FBFetch refactor + arm support

src/gpu/gl/GrGLCaps.cpp

Index: src/gpu/gl/GrGLCaps.cpp
diff --git a/src/gpu/gl/GrGLCaps.cpp b/src/gpu/gl/GrGLCaps.cpp
index 8474873ffff5d937f5edc2084e67e0bc5002ac17..6ee3bb527e610f422c1e45652254435655dca88b 100644
--- a/src/gpu/gl/GrGLCaps.cpp
+++ b/src/gpu/gl/GrGLCaps.cpp
@@ -22,7 +22,6 @@ void GrGLCaps::reset() {
     fStencilFormats.reset();
     fStencilVerifiedColorConfigs.reset();
     fMSFBOType = kNone_MSFBOType;
-    fFBFetchType = kNone_FBFetchType;
     fInvalidateFBType = kNone_InvalidateFBType;
     fLATCAlias = kLATC_LATCAlias;
     fMapBufferType = kNone_MapBufferType;
@@ -48,6 +47,9 @@ void GrGLCaps::reset() {
     fIsCoreProfile = false;
     fFullClearIsFree = false;
     fDropsTileOnZeroDivide = false;
+    fFBFetchSupport = false;
+    fFBFetchColorName = NULL;
+    fFBFetchExtensionString = NULL;
 }
 
 GrGLCaps::GrGLCaps(const GrGLCaps& caps) : GrDrawTargetCaps() {
@@ -65,7 +67,6 @@ GrGLCaps& GrGLCaps::operator= (const GrGLCaps& caps) {
     fMaxFragmentTextureUnits = caps.fMaxFragmentTextureUnits;
     fMaxFixedFunctionTextureCoords = caps.fMaxFixedFunctionTextureCoords;
     fMSFBOType = caps.fMSFBOType;
-    fFBFetchType = caps.fFBFetchType;
     fInvalidateFBType = caps.fInvalidateFBType;
     fMapBufferType = caps.fMapBufferType;
     fRGBA8RenderbufferSupport = caps.fRGBA8RenderbufferSupport;
@@ -86,6 +87,9 @@ GrGLCaps& GrGLCaps::operator= (const GrGLCaps& caps) {
     fIsCoreProfile = caps.fIsCoreProfile;
     fFullClearIsFree = caps.fFullClearIsFree;
     fDropsTileOnZeroDivide = caps.fDropsTileOnZeroDivide;
+    fFBFetchSupport = caps.fFBFetchSupport;
+    fFBFetchColorName = caps.fFBFetchColorName;
+    fFBFetchExtensionString = caps.fFBFetchExtensionString;
 
     return *this;
 }
@@ -233,9 +237,19 @@ bool GrGLCaps::init(const GrGLContextInfo& ctxInfo, const GrGLInterface* gli) {
 
     if (kGLES_GrGLStandard == standard) {
         if (ctxInfo.hasExtension("GL_EXT_shader_framebuffer_fetch")) {
-            fFBFetchType = kEXT_FBFetchType;
+            fFBFetchSupport = true;
+            fFBFetchColorName = "gl_LastFragData[0]";
+            fFBFetchExtensionString = "GL_EXT_shader_framebuffer_fetch";
         } else if (ctxInfo.hasExtension("GL_NV_shader_framebuffer_fetch")) {
-            fFBFetchType = kNV_FBFetchType;
+            fFBFetchSupport = true;
+            fFBFetchColorName = "gl_LastFragData[0]";
+            fFBFetchExtensionString = "GL_NV_shader_framebuffer_fetch";
+        } else if (ctxInfo.hasExtension("GL_ARM_shader_framebuffer_fetch")) {
+            // The arm extension also requires an additional flag which we will set onResetContext
+            // This is all temporary.
+            fFBFetchSupport = true;
+            fFBFetchColorName = "gl_LastFragColorARM";
+            fFBFetchExtensionString = "GL_ARM_shader_framebuffer_fetch";
         }
     }
 
@@ -335,7 +349,8 @@ bool GrGLCaps::init(const GrGLContextInfo& ctxInfo, const GrGLInterface* gli) {
 
     fGpuTracingSupport = ctxInfo.hasExtension("GL_EXT_debug_marker");
 
-    fDstReadInShaderSupport = kNone_FBFetchType != fFBFetchType;
+    // For now these two are equivalent but we could have dst read in shader via some other method
+    fDstReadInShaderSupport = fFBFetchSupport;
 
     // Disable scratch texture reuse on Mali and Adreno devices
     fReuseScratchTextures = kARM_GrGLVendor != ctxInfo.vendor() &&
@@ -775,16 +790,6 @@ SkString GrGLCaps::dump() const {
     GR_STATIC_ASSERT(6 == kES_EXT_MsToTexture_MSFBOType);
     GR_STATIC_ASSERT(SK_ARRAY_COUNT(kMSFBOExtStr) == kLast_MSFBOType + 1);
 
-    static const char* kFBFetchTypeStr[] = {
-        "None",
-        "EXT",
-        "NV",
-    };
-    GR_STATIC_ASSERT(0 == kNone_FBFetchType);
-    GR_STATIC_ASSERT(1 == kEXT_FBFetchType);
-    GR_STATIC_ASSERT(2 == kNV_FBFetchType);
-    GR_STATIC_ASSERT(SK_ARRAY_COUNT(kFBFetchTypeStr) == kLast_FBFetchType + 1);
-
     static const char* kInvalidateFBTypeStr[] = {
         "None",
         "Discard",
@@ -809,7 +814,7 @@ SkString GrGLCaps::dump() const {
 
     r.appendf("Core Profile: %s\n", (fIsCoreProfile ? "YES" : "NO"));
     r.appendf("MSAA Type: %s\n", kMSFBOExtStr[fMSFBOType]);
-    r.appendf("FB Fetch Type: %s\n", kFBFetchTypeStr[fFBFetchType]);
+    r.appendf("FB Fetch Support: %s\n", (fFBFetchSupport ? "YES" : "NO"));
     r.appendf("Invalidate FB Type: %s\n", kInvalidateFBTypeStr[fInvalidateFBType]);
     r.appendf("Map Buffer Type: %s\n", kMapBufferTypeStr[fMapBufferType]);
     r.appendf("Max FS Uniform Vectors: %d\n", fMaxFragmentUniformVectors);