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/*
* Copyright 2013 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#include "SkBitmapAlphaThresholdShader.h"
class BATShader : public SkShader {
public:
SK_DECLARE_INST_COUNT(SkThresholdShader);
BATShader(const SkBitmap& bitmap, SkRegion region, U8CPU);
BATShader(SkFlattenableReadBuffer& buffer) : INHERITED(buffer) {
// We should probably do something here.
}
virtual void shadeSpan(int x, int y, SkPMColor[], int count) SK_OVERRIDE {};
#if SK_SUPPORT_GPU
virtual GrEffectRef* asNewEffect(GrContext* context, const SkPaint& paint) const SK_OVERRIDE;
#endif
SK_DEVELOPER_TO_STRING();
SK_DECLARE_PUBLIC_FLATTENABLE_DESERIALIZATION_PROCS(BATShader)
private:
SkBitmap fBitmap;
SkRegion fRegion;
U8CPU fThreshold;
typedef SkShader INHERITED;
};
SkShader* SkBitmapAlphaThresholdShader::Create(const SkBitmap& bitmap,
const SkRegion& region,
U8CPU threshold) {
SkASSERT(threshold < 256);
return SkNEW_ARGS(BATShader, (bitmap, region, threshold));
}
BATShader::BATShader(const SkBitmap& bitmap, SkRegion region, U8CPU threshold)
: fBitmap(bitmap)
, fRegion(region)
, fThreshold(threshold) {
};
#ifdef SK_DEVELOPER
void BATShader::toString(SkString* str) const {
str->append("BATShader: (");
fBitmap.toString(str);
this->INHERITED::toString(str);
str->append(")");
}
#endif
#if SK_SUPPORT_GPU
#include "GrContext.h"
#include "GrCoordTransform.h"
#include "GrEffect.h"
#include "gl/GrGLEffect.h"
#include "GrTBackendEffectFactory.h"
#include "GrTextureAccess.h"
#include "SkGr.h"
/**
* Could create specializations for some simple cases:
* - The region is empty.
* - The region fully contains the bitmap.
* - The regions is 1 rect (or maybe a small number of rects).
*/
class ThresholdEffect : public GrEffect {
public:
virtual const GrBackendEffectFactory& getFactory() const SK_OVERRIDE {
return GrTBackendEffectFactory<ThresholdEffect>::getInstance();
}
static GrEffectRef* Create(GrTexture* bmpTexture, const SkMatrix& bmpMatrix,
GrTexture* maskTexture, const SkMatrix& maskMatrix,
U8CPU threshold) {
SkScalar thresh = SkIntToScalar(threshold) / 255;
AutoEffectUnref effect(SkNEW_ARGS(ThresholdEffect, (bmpTexture, bmpMatrix,
maskTexture, maskMatrix,
thresh)));
return CreateEffectRef(effect);
}
virtual void getConstantColorComponents(GrColor* color,
uint32_t* validFlags) const SK_OVERRIDE {
if ((kA_GrColorComponentFlag & *validFlags) && 0 == GrColorUnpackA(*color)) {
return;
}
*validFlags = 0;
return;
}
static const char* Name() { return "Bitmap Alpha Threshold"; }
class GLEffect : public GrGLEffect {
public:
GLEffect(const GrBackendEffectFactory& factory,
const GrDrawEffect& e)
: GrGLEffect(factory)
, fPrevThreshold(-SK_Scalar1) {
}
virtual void emitCode(GrGLShaderBuilder* builder,
const GrDrawEffect& drawEffect,
EffectKey key,
const char* outputColor,
const char* inputColor,
const TransformedCoordsArray& coords,
const TextureSamplerArray& samplers) SK_OVERRIDE {
// put bitmap color in "color"
builder->fsCodeAppend("\t\tvec4 color = ");
builder->fsAppendTextureLookup(samplers[0], coords[0].c_str(), coords[0].type());
builder->fsCodeAppend(";\n");
// put alpha from mask texture in "mask"
builder->fsCodeAppend("\t\tfloat mask = ");
builder->fsAppendTextureLookup(samplers[1], coords[1].c_str(), coords[1].type());
builder->fsCodeAppend(".a;\n");
const char* threshold;
fThresholdUniHandle = builder->addUniform(GrGLShaderBuilder::kFragment_Visibility,
kFloat_GrSLType,
"threshold",
&threshold);
builder->fsCodeAppendf("\t\tfloat thresh = %s;\n", threshold);
builder->fsCodeAppend("\t\tif (mask < 0.5) {\n"
"\t\t\tif (color.a > thresh) {\n"
"\t\t\t\tfloat scale = thresh / color.a;\n"
"\t\t\t\tcolor.rgb *= scale;\n"
"\t\t\t\tcolor.a = thresh;\n"
"\t\t\t}\n"
"\t\t} else if (color.a < thresh) {\n"
"\t\t\tfloat scale = thresh / color.a;\n"
"\t\t\tcolor.rgb *= scale;\n"
"\t\t\tcolor.a = thresh;\n"
"\t\t}\n");
builder->fsCodeAppend("color = ");
