Implement support for mixed sampled render targets

src/gpu/gl/GrGLGpu.cpp

Index: src/gpu/gl/GrGLGpu.cpp
diff --git a/src/gpu/gl/GrGLGpu.cpp b/src/gpu/gl/GrGLGpu.cpp
index 08e83ec197c59b03362d7a08a17d7005cdad2c1e..960285c4b55566e8ddc10e5973b0a5249ce70712 100644
--- a/src/gpu/gl/GrGLGpu.cpp
+++ b/src/gpu/gl/GrGLGpu.cpp
@@ -373,6 +373,7 @@ void GrGLGpu::onResetContext(uint32_t resetBits) {
 
     if (resetBits & kMSAAEnable_GrGLBackendState) {
         fMSAAEnabled = kUnknown_TriState;
+        GL_CALL(CoverageModulation(GR_GL_RGBA));

[Chris Dalton, 2015/06/10 19:52:39]

We need to wrap this in a check for mixedSamplesSupport().

A comment about what it does and why it's ok to call it here seems fitting as
well.

     }
 
     fHWActiveTextureUnitIdx = -1; // invalid
@@ -504,6 +505,11 @@ GrRenderTarget* GrGLGpu::onWrapBackendRenderTarget(const GrBackendRenderTargetDe
     idDesc.fRTFBOID = static_cast<GrGLuint>(wrapDesc.fRenderTargetHandle);
     idDesc.fMSColorRenderbufferID = 0;
     idDesc.fTexFBOID = GrGLRenderTarget::kUnresolvableFBOID;
+    idDesc.fSampleConfig = ((wrapDesc.fFlags & kStencilMSAAOnly_GrBackendRenderTargetFlags) &&
+                            this->caps()->shaderCaps()->mixedSamplesSupport()) ?
+                           GrRenderTarget::kStencil_SampleConfig :
+                           GrRenderTarget::kUnified_SampleConfig;

[Chris Dalton, 2015/06/10 19:52:39]

If we block the mixed samples due to it not being supported, then we need to set
the sample count to zero as well. Otherwise it will render as if both the color
and stencil buffers are multisampled.

[Chris Dalton, 2015/06/10 20:55:56]

Looks like we're taking out kStencilMSAAOnly_GrBackendRenderTargetFlags so we
can ignore that last comment. Mixed samples just won't be supported with backend
RTs.

+
     idDesc.fLifeCycle = GrGpuResource::kWrapped_LifeCycle;
 
     GrSurfaceDesc desc;
@@ -851,6 +857,7 @@ static bool renderbuffer_storage_msaa(const GrGLContext& ctx,
     switch (ctx.caps()->msFBOType()) {
         case GrGLCaps::kDesktop_ARB_MSFBOType:
         case GrGLCaps::kDesktop_EXT_MSFBOType:
+        case GrGLCaps::kMixedSamples_MSFBOType:
         case GrGLCaps::kES_3_0_MSFBOType:
             GL_ALLOC_CALL(ctx.interface(),
                             RenderbufferStorageMultisample(GR_GL_RENDERBUFFER,
@@ -888,6 +895,9 @@ bool GrGLGpu::createRenderTargetObjects(const GrSurfaceDesc& desc,
     idDesc->fRTFBOID = 0;
     idDesc->fTexFBOID = 0;
     idDesc->fLifeCycle = lifeCycle;
+    idDesc->fSampleConfig = GrGLCaps::kMixedSamples_MSFBOType ==
+                            this->glCaps().msFBOType() ? GrRenderTarget::kStencil_SampleConfig :
+                                                         GrRenderTarget::kUnified_SampleConfig;
 
     GrGLenum status;
 
@@ -1170,7 +1180,7 @@ bool GrGLGpu::createStencilAttachmentForRenderTarget(GrRenderTarget* rt, int wid
     SkASSERT(width >= rt->width());
     SkASSERT(height >= rt->height());
 
-    int samples = rt->numSamples();
+    int samples = rt->numStencilSamples();
     GrGLStencilAttachment::IDDesc sbDesc;
 
     int stencilFmtCnt = this->glCaps().stencilFormats().count();
@@ -2090,7 +2100,7 @@ void GrGLGpu::flushStencil(const GrStencilSettings& stencilSettings) {
 }
 
 void GrGLGpu::flushHWAAState(GrRenderTarget* rt, bool useHWAA) {
-    SkASSERT(!useHWAA || rt->isMultisampled());
+    SkASSERT(!useHWAA || rt->isStencilBufferMultisampled());
 
     if (this->glCaps().multisampleDisableSupport()) {
         if (useHWAA) {