void onEmitCode(EmitArgs& args, GrGPArgs* gpArgs) override {
const QuadEdgeEffect& qe = args.fGP.cast<QuadEdgeEffect>();
GrGLSLGPBuilder* pb = args.fPB;
GrGLSLVertexBuilder* vertBuilder = args.fVertBuilder;
GrGLSLVaryingHandler* varyingHandler = args.fVaryingHandler;
// emit attributes
varyingHandler->emitAttributes(qe);
GrGLSLVertToFrag v(kVec4f_GrSLType);
varyingHandler->addVarying("QuadEdge", &v);
vertBuilder->codeAppendf("%s = %s;", v.vsOut(), qe.inQuadEdge()->fName);
GrGLSLFragmentBuilder* fragBuilder = args.fFragBuilder;
// Setup pass through color
if (!qe.colorIgnored()) {
this->setupUniformColor(pb, fragBuilder, args.fOutputColor, &fColorUniform);
}
// Setup position
this->setupPosition(pb, vertBuilder, gpArgs, qe.inPosition()->fName);
// emit transforms
this->emitTransforms(args.fPB,
vertBuilder,
varyingHandler,
gpArgs->fPositionVar,
qe.inPosition()->fName,
qe.localMatrix(),
args.fTransformsIn,
args.fTransformsOut);
SkAssertResult(fragBuilder->enableFeature(
GrGLSLFragmentShaderBuilder::kStandardDerivatives_GLSLFeature));
fragBuilder->codeAppendf("float edgeAlpha;");
// keep the derivative instructions outside the conditional
fragBuilder->codeAppendf("vec2 duvdx = dFdx(%s.xy);", v.fsIn());
fragBuilder->codeAppendf("vec2 duvdy = dFdy(%s.xy);", v.fsIn());
fragBuilder->codeAppendf("if (%s.z > 0.0 && %s.w > 0.0) {", v.fsIn(), v.fsIn());
// today we know z and w are in device space. We could use derivatives
fragBuilder->codeAppendf("edgeAlpha = min(min(%s.z, %s.w) + 0.5, 1.0);", v.fsIn(),
v.fsIn());
fragBuilder->codeAppendf ("} else {");
fragBuilder->codeAppendf("vec2 gF = vec2(2.0*%s.x*duvdx.x - duvdx.y,"
" 2.0*%s.x*duvdy.x - duvdy.y);",
v.fsIn(), v.fsIn());
fragBuilder->codeAppendf("edgeAlpha = (%s.x*%s.x - %s.y);", v.fsIn(), v.fsIn(),
v.fsIn());
fragBuilder->codeAppendf("edgeAlpha = "
"clamp(0.5 - edgeAlpha / length(gF), 0.0, 1.0);}");
fragBuilder->codeAppendf("%s = vec4(edgeAlpha);", args.fOutputCoverage);
}
void onEmitCode(EmitArgs& args, GrGPArgs* gpArgs) override {
const PLSFinishEffect& fe = args.fGP.cast<PLSFinishEffect>();
GrGLSLVertexBuilder* vsBuilder = args.fVertBuilder;
GrGLSLVaryingHandler* varyingHandler = args.fVaryingHandler;
GrGLSLUniformHandler* uniformHandler = args.fUniformHandler;
fUseEvenOdd = uniformHandler->addUniform(kFragment_GrShaderFlag,
kFloat_GrSLType, kLow_GrSLPrecision,
"useEvenOdd");
const char* useEvenOdd = uniformHandler->getUniformCStr(fUseEvenOdd);
varyingHandler->emitAttributes(fe);
this->setupPosition(vsBuilder, gpArgs, fe.inPosition()->fName);
this->emitTransforms(vsBuilder, varyingHandler, uniformHandler, gpArgs->fPositionVar,
fe.inPosition()->fName, fe.localMatrix(), args.fTransformsIn,
args.fTransformsOut);
GrGLSLFragmentBuilder* fsBuilder = args.fFragBuilder;
SkAssertResult(fsBuilder->enableFeature(
GrGLSLFragmentShaderBuilder::kPixelLocalStorage_GLSLFeature));
fsBuilder->declAppendf(GR_GL_PLS_PATH_DATA_DECL);
