Take the dest color as an input to SkBlenderBase::asFragmentProcessor.
Previously, the dest color was implicitly the surface that we were
drawing onto. When setting the blender on an SkPaint, this is still the
case. For other uses, e.g. a SkBlendImageFilter, the caller may want to
supply an arbitrary input FP.
Bug: skia:12085, skia:12205
Change-Id: I254be006a0f374711fa64f49e0ba339578d8d83a
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/430059
Commit-Queue: John Stiles <johnstiles@google.com>
Auto-Submit: John Stiles <johnstiles@google.com>
Reviewed-by: Brian Osman <brianosman@google.com>
diff --git a/src/core/SkBlendModeBlender.cpp b/src/core/SkBlendModeBlender.cpp
index 19dcc78..5b261e3 100644
--- a/src/core/SkBlendModeBlender.cpp
+++ b/src/core/SkBlendModeBlender.cpp
@@ -69,11 +69,16 @@
#if SK_SUPPORT_GPU
std::unique_ptr<GrFragmentProcessor> SkBlendModeBlender::asFragmentProcessor(
- std::unique_ptr<GrFragmentProcessor> inputFP, const GrFPArgs& fpArgs) const {
- // Using a SkBlendModeBlender on the GPU side isn't supported; we should use GrXferProcessor to
- // perform this blend instead. The Xfer processor is able to perform coefficient-based blends
- // without readback, so it's more efficient.
- SkDEBUGFAIL("SkBlendModeBlender::asFragmentProcessor is not supported");
+ std::unique_ptr<GrFragmentProcessor> srcFP,
+ std::unique_ptr<GrFragmentProcessor> dstFP,
+ const GrFPArgs& fpArgs) const {
+ // Note that for the final blend onto the canvas, we should prefer to use the GrXferProcessor
+ // instead of a SkBlendModeBlender to perform the blend. The Xfer processor is able to perform
+ // coefficient-based blends directly, without readback. This will be much more efficient.
+
+ // TODO(skia:12085, skia:12205): We will be able to use Blenders in other contexts, such as
+ // in a SkBlendImageFilter; in that case we will need to supply a blend function.
+ SkDEBUGFAIL("SkBlendModeBlender::asFragmentProcessor is not yet implemented");
return nullptr;
}
#endif
diff --git a/src/core/SkBlendModeBlender.h b/src/core/SkBlendModeBlender.h
index 39d8218..a518618 100644
--- a/src/core/SkBlendModeBlender.h
+++ b/src/core/SkBlendModeBlender.h
@@ -18,7 +18,9 @@
#if SK_SUPPORT_GPU
std::unique_ptr<GrFragmentProcessor> asFragmentProcessor(
- std::unique_ptr<GrFragmentProcessor> inputFP, const GrFPArgs& fpArgs) const override;
+ std::unique_ptr<GrFragmentProcessor> srcFP,
+ std::unique_ptr<GrFragmentProcessor> dstFP,
+ const GrFPArgs& fpArgs) const override;
#endif
SK_FLATTENABLE_HOOKS(SkBlendModeBlender)
diff --git a/src/core/SkBlenderBase.h b/src/core/SkBlenderBase.h
index 431b26c..bc55139 100644
--- a/src/core/SkBlenderBase.h
+++ b/src/core/SkBlenderBase.h
@@ -42,10 +42,12 @@
#if SK_SUPPORT_GPU
/**
* Returns a GrFragmentProcessor that implements this blend for the GPU backend.
- * The GrFragmentProcessor expects a premultiplied input and returns a premultiplied output.
+ * The GrFragmentProcessor expects premultiplied inputs and returns a premultiplied output.
