1 files changed, 43 insertions, 0 deletions
diff --git a/src/gpu/GrGpu.cpp b/src/gpu/GrGpu.cpp
index a8b022a36d..eb005d110a 100644
--- a/src/gpu/GrGpu.cpp
+++ b/src/gpu/GrGpu.cpp
@@ -36,6 +36,7 @@ GrGpu::GrGpu(GrContext* context)
     : fResetTimestamp(kExpiredTimestamp+1)
     , fResetBits(kAll_GrBackendState)
     , fContext(context) {
+    fMultisampleSpecs.emplace_back(0, 0, nullptr); // Index 0 is an invalid unique id.
 }
 
 GrGpu::~GrGpu() {}
@@ -422,6 +423,48 @@ void GrGpu::didWriteToSurface(GrSurface* surface, const SkIRect* bounds, uint32_
     }
 }
 
+const GrGpu::MultisampleSpecs& GrGpu::queryMultisampleSpecs(const GrPipeline& pipeline) {
+    GrRenderTarget* rt = pipeline.renderTarget();
+    SkASSERT(rt->numStencilSamples() > 1);
+
+    GrStencilSettings stencil;
+    if (pipeline.isStencilEnabled()) {
+        // TODO: attach stencil and create settings during render target flush.
+        SkASSERT(rt->renderTargetPriv().getStencilAttachment());
+        stencil.reset(*pipeline.getUserStencil(), pipeline.hasStencilClip(),
+                      rt->renderTargetPriv().numStencilBits());
+    }
+
+    int effectiveSampleCnt;
+    SkSTArray<16, SkPoint, true> pattern;
+    this->onQueryMultisampleSpecs(rt, pipeline.proxy()->origin(), stencil,
+                                  &effectiveSampleCnt, &pattern);
+    SkASSERT(effectiveSampleCnt >= rt->numStencilSamples());
+
+    uint8_t id;
+    if (this->caps()->sampleLocationsSupport()) {
+        SkASSERT(pattern.count() == effectiveSampleCnt);
+        const auto& insertResult = fMultisampleSpecsIdMap.insert(
+            MultisampleSpecsIdMap::value_type(pattern, SkTMin(fMultisampleSpecs.count(), 255)));
+        id = insertResult.first->second;
+        if (insertResult.second) {
+            // This means the insert did not find the pattern in the map already, and therefore an
+            // actual insertion took place. (We don't expect to see many unique sample patterns.)
+            const SkPoint* sampleLocations = insertResult.first->first.begin();
+            SkASSERT(id == fMultisampleSpecs.count());
+            fMultisampleSpecs.emplace_back(id, effectiveSampleCnt, sampleLocations);
+        }
+    } else {
+        id = effectiveSampleCnt;
+        for (int i = fMultisampleSpecs.count(); i <= id; ++i) {
+            fMultisampleSpecs.emplace_back(i, i, nullptr);
+        }
+    }
+    SkASSERT(id > 0);
+
+    return fMultisampleSpecs[id];
+}
+
 bool GrGpu::SamplePatternComparator::operator()(const SamplePattern& a,
                                                 const SamplePattern& b) const {
     if (a.count() != b.count()) {