re-land of added sk_FragCoord support to skslc

BUG=skia:

Change-Id: Ifac1aa39839058787ad1794200c3dbb93c147a69
Reviewed-on: https://skia-review.googlesource.com/5850
Reviewed-by: Ethan Nicholas <ethannicholas@google.com>
Commit-Queue: Ethan Nicholas <ethannicholas@google.com>

1 files changed, 1 insertions, 43 deletions

diff --git a/src/gpu/glsl/GrGLSLFragmentShaderBuilder.cpp b/src/gpu/glsl/GrGLSLFragmentShaderBuilder.cpp
index 8355f1de7d..7ef734876c 100644
--- a/src/gpu/glsl/GrGLSLFragmentShaderBuilder.cpp
+++ b/src/gpu/glsl/GrGLSLFragmentShaderBuilder.cpp
@@ -132,49 +132,7 @@ SkString GrGLSLFragmentShaderBuilder::ensureCoords2D(const GrShaderVar& coords)
 
 const char* GrGLSLFragmentShaderBuilder::fragmentPosition() {
     SkDEBUGCODE(fUsedProcessorFeatures |= GrProcessor::kFragmentPosition_RequiredFeature;)
-
-    const GrShaderCaps* shaderCaps = fProgramBuilder->shaderCaps();
-    // We only declare "gl_FragCoord" when we're in the case where we want to use layout qualifiers
-    // to reverse y. Otherwise it isn't necessary and whether the "in" qualifier appears in the
-    // declaration varies in earlier GLSL specs. So it is simpler to omit it.
-    if (kTopLeft_GrSurfaceOrigin == this->getSurfaceOrigin()) {
-        fSetupFragPosition = true;
-        return "gl_FragCoord";
-    } else if (const char* extension = shaderCaps->fragCoordConventionsExtensionString()) {
-        if (!fSetupFragPosition) {
-            if (shaderCaps->generation() < k150_GrGLSLGeneration) {
-                this->addFeature(1 << kFragCoordConventions_GLSLPrivateFeature,
-                                 extension);
-            }
-            fInputs.push_back().set(kVec4f_GrSLType,
-                                    "gl_FragCoord",
-                                    GrShaderVar::kIn_TypeModifier,
-                                    kDefault_GrSLPrecision,
-                                    "origin_upper_left");
-            fSetupFragPosition = true;
-        }
-        return "gl_FragCoord";
-    } else {
-        static const char* kTempName = "tmpXYFragCoord";
-        static const char* kCoordName = "fragCoordYDown";
-        if (!fSetupFragPosition) {
-            const char* rtHeightName;
-
-            fProgramBuilder->addRTHeightUniform("RTHeight", &rtHeightName);
-
-            // The Adreno compiler seems to be very touchy about access to "gl_FragCoord".
-            // Accessing glFragCoord.zw can cause a program to fail to link. Additionally,
-            // depending on the surrounding code, accessing .xy with a uniform involved can
-            // do the same thing. Copying gl_FragCoord.xy into a temp vec2 beforehand
-            // (and only accessing .xy) seems to "fix" things.
-            this->codePrependf("\thighp vec4 %s = vec4(%s.x, %s - %s.y, 1.0, 1.0);\n", kCoordName,
-                               kTempName, rtHeightName, kTempName);
-            this->codePrependf("highp vec2 %s = gl_FragCoord.xy;", kTempName);
-            fSetupFragPosition = true;
-        }
-        SkASSERT(fProgramBuilder->fUniformHandles.fRTHeightUni.isValid());
-        return kCoordName;
-    }
+    return "sk_FragCoord";
 }
 
 const char* GrGLSLFragmentShaderBuilder::distanceVectorName() const {