*/
virtual std::unique_ptr<GrFragmentProcessor> asFragmentProcessor(
- std::unique_ptr<GrFragmentProcessor> inputFP, const GrFPArgs& fpArgs) const = 0;
+ std::unique_ptr<GrFragmentProcessor> srcFP,
+ std::unique_ptr<GrFragmentProcessor> dstFP,
+ const GrFPArgs& fpArgs) const = 0;
#endif
virtual SkRuntimeEffect* asRuntimeEffect() const { return nullptr; }
diff --git a/src/core/SkRuntimeEffect.cpp b/src/core/SkRuntimeEffect.cpp
index 7e35ba7..03c7a63 100644
--- a/src/core/SkRuntimeEffect.cpp
+++ b/src/core/SkRuntimeEffect.cpp
@@ -694,8 +694,12 @@
childFPs.push_back(nullptr);
}
}
- auto fp = GrSkSLFP::MakeWithData(
- std::move(effect), name, std::move(inputFP), std::move(uniforms), SkMakeSpan(childFPs));
+ auto fp = GrSkSLFP::MakeWithData(std::move(effect),
+ name,
+ std::move(inputFP),
+ /*destColorFP=*/nullptr,
+ std::move(uniforms),
+ SkMakeSpan(childFPs));
SkASSERT(fp);
return GrFPSuccess(std::move(fp));
}
@@ -1066,13 +1070,19 @@
#if SK_SUPPORT_GPU
std::unique_ptr<GrFragmentProcessor> asFragmentProcessor(
- std::unique_ptr<GrFragmentProcessor> inputFP, const GrFPArgs& args) const override {
+ std::unique_ptr<GrFragmentProcessor> srcFP,
+ std::unique_ptr<GrFragmentProcessor> dstFP,
+ const GrFPArgs& args) const override {
sk_sp<SkData> uniforms = get_xformed_uniforms(fEffect.get(), fUniforms,
args.fDstColorInfo->colorSpace());
SkASSERT(uniforms);
- return GrSkSLFP::MakeWithData(fEffect, "runtime_blender", std::move(inputFP),
- std::move(uniforms), /*childFPs=*/{});
+ return GrSkSLFP::MakeWithData(fEffect,
+ "runtime_blender",
+ std::move(srcFP),
+ std::move(dstFP),
+ std::move(uniforms),
+ /*childFPs=*/{});
}
#endif
@@ -1185,6 +1195,7 @@
auto fp = GrSkSLFP::MakeWithData(sk_ref_sp(this),
"runtime_image",
/*inputFP=*/nullptr,
+ /*destColorFP=*/nullptr,
std::move(uniforms),
SkMakeSpan(childFPs));
diff --git a/src/gpu/SkGr.cpp b/src/gpu/SkGr.cpp
index e80361d..72b7d10 100644
--- a/src/gpu/SkGr.cpp
+++ b/src/gpu/SkGr.cpp
@@ -512,9 +512,12 @@
grPaint->setXPFactory(SkBlendMode_AsXPFactory(bm.value()));
}
} else {
- // Apply the custom blend, and force the XP to kSrc. We don't honor the SkBlendMode when a
- // custom blend is applied.
- paintFP = as_BB(skPaint.getBlender())->asFragmentProcessor(std::move(paintFP), fpArgs);
+ // Apply a custom blend against the destination color, and force the XP to kSrc so that the
+ // computed result is applied directly to the canvas while still honoring the alpha.
+ paintFP = as_BB(skPaint.getBlender())->asFragmentProcessor(
+ std::move(paintFP),
+ GrFragmentProcessor::DestColor(),
+ fpArgs);
grPaint->setXPFactory(SkBlendMode_AsXPFactory(SkBlendMode::kSrc));
}
diff --git a/src/gpu/effects/GrSkSLFP.cpp b/src/gpu/effects/GrSkSLFP.cpp
index 1bd7a3d..0166ce9 100644
--- a/src/gpu/effects/GrSkSLFP.cpp
+++ b/src/gpu/effects/GrSkSLFP.cpp
@@ -194,14 +194,15 @@
args.fFragBuilder->codeAppendf("float2 %s = %s;\n", coords, args.fSampleCoord);
}
- // For blend effects, we need to copy the dest-color to a local variable as well.
+ // For runtime blends, the destination color is stored as a child FP.
+ // Invoke that FP here and store it in a local variable.