SkString outStr;
outStr.appendf("\t\t%s = ", outputColor);
GrGLSLModulatef<4>(&outStr, inputColor, "color");
outStr.append(";\n");
builder->fsCodeAppend(outStr.c_str());
}
virtual void setData(const GrGLUniformManager& uman, const GrDrawEffect& e) SK_OVERRIDE {
const ThresholdEffect& effect = e.castEffect<ThresholdEffect>();
if (fPrevThreshold != effect.fThreshold) {
uman.set1f(fThresholdUniHandle, effect.fThreshold);
}
}
private:
GrGLUniformManager::UniformHandle fThresholdUniHandle;
SkScalar fPrevThreshold;
};
GR_DECLARE_EFFECT_TEST;
private:
ThresholdEffect(GrTexture* bmpTexture, const SkMatrix& bmpMatrix,
GrTexture* maskTexture, const SkMatrix& maskMatrix,
SkScalar threshold)
: fBmpTransform(kLocal_GrCoordSet, bmpMatrix, bmpTexture)
, fBmpAccess(bmpTexture, GrTextureParams())
, fMaskTransform(kLocal_GrCoordSet, maskMatrix, maskTexture)
, fMaskAccess(maskTexture, GrTextureParams())
, fThreshold(threshold) {
this->addCoordTransform(&fBmpTransform);
this->addTextureAccess(&fBmpAccess);
this->addCoordTransform(&fMaskTransform);
this->addTextureAccess(&fMaskAccess);
}
virtual bool onIsEqual(const GrEffect& other) const SK_OVERRIDE {
const ThresholdEffect& e = CastEffect<ThresholdEffect>(other);
return e.fBmpAccess.getTexture() == fBmpAccess.getTexture() &&
e.fMaskAccess.getTexture() == fMaskAccess.getTexture() &&
e.fBmpTransform.getMatrix() == fBmpTransform.getMatrix() &&
e.fMaskTransform.getMatrix() == fMaskTransform.getMatrix() &&
e.fThreshold == fThreshold;
}
GrCoordTransform fBmpTransform;
GrTextureAccess fBmpAccess;
GrCoordTransform fMaskTransform;
GrTextureAccess fMaskAccess;
SkScalar fThreshold;
};
GR_DEFINE_EFFECT_TEST(ThresholdEffect);
GrEffectRef* ThresholdEffect::TestCreate(SkRandom* rand,
GrContext*,
const GrDrawTargetCaps&,
GrTexture* textures[]) {
GrTexture* bmpTex = textures[GrEffectUnitTest::kSkiaPMTextureIdx];
GrTexture* maskTex = textures[GrEffectUnitTest::kAlphaTextureIdx];
U8CPU thresh = rand->nextU() % 0xff;
return ThresholdEffect::Create(bmpTex, SkMatrix::I(), maskTex, SkMatrix::I(), thresh);
}
GrEffectRef* BATShader::asNewEffect(GrContext* context, const SkPaint& paint) const {
SkMatrix localInverse;
if (!this->getLocalMatrix().invert(&localInverse)) {
return NULL;
}
GrTextureDesc maskDesc;
if (context->isConfigRenderable(kAlpha_8_GrPixelConfig)) {
maskDesc.fConfig = kAlpha_8_GrPixelConfig;
} else {
maskDesc.fConfig = kRGBA_8888_GrPixelConfig;
}
maskDesc.fFlags = kRenderTarget_GrTextureFlagBit | kNoStencil_GrTextureFlagBit;
const SkIRect& bounds = fRegion.getBounds();
// Add one pixel of border to ensure that clamp mode will be all zeros
// the outside.
maskDesc.fWidth = bounds.width() + 2;
maskDesc.fHeight = bounds.height() + 2;
GrAutoScratchTexture ast(context, maskDesc, GrContext::kApprox_ScratchTexMatch);
GrTexture* maskTexture = ast.texture();
if (NULL == maskTexture) {
return NULL;
}
GrPaint grPaint;
grPaint.setBlendFunc(kOne_GrBlendCoeff, kZero_GrBlendCoeff);
SkRegion::Iterator iter(fRegion);
context->setRenderTarget(maskTexture->asRenderTarget());
context->clear(NULL, 0x0);
// offset to ensure border is zero on top/left
SkMatrix matrix;
matrix.setTranslate(SK_Scalar1, SK_Scalar1);
context->setMatrix(matrix);
while (!iter.done()) {
SkRect rect = SkRect::MakeFromIRect(iter.rect());
context->drawRect(grPaint, rect);
iter.next();
}
GrTexture* bmpTexture = GrLockAndRefCachedBitmapTexture(context, fBitmap, NULL);
if (NULL == bmpTexture) {
return NULL;
}
SkMatrix bmpMatrix = localInverse;
bmpMatrix.postIDiv(bmpTexture->width(), bmpTexture->height());
SkMatrix maskMatrix = localInverse;
// compensate for the border
maskMatrix.postTranslate(SK_Scalar1, SK_Scalar1);
maskMatrix.postIDiv(maskTexture->width(), maskTexture->height());
GrEffectRef* effect = ThresholdEffect::Create(bmpTexture, bmpMatrix,
maskTexture, maskMatrix,
fThreshold);
GrUnlockAndUnrefCachedBitmapTexture(bmpTexture);
return effect;
}
#endif