Fix mixed samples stencil clip

src/gpu/GrClipMaskManager.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 "GrClipMaskManager.h"
 #include "GrCaps.h"
 #include "GrDrawingManager.h"
@@ skipping 350 matching lines @@
             if (nullptr == devBounds ||
                 !SkRect::Make(scissorSpaceIBounds).contains(*devBounds)) {
                 out->fScissorState.set(scissorSpaceIBounds);
             }
             this->setPipelineBuilderStencil(pipelineBuilder, ars);
             out->fClipCoverageFP.reset(clipFP);
             return true;
         }
     }
 
-    // If MSAA is enabled we can do everything in the stencil buffer.
-    if (0 == rt->numStencilSamples() && requiresAA) {
+    SkASSERT(!pipelineBuilder.isHWAntialias() || rt->isStencilBufferMultisampled());
+
+    bool hasHWAntialias = pipelineBuilder.isHWAntialias();
+
+    if (rt->isStencilBufferMultisampled() && !hasHWAntialias) {
+        if (!this->caps()->multisampleDisableSupport()) {
+            hasHWAntialias = true; // This will be on regardless, it's impossible to turn it off.
+        } else if (this->caps()->programmableSampleLocationsSupport()) {
+            // Enable HW antialias, but leave the draw non-antialiased by co-centering the samples.
+            out->fIsCoCenteredMultisampledDraw = true;
+            hasHWAntialias = true;
+        }
+    }
+
+    // If we have HW antialias, or don't need AA, we can do everything in the stencil buffer.
+    if (!hasHWAntialias && requiresAA) {
         SkAutoTUnref<GrTexture> result;
 
         // The top-left of the mask corresponds to the top-left corner of the bounds.
         SkVector clipToMaskOffset = {
             SkIntToScalar(-clipSpaceIBounds.fLeft),
             SkIntToScalar(-clipSpaceIBounds.fTop)
         };
 
         if (this->useSWOnlyPath(pipelineBuilder, rt, clipToMaskOffset, elements)) {
             // The clip geometry is complex enough that it will be more efficient to create it
@@ skipping 713 matching lines @@
 
 ////////////////////////////////////////////////////////////////////////////////
 
 void GrClipMaskManager::adjustPathStencilParams(const GrStencilAttachment* stencilAttachment,
                                                 GrStencilSettings* settings) {
     if (stencilAttachment) {
         int stencilBits = stencilAttachment->bits();
         this->adjustStencilParams(settings, fClipMode, stencilBits);
     }
 }