Fix various issues with framebuffer fetch
This CL does two things. First it fixes a bug of ours where when using
a custom fbFetch variable (es 3.0 and higher), we sometimes overwrite
the out color and then attempt to use it as the dst color later. This is
fixed here by using an intermediate variable.
Secondly I've added a workaround to an andreno fbFetch where reading from
the outColor always returns the original dstColor even if we've overwritten
the value.
BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2248403003
Review-Url: https://codereview.chromium.org/2248403003
diff --git a/src/gpu/glsl/GrGLSLFragmentShaderBuilder.cpp b/src/gpu/glsl/GrGLSLFragmentShaderBuilder.cpp
index e6ecf8c..4513a69 100644
--- a/src/gpu/glsl/GrGLSLFragmentShaderBuilder.cpp
+++ b/src/gpu/glsl/GrGLSLFragmentShaderBuilder.cpp
@@ -15,7 +15,7 @@
#include "glsl/GrGLSLUniformHandler.h"
#include "glsl/GrGLSLVarying.h"
-const char* GrGLSLFragmentShaderBuilder::kDstTextureColorName = "_dstColor";
+const char* GrGLSLFragmentShaderBuilder::kDstColorName = "_dstColor";
static const char* sample_offset_array_name(GrGLSLFPFragmentBuilder::Coordinates coords) {
static const char* kArrayNames[] = {
@@ -264,11 +264,11 @@
this->enableCustomOutput();
fOutputs[fCustomColorOutputIndex].setTypeModifier(GrShaderVar::kInOut_TypeModifier);
fbFetchColorName = DeclaredColorOutputName();
+ // Set the dstColor to an intermediate variable so we don't override it with the output
+ this->codeAppendf("vec4 %s = %s;", kDstColorName, fbFetchColorName);
}
- return fbFetchColorName;
- } else {
- return kDstTextureColorName;
}
+ return kDstColorName;
}
void GrGLSLFragmentShaderBuilder::enableAdvancedBlendEquationIfNeeded(GrBlendEquation equation) {