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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 "gl/builders/GrGLProgramBuilder.h"
#include "GrDistanceFieldTextureEffect.h"
#include "gl/GrGLEffect.h"
#include "gl/GrGLSL.h"
#include "gl/GrGLTexture.h"
#include "gl/GrGLVertexEffect.h"
#include "GrTBackendEffectFactory.h"
#include "GrTexture.h"
#include "SkDistanceFieldGen.h"
// To get optical sizes people don't complain about when we blit correctly,
// we need to slightly bold each glyph. On the Mac, we need a larger bold value.
#if defined(SK_BUILD_FOR_MAC)
#define SK_DistanceFieldLCDFactor "0.33"
#define SK_DistanceFieldNonLCDFactor "0.25"
#else
#define SK_DistanceFieldLCDFactor "0.05"
#define SK_DistanceFieldNonLCDFactor "0.05"
#endif
// Assuming a radius of the diagonal of the fragment, hence a factor of sqrt(2)/2
#define SK_DistanceFieldAAFactor "0.7071"
class GrGLDistanceFieldTextureEffect : public GrGLVertexEffect {
public:
GrGLDistanceFieldTextureEffect(const GrBackendEffectFactory& factory,
const GrDrawEffect& drawEffect)
: INHERITED (factory)
, fTextureSize(SkISize::Make(-1,-1)) {}
virtual void emitCode(GrGLFullProgramBuilder* builder,
const GrDrawEffect& drawEffect,
const GrEffectKey& key,
const char* outputColor,
const char* inputColor,
const TransformedCoordsArray&,
const TextureSamplerArray& samplers) SK_OVERRIDE {
SkASSERT(1 == drawEffect.castEffect<GrDistanceFieldTextureEffect>().numVertexAttribs());
GrGLFragmentShaderBuilder* fsBuilder = builder->getFragmentShaderBuilder();
SkAssertResult(fsBuilder->enableFeature(
GrGLFragmentShaderBuilder::kStandardDerivatives_GLSLFeature));
const GrDistanceFieldTextureEffect& dfTexEffect =
drawEffect.castEffect<GrDistanceFieldTextureEffect>();
SkString fsCoordName;
const char* vsCoordName;
const char* fsCoordNamePtr;
builder->addVarying(kVec2f_GrSLType, "textureCoords", &vsCoordName, &fsCoordNamePtr);
fsCoordName = fsCoordNamePtr;
GrGLVertexShaderBuilder* vsBuilder = builder->getVertexShaderBuilder();
const SkString* attr0Name =
vsBuilder->getEffectAttributeName(drawEffect.getVertexAttribIndices()[0]);
vsBuilder->codeAppendf("\t%s = %s;\n", vsCoordName, attr0Name->c_str());
const char* textureSizeUniName = NULL;
fTextureSizeUni = builder->addUniform(GrGLProgramBuilder::kFragment_Visibility,
kVec2f_GrSLType, "TextureSize",
&textureSizeUniName);
fsBuilder->codeAppend("\tvec4 texColor = ");
fsBuilder->appendTextureLookup(samplers[0],
fsCoordName.c_str(),
kVec2f_GrSLType);
fsBuilder->codeAppend(";\n");
fsBuilder->codeAppend("\tfloat distance = "
SK_DistanceFieldMultiplier "*(texColor.r - " SK_DistanceFieldThreshold ")"
"+ " SK_DistanceFieldNonLCDFactor ";\n");
// we adjust for the effect of the transformation on the distance by using
// the length of the gradient of the texture coordinates. We use st coordinates
// to ensure we're mapping 1:1 from texel space to pixel space.
