Draft change to start pulling uniform color into GP

src/gpu/GrGeometryProcessor.cpp

+/*
+ * Copyright 2014 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "GrGeometryProcessor.h"
+
+#include "gl/GrGLGeometryProcessor.h"
+#include "GrInvariantOutput.h"
+
+///////////////////////////////////////////////////////////////////////////////////////////////////
+
+void GrGeometryProcessor::getInvariantOutputColor(GrInitInvariantOutput* out) const {
+    if (fHasVertexColor) {
+        if (fOpaqueVertexColors) {
+            out->setUnknownOpaqueFourComponents();
+        } else {
+            out->setUnknownFourComponents();
+        }
+    } else {
+        out->setKnownFourComponents(fColor);
+    }
+    this->onGetInvariantOutputColor(out);

[bsalomon, 2014/12/12 14:29:35]

this flow seems odd to me... should we always be giving the subclass a whack at
it? I don't follow the different cases and how the responsibilities for this and
emitting color-related code are split between the base class and subclasses.

I think somewhere in the base class need a comment that is as clear as possible
about how color and coverage are computed in GPs (including overrides) and how
that ties together the code generation, color/cov input types, the new helpers,
batch trackers, etc. It's *really* hard to keep straight.

+}
+
+void GrGeometryProcessor::getInvariantOutputCoverage(GrInitInvariantOutput* out) const {
+    this->onGetInvariantOutputCoverage(out);
+}
+
+///////////////////////////////////////////////////////////////////////////////////////////////////
+
+void GrPathProcessor::getInvariantOutputColor(GrInitInvariantOutput* out) const {
+    out->setKnownFourComponents(fColor);
+}
+
+void GrPathProcessor::getInvariantOutputCoverage(GrInitInvariantOutput* out) const {
+    out->setKnownSingleComponent(0xff);
+}
+///////////////////////////////////////////////////////////////////////////////////////////////////
+
+#include "gl/builders/GrGLProgramBuilder.h"
+
+void GrGLGeometryProcessor::setupColor(GrGLGPBuilder* pb,
+                                       GPInput outputType,
+                                       const char* outputName,
+                                       const GrGeometryProcessor::GrAttribute* colorAttr,
+                                       UniformHandle* colorUniform) {
+    GrGLGPFragmentBuilder* fs = pb->getFragmentShaderBuilder();
+    if (kUniform_GPInput == outputType) {
+        const char* fragColor;
+        *colorUniform = pb->addUniform(GrGLProgramBuilder::kFragment_Visibility,
+                                       kVec4f_GrSLType,
+                                       kDefault_GrSLPrecision,
+                                       "Color",
+                                       &fragColor);
+        fs->codeAppendf("%s = %s;", outputName, fragColor);
+    } else if (kAttribute_GPInput == outputType) {
+        SkASSERT(colorAttr);
+        pb->addPassThroughAttribute(colorAttr, outputName);
+    } else {
+        fs->codeAppendf("%s = vec4(1);", outputName);
+    }
+}