fsBuilder->codeAppend("float coverage;");
fsBuilder->codeAppendf("if (%s != 0.0) {", useEvenOdd);
fsBuilder->codeAppend("coverage = float(abs(pls.windings[0]) % 2) * 0.25;");
fsBuilder->codeAppend("coverage += float(abs(pls.windings[1]) % 2) * 0.25;");
fsBuilder->codeAppend("coverage += float(abs(pls.windings[2]) % 2) * 0.25;");
fsBuilder->codeAppend("coverage += float(abs(pls.windings[3]) % 2) * 0.25;");
fsBuilder->codeAppend("} else {");
fsBuilder->codeAppend("coverage = pls.windings[0] != 0 ? 0.25 : 0.0;");
fsBuilder->codeAppend("coverage += pls.windings[1] != 0 ? 0.25 : 0.0;");
fsBuilder->codeAppend("coverage += pls.windings[2] != 0 ? 0.25 : 0.0;");
fsBuilder->codeAppend("coverage += pls.windings[3] != 0 ? 0.25 : 0.0;");
fsBuilder->codeAppend("}");
if (!fe.colorIgnored()) {
this->setupUniformColor(fsBuilder, uniformHandler, args.fOutputColor,
&fColorUniform);
}
fsBuilder->codeAppendf("%s = vec4(coverage);", args.fOutputCoverage);
fsBuilder->codeAppendf("%s = vec4(1.0, 0.0, 1.0, 1.0);", args.fOutputColor);
}
void onEmitCode(EmitArgs& args, GrGPArgs* gpArgs) override {
const PLSQuadEdgeEffect& qe = args.fGP.cast<PLSQuadEdgeEffect>();
GrGLSLVertexBuilder* vsBuilder = args.fVertBuilder;
GrGLSLVaryingHandler* varyingHandler = args.fVaryingHandler;
GrGLSLUniformHandler* uniformHandler = args.fUniformHandler;
// emit attributes
varyingHandler->emitAttributes(qe);
GrGLSLVertToFrag uv(kVec2f_GrSLType);
varyingHandler->addVarying("uv", &uv, kHigh_GrSLPrecision);
vsBuilder->codeAppendf("%s = %s;", uv.vsOut(), qe.inUV()->fName);
GrGLSLVertToFrag ep1(kVec2f_GrSLType);
varyingHandler->addVarying("endpoint1", &ep1, kHigh_GrSLPrecision);
vsBuilder->codeAppendf("%s = vec2(%s.x, %s.y);", ep1.vsOut(),
qe.inEndpoint1()->fName, qe.inEndpoint1()->fName);
GrGLSLVertToFrag ep2(kVec2f_GrSLType);
varyingHandler->addVarying("endpoint2", &ep2, kHigh_GrSLPrecision);
vsBuilder->codeAppendf("%s = vec2(%s.x, %s.y);", ep2.vsOut(),
qe.inEndpoint2()->fName, qe.inEndpoint2()->fName);
GrGLSLVertToFrag delta(kVec2f_GrSLType);
varyingHandler->addVarying("delta", &delta, kHigh_GrSLPrecision);
vsBuilder->codeAppendf("%s = vec2(%s.x - %s.x, %s.y - %s.y) * 0.5;",
delta.vsOut(), ep1.vsOut(), ep2.vsOut(), ep2.vsOut(),
ep1.vsOut());
GrGLSLVertToFrag windings(kInt_GrSLType);
varyingHandler->addFlatVarying("windings", &windings, kLow_GrSLPrecision);
vsBuilder->codeAppendf("%s = %s;",
windings.vsOut(), qe.inWindings()->fName);
// Setup position
this->setupPosition(vsBuilder, gpArgs, qe.inPosition()->fName);
// emit transforms
this->emitTransforms(vsBuilder, varyingHandler, uniformHandler, gpArgs->fPositionVar,
qe.inPosition()->fName, qe.localMatrix(), args.fTransformsIn,
args.fTransformsOut);
GrGLSLFragmentBuilder* fsBuilder = args.fFragBuilder;
SkAssertResult(fsBuilder->enableFeature(
GrGLSLFragmentShaderBuilder::kPixelLocalStorage_GLSLFeature));
SkAssertResult(fsBuilder->enableFeature(
