);
if (fDstToIndexClass != kPerspective_MatrixClass) {
dstProc(fDstToIndex, SkIntToScalar(x) + SK_ScalarHalf,
SkIntToScalar(y) + SK_ScalarHalf, &srcPt);
SkScalar sdx = fDstToIndex.getScaleX();
SkScalar sdy = fDstToIndex.getSkewY();
if (fDstToIndexClass == kFixedStepInX_MatrixClass) {
SkFixed storage[2];
(void)fDstToIndex.fixedStepInX(SkIntToScalar(y),
&storage[0], &storage[1]);
sdx = SkFixedToScalar(storage[0]);
sdy = SkFixedToScalar(storage[1]);
} else {
SkASSERT(fDstToIndexClass == kLinear_MatrixClass);
}
RadialShadeProc shadeProc = shadeSpan_radial_repeat;
if (SkShader::kClamp_TileMode == radialGradient.fTileMode) {
shadeProc = shadeSpan_radial_clamp2;
} else if (SkShader::kMirror_TileMode == radialGradient.fTileMode) {
shadeProc = shadeSpan_radial_mirror;
} else {
SkASSERT(SkShader::kRepeat_TileMode == radialGradient.fTileMode);
}
(*shadeProc)(srcPt.fX, sdx, srcPt.fY, sdy, dstC, cache, count, toggle);
} else { // perspective case
SkScalar dstX = SkIntToScalar(x);
SkScalar dstY = SkIntToScalar(y);
do {
dstProc(fDstToIndex, dstX, dstY, &srcPt);
unsigned fi = proc(SkScalarToFixed(srcPt.length()));
SkASSERT(fi <= 0xFFFF);
*dstC++ = cache[fi >> SkGradientShaderBase::kCache32Shift];
dstX += SK_Scalar1;
} while (--count != 0);
}
}
/////////////////////////////////////////////////////////////////////
#if SK_SUPPORT_GPU
#include "SkGr.h"
#include "gl/builders/GrGLProgramBuilder.h"
class GrGLRadialGradient : public GrGLGradientEffect {
public:
GrGLRadialGradient(const GrProcessor&) {}
virtual ~GrGLRadialGradient() { }
virtual void emitCode(GrGLFPBuilder*,
const GrFragmentProcessor&,
const char* outputColor,
const char* inputColor,
const TransformedCoordsArray&,
const TextureSamplerArray&) override;
static void GenKey(const GrProcessor& processor, const GrGLSLCaps&, GrProcessorKeyBuilder* b) {
b->add32(GenBaseGradientKey(processor));
}
private:
typedef GrGLGradientEffect INHERITED;
};
/////////////////////////////////////////////////////////////////////
class GrRadialGradient : public GrGradientEffect {
public:
static GrFragmentProcessor* Create(GrContext* ctx,
const SkRadialGradient& shader,
const SkMatrix& matrix,
SkShader::TileMode tm) {
return SkNEW_ARGS(GrRadialGradient, (ctx, shader, matrix, tm));
}
virtual ~GrRadialGradient() { }
const char* name() const override { return "Radial Gradient"; }
virtual void getGLProcessorKey(const GrGLSLCaps& caps,
GrProcessorKeyBuilder* b) const override {
GrGLRadialGradient::GenKey(*this, caps, b);
}
GrGLFragmentProcessor* createGLInstance() const override {
return SkNEW_ARGS(GrGLRadialGradient, (*this));
}
private:
GrRadialGradient(GrContext* ctx,
const SkRadialGradient& shader,
const SkMatrix& matrix,
SkShader::TileMode tm)
: INHERITED(ctx, shader, matrix, tm) {
this->initClassID<GrRadialGradient>();
}
GR_DECLARE_FRAGMENT_PROCESSOR_TEST;
typedef GrGradientEffect INHERITED;
};
/////////////////////////////////////////////////////////////////////
GR_DEFINE_FRAGMENT_PROCESSOR_TEST(GrRadialGradient);
GrFragmentProcessor* GrRadialGradient::TestCreate(SkRandom* random,
GrContext* context,
const GrDrawTargetCaps&,
GrTexture**) {
SkPoint center = {random->nextUScalar1(), random->nextUScalar1()};
SkScalar radius = random->nextUScalar1();
SkColor colors[kMaxRandomGradientColors];
SkScalar stopsArray[kMaxRandomGradientColors];
SkScalar* stops = stopsArray;
SkShader::TileMode tm;
int colorCount = RandomGradientParams(random, colors, &stops, &tm);
SkAutoTUnref<SkShader> shader(SkGradientShader::CreateRadial(center, radius,
colors, stops, colorCount,
tm));
SkPaint paint;
GrColor paintColor;
GrFragmentProcessor* fp;
SkAssertResult(shader->asFragmentProcessor(context, paint,
GrTest::TestMatrix(random), NULL,
&paintColor, &fp));
return fp;
}
/////////////////////////////////////////////////////////////////////
void GrGLRadialGradient::emitCode(GrGLFPBuilder* builder,
const GrFragmentProcessor& fp,
const char* outputColor,
const char* inputColor,
const TransformedCoordsArray& coords,
const TextureSamplerArray& samplers) {
const GrRadialGradient& ge = fp.cast<GrRadialGradient>();
this->emitUniforms(builder, ge);
SkString t("length(");
t.append(builder->getFragmentShaderBuilder()->ensureFSCoords2D(coords, 0));
t.append(")");
this->emitColor(builder, ge, t.c_str(), outputColor, inputColor, samplers);
}
/////////////////////////////////////////////////////////////////////
bool SkRadialGradient::asFragmentProcessor(GrContext* context, const SkPaint& paint,
const SkMatrix& viewM,
const SkMatrix* localMatrix, GrColor* paintColor,
GrFragmentProcessor** fp) const {
SkASSERT(context);
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);
*paintColor = SkColor2GrColorJustAlpha(paint.getColor());
*fp = GrRadialGradient::Create(context, *this, matrix, fTileMode);
return true;
}
#else
bool SkRadialGradient::asFragmentProcessor(GrContext*, const SkPaint&, const SkMatrix&,
const SkMatrix*, GrColor*,
GrFragmentProcessor**) const {
SkDEBUGFAIL("Should not call in GPU-less build");
return false;
}
#endif
#ifndef SK_IGNORE_TO_STRING
void SkRadialGradient::toString(SkString* str) const {
str->append("SkRadialGradient: (");
str->append("center: (");
str->appendScalar(fCenter.fX);
str->append(", ");
str->appendScalar(fCenter.fY);
str->append(") radius: ");
str->appendScalar(fRadius);
str->append(" ");
this->INHERITED::toString(str);
str->append(")");
}
#endif