void onEmitCode(EmitArgs& args, GrGPArgs* gpArgs) override{
const GrDistanceFieldA8TextGeoProc& dfTexEffect =
args.fGP.cast<GrDistanceFieldA8TextGeoProc>();
GrGLGPBuilder* pb = args.fPB;
GrGLFragmentBuilder* fsBuilder = args.fPB->getFragmentShaderBuilder();
SkAssertResult(fsBuilder->enableFeature(
GrGLFragmentShaderBuilder::kStandardDerivatives_GLSLFeature));
GrGLVertexBuilder* vsBuilder = args.fPB->getVertexShaderBuilder();
// emit attributes
vsBuilder->emitAttributes(dfTexEffect);
#ifdef SK_GAMMA_APPLY_TO_A8
// adjust based on gamma
const char* distanceAdjustUniName = NULL;
// width, height, 1/(3*width)
fDistanceAdjustUni = args.fPB->addUniform(GrGLProgramBuilder::kFragment_Visibility,
kFloat_GrSLType, kDefault_GrSLPrecision,
"DistanceAdjust", &distanceAdjustUniName);
#endif
// Setup pass through color
if (!dfTexEffect.colorIgnored()) {
if (dfTexEffect.hasVertexColor()) {
pb->addPassThroughAttribute(dfTexEffect.inColor(), args.fOutputColor);
} else {
this->setupUniformColor(pb, args.fOutputColor, &fColorUniform);
}
}
// Setup position
this->setupPosition(pb, gpArgs, dfTexEffect.inPosition()->fName, dfTexEffect.viewMatrix(),
&fViewMatrixUniform);
// emit transforms
this->emitTransforms(args.fPB, gpArgs->fPositionVar, dfTexEffect.inPosition()->fName,
args.fTransformsIn, args.fTransformsOut);
// add varyings
GrGLVertToFrag recipScale(kFloat_GrSLType);
GrGLVertToFrag st(kVec2f_GrSLType);
bool isSimilarity = SkToBool(dfTexEffect.getFlags() & kSimilarity_DistanceFieldEffectFlag);
args.fPB->addVarying("IntTextureCoords", &st, kHigh_GrSLPrecision);
vsBuilder->codeAppendf("%s = %s;", st.vsOut(), dfTexEffect.inTextureCoords()->fName);
GrGLVertToFrag uv(kVec2f_GrSLType);
args.fPB->addVarying("TextureCoords", &uv, kHigh_GrSLPrecision);
// this is only used with text, so our texture bounds always match the glyph atlas
vsBuilder->codeAppendf("%s = vec2(" GR_FONT_ATLAS_A8_RECIP_WIDTH ", "
GR_FONT_ATLAS_RECIP_HEIGHT ")*%s;", uv.vsOut(),
dfTexEffect.inTextureCoords()->fName);
// Use highp to work around aliasing issues
fsBuilder->codeAppend(GrGLShaderVar::PrecisionString(kHigh_GrSLPrecision,
pb->ctxInfo().standard()));
fsBuilder->codeAppendf("vec2 uv = %s;\n", uv.fsIn());
fsBuilder->codeAppend("\tfloat texColor = ");
fsBuilder->appendTextureLookup(args.fSamplers[0],
"uv",
kVec2f_GrSLType);
fsBuilder->codeAppend(".r;\n");
fsBuilder->codeAppend("\tfloat distance = "
SK_DistanceFieldMultiplier "*(texColor - " SK_DistanceFieldThreshold ");");
#ifdef SK_GAMMA_APPLY_TO_A8
// adjust width based on gamma
fsBuilder->codeAppendf("distance -= %s;", distanceAdjustUniName);
#endif
fsBuilder->codeAppend("float afwidth;");
if (isSimilarity) {
// For uniform scale, 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.
