fix for perf regression on ugamsolutions / msaa16

src/gpu/GrBatchFontCache.h

 /*
  * Copyright 2015 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef GrBatchFontCache_DEFINED
 #define GrBatchFontCache_DEFINED
 
@@ skipping 57 matching lines @@
     int fAtlasedGlyphs;
 
     GrGlyph* generateGlyph(GrGlyph::PackedID packed, GrFontScaler* scaler);
 
     friend class GrBatchFontCache;
 };
 
 /*
  * GrBatchFontCache manages strikes which are indexed by a GrFontScaler.  These strikes can then be
  * used to individual Glyph Masks.  The GrBatchFontCache also manages GrBatchAtlases, though this is
- * more or less transparent to the client(aside from atlasGeneration, described below)
+ * more or less transparent to the client(aside from atlasGeneration, described below).
+ * Note - we used to initialize the backing atlas for the GrBatchFontCache at initialization time.
+ * However, this caused a regression, even when the GrBatchFontCache was unused.  We now initialize
+ * the backing atlases lazily.  Its not immediately clear why this improves the situation.
  */
 class GrBatchFontCache {
 public:
-    GrBatchFontCache();
+    GrBatchFontCache(GrContext*);
     ~GrBatchFontCache();
 
-    // Initializes the GrBatchFontCache on the owning GrContext
-    void init(GrContext*);
-
     inline GrBatchTextStrike* getStrike(GrFontScaler* scaler) {
-
         GrBatchTextStrike* strike = fCache.find(*(scaler->getKey()));
         if (NULL == strike) {
             strike = this->generateStrike(scaler);
         }
         return strike;
     }
 
-    bool hasGlyph(GrGlyph* glyph);
+    void freeAll();
+
+    // if getTexture returns NULL, the client must not try to use other functions on the
+    // GrBatchFontCache which use the atlas.  This function *must* be called first, before other
+    // functions which use the atlas.
+    GrTexture* getTexture(GrMaskFormat format) {
+        if (this->initAtlas(format)) {
+            return this->getAtlas(format)->getTexture();
+        }
+        return NULL;
+    }
+
+    bool hasGlyph(GrGlyph* glyph) {
+        SkASSERT(glyph);
+        return this->getAtlas(glyph->fMaskFormat)->hasID(glyph->fID);
+    }
 
     // To ensure the GrBatchAtlas does not evict the Glyph Mask from its texture backing store,
     // the client must pass in the currentToken from the GrBatchTarget along with the GrGlyph.
     // A BulkUseTokenUpdater is used to manage bulk last use token updating in the Atlas.
     // For convenience, this function will also set the use token for the current glyph if required
     // NOTE: the bulk uploader is only valid if the subrun has a valid atlasGeneration
-    void addGlyphToBulkAndSetUseToken(GrBatchAtlas::BulkUseTokenUpdater*, GrGlyph*,
-                                      GrBatchAtlas::BatchToken);
+    void addGlyphToBulkAndSetUseToken(GrBatchAtlas::BulkUseTokenUpdater* updater,
+                                      GrGlyph* glyph, GrBatchAtlas::BatchToken token) {
+        SkASSERT(glyph);
+        updater->add(glyph->fID);
+        this->getAtlas(glyph->fMaskFormat)->setLastUseToken(glyph->fID, token);
+    }
 
-    void setUseTokenBulk(const GrBatchAtlas::BulkUseTokenUpdater&, GrBatchAtlas::BatchToken,
-                         GrMaskFormat);
+    void setUseTokenBulk(const GrBatchAtlas::BulkUseTokenUpdater& updater,
+                         GrBatchAtlas::BatchToken token,
+                         GrMaskFormat format) {
+        this->getAtlas(format)->setLastUseTokenBulk(updater, token);
+    }
 
     // add to texture atlas that matches this format
-    bool addToAtlas(GrBatchTextStrike*, GrBatchAtlas::AtlasID*, GrBatchTarget*,
-                    GrMaskFormat, int width, int height, const void* image,
-                    SkIPoint16* loc);
+    bool addToAtlas(GrBatchTextStrike* strike, GrBatchAtlas::AtlasID* id,
+                    GrBatchTarget* batchTarget,
+                    GrMaskFormat format, int width, int height, const void* image,
+                    SkIPoint16* loc) {
+        fPreserveStrike = strike;
+        return this->getAtlas(format)->addToAtlas(id, batchTarget, width, height, image, loc);
+    }
 
     // Some clients may wish to verify the integrity of the texture backing store of the
     // GrBatchAtlas.  The atlasGeneration returned below is a monitonically increasing number which
     // changes everytime something is removed from the texture backing store.
-    uint64_t atlasGeneration(GrMaskFormat) const;
+    uint64_t atlasGeneration(GrMaskFormat format) const {
+        return this->getAtlas(format)->atlasGeneration();
+    }
 
-    void freeAll();
-
-    GrTexture* getTexture(GrMaskFormat);
     GrPixelConfig getPixelConfig(GrMaskFormat) const;
 
     void dump() const;
 
 private:
     // There is a 1:1 mapping between GrMaskFormats and atlas indices
-    static int MaskFormatToAtlasIndex(GrMaskFormat);
-    static GrMaskFormat AtlasIndexToMaskFormat(int atlasIndex);
+    static int MaskFormatToAtlasIndex(GrMaskFormat format) {
+        static const int sAtlasIndices[] = {
+            kA8_GrMaskFormat,
+            kA565_GrMaskFormat,
+            kARGB_GrMaskFormat,
+        };
+        SK_COMPILE_ASSERT(SK_ARRAY_COUNT(sAtlasIndices) == kMaskFormatCount, array_size_mismatch);
 
-    GrBatchTextStrike* generateStrike(GrFontScaler*);
+        SkASSERT(sAtlasIndices[format] < kMaskFormatCount);
+        return sAtlasIndices[format];
+    }
 
-    inline GrBatchAtlas* getAtlas(GrMaskFormat) const;
+    bool initAtlas(GrMaskFormat);
+
+    GrBatchTextStrike* generateStrike(GrFontScaler* scaler) {
+        GrBatchTextStrike* strike = SkNEW_ARGS(GrBatchTextStrike, (this, scaler->getKey()));
+        fCache.add(strike);
+        return strike;
+    }
+
+    GrBatchAtlas* getAtlas(GrMaskFormat format) const {
+        int atlasIndex = MaskFormatToAtlasIndex(format);
+        SkASSERT(fAtlases[atlasIndex]);
+        return fAtlases[atlasIndex];
+    }
 
     static void HandleEviction(GrBatchAtlas::AtlasID, void*);
 
+    GrContext* fContext;
     SkTDynamicHash<GrBatchTextStrike, GrFontDescKey> fCache;
-
     GrBatchAtlas* fAtlases[kMaskFormatCount];
     GrBatchTextStrike* fPreserveStrike;
 };
 
 #endif