fsBuilder->codeAppendf("\tvec2 uv = %s;\n", fsCoordName.c_str());
fsBuilder->codeAppendf("\tvec2 st = uv*%s;\n", textureSizeUniName);
fsBuilder->codeAppend("\tfloat afwidth;\n");
if (dfTexEffect.getFlags() & kSimilarity_DistanceFieldEffectFlag) {
// this gives us a smooth step across approximately one fragment
fsBuilder->codeAppend("\tafwidth = " SK_DistanceFieldAAFactor "*dFdx(st.x);\n");
} else {
fsBuilder->codeAppend("\tvec2 Jdx = dFdx(st);\n");
fsBuilder->codeAppend("\tvec2 Jdy = dFdy(st);\n");
fsBuilder->codeAppend("\tvec2 uv_grad;\n");
if (builder->ctxInfo().caps()->dropsTileOnZeroDivide()) {
// this is to compensate for the Adreno, which likes to drop tiles on division by 0
fsBuilder->codeAppend("\tfloat uv_len2 = dot(uv, uv);\n");
fsBuilder->codeAppend("\tif (uv_len2 < 0.0001) {\n");
fsBuilder->codeAppend("\t\tuv_grad = vec2(0.7071, 0.7071);\n");
fsBuilder->codeAppend("\t} else {\n");
fsBuilder->codeAppend("\t\tuv_grad = uv*inversesqrt(uv_len2);\n");
fsBuilder->codeAppend("\t}\n");
} else {
fsBuilder->codeAppend("\tuv_grad = normalize(uv);\n");
}
fsBuilder->codeAppend("\tvec2 grad = vec2(uv_grad.x*Jdx.x + uv_grad.y*Jdy.x,\n");
fsBuilder->codeAppend("\t uv_grad.x*Jdx.y + uv_grad.y*Jdy.y);\n");
// this gives us a smooth step across approximately one fragment
fsBuilder->codeAppend("\tafwidth = " SK_DistanceFieldAAFactor "*length(grad);\n");
}
fsBuilder->codeAppend("\tfloat val = smoothstep(-afwidth, afwidth, distance);\n");
#ifdef SK_GAMMA_APPLY_TO_A8
// adjust based on gamma
const char* luminanceUniName = NULL;
// width, height, 1/(3*width)
fLuminanceUni = builder->addUniform(GrGLProgramBuilder::kFragment_Visibility,
kFloat_GrSLType, "Luminance",
&luminanceUniName);
fsBuilder->codeAppendf("\tuv = vec2(val, %s);\n", luminanceUniName);
fsBuilder->codeAppend("\tvec4 gammaColor = ");
fsBuilder->appendTextureLookup(samplers[1], "uv", kVec2f_GrSLType);
fsBuilder->codeAppend(";\n");
fsBuilder->codeAppend("\tval = gammaColor.r;\n");
#endif
fsBuilder->codeAppendf("\t%s = %s;\n", outputColor,
(GrGLSLExpr4(inputColor) * GrGLSLExpr1("val")).c_str());
}
virtual void setData(const GrGLProgramDataManager& pdman,
const GrDrawEffect& drawEffect) SK_OVERRIDE {
SkASSERT(fTextureSizeUni.isValid());
GrTexture* texture = drawEffect.effect()->texture(0);
if (texture->width() != fTextureSize.width() ||
texture->height() != fTextureSize.height()) {
fTextureSize = SkISize::Make(texture->width(), texture->height());
pdman.set2f(fTextureSizeUni,
SkIntToScalar(fTextureSize.width()),
SkIntToScalar(fTextureSize.height()));
}
#ifdef SK_GAMMA_APPLY_TO_A8
const GrDistanceFieldTextureEffect& dfTexEffect =
drawEffect.castEffect<GrDistanceFieldTextureEffect>();
float luminance = dfTexEffect.getLuminance();
if (luminance != fLuminance) {
pdman.set1f(fLuminanceUni, luminance);
fLuminance = luminance;
}
#endif
}
static inline void GenKey(const GrDrawEffect& drawEffect, const GrGLCaps&,
GrEffectKeyBuilder* b) {
const GrDistanceFieldTextureEffect& dfTexEffect =
drawEffect.castEffect<GrDistanceFieldTextureEffect>();
