Add "sample locations" feature to GrProcessor

src/gpu/GrCaps.cpp

Index: src/gpu/GrCaps.cpp
diff --git a/src/gpu/GrCaps.cpp b/src/gpu/GrCaps.cpp
index c544d6ef772fa979ba2bb01e402c54ba7e217c82..417f7b4e7917248d07b2d29cff3ed9dcf097a58e 100644
--- a/src/gpu/GrCaps.cpp
+++ b/src/gpu/GrCaps.cpp
@@ -80,7 +80,7 @@ void GrShaderCaps::applyOptionsOverrides(const GrContextOptions& options) {
 
 ///////////////////////////////////////////////////////////////////////////////
 
-GrCaps::GrCaps(const GrContextOptions& options) {
+GrCaps::GrCaps(const GrContextOptions& options) : fMultisampleSpecsAllocator(1) {
     fMipMapSupport = false;
     fNPOTTextureTileSupport = false;
     fTwoSidedStencilSupport = false;
@@ -132,6 +132,68 @@ void GrCaps::applyOptionsOverrides(const GrContextOptions& options) {
     this->onApplyOptionsOverrides(options);
 }
 
+inline static uint8_t multisample_specs_id(uint8_t numSamples, GrSurfaceOrigin origin,
+                                           const GrCaps& caps) {
+    if (!caps.sampleLocationsSupport()) {
+        return numSamples;
+    }
+
+    SkASSERT(numSamples < 128);
+    SkASSERT(kTopLeft_GrSurfaceOrigin == origin || kBottomLeft_GrSurfaceOrigin == origin);
+    return (numSamples << 1) | (origin - 1);
+
+    GR_STATIC_ASSERT(1 == kTopLeft_GrSurfaceOrigin);
+    GR_STATIC_ASSERT(2 == kBottomLeft_GrSurfaceOrigin);
+}
+
+const GrCaps::MultisampleSpecs&
+GrCaps::getMultisampleSpecs(const GrSurfaceDesc& desc,
+                            const QueryMultisampleFunctor& queryMultisample) const {
+    uint8_t surfDescKey = multisample_specs_id(desc.fSampleCnt, desc.fOrigin, *this);
+    if (fMultisampleSpecsMap.count() > surfDescKey && fMultisampleSpecsMap[surfDescKey]) {
+#if !defined(SK_DEBUG)
+        // In debug mode we query the multisample info every time and verify the caching is correct.
+        return *fMultisampleSpecsMap[surfDescKey];
+#endif
+    }
+    int effectiveSampleCnt;
+    SkAutoTDeleteArray<SkPoint> locations(nullptr);
+    queryMultisample(&effectiveSampleCnt, &locations);
+    SkASSERT(effectiveSampleCnt && effectiveSampleCnt >= desc.fSampleCnt);
+    uint8_t effectiveKey = multisample_specs_id(effectiveSampleCnt, desc.fOrigin, *this);
+    if (fMultisampleSpecsMap.count() > effectiveKey && fMultisampleSpecsMap[effectiveKey]) {
+        const MultisampleSpecs& specs = *fMultisampleSpecsMap[effectiveKey];
+        SkASSERT(effectiveKey == specs.fUniqueID);
+        SkASSERT(effectiveSampleCnt == specs.fEffectiveSampleCnt);
+        SkASSERT(!this->sampleLocationsSupport() || !memcmp(locations.get(),
+                                                            specs.fSampleLocations.get(),
+                                                            effectiveSampleCnt * sizeof(SkPoint)));
+        SkASSERT(surfDescKey <= effectiveKey);
+        SkASSERT(!fMultisampleSpecsMap[surfDescKey] || fMultisampleSpecsMap[surfDescKey] == &specs);
+        fMultisampleSpecsMap[surfDescKey] = &specs;
+        return specs;
+    }
+    const MultisampleSpecs& specs = *new (&fMultisampleSpecsAllocator)
+        MultisampleSpecs{effectiveKey, effectiveSampleCnt, locations.detach()};
+    if (fMultisampleSpecsMap.count() <= effectiveKey) {
+        int n = 1 + effectiveKey - fMultisampleSpecsMap.count();
+        fMultisampleSpecsMap.push_back_n(n, (const MultisampleSpecs*) nullptr);
+    }
+    fMultisampleSpecsMap[effectiveKey] = &specs;
+    if (effectiveSampleCnt != desc.fSampleCnt) {
+        SkASSERT(surfDescKey < effectiveKey);
+        fMultisampleSpecsMap[surfDescKey] = &specs;
+    }
+    return specs;
+}
+
+const GrCaps::MultisampleSpecs& GrCaps::getMultisampleSpecs(uint8_t uniqueID) const {
+    SkASSERT(fMultisampleSpecsMap.count() > uniqueID && fMultisampleSpecsMap[uniqueID]);
+    const MultisampleSpecs& specs = *fMultisampleSpecsMap[uniqueID];
+    SkASSERT(specs.fUniqueID == uniqueID);
+    return specs;
+}
+
 static SkString map_flags_to_string(uint32_t flags) {
     SkString str;
     if (GrCaps::kNone_MapFlags == flags) {