const char* destColor = "half4(1)";
SkString destColorVarName;
- if (fp.willReadDstColor()) {
+ if (fp.fDestColorChildIndex >= 0) {
destColorVarName = args.fFragBuilder->newTmpVarName("destColor");
destColor = destColorVarName.c_str();
- args.fFragBuilder->codeAppendf(
- "half4 %s = %s;\n", destColor, args.fFragBuilder->dstColor());
+ SkString childFP = this->invokeChild(fp.fDestColorChildIndex, args);
+ args.fFragBuilder->codeAppendf("half4 %s = %s;", destColor, childFP.c_str());
}
FPCallbacks callbacks(this,
@@ -257,6 +258,7 @@
sk_sp<SkRuntimeEffect> effect,
const char* name,
std::unique_ptr<GrFragmentProcessor> inputFP,
+ std::unique_ptr<GrFragmentProcessor> destColorFP,
sk_sp<SkData> uniforms,
SkSpan<std::unique_ptr<GrFragmentProcessor>> childFPs) {
if (uniforms->size() != effect->uniformSize()) {
@@ -273,6 +275,9 @@
if (inputFP) {
fp->setInput(std::move(inputFP));
}
+ if (destColorFP) {
+ fp->setDestColorFP(std::move(destColorFP));
+ }
return fp;
}
@@ -289,10 +294,6 @@
if (fEffect->usesSampleCoords()) {
this->setUsesSampleCoordsDirectly();
}
-
- if (fEffect->allowBlender()) {
- this->setWillReadDstColor();
- }
}
GrSkSLFP::GrSkSLFP(const GrSkSLFP& other)
@@ -310,15 +311,12 @@
this->setUsesSampleCoordsDirectly();
}
- if (fEffect->allowBlender()) {
- this->setWillReadDstColor();
- }
-
this->cloneAndRegisterAllChildProcessors(other);
}
void GrSkSLFP::addChild(std::unique_ptr<GrFragmentProcessor> child, bool mergeOptFlags) {
SkASSERTF(fInputChildIndex == -1, "all addChild calls must happen before setInput");
+ SkASSERTF(fDestColorChildIndex == -1, "all addChild calls must happen before setDestColorFP");
int childIndex = this->numChildProcessors();
SkASSERT((size_t)childIndex < fEffect->fSampleUsages.size());
if (mergeOptFlags) {
@@ -330,11 +328,20 @@
void GrSkSLFP::setInput(std::unique_ptr<GrFragmentProcessor> input) {
SkASSERTF(fInputChildIndex == -1, "setInput should not be called more than once");
fInputChildIndex = this->numChildProcessors();
- SkASSERT((size_t)fInputChildIndex == fEffect->fSampleUsages.size());
+ SkASSERT((size_t)fInputChildIndex >= fEffect->fSampleUsages.size());
this->mergeOptimizationFlags(ProcessorOptimizationFlags(input.get()));
this->registerChild(std::move(input), SkSL::SampleUsage::PassThrough());
}
+void GrSkSLFP::setDestColorFP(std::unique_ptr<GrFragmentProcessor> destColorFP) {
+ SkASSERTF(fEffect->allowBlender(), "dest colors are only used by blend effects");
+ SkASSERTF(fDestColorChildIndex == -1, "setDestColorFP should not be called more than once");
+ fDestColorChildIndex = this->numChildProcessors();
+ SkASSERT((size_t)fDestColorChildIndex >= fEffect->fSampleUsages.size());
+ this->mergeOptimizationFlags(ProcessorOptimizationFlags(destColorFP.get()));
+ this->registerChild(std::move(destColorFP), SkSL::SampleUsage::PassThrough());
+}
+
std::unique_ptr<GrGLSLFragmentProcessor> GrSkSLFP::onMakeProgramImpl() const {
return std::make_unique<GrGLSLSkSLFP>();
}
diff --git a/src/gpu/effects/GrSkSLFP.h b/src/gpu/effects/GrSkSLFP.h
index 5448884..b7affa6 100644
--- a/src/gpu/effects/GrSkSLFP.h
+++ b/src/gpu/effects/GrSkSLFP.h
@@ -100,6 +100,7 @@
sk_sp<SkRuntimeEffect> effect,
const char* name,
std::unique_ptr<GrFragmentProcessor> inputFP,
+ std::unique_ptr<GrFragmentProcessor> destColorFP,
sk_sp<SkData> uniforms,
SkSpan<std::unique_ptr<GrFragmentProcessor>> childFPs);
@@ -164,6 +165,7 @@
void addChild(std::unique_ptr<GrFragmentProcessor> child, bool mergeOptFlags);
void setInput(std::unique_ptr<GrFragmentProcessor> input);
+ void setDestColorFP(std::unique_ptr<GrFragmentProcessor> destColorFP);
std::unique_ptr<GrGLSLFragmentProcessor> onMakeProgramImpl() const override;
@@ -365,6 +367,7 @@
const char* fName;
uint32_t fUniformSize;
int fInputChildIndex = -1;
+ int fDestColorChildIndex = -1;
GR_DECLARE_FRAGMENT_PROCESSOR_TEST