// this gives us a smooth step across approximately one fragment
// we use y to work around a Mali400 bug in the x direction
fsBuilder->codeAppendf("afwidth = abs(" SK_DistanceFieldAAFactor "*dFdy(%s.y));",
st.fsIn());
} else {
// For general transforms, to determine the amount of correction we multiply a unit
// vector pointing along the SDF gradient direction by the Jacobian of the st coords
// (which is the inverse transform for this fragment) and take the length of the result.
fsBuilder->codeAppend("vec2 dist_grad = vec2(dFdx(distance), dFdy(distance));");
// the length of the gradient may be 0, so we need to check for this
// this also compensates for the Adreno, which likes to drop tiles on division by 0
fsBuilder->codeAppend("float dg_len2 = dot(dist_grad, dist_grad);");
fsBuilder->codeAppend("if (dg_len2 < 0.0001) {");
fsBuilder->codeAppend("dist_grad = vec2(0.7071, 0.7071);");
fsBuilder->codeAppend("} else {");
fsBuilder->codeAppend("dist_grad = dist_grad*inversesqrt(dg_len2);");
fsBuilder->codeAppend("}");
fsBuilder->codeAppendf("vec2 Jdx = dFdx(%s);", st.fsIn());
fsBuilder->codeAppendf("vec2 Jdy = dFdy(%s);", st.fsIn());
fsBuilder->codeAppend("vec2 grad = vec2(dist_grad.x*Jdx.x + dist_grad.y*Jdy.x,");
fsBuilder->codeAppend(" dist_grad.x*Jdx.y + dist_grad.y*Jdy.y);");
// this gives us a smooth step across approximately one fragment
fsBuilder->codeAppend("afwidth = " SK_DistanceFieldAAFactor "*length(grad);");
}
fsBuilder->codeAppend("float val = smoothstep(-afwidth, afwidth, distance);");
fsBuilder->codeAppendf("%s = vec4(val);", args.fOutputCoverage);
}
void onEmitCode(EmitArgs& args, GrGPArgs* gpArgs) override{
const GrDistanceFieldLCDTextGeoProc& dfTexEffect =
args.fGP.cast<GrDistanceFieldLCDTextGeoProc>();
GrGLGPBuilder* pb = args.fPB;
GrGLVertexBuilder* vsBuilder = args.fPB->getVertexShaderBuilder();
// emit attributes
vsBuilder->emitAttributes(dfTexEffect);
// setup pass through color
if (!dfTexEffect.colorIgnored()) {
this->setupUniformColor(pb, args.fOutputColor, &fColorUniform);
}
// Setup position
this->setupPosition(pb, gpArgs, dfTexEffect.inPosition()->fName, dfTexEffect.viewMatrix(),
&fViewMatrixUniform);
// emit transforms
this->emitTransforms(args.fPB, gpArgs->fPositionVar, dfTexEffect.inPosition()->fName,
args.fTransformsIn, args.fTransformsOut);
// set up varyings
bool isUniformScale = SkToBool(dfTexEffect.getFlags() & kUniformScale_DistanceFieldEffectMask);
GrGLVertToFrag recipScale(kFloat_GrSLType);
GrGLVertToFrag st(kVec2f_GrSLType);
args.fPB->addVarying("IntTextureCoords", &st, kHigh_GrSLPrecision);
vsBuilder->codeAppendf("%s = %s;", st.vsOut(), dfTexEffect.inTextureCoords()->fName);
GrGLVertToFrag uv(kVec2f_GrSLType);
args.fPB->addVarying("TextureCoords", &uv, kHigh_GrSLPrecision);
// this is only used with text, so our texture bounds always match the glyph atlas
vsBuilder->codeAppendf("%s = vec2(" GR_FONT_ATLAS_A8_RECIP_WIDTH ", "
GR_FONT_ATLAS_RECIP_HEIGHT ")*%s;", uv.vsOut(),
dfTexEffect.inTextureCoords()->fName);
// add frag shader code
GrGLFragmentBuilder* fsBuilder = args.fPB->getFragmentShaderBuilder();
SkAssertResult(fsBuilder->enableFeature(
GrGLFragmentShaderBuilder::kStandardDerivatives_GLSLFeature));
// create LCD offset adjusted by inverse of transform
// Use highp to work around aliasing issues
fsBuilder->codeAppend(GrGLShaderVar::PrecisionString(kHigh_GrSLPrecision,