GrGLSLFragmentShaderBuilder::kStandardDerivatives_GLSLFeature));
static const int QUAD_ARGS = 2;
GrGLSLShaderVar inQuadArgs[QUAD_ARGS] = {
GrGLSLShaderVar("dot", kFloat_GrSLType, 0, kHigh_GrSLPrecision),
GrGLSLShaderVar("uv", kVec2f_GrSLType, 0, kHigh_GrSLPrecision)
};
SkString inQuadName;
const char* inQuadCode = "if (uv.x * uv.x <= uv.y) {"
"return dot >= 0.0;"
"} else {"
"return false;"
"}";
fsBuilder->emitFunction(kBool_GrSLType, "in_quad", QUAD_ARGS, inQuadArgs, inQuadCode,
&inQuadName);
fsBuilder->declAppendf(GR_GL_PLS_PATH_DATA_DECL);
// keep the derivative instructions outside the conditional
fsBuilder->codeAppendf("highp vec2 uvdX = dFdx(%s);", uv.fsIn());
fsBuilder->codeAppendf("highp vec2 uvdY = dFdy(%s);", uv.fsIn());
fsBuilder->codeAppend("highp vec2 uvIncX = uvdX * 0.45 + uvdY * -0.1;");
fsBuilder->codeAppend("highp vec2 uvIncY = uvdX * 0.1 + uvdY * 0.55;");
fsBuilder->codeAppendf("highp vec2 uv = %s.xy - uvdX * 0.35 - uvdY * 0.25;",
uv.fsIn());
fsBuilder->codeAppendf("highp vec2 firstSample = %s.xy - vec2(0.25);",
fsBuilder->fragmentPosition());
fsBuilder->codeAppendf("highp float d = dot(%s, (firstSample - %s).yx) * 2.0;",
delta.fsIn(), ep1.fsIn());
fsBuilder->codeAppendf("pls.windings[0] += %s(d, uv) ? %s : 0;", inQuadName.c_str(),
windings.fsIn());
fsBuilder->codeAppend("uv += uvIncX;");
fsBuilder->codeAppendf("d += %s.x;", delta.fsIn());
fsBuilder->codeAppendf("pls.windings[1] += %s(d, uv) ? %s : 0;", inQuadName.c_str(),
windings.fsIn());
fsBuilder->codeAppend("uv += uvIncY;");
fsBuilder->codeAppendf("d += %s.y;", delta.fsIn());
fsBuilder->codeAppendf("pls.windings[2] += %s(d, uv) ? %s : 0;", inQuadName.c_str(),
windings.fsIn());
fsBuilder->codeAppend("uv -= uvIncX;");
fsBuilder->codeAppendf("d -= %s.x;", delta.fsIn());
fsBuilder->codeAppendf("pls.windings[3] += %s(d, uv) ? %s : 0;", inQuadName.c_str(),
windings.fsIn());
}
void onEmitCode(EmitArgs& args, GrGPArgs* gpArgs) override {
const PLSAATriangleEffect& te = args.fGP.cast<PLSAATriangleEffect>();
GrGLSLVertexBuilder* vsBuilder = args.fVertBuilder;
GrGLSLVaryingHandler* varyingHandler = args.fVaryingHandler;
GrGLSLUniformHandler* uniformHandler = args.fUniformHandler;
varyingHandler->emitAttributes(te);
this->setupPosition(vsBuilder, gpArgs, te.inPosition()->fName);
GrGLSLVertToFrag v1(kVec2f_GrSLType);
varyingHandler->addVarying("Vertex1", &v1, kHigh_GrSLPrecision);
vsBuilder->codeAppendf("%s = vec2(%s.x, %s.y);",
v1.vsOut(),
te.inVertex1()->fName,
te.inVertex1()->fName);
GrGLSLVertToFrag v2(kVec2f_GrSLType);
varyingHandler->addVarying("Vertex2", &v2, kHigh_GrSLPrecision);
vsBuilder->codeAppendf("%s = vec2(%s.x, %s.y);",
v2.vsOut(),
te.inVertex2()->fName,
te.inVertex2()->fName);
GrGLSLVertToFrag v3(kVec2f_GrSLType);
varyingHandler->addVarying("Vertex3", &v3, kHigh_GrSLPrecision);
vsBuilder->codeAppendf("%s = vec2(%s.x, %s.y);",
v3.vsOut(),
te.inVertex3()->fName,
te.inVertex3()->fName);
