Refactor GrColorSpaceXformHelper

Nonlinear blending mode is going to (sometimes) require additional
uniforms and shader code for color space transformation.

This change just alters the usage of the helper struct so that we can
hide any new logic (without having to change all the FPs that use it).

BUG=skia:

Change-Id: I913478a387973f5bad5aa09a29f85d21daacab94
Reviewed-on: https://skia-review.googlesource.com/9414
Reviewed-by: Robert Phillips <robertphillips@google.com>
Commit-Queue: Brian Osman <brianosman@google.com>

2 files changed, 22 insertions, 17 deletions

diff --git a/src/gpu/glsl/GrGLSLColorSpaceXformHelper.h b/src/gpu/glsl/GrGLSLColorSpaceXformHelper.h
index 5e112f9f91..1571b06231 100644
--- a/src/gpu/glsl/GrGLSLColorSpaceXformHelper.h
+++ b/src/gpu/glsl/GrGLSLColorSpaceXformHelper.h
@@ -12,29 +12,33 @@
 #include "GrGLSLUniformHandler.h"
 
 /**
- * Stack helper class to assist with using GrColorSpaceXform within an FP's emitCode function.
- * This injects the uniform declaration, and stores the information needed to generate correct
- * gamut-transformation shader code.
+ * Helper class to assist with using GrColorSpaceXform within an FP. This manages all of the
+ * uniforms needed, and can be passed to shader builder functions to automatically generate the
+ * correct color space transformation code.
  */
 class GrGLSLColorSpaceXformHelper : public SkNoncopyable {
 public:
-    GrGLSLColorSpaceXformHelper(GrGLSLUniformHandler* uniformHandler,
-                                GrColorSpaceXform* colorSpaceXform,
-                                GrGLSLProgramDataManager::UniformHandle* handle) {
-        SkASSERT(uniformHandler && handle);
+    GrGLSLColorSpaceXformHelper() : fValid(false) {}
+
+    void emitCode(GrGLSLUniformHandler* uniformHandler, GrColorSpaceXform* colorSpaceXform) {
+        SkASSERT(uniformHandler);
         if (colorSpaceXform) {
-            *handle = uniformHandler->addUniform(kFragment_GrShaderFlag, kMat44f_GrSLType,
-                                                 kDefault_GrSLPrecision, "ColorXform",
-                                                 &fXformMatrix);
-        } else {
-            fXformMatrix = nullptr;
+            fGamutXformVar = uniformHandler->addUniform(kFragment_GrShaderFlag, kMat44f_GrSLType,
+                                                        kDefault_GrSLPrecision, "ColorXform");
+            fValid = true;
         }
     }
 
-    const char* getXformMatrix() const { return fXformMatrix; }
+    void setData(const GrGLSLProgramDataManager& pdman, GrColorSpaceXform* colorSpaceXform) {
+        pdman.setSkMatrix44(fGamutXformVar, colorSpaceXform->srcToDst());
+    }
+
+    bool isValid() const { return fValid; }
+    GrGLSLProgramDataManager::UniformHandle const gamutXformUniform() { return fGamutXformVar; }
 
 private:
-    const char* fXformMatrix;
+    GrGLSLProgramDataManager::UniformHandle fGamutXformVar;
+    bool fValid;
 };
 
 #endif
diff --git a/src/gpu/glsl/GrGLSLShaderBuilder.cpp b/src/gpu/glsl/GrGLSLShaderBuilder.cpp
index 17f7f10287..865876611a 100644
--- a/src/gpu/glsl/GrGLSLShaderBuilder.cpp
+++ b/src/gpu/glsl/GrGLSLShaderBuilder.cpp
@@ -91,7 +91,7 @@ void GrGLSLShaderBuilder::appendTextureLookup(SamplerHandle samplerHandle,
                                               const char* coordName,
                                               GrSLType varyingType,
                                               GrGLSLColorSpaceXformHelper* colorXformHelper) {
-    if (colorXformHelper && colorXformHelper->getXformMatrix()) {
+    if (colorXformHelper && colorXformHelper->isValid()) {
         // With a color gamut transform, we need to wrap the lookup in another function call
         SkString lookup;
         this->appendTextureLookup(&lookup, samplerHandle, coordName, varyingType);
@@ -109,7 +109,7 @@ void GrGLSLShaderBuilder::appendTextureLookupAndModulate(
                                                     GrGLSLColorSpaceXformHelper* colorXformHelper) {
     SkString lookup;
     this->appendTextureLookup(&lookup, samplerHandle, coordName, varyingType);
-    if (colorXformHelper && colorXformHelper->getXformMatrix()) {
+    if (colorXformHelper && colorXformHelper->isValid()) {
         SkString xform;
         this->appendColorGamutXform(&xform, lookup.c_str(), colorXformHelper);
         this->codeAppend((GrGLSLExpr4(modulation) * GrGLSLExpr4(xform)).c_str());
@@ -141,8 +141,9 @@ void GrGLSLShaderBuilder::appendColorGamutXform(SkString* out,
                        functionBody.c_str(),
                        &colorGamutXformFuncName);
 
+    GrGLSLUniformHandler* uniformHandler = fProgramBuilder->uniformHandler();
     out->appendf("%s(%s, %s)", colorGamutXformFuncName.c_str(), srcColor,
-                 colorXformHelper->getXformMatrix());
+                 uniformHandler->getUniformCStr(colorXformHelper->gamutXformUniform()));
 }
 
 void GrGLSLShaderBuilder::appendColorGamutXform(const char* srcColor,