b->add32(dfTexEffect.getFlags());
}
private:
GrGLProgramDataManager::UniformHandle fTextureSizeUni;
SkISize fTextureSize;
GrGLProgramDataManager::UniformHandle fLuminanceUni;
float fLuminance;
typedef GrGLVertexEffect INHERITED;
};
///////////////////////////////////////////////////////////////////////////////
GrDistanceFieldTextureEffect::GrDistanceFieldTextureEffect(GrTexture* texture,
const GrTextureParams& params,
#ifdef SK_GAMMA_APPLY_TO_A8
GrTexture* gamma,
const GrTextureParams& gammaParams,
float luminance,
#endif
uint32_t flags)
: fTextureAccess(texture, params)
#ifdef SK_GAMMA_APPLY_TO_A8
, fGammaTextureAccess(gamma, gammaParams)
, fLuminance(luminance)
#endif
, fFlags(flags & kNonLCD_DistanceFieldEffectMask) {
SkASSERT(!(flags & ~kNonLCD_DistanceFieldEffectMask));
this->addTextureAccess(&fTextureAccess);
#ifdef SK_GAMMA_APPLY_TO_A8
this->addTextureAccess(&fGammaTextureAccess);
#endif
this->addVertexAttrib(kVec2f_GrSLType);
}
bool GrDistanceFieldTextureEffect::onIsEqual(const GrEffect& other) const {
const GrDistanceFieldTextureEffect& cte = CastEffect<GrDistanceFieldTextureEffect>(other);
return fTextureAccess == cte.fTextureAccess &&
#ifdef SK_GAMMA_APPLY_TO_A8
fGammaTextureAccess == cte.fGammaTextureAccess &&
fLuminance == cte.fLuminance &&
#endif
fFlags == cte.fFlags;
}
void GrDistanceFieldTextureEffect::getConstantColorComponents(GrColor* color,
uint32_t* validFlags) const {
if ((*validFlags & kA_GrColorComponentFlag) && 0xFF == GrColorUnpackA(*color) &&
GrPixelConfigIsOpaque(this->texture(0)->config())) {
*validFlags = kA_GrColorComponentFlag;
} else {
*validFlags = 0;
}
}
const GrBackendEffectFactory& GrDistanceFieldTextureEffect::getFactory() const {
return GrTBackendEffectFactory<GrDistanceFieldTextureEffect>::getInstance();
}
///////////////////////////////////////////////////////////////////////////////
GR_DEFINE_EFFECT_TEST(GrDistanceFieldTextureEffect);
GrEffect* GrDistanceFieldTextureEffect::TestCreate(SkRandom* random,
GrContext*,
const GrDrawTargetCaps&,
GrTexture* textures[]) {
int texIdx = random->nextBool() ? GrEffectUnitTest::kSkiaPMTextureIdx :
GrEffectUnitTest::kAlphaTextureIdx;
#ifdef SK_GAMMA_APPLY_TO_A8
int texIdx2 = random->nextBool() ? GrEffectUnitTest::kSkiaPMTextureIdx :
GrEffectUnitTest::kAlphaTextureIdx;
#endif
static const SkShader::TileMode kTileModes[] = {
SkShader::kClamp_TileMode,
SkShader::kRepeat_TileMode,
SkShader::kMirror_TileMode,
};
SkShader::TileMode tileModes[] = {
kTileModes[random->nextULessThan(SK_ARRAY_COUNT(kTileModes))],
kTileModes[random->nextULessThan(SK_ARRAY_COUNT(kTileModes))],
};
GrTextureParams params(tileModes, random->nextBool() ? GrTextureParams::kBilerp_FilterMode :
GrTextureParams::kNone_FilterMode);
#ifdef SK_GAMMA_APPLY_TO_A8
GrTextureParams params2(tileModes, random->nextBool() ? GrTextureParams::kBilerp_FilterMode :
GrTextureParams::kNone_FilterMode);
#endif
return GrDistanceFieldTextureEffect::Create(textures[texIdx], params,
#ifdef SK_GAMMA_APPLY_TO_A8
textures[texIdx2], params2,
random->nextF(),
#endif
random->nextBool() ?