GrGLSLVertToFrag delta1(kVec2f_GrSLType);
varyingHandler->addVarying("delta1", &delta1, kHigh_GrSLPrecision);
vsBuilder->codeAppendf("%s = vec2(%s.x - %s.x, %s.y - %s.y) * 0.5;",
delta1.vsOut(), v1.vsOut(), v2.vsOut(), v2.vsOut(), v1.vsOut());
GrGLSLVertToFrag delta2(kVec2f_GrSLType);
varyingHandler->addVarying("delta2", &delta2, kHigh_GrSLPrecision);
vsBuilder->codeAppendf("%s = vec2(%s.x - %s.x, %s.y - %s.y) * 0.5;",
delta2.vsOut(), v2.vsOut(), v3.vsOut(), v3.vsOut(), v2.vsOut());
GrGLSLVertToFrag delta3(kVec2f_GrSLType);
varyingHandler->addVarying("delta3", &delta3, kHigh_GrSLPrecision);
vsBuilder->codeAppendf("%s = vec2(%s.x - %s.x, %s.y - %s.y) * 0.5;",
delta3.vsOut(), v3.vsOut(), v1.vsOut(), v1.vsOut(), v3.vsOut());
GrGLSLVertToFrag windings(kInt_GrSLType);
varyingHandler->addFlatVarying("windings", &windings, kLow_GrSLPrecision);
vsBuilder->codeAppendf("%s = %s;",
windings.vsOut(), te.inWindings()->fName);
// emit transforms
this->emitTransforms(vsBuilder, varyingHandler, uniformHandler, gpArgs->fPositionVar,
te.inPosition()->fName, te.localMatrix(), args.fTransformsIn,
args.fTransformsOut);
GrGLSLFragmentBuilder* fsBuilder = args.fFragBuilder;
SkAssertResult(fsBuilder->enableFeature(
GrGLSLFragmentShaderBuilder::kPixelLocalStorage_GLSLFeature));
SkAssertResult(fsBuilder->enableFeature(
GrGLSLFragmentShaderBuilder::kStandardDerivatives_GLSLFeature));
fsBuilder->declAppendf(GR_GL_PLS_PATH_DATA_DECL);
// Compute four subsamples, each shifted a quarter pixel along x and y from
// gl_FragCoord. The oriented box positioning of the subsamples is of course not
// optimal, but it greatly simplifies the math and this simplification is necessary for
// performance reasons.
fsBuilder->codeAppendf("highp vec2 firstSample = %s.xy - vec2(0.25);",
fsBuilder->fragmentPosition());
fsBuilder->codeAppendf("highp vec2 delta1 = %s;", delta1.fsIn());
fsBuilder->codeAppendf("highp vec2 delta2 = %s;", delta2.fsIn());
fsBuilder->codeAppendf("highp vec2 delta3 = %s;", delta3.fsIn());
// Check whether first sample is inside the triangle by computing three dot products. If
// all are < 0, we're inside. The first vector in each case is half of what it is
// "supposed" to be, because we re-use them later as adjustment factors for which half
// is the correct value, so we multiply the dots by two to compensate.
fsBuilder->codeAppendf("highp float d1 = dot(delta1, (firstSample - %s).yx) * 2.0;",
v1.fsIn());
fsBuilder->codeAppendf("highp float d2 = dot(delta2, (firstSample - %s).yx) * 2.0;",
v2.fsIn());
fsBuilder->codeAppendf("highp float d3 = dot(delta3, (firstSample - %s).yx) * 2.0;",
v3.fsIn());
fsBuilder->codeAppend("highp float dmax = max(d1, max(d2, d3));");
fsBuilder->codeAppendf("pls.windings[0] += (dmax <= 0.0) ? %s : 0;", windings.fsIn());
// for subsequent samples, we don't recalculate the entire dot product -- just adjust it
// to the value it would have if we did recompute it.
