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 fe52a540c6285a8637f1b5a540470592fc764b08..2597dd3a183f637bfe37a8f192b3a02dc15f4f89 100644
--- a/src/gpu/gl/GrGLCaps.cpp
+++ b/src/gpu/gl/GrGLCaps.cpp
@@ -770,6 +770,8 @@ 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 (ctxInfo.hasExtension("GL_NV_framebuffer_mixed_samples")) {
+            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")) {
@@ -780,7 +782,9 @@ void GrGLCaps::initFSAASupport(const GrGLContextInfo& ctxInfo, const GrGLInterfa
             fMSFBOType = kES_Apple_MSFBOType;
         }
     } else {
-        if ((ctxInfo.version() >= GR_GL_VER(3,0)) ||
+        if (ctxInfo.hasExtension("GL_NV_framebuffer_mixed_samples")) {

[Chris Dalton, 2015/04/08 04:55:26]

We may consider only using MixedSamples if the context also has nvpr, since
right now that's the only thing that actually uses it.

[vbuzinov, 2015/04/08 12:05:30]

Done.  Should the caps property (fFBMixedSamplesSupport) be set to false in such
a case too?  So that GrGLGpu doesn't call glCoverageModulation for nothing?

+            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") &&
@@ -992,6 +996,7 @@ SkString GrGLCaps::dump() const {
         "Apple",
         "IMG MS To Texture",
         "EXT MS To Texture",
+        "Stencil",

[Mark Kilgard, 2015/04/08 03:20:09]

Stencil doesn't seem sufficiently descriptive

would "MixedSamples" be a more descriptive string here?

that's more consistent with kMixedSamples_MSFBOType

[vbuzinov, 2015/04/08 12:05:30]

Done.

     };
     GR_STATIC_ASSERT(0 == kNone_MSFBOType);
     GR_STATIC_ASSERT(1 == kDesktop_ARB_MSFBOType);
@@ -1000,6 +1005,7 @@ 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[] = {