pb->ctxInfo().standard()));
fsBuilder->codeAppendf("vec2 uv = %s;\n", uv.fsIn());
fsBuilder->codeAppend(GrGLShaderVar::PrecisionString(kHigh_GrSLPrecision,
pb->ctxInfo().standard()));
if (dfTexEffect.getFlags() & kBGR_DistanceFieldEffectFlag) {
fsBuilder->codeAppend("float delta = -" GR_FONT_ATLAS_LCD_DELTA ";\n");
} else {
fsBuilder->codeAppend("float delta = " GR_FONT_ATLAS_LCD_DELTA ";\n");
}
if (isUniformScale) {
fsBuilder->codeAppendf("float dy = abs(dFdy(%s.y));", st.fsIn());
fsBuilder->codeAppend("vec2 offset = vec2(dy*delta, 0.0);");
} else {
fsBuilder->codeAppendf("vec2 st = %s;\n", st.fsIn());
fsBuilder->codeAppend("vec2 Jdx = dFdx(st);");
fsBuilder->codeAppend("vec2 Jdy = dFdy(st);");
fsBuilder->codeAppend("vec2 offset = delta*Jdx;");
}
// green is distance to uv center
fsBuilder->codeAppend("\tvec4 texColor = ");
fsBuilder->appendTextureLookup(args.fSamplers[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(args.fSamplers[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(args.fSamplers[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"));");
// adjust width based on gamma
const char* distanceAdjustUniName = NULL;
fDistanceAdjustUni = args.fPB->addUniform(GrGLProgramBuilder::kFragment_Visibility,
kVec3f_GrSLType, kDefault_GrSLPrecision,
"DistanceAdjust", &distanceAdjustUniName);
fsBuilder->codeAppendf("distance -= %s;", distanceAdjustUniName);
// 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("float afwidth;");
if (isUniformScale) {
// For uniform scale, 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.
// this gives us a smooth step across approximately one fragment
fsBuilder->codeAppend("afwidth = " SK_DistanceFieldAAFactor "*dy;");
} else {
// For general transforms, to determine the amount of correction we multiply a unit
// vector pointing along the SDF gradient direction by the Jacobian of the st coords
// (which is the inverse transform for this fragment) and take the length of the result.
fsBuilder->codeAppend("vec2 dist_grad = vec2(dFdx(distance.r), dFdy(distance.r));");
// the length of the gradient may be 0, so we need to check for this
// this also compensates for the Adreno, which likes to drop tiles on division by 0
fsBuilder->codeAppend("float dg_len2 = dot(dist_grad, dist_grad);");
fsBuilder->codeAppend("if (dg_len2 < 0.0001) {");
fsBuilder->codeAppend("dist_grad = vec2(0.7071, 0.7071);");
fsBuilder->codeAppend("} else {");
fsBuilder->codeAppend("dist_grad = dist_grad*inversesqrt(dg_len2);");
fsBuilder->codeAppend("}");
fsBuilder->codeAppend("vec2 grad = vec2(dist_grad.x*Jdx.x + dist_grad.y*Jdy.x,");
fsBuilder->codeAppend(" dist_grad.x*Jdx.y + dist_grad.y*Jdy.y);");
// this gives us a smooth step across approximately one fragment
fsBuilder->codeAppend("afwidth = " SK_DistanceFieldAAFactor "*length(grad);");
}
fsBuilder->codeAppend(
"vec4 val = vec4(smoothstep(vec3(-afwidth), vec3(afwidth), distance), 1.0);");
fsBuilder->codeAppendf("%s = vec4(val);", args.fOutputCoverage);
}
void onEmitCode(EmitArgs& args, GrGPArgs* gpArgs) override{
const GrDistanceFieldPathGeoProc& dfTexEffect = args.fGP.cast<GrDistanceFieldPathGeoProc>();
GrGLGPBuilder* pb = args.fPB;
GrGLFragmentBuilder* fsBuilder = args.fPB->getFragmentShaderBuilder();
SkAssertResult(fsBuilder->enableFeature(
GrGLFragmentShaderBuilder::kStandardDerivatives_GLSLFeature));