fsBuilder->codeAppend("d1 += delta1.x;");
fsBuilder->codeAppend("d2 += delta2.x;");
fsBuilder->codeAppend("d3 += delta3.x;");
fsBuilder->codeAppend("dmax = max(d1, max(d2, d3));");
fsBuilder->codeAppendf("pls.windings[1] += (dmax <= 0.0) ? %s : 0;", windings.fsIn());
fsBuilder->codeAppend("d1 += delta1.y;");
fsBuilder->codeAppend("d2 += delta2.y;");
fsBuilder->codeAppend("d3 += delta3.y;");
fsBuilder->codeAppend("dmax = max(d1, max(d2, d3));");
fsBuilder->codeAppendf("pls.windings[2] += (dmax <= 0.0) ? %s : 0;", windings.fsIn());
fsBuilder->codeAppend("d1 -= delta1.x;");
fsBuilder->codeAppend("d2 -= delta2.x;");
fsBuilder->codeAppend("d3 -= delta3.x;");
fsBuilder->codeAppend("dmax = max(d1, max(d2, d3));");
fsBuilder->codeAppendf("pls.windings[3] += (dmax <= 0.0) ? %s : 0;", windings.fsIn());
}
void onEmitCode(EmitArgs& args, GrGPArgs* gpArgs) override{
const GrDistanceFieldLCDTextGeoProc& dfTexEffect =
args.fGP.cast<GrDistanceFieldLCDTextGeoProc>();
GrGLSLVertexBuilder* vertBuilder = args.fVertBuilder;
GrGLSLVaryingHandler* varyingHandler = args.fVaryingHandler;
GrGLSLUniformHandler* uniformHandler = args.fUniformHandler;
// emit attributes
varyingHandler->emitAttributes(dfTexEffect);
GrGLSLFragmentBuilder* fragBuilder = args.fFragBuilder;
// setup pass through color
if (!dfTexEffect.colorIgnored()) {
varyingHandler->addPassThroughAttribute(dfTexEffect.inColor(), args.fOutputColor);
}
// Setup position
this->setupPosition(vertBuilder,
uniformHandler,
gpArgs,
dfTexEffect.inPosition()->fName,
dfTexEffect.viewMatrix(),
&fViewMatrixUniform);
// emit transforms
this->emitTransforms(vertBuilder,
varyingHandler,
uniformHandler,
gpArgs->fPositionVar,
dfTexEffect.inPosition()->fName,
args.fTransformsIn,
args.fTransformsOut);
// set up varyings
bool isUniformScale = SkToBool(dfTexEffect.getFlags() & kUniformScale_DistanceFieldEffectMask);
GrGLSLVertToFrag recipScale(kFloat_GrSLType);
GrGLSLVertToFrag st(kVec2f_GrSLType);
varyingHandler->addVarying("IntTextureCoords", &st, kHigh_GrSLPrecision);
vertBuilder->codeAppendf("%s = %s;", st.vsOut(), dfTexEffect.inTextureCoords()->fName);
// compute numbers to be hardcoded to convert texture coordinates from int to float
SkASSERT(dfTexEffect.numTextures() == 1);
GrTexture* atlas = dfTexEffect.textureAccess(0).getTexture();
SkASSERT(atlas && SkIsPow2(atlas->width()) && SkIsPow2(atlas->height()));
SkScalar recipWidth = 1.0f / atlas->width();
SkScalar recipHeight = 1.0f / atlas->height();
GrGLSLVertToFrag uv(kVec2f_GrSLType);
varyingHandler->addVarying("TextureCoords", &uv, kHigh_GrSLPrecision);
vertBuilder->codeAppendf("%s = vec2(%.*f, %.*f) * %s;", uv.vsOut(),
GR_SIGNIFICANT_POW2_DECIMAL_DIG, recipWidth,
GR_SIGNIFICANT_POW2_DECIMAL_DIG, recipHeight,
dfTexEffect.inTextureCoords()->fName);
// add frag shader code
SkAssertResult(fragBuilder->enableFeature(
GrGLSLFragmentShaderBuilder::kStandardDerivatives_GLSLFeature));
// create LCD offset adjusted by inverse of transform
// Use highp to work around aliasing issues
fragBuilder->codeAppend(GrGLSLShaderVar::PrecisionString(args.fGLSLCaps,
kHigh_GrSLPrecision));
fragBuilder->codeAppendf("vec2 uv = %s;\n", uv.fsIn());
