Implement support for mixed sampled render targets

src/gpu/gl/GrGLCaps.cpp

 /*
  * Copyright 2012 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 
 #include "GrGLCaps.h"
 
@@ skipping 752 matching lines @@
 void GrGLCaps::initFSAASupport(const GrGLContextInfo& ctxInfo, const GrGLInterface* gli) {
 
     fMSFBOType = kNone_MSFBOType;
     if (kGL_GrGLStandard != ctxInfo.standard()) {
         // We prefer the EXT/IMG extension over ES3 MSAA because we've observed
         // ES3 driver bugs on at least one device with a tiled GPU (N10).
         if (ctxInfo.hasExtension("GL_EXT_multisampled_render_to_texture")) {
             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")) {
             // chrome's extension is equivalent to the EXT msaa
             // and fbo_blit extensions.
             fMSFBOType = kDesktop_EXT_MSFBOType;
         } else if (ctxInfo.hasExtension("GL_APPLE_framebuffer_multisample")) {
             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") &&
                    ctxInfo.hasExtension("GL_EXT_framebuffer_blit")) {
             fMSFBOType = GrGLCaps::kDesktop_EXT_MSFBOType;
         }
     }
 }
 
 namespace {
@@ skipping 191 matching lines @@
     }
 
     static const char* kMSFBOExtStr[] = {
         "None",
         "ARB",
         "EXT",
         "ES 3.0",
         "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);
     GR_STATIC_ASSERT(2 == kDesktop_EXT_MSFBOType);
     GR_STATIC_ASSERT(3 == kES_3_0_MSFBOType);
     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[] = {
         "None",
         "Discard",
         "Invalidate",
     };
     GR_STATIC_ASSERT(0 == kNone_InvalidateFBType);
     GR_STATIC_ASSERT(1 == kDiscard_InvalidateFBType);
     GR_STATIC_ASSERT(2 == kInvalidate_InvalidateFBType);
@@ skipping 37 matching lines @@
     r.appendf("Two Format Limit: %s\n", (fTwoFormatLimit ? "YES": "NO"));
     r.appendf("Fragment coord conventions support: %s\n",
              (fFragCoordsConventionSupport ? "YES": "NO"));
     r.appendf("Vertex array object support: %s\n", (fVertexArrayObjectSupport ? "YES": "NO"));
     r.appendf("Use non-VBO for dynamic data: %s\n",
              (fUseNonVBOVertexAndIndexDynamicData ? "YES" : "NO"));
     r.appendf("Full screen clear is free: %s\n", (fFullClearIsFree ? "YES" : "NO"));
     r.appendf("Drops tile on zero divide: %s\n", (fDropsTileOnZeroDivide ? "YES" : "NO"));
     return r;
 }