GrGLVertexBuilder* vsBuilder = args.fPB->getVertexShaderBuilder();
// emit attributes
vsBuilder->emitAttributes(dfTexEffect);
GrGLVertToFrag v(kVec2f_GrSLType);
args.fPB->addVarying("TextureCoords", &v, kHigh_GrSLPrecision);
// setup pass through color
if (!dfTexEffect.colorIgnored()) {
if (dfTexEffect.hasVertexColor()) {
pb->addPassThroughAttribute(dfTexEffect.inColor(), args.fOutputColor);
} else {
this->setupUniformColor(pb, args.fOutputColor, &fColorUniform);
}
}
vsBuilder->codeAppendf("%s = %s;", v.vsOut(), dfTexEffect.inTextureCoords()->fName);
// Setup position
this->setupPosition(pb, gpArgs, dfTexEffect.inPosition()->fName, dfTexEffect.viewMatrix(),
&fViewMatrixUniform);
// emit transforms
this->emitTransforms(args.fPB, gpArgs->fPositionVar, dfTexEffect.inPosition()->fName,
args.fTransformsIn, args.fTransformsOut);
const char* textureSizeUniName = NULL;
fTextureSizeUni = args.fPB->addUniform(GrGLProgramBuilder::kFragment_Visibility,
kVec2f_GrSLType, kDefault_GrSLPrecision,
"TextureSize", &textureSizeUniName);
// Use highp to work around aliasing issues
fsBuilder->codeAppend(GrGLShaderVar::PrecisionString(kHigh_GrSLPrecision,
pb->ctxInfo().standard()));
fsBuilder->codeAppendf("vec2 uv = %s;", v.fsIn());
fsBuilder->codeAppend("float texColor = ");
fsBuilder->appendTextureLookup(args.fSamplers[0],
"uv",
kVec2f_GrSLType);
fsBuilder->codeAppend(".r;");
fsBuilder->codeAppend("float distance = "
SK_DistanceFieldMultiplier "*(texColor - " SK_DistanceFieldThreshold ");");
fsBuilder->codeAppend(GrGLShaderVar::PrecisionString(kHigh_GrSLPrecision,
pb->ctxInfo().standard()));
fsBuilder->codeAppendf("vec2 st = uv*%s;", textureSizeUniName);
fsBuilder->codeAppend("float afwidth;");
if (dfTexEffect.getFlags() & kSimilarity_DistanceFieldEffectFlag) {
// For uniform scale, 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.
// this gives us a smooth step across approximately one fragment
fsBuilder->codeAppend("afwidth = abs(" SK_DistanceFieldAAFactor "*dFdy(st.y));");
} else {
// For general transforms, to determine the amount of correction we multiply a unit
// vector pointing along the SDF gradient direction by the Jacobian of the st coords
// (which is the inverse transform for this fragment) and take the length of the result.
fsBuilder->codeAppend("vec2 dist_grad = vec2(dFdx(distance), dFdy(distance));");
// the length of the gradient may be 0, so we need to check for this
// this also compensates for the Adreno, which likes to drop tiles on division by 0
fsBuilder->codeAppend("float dg_len2 = dot(dist_grad, dist_grad);");
fsBuilder->codeAppend("if (dg_len2 < 0.0001) {");
fsBuilder->codeAppend("dist_grad = vec2(0.7071, 0.7071);");
fsBuilder->codeAppend("} else {");
fsBuilder->codeAppend("dist_grad = dist_grad*inversesqrt(dg_len2);");
fsBuilder->codeAppend("}");
fsBuilder->codeAppend("vec2 Jdx = dFdx(st);");
fsBuilder->codeAppend("vec2 Jdy = dFdy(st);");
fsBuilder->codeAppend("vec2 grad = vec2(dist_grad.x*Jdx.x + dist_grad.y*Jdy.x,");
fsBuilder->codeAppend(" dist_grad.x*Jdx.y + dist_grad.y*Jdy.y);");
// this gives us a smooth step across approximately one fragment
fsBuilder->codeAppend("afwidth = " SK_DistanceFieldAAFactor "*length(grad);");
}
fsBuilder->codeAppend("float val = smoothstep(-afwidth, afwidth, distance);");
fsBuilder->codeAppendf("%s = vec4(val);", args.fOutputCoverage);
}