fragBuilder->codeAppend(GrGLSLShaderVar::PrecisionString(args.fGLSLCaps,
kHigh_GrSLPrecision));
SkScalar lcdDelta = 1.0f / (3.0f * atlas->width());
if (dfTexEffect.getFlags() & kBGR_DistanceFieldEffectFlag) {
fragBuilder->codeAppendf("float delta = -%.*f;\n", SK_FLT_DECIMAL_DIG, lcdDelta);
} else {
fragBuilder->codeAppendf("float delta = %.*f;\n", SK_FLT_DECIMAL_DIG, lcdDelta);
}
if (isUniformScale) {
fragBuilder->codeAppendf("float dy = abs(dFdy(%s.y));", st.fsIn());
fragBuilder->codeAppend("vec2 offset = vec2(dy*delta, 0.0);");
} else {
fragBuilder->codeAppendf("vec2 st = %s;\n", st.fsIn());
fragBuilder->codeAppend("vec2 Jdx = dFdx(st);");
fragBuilder->codeAppend("vec2 Jdy = dFdy(st);");
fragBuilder->codeAppend("vec2 offset = delta*Jdx;");
}
// green is distance to uv center
fragBuilder->codeAppend("\tvec4 texColor = ");
fragBuilder->appendTextureLookup(args.fSamplers[0], "uv", kVec2f_GrSLType);
fragBuilder->codeAppend(";\n");
fragBuilder->codeAppend("\tvec3 distance;\n");
fragBuilder->codeAppend("\tdistance.y = texColor.r;\n");
// red is distance to left offset
fragBuilder->codeAppend("\tvec2 uv_adjusted = uv - offset;\n");
fragBuilder->codeAppend("\ttexColor = ");
fragBuilder->appendTextureLookup(args.fSamplers[0], "uv_adjusted", kVec2f_GrSLType);
fragBuilder->codeAppend(";\n");
fragBuilder->codeAppend("\tdistance.x = texColor.r;\n");
// blue is distance to right offset
fragBuilder->codeAppend("\tuv_adjusted = uv + offset;\n");
fragBuilder->codeAppend("\ttexColor = ");
fragBuilder->appendTextureLookup(args.fSamplers[0], "uv_adjusted", kVec2f_GrSLType);
fragBuilder->codeAppend(";\n");
fragBuilder->codeAppend("\tdistance.z = texColor.r;\n");
fragBuilder->codeAppend("\tdistance = "
"vec3(" SK_DistanceFieldMultiplier ")*(distance - vec3(" SK_DistanceFieldThreshold"));");
// adjust width based on gamma
const char* distanceAdjustUniName = nullptr;
fDistanceAdjustUni = uniformHandler->addUniform(GrGLSLUniformHandler::kFragment_Visibility,
kVec3f_GrSLType, kDefault_GrSLPrecision,
"DistanceAdjust", &distanceAdjustUniName);
fragBuilder->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.
fragBuilder->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
fragBuilder->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.
fragBuilder->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
fragBuilder->codeAppend("float dg_len2 = dot(dist_grad, dist_grad);");
fragBuilder->codeAppend("if (dg_len2 < 0.0001) {");
fragBuilder->codeAppend("dist_grad = vec2(0.7071, 0.7071);");
fragBuilder->codeAppend("} else {");
fragBuilder->codeAppend("dist_grad = dist_grad*inversesqrt(dg_len2);");
fragBuilder->codeAppend("}");
fragBuilder->codeAppend("vec2 grad = vec2(dist_grad.x*Jdx.x + dist_grad.y*Jdy.x,");
fragBuilder->codeAppend(" dist_grad.x*Jdx.y + dist_grad.y*Jdy.y);");
// this gives us a smooth step across approximately one fragment
fragBuilder->codeAppend("afwidth = " SK_DistanceFieldAAFactor "*length(grad);");
}
fragBuilder->codeAppend(
"vec4 val = vec4(smoothstep(vec3(-afwidth), vec3(afwidth), distance), 1.0);");
// set alpha to be max of rgb coverage
fragBuilder->codeAppend("val.a = max(max(val.r, val.g), val.b);");