kSimilarity_DistanceFieldEffectFlag : 0);
}
///////////////////////////////////////////////////////////////////////////////
class GrGLDistanceFieldLCDTextureEffect : public GrGLVertexEffect {
public:
GrGLDistanceFieldLCDTextureEffect(const GrBackendEffectFactory& factory,
const GrDrawEffect& drawEffect)
: INHERITED (factory)
, fTextureSize(SkISize::Make(-1,-1)) {}
virtual void emitCode(GrGLFullProgramBuilder* builder,
const GrDrawEffect& drawEffect,
const GrEffectKey& key,
const char* outputColor,
const char* inputColor,
const TransformedCoordsArray&,
const TextureSamplerArray& samplers) SK_OVERRIDE {
SkASSERT(1 == drawEffect.castEffect<GrDistanceFieldLCDTextureEffect>().numVertexAttribs());
const GrDistanceFieldLCDTextureEffect& dfTexEffect =
drawEffect.castEffect<GrDistanceFieldLCDTextureEffect>();
SkString fsCoordName;
const char* vsCoordName;
const char* fsCoordNamePtr;
builder->addVarying(kVec2f_GrSLType, "textureCoords", &vsCoordName, &fsCoordNamePtr);
fsCoordName = fsCoordNamePtr;
GrGLVertexShaderBuilder* vsBuilder = builder->getVertexShaderBuilder();
const SkString* attr0Name =
vsBuilder->getEffectAttributeName(drawEffect.getVertexAttribIndices()[0]);
vsBuilder->codeAppendf("\t%s = %s;\n", vsCoordName, attr0Name->c_str());
const char* textureSizeUniName = NULL;
// width, height, 1/(3*width)
fTextureSizeUni = builder->addUniform(GrGLProgramBuilder::kFragment_Visibility,
kVec3f_GrSLType, "TextureSize",
&textureSizeUniName);
GrGLFragmentShaderBuilder* fsBuilder = builder->getFragmentShaderBuilder();
SkAssertResult(fsBuilder->enableFeature(
GrGLFragmentShaderBuilder::kStandardDerivatives_GLSLFeature));
// create LCD offset adjusted by inverse of transform
fsBuilder->codeAppendf("\tvec2 uv = %s;\n", fsCoordName.c_str());
fsBuilder->codeAppendf("\tvec2 st = uv*%s.xy;\n", textureSizeUniName);
bool isUniformScale = !!(dfTexEffect.getFlags() & kUniformScale_DistanceFieldEffectMask);
if (isUniformScale) {
fsBuilder->codeAppend("\tfloat dx = dFdx(st.x);\n");
fsBuilder->codeAppendf("\tvec2 offset = vec2(dx*%s.z, 0.0);\n", textureSizeUniName);
} else {
fsBuilder->codeAppend("\tvec2 Jdx = dFdx(st);\n");
fsBuilder->codeAppend("\tvec2 Jdy = dFdy(st);\n");
fsBuilder->codeAppendf("\tvec2 offset = %s.z*Jdx;\n", textureSizeUniName);
}
// green is distance to uv center
fsBuilder->codeAppend("\tvec4 texColor = ");
fsBuilder->appendTextureLookup(samplers[0], "uv", kVec2f_GrSLType);
fsBuilder->codeAppend(";\n");
fsBuilder->codeAppend("\tvec3 distance;\n");
fsBuilder->codeAppend("\tdistance.y = texColor.r;\n");
// red is distance to left offset
fsBuilder->codeAppend("\tvec2 uv_adjusted = uv - offset;\n");
fsBuilder->codeAppend("\ttexColor = ");
fsBuilder->appendTextureLookup(samplers[0], "uv_adjusted", kVec2f_GrSLType);
fsBuilder->codeAppend(";\n");
fsBuilder->codeAppend("\tdistance.x = texColor.r;\n");
// blue is distance to right offset
fsBuilder->codeAppend("\tuv_adjusted = uv + offset;\n");
fsBuilder->codeAppend("\ttexColor = ");
fsBuilder->appendTextureLookup(samplers[0], "uv_adjusted", kVec2f_GrSLType);
fsBuilder->codeAppend(";\n");
fsBuilder->codeAppend("\tdistance.z = texColor.r;\n");
fsBuilder->codeAppend("\tdistance = "
"vec3(" SK_DistanceFieldMultiplier ")*(distance - vec3(" SK_DistanceFieldThreshold"))"
"+ vec3(" SK_DistanceFieldLCDFactor ");\n");
// we adjust for the effect of the transformation on the distance by using
// the length of the gradient of the texture coordinates. We use st coordinates
// to ensure we're mapping 1:1 from texel space to pixel space.
// To be strictly correct, we should compute the anti-aliasing factor separately
// for each color component. However, this is only important when using perspective
// transformations, and even then using a single factor seems like a reasonable
// trade-off between quality and speed.
