Implement support for mixed sampled render targets

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 40405fd55c1549660127ce6b6ffc4951177b0a03..33973c5fea410b4132ff7d6eaec2875f525b4250 100644
--- a/src/gpu/gl/GrGLCaps.cpp
+++ b/src/gpu/gl/GrGLCaps.cpp
@@ -237,7 +237,7 @@ void GrGLCaps::init(const GrContextOptions& contextOptions,
         fES2CompatibilitySupport = true;
     }
 
-    if (kGL_GrGLStandard == standard) {
+    if (kGL_GrGLStandard == standard || fShaderCaps->mixedSamplesSupport()) {

[Chris Dalton, 2015/06/11 23:34:38]

This won't quite work. See below how mixed samples support isn't initialized
until after this line. (In fact, it checks fMultisampleDisableSupport when
deciding if we can use mixed samples :) My bad for suggesting we do it this way.

I think we should take out the mixedSamplesSupport check entirely. The reason
being, ES is already locked out from using mixed samples because it dosen't have
dual source blending. NVIDIA is actively working on extensions that allow both
disabling multisample and dual source blend on ES, so we can wait until those
specs are published.

In other words, leave this line as:

 if (kGL_GrGLStandard == standard) {

In the future, once the specs are finished, we can change the ES branch to:

 fMultisampleDisableSupport =
ctxInfo.hasExtension("GL_EXT_multisample_compatibility");

         fMultisampleDisableSupport = true;
     } else {
         fMultisampleDisableSupport = false;
@@ -789,6 +789,8 @@ void GrGLCaps::initFSAASupport(const GrGLContextInfo& ctxInfo, const GrGLInterfa
             fMSFBOType = kES_EXT_MsToTexture_MSFBOType;
         } else if (ctxInfo.hasExtension("GL_IMG_multisampled_render_to_texture")) {
             fMSFBOType = kES_IMG_MsToTexture_MSFBOType;
+        } else if (fShaderCaps->mixedSamplesSupport() && fShaderCaps->pathRenderingSupport()) {
+            fMSFBOType = kMixedSamples_MSFBOType;
         } else if (ctxInfo.version() >= GR_GL_VER(3,0)) {
             fMSFBOType = GrGLCaps::kES_3_0_MSFBOType;
         } else if (ctxInfo.hasExtension("GL_CHROMIUM_framebuffer_multisample")) {
@@ -799,7 +801,9 @@ void GrGLCaps::initFSAASupport(const GrGLContextInfo& ctxInfo, const GrGLInterfa
             fMSFBOType = kES_Apple_MSFBOType;
         }
     } else {
-        if ((ctxInfo.version() >= GR_GL_VER(3,0)) ||
+        if (fShaderCaps->mixedSamplesSupport() && fShaderCaps->pathRenderingSupport()) {
+            fMSFBOType = kMixedSamples_MSFBOType;
+        } else if ((ctxInfo.version() >= GR_GL_VER(3,0)) ||
             ctxInfo.hasExtension("GL_ARB_framebuffer_object")) {
             fMSFBOType = GrGLCaps::kDesktop_ARB_MSFBOType;
         } else if (ctxInfo.hasExtension("GL_EXT_framebuffer_multisample") &&
@@ -932,6 +936,7 @@ SkString GrGLCaps::dump() const {
         "Apple",
         "IMG MS To Texture",
         "EXT MS To Texture",
+        "MixedSamples",
     };
     GR_STATIC_ASSERT(0 == kNone_MSFBOType);
     GR_STATIC_ASSERT(1 == kDesktop_ARB_MSFBOType);
@@ -940,6 +945,7 @@ SkString GrGLCaps::dump() const {
     GR_STATIC_ASSERT(4 == kES_Apple_MSFBOType);
     GR_STATIC_ASSERT(5 == kES_IMG_MsToTexture_MSFBOType);
     GR_STATIC_ASSERT(6 == kES_EXT_MsToTexture_MSFBOType);
+    GR_STATIC_ASSERT(7 == kMixedSamples_MSFBOType);
     GR_STATIC_ASSERT(SK_ARRAY_COUNT(kMSFBOExtStr) == kLast_MSFBOType + 1);
 
     static const char* kInvalidateFBTypeStr[] = {