fragBuilder->codeAppendf("%s = val;", args.fOutputCoverage);
}
void onEmitCode(EmitArgs& args, GrGPArgs* gpArgs) override{
const GrDistanceFieldA8TextGeoProc& dfTexEffect =
args.fGP.cast<GrDistanceFieldA8TextGeoProc>();
GrGLSLFragmentBuilder* fragBuilder = args.fFragBuilder;
SkAssertResult(fragBuilder->enableFeature(
GrGLSLFragmentShaderBuilder::kStandardDerivatives_GLSLFeature));
GrGLSLVertexBuilder* vertBuilder = args.fVertBuilder;
GrGLSLVaryingHandler* varyingHandler = args.fVaryingHandler;
GrGLSLUniformHandler* uniformHandler = args.fUniformHandler;
// emit attributes
varyingHandler->emitAttributes(dfTexEffect);
#ifdef SK_GAMMA_APPLY_TO_A8
// adjust based on gamma
const char* distanceAdjustUniName = nullptr;
// width, height, 1/(3*width)
fDistanceAdjustUni = uniformHandler->addUniform(GrGLSLUniformHandler::kFragment_Visibility,
kFloat_GrSLType, kDefault_GrSLPrecision,
"DistanceAdjust", &distanceAdjustUniName);
#endif
// Setup pass through color
if (!dfTexEffect.colorIgnored()) {
varyingHandler->addPassThroughAttribute(dfTexEffect.inColor(), args.fOutputColor);
}
// Setup position
this->setupPosition(vertBuilder,
uniformHandler,
gpArgs,
dfTexEffect.inPosition()->fName,
dfTexEffect.viewMatrix(),
&fViewMatrixUniform);
// emit transforms
this->emitTransforms(vertBuilder,
varyingHandler,
uniformHandler,
gpArgs->fPositionVar,
dfTexEffect.inPosition()->fName,
args.fTransformsIn,
args.fTransformsOut);
// add varyings
GrGLSLVertToFrag recipScale(kFloat_GrSLType);
GrGLSLVertToFrag st(kVec2f_GrSLType);
bool isSimilarity = SkToBool(dfTexEffect.getFlags() & kSimilarity_DistanceFieldEffectFlag);
varyingHandler->addVarying("IntTextureCoords", &st, kHigh_GrSLPrecision);
vertBuilder->codeAppendf("%s = %s;", st.vsOut(), dfTexEffect.inTextureCoords()->fName);
// compute numbers to be hardcoded to convert texture coordinates from int to float
SkASSERT(dfTexEffect.numTextures() == 1);
GrTexture* atlas = dfTexEffect.textureAccess(0).getTexture();
SkASSERT(atlas && SkIsPow2(atlas->width()) && SkIsPow2(atlas->height()));
SkScalar recipWidth = 1.0f / atlas->width();
SkScalar recipHeight = 1.0f / atlas->height();
GrGLSLVertToFrag uv(kVec2f_GrSLType);
varyingHandler->addVarying("TextureCoords", &uv, kHigh_GrSLPrecision);
vertBuilder->codeAppendf("%s = vec2(%.*f, %.*f) * %s;", uv.vsOut(),
GR_SIGNIFICANT_POW2_DECIMAL_DIG, recipWidth,
GR_SIGNIFICANT_POW2_DECIMAL_DIG, recipHeight,
dfTexEffect.inTextureCoords()->fName);
// Use highp to work around aliasing issues
fragBuilder->codeAppend(GrGLSLShaderVar::PrecisionString(args.fGLSLCaps,
kHigh_GrSLPrecision));
fragBuilder->codeAppendf("vec2 uv = %s;\n", uv.fsIn());
fragBuilder->codeAppend("\tfloat texColor = ");
fragBuilder->appendTextureLookup(args.fSamplers[0],
"uv",
kVec2f_GrSLType);
fragBuilder->codeAppend(".r;\n");
fragBuilder->codeAppend("\tfloat distance = "
SK_DistanceFieldMultiplier "*(texColor - " SK_DistanceFieldThreshold ");");
#ifdef SK_GAMMA_APPLY_TO_A8
// adjust width based on gamma
fragBuilder->codeAppendf("distance -= %s;", distanceAdjustUniName);
#endif
fragBuilder->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
fragBuilder->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.