fsBuilder->codeAppend("\tfloat afwidth;\n");
if (isUniformScale) {
// this gives us a smooth step across approximately one fragment
fsBuilder->codeAppend("\tafwidth = " SK_DistanceFieldAAFactor "*dx;\n");
} else {
fsBuilder->codeAppend("\tvec2 uv_grad;\n");
if (builder->ctxInfo().caps()->dropsTileOnZeroDivide()) {
// this is to compensate for the Adreno, which likes to drop tiles on division by 0
fsBuilder->codeAppend("\tfloat uv_len2 = dot(uv, uv);\n");
fsBuilder->codeAppend("\tif (uv_len2 < 0.0001) {\n");
fsBuilder->codeAppend("\t\tuv_grad = vec2(0.7071, 0.7071);\n");
fsBuilder->codeAppend("\t} else {\n");
fsBuilder->codeAppend("\t\tuv_grad = uv*inversesqrt(uv_len2);\n");
fsBuilder->codeAppend("\t}\n");
} else {
fsBuilder->codeAppend("\tuv_grad = normalize(uv);\n");
}
fsBuilder->codeAppend("\tvec2 grad = vec2(uv_grad.x*Jdx.x + uv_grad.y*Jdy.x,\n");
fsBuilder->codeAppend("\t uv_grad.x*Jdx.y + uv_grad.y*Jdy.y);\n");
// this gives us a smooth step across approximately one fragment
fsBuilder->codeAppend("\tafwidth = " SK_DistanceFieldAAFactor "*length(grad);\n");
}
fsBuilder->codeAppend("\tvec4 val = vec4(smoothstep(vec3(-afwidth), vec3(afwidth), distance), 1.0);\n");
// adjust based on gamma
const char* textColorUniName = NULL;
// width, height, 1/(3*width)
fTextColorUni = builder->addUniform(GrGLProgramBuilder::kFragment_Visibility,
kVec3f_GrSLType, "TextColor",
&textColorUniName);
fsBuilder->codeAppendf("\tuv = vec2(val.x, %s.x);\n", textColorUniName);
fsBuilder->codeAppend("\tvec4 gammaColor = ");
fsBuilder->appendTextureLookup(samplers[1], "uv", kVec2f_GrSLType);
fsBuilder->codeAppend(";\n");
fsBuilder->codeAppend("\tval.x = gammaColor.r;\n");
fsBuilder->codeAppendf("\tuv = vec2(val.y, %s.y);\n", textColorUniName);
fsBuilder->codeAppend("\tgammaColor = ");
fsBuilder->appendTextureLookup(samplers[1], "uv", kVec2f_GrSLType);
fsBuilder->codeAppend(";\n");
fsBuilder->codeAppend("\tval.y = gammaColor.r;\n");
fsBuilder->codeAppendf("\tuv = vec2(val.z, %s.z);\n", textColorUniName);
fsBuilder->codeAppend("\tgammaColor = ");
fsBuilder->appendTextureLookup(samplers[1], "uv", kVec2f_GrSLType);
fsBuilder->codeAppend(";\n");
fsBuilder->codeAppend("\tval.z = gammaColor.r;\n");
fsBuilder->codeAppendf("\t%s = %s;\n", outputColor,
(GrGLSLExpr4(inputColor) * GrGLSLExpr4("val")).c_str());
}
virtual void setData(const GrGLProgramDataManager& pdman,
const GrDrawEffect& drawEffect) SK_OVERRIDE {
SkASSERT(fTextureSizeUni.isValid());
SkASSERT(fTextColorUni.isValid());
const GrDistanceFieldLCDTextureEffect& dfTexEffect =
drawEffect.castEffect<GrDistanceFieldLCDTextureEffect>();
GrTexture* texture = drawEffect.effect()->texture(0);
if (texture->width() != fTextureSize.width() ||
texture->height() != fTextureSize.height()) {
fTextureSize = SkISize::Make(texture->width(), texture->height());
float delta = 1.0f/(3.0f*texture->width());
if (dfTexEffect.getFlags() & kBGR_DistanceFieldEffectFlag) {
delta = -delta;
}
pdman.set3f(fTextureSizeUni,
SkIntToScalar(fTextureSize.width()),
SkIntToScalar(fTextureSize.height()),
delta);
}
GrColor textColor = dfTexEffect.getTextColor();
if (textColor != fTextColor) {
static const float ONE_OVER_255 = 1.f / 255.f;
pdman.set3f(fTextColorUni,
GrColorUnpackR(textColor) * ONE_OVER_255,
GrColorUnpackG(textColor) * ONE_OVER_255,
GrColorUnpackB(textColor) * ONE_OVER_255);
fTextColor = textColor;
}
}
static inline void GenKey(const GrDrawEffect& drawEffect, const GrGLCaps&,
GrEffectKeyBuilder* b) {
const GrDistanceFieldLCDTextureEffect& dfTexEffect =
drawEffect.castEffect<GrDistanceFieldLCDTextureEffect>();
b->add32(dfTexEffect.getFlags());
}
private:
GrGLProgramDataManager::UniformHandle fTextureSizeUni;
SkISize fTextureSize;
GrGLProgramDataManager::UniformHandle fTextColorUni;
SkColor fTextColor;
typedef GrGLVertexEffect INHERITED;
};
///////////////////////////////////////////////////////////////////////////////
GrDistanceFieldLCDTextureEffect::GrDistanceFieldLCDTextureEffect(
GrTexture* texture, const GrTextureParams& params,
GrTexture* gamma, const GrTextureParams& gParams,
SkColor textColor,
uint32_t flags)
: fTextureAccess(texture, params)
, fGammaTextureAccess(gamma, gParams)
, fTextColor(textColor)
, fFlags(flags & kLCD_DistanceFieldEffectMask) {
SkASSERT(!(flags & ~kLCD_DistanceFieldEffectMask) && (flags & kUseLCD_DistanceFieldEffectFlag));
this->addTextureAccess(&fTextureAccess);
this->addTextureAccess(&fGammaTextureAccess);
this->addVertexAttrib(kVec2f_GrSLType);
}
bool GrDistanceFieldLCDTextureEffect::onIsEqual(const GrEffect& other) const {
const GrDistanceFieldLCDTextureEffect& cte =
CastEffect<GrDistanceFieldLCDTextureEffect>(other);
return (fTextureAccess == cte.fTextureAccess &&
fGammaTextureAccess == cte.fGammaTextureAccess &&
fTextColor == cte.fTextColor &&
fFlags == cte.fFlags);
}
void GrDistanceFieldLCDTextureEffect::getConstantColorComponents(GrColor* color,
uint32_t* validFlags) const {
if ((*validFlags & kA_GrColorComponentFlag) && 0xFF == GrColorUnpackA(*color) &&
GrPixelConfigIsOpaque(this->texture(0)->config())) {
*validFlags = kA_GrColorComponentFlag;
} else {
*validFlags = 0;
}
}
const GrBackendEffectFactory& GrDistanceFieldLCDTextureEffect::getFactory() const {
return GrTBackendEffectFactory<GrDistanceFieldLCDTextureEffect>::getInstance();
}
///////////////////////////////////////////////////////////////////////////////
GR_DEFINE_EFFECT_TEST(GrDistanceFieldLCDTextureEffect);
GrEffect* GrDistanceFieldLCDTextureEffect::TestCreate(SkRandom* random,
GrContext*,
const GrDrawTargetCaps&,
GrTexture* textures[]) {
int texIdx = random->nextBool() ? GrEffectUnitTest::kSkiaPMTextureIdx :
GrEffectUnitTest::kAlphaTextureIdx;
int texIdx2 = random->nextBool() ? GrEffectUnitTest::kSkiaPMTextureIdx :
GrEffectUnitTest::kAlphaTextureIdx;
static const SkShader::TileMode kTileModes[] = {
SkShader::kClamp_TileMode,
SkShader::kRepeat_TileMode,
SkShader::kMirror_TileMode,
};
SkShader::TileMode tileModes[] = {
kTileModes[random->nextULessThan(SK_ARRAY_COUNT(kTileModes))],
kTileModes[random->nextULessThan(SK_ARRAY_COUNT(kTileModes))],
};
GrTextureParams params(tileModes, random->nextBool() ? GrTextureParams::kBilerp_FilterMode :
GrTextureParams::kNone_FilterMode);
GrTextureParams params2(tileModes, random->nextBool() ? GrTextureParams::kBilerp_FilterMode :
GrTextureParams::kNone_FilterMode);
GrColor textColor = GrColorPackRGBA(random->nextULessThan(256),
random->nextULessThan(256),
random->nextULessThan(256),
random->nextULessThan(256));
uint32_t flags = kUseLCD_DistanceFieldEffectFlag;
flags |= random->nextBool() ? kUniformScale_DistanceFieldEffectMask : 0;
flags |= random->nextBool() ? kBGR_DistanceFieldEffectFlag : 0;
return GrDistanceFieldLCDTextureEffect::Create(textures[texIdx], params,
textures[texIdx2], params2,
textColor,
flags);
}