fragBuilder->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
fragBuilder->codeAppend("float dg_len2 = dot(dist_grad, dist_grad);");
fragBuilder->codeAppend("if (dg_len2 < 0.0001) {");
fragBuilder->codeAppend("dist_grad = vec2(0.7071, 0.7071);");
fragBuilder->codeAppend("} else {");
fragBuilder->codeAppend("dist_grad = dist_grad*inversesqrt(dg_len2);");
fragBuilder->codeAppend("}");
fragBuilder->codeAppendf("vec2 Jdx = dFdx(%s);", st.fsIn());
fragBuilder->codeAppendf("vec2 Jdy = dFdy(%s);", st.fsIn());
fragBuilder->codeAppend("vec2 grad = vec2(dist_grad.x*Jdx.x + dist_grad.y*Jdy.x,");
fragBuilder->codeAppend(" dist_grad.x*Jdx.y + dist_grad.y*Jdy.y);");
// this gives us a smooth step across approximately one fragment
fragBuilder->codeAppend("afwidth = " SK_DistanceFieldAAFactor "*length(grad);");
}
fragBuilder->codeAppend("float val = smoothstep(-afwidth, afwidth, distance);");
fragBuilder->codeAppendf("%s = vec4(val);", args.fOutputCoverage);
}
void onEmitCode(EmitArgs& args, GrGPArgs* gpArgs) override{
const GrDistanceFieldPathGeoProc& dfTexEffect = args.fGP.cast<GrDistanceFieldPathGeoProc>();
GrGLSLFragmentBuilder* fragBuilder = args.fFragBuilder;
SkAssertResult(fragBuilder->enableFeature(
GrGLSLFragmentShaderBuilder::kStandardDerivatives_GLSLFeature));
GrGLSLVertexBuilder* vertBuilder = args.fVertBuilder;
GrGLSLVaryingHandler* varyingHandler = args.fVaryingHandler;
GrGLSLUniformHandler* uniformHandler = args.fUniformHandler;
// emit attributes
varyingHandler->emitAttributes(dfTexEffect);
GrGLSLVertToFrag v(kVec2f_GrSLType);
varyingHandler->addVarying("TextureCoords", &v, kHigh_GrSLPrecision);
// setup pass through color
if (!dfTexEffect.colorIgnored()) {
varyingHandler->addPassThroughAttribute(dfTexEffect.inColor(), args.fOutputColor);
}
vertBuilder->codeAppendf("%s = %s;", v.vsOut(), dfTexEffect.inTextureCoords()->fName);
// Setup position
this->setupPosition(vertBuilder,
uniformHandler,
gpArgs,
dfTexEffect.inPosition()->fName,
dfTexEffect.viewMatrix(),
&fViewMatrixUniform);
// emit transforms
this->emitTransforms(vertBuilder,
varyingHandler,
uniformHandler,
gpArgs->fPositionVar,
dfTexEffect.inPosition()->fName,
args.fTransformsIn,
args.fTransformsOut);
const char* textureSizeUniName = nullptr;
fTextureSizeUni = uniformHandler->addUniform(GrGLSLUniformHandler::kFragment_Visibility,
kVec2f_GrSLType, kDefault_GrSLPrecision,
"TextureSize", &textureSizeUniName);
// Use highp to work around aliasing issues
fragBuilder->codeAppend(GrGLSLShaderVar::PrecisionString(args.fGLSLCaps,
kHigh_GrSLPrecision));
fragBuilder->codeAppendf("vec2 uv = %s;", v.fsIn());
fragBuilder->codeAppend("float texColor = ");
fragBuilder->appendTextureLookup(args.fSamplers[0],
"uv",
kVec2f_GrSLType);
fragBuilder->codeAppend(".r;");
fragBuilder->codeAppend("float distance = "
SK_DistanceFieldMultiplier "*(texColor - " SK_DistanceFieldThreshold ");");
fragBuilder->codeAppend(GrGLSLShaderVar::PrecisionString(args.fGLSLCaps,
kHigh_GrSLPrecision));
fragBuilder->codeAppendf("vec2 st = uv*%s;", textureSizeUniName);
fragBuilder->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
fragBuilder->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.
fragBuilder->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
fragBuilder->codeAppend("float dg_len2 = dot(dist_grad, dist_grad);");
fragBuilder->codeAppend("if (dg_len2 < 0.0001) {");
fragBuilder->codeAppend("dist_grad = vec2(0.7071, 0.7071);");
fragBuilder->codeAppend("} else {");
fragBuilder->codeAppend("dist_grad = dist_grad*inversesqrt(dg_len2);");
fragBuilder->codeAppend("}");
fragBuilder->codeAppend("vec2 Jdx = dFdx(st);");
fragBuilder->codeAppend("vec2 Jdy = dFdy(st);");
fragBuilder->codeAppend("vec2 grad = vec2(dist_grad.x*Jdx.x + dist_grad.y*Jdy.x,");
fragBuilder->codeAppend(" dist_grad.x*Jdx.y + dist_grad.y*Jdy.y);");
// this gives us a smooth step across approximately one fragment
fragBuilder->codeAppend("afwidth = " SK_DistanceFieldAAFactor "*length(grad);");
}
fragBuilder->codeAppend("float val = smoothstep(-afwidth, afwidth, distance);");
fragBuilder->codeAppendf("%s = vec4(val);", args.fOutputCoverage);
}