Restore text vertex buffer alloc and other optimizations.

Modifies the fontcache GM to ensure that the font cache is forced to flush.

Committed: https://skia.googlesource.com/skia/+/9c3d24b9d1ba3d955094ff0cb1ba2d11e1c1adca

R=bsalomon@google.com, robertphillips@google.com

Author: jvanverth@google.com

Review URL: https://codereview.chromium.org/466363009
diff --git a/src/gpu/GrDistanceFieldTextContext.cpp b/src/gpu/GrDistanceFieldTextContext.cpp
index dc0ea95..429897d 100755
--- a/src/gpu/GrDistanceFieldTextContext.cpp
+++ b/src/gpu/GrDistanceFieldTextContext.cpp
@@ -60,24 +60,20 @@
 GrDistanceFieldTextContext::GrDistanceFieldTextContext(GrContext* context,
                                                        const SkDeviceProperties& properties,
                                                        bool enable)
-                                                    : GrTextContext(context, properties) {
+                                                    : GrTextContext(context, properties)
+                                                    , fStrike(NULL)
 #if SK_FORCE_DISTANCEFIELD_FONTS
-    fEnableDFRendering = true;
+                                                    , fEnableDFRendering(true)
 #else
-    fEnableDFRendering = enable;
+                                                    , fEnableDFRendering(enable)
 #endif
-    fStrike = NULL;
-    fGammaTexture = NULL;
-
-    fCurrTexture = NULL;
-    fCurrVertex = 0;
-    fEffectTextureUniqueID = SK_InvalidUniqueID;
-    fEffectColor = GrColor_ILLEGAL;
-    fEffectFlags = 0;
-
-    fVertices = NULL;
-    fMaxVertices = 0;
-
+                                                    , fEffectTextureUniqueID(SK_InvalidUniqueID)
+                                                    , fEffectColor(GrColor_ILLEGAL)
+                                                    , fEffectFlags(0)
+                                                    , fGammaTexture(NULL)
+                                                    , fVertices(NULL)
+                                                    , fVertexCount(0)
+                                                    , fCurrVertex(0) {
     fVertexBounds.setLargestInverted();
 }
 
@@ -126,7 +122,9 @@
     GrTextureParams params(SkShader::kRepeat_TileMode, GrTextureParams::kBilerp_FilterMode);
     GrTextureParams gammaParams(SkShader::kClamp_TileMode, GrTextureParams::kNone_FilterMode);
     
-    uint32_t textureUniqueID = fCurrTexture->getUniqueID();
+    GrTexture* currTexture = fStrike->getTexture();
+    SkASSERT(currTexture);
+    uint32_t textureUniqueID = currTexture->getUniqueID();
     
     // set up any flags
     uint32_t flags = 0;
@@ -144,7 +142,7 @@
         flags != fEffectFlags) {
         if (fUseLCDText) {
             GrColor colorNoPreMul = skcolor_to_grcolor_nopremultiply(filteredColor);
-            fCachedEffect.reset(GrDistanceFieldLCDTextureEffect::Create(fCurrTexture,
+            fCachedEffect.reset(GrDistanceFieldLCDTextureEffect::Create(currTexture,
                                                                         params,
                                                                         fGammaTexture,
                                                                         gammaParams,
@@ -154,14 +152,14 @@
 #ifdef SK_GAMMA_APPLY_TO_A8
             U8CPU lum = SkColorSpaceLuminance::computeLuminance(fDeviceProperties.fGamma,
                                                                 filteredColor);
-            fCachedEffect.reset(GrDistanceFieldTextureEffect::Create(fCurrTexture,
+            fCachedEffect.reset(GrDistanceFieldTextureEffect::Create(currTexture,
                                                                      params,
                                                                      fGammaTexture,
                                                                      gammaParams,
                                                                      lum/255.f,
                                                                      flags));
 #else
-            fCachedEffect.reset(GrDistanceFieldTextureEffect::Create(fCurrTexture,
+            fCachedEffect.reset(GrDistanceFieldTextureEffect::Create(currTexture,
                                                                      params, flags));
 #endif
         }
@@ -230,26 +228,17 @@
         fDrawTarget->drawIndexedInstances(kTriangles_GrPrimitiveType,
                                           nGlyphs,
                                           4, 6, &fVertexBounds);
-        fDrawTarget->resetVertexSource();
-        fVertices = NULL;
-        fMaxVertices = 0;
         fCurrVertex = 0;
-        SkSafeSetNull(fCurrTexture);
         fVertexBounds.setLargestInverted();
     }
+    
+    fDrawTarget->resetVertexSource();
+    fVertices = NULL;
 }
 
 void GrDistanceFieldTextContext::drawPackedGlyph(GrGlyph::PackedID packed,
                                                  SkFixed vx, SkFixed vy,
                                                  GrFontScaler* scaler) {
-    if (NULL == fDrawTarget) {
-        return;
-    }
-    
-    if (NULL == fStrike) {
-        fStrike = fContext->getFontCache()->getStrike(scaler, true);
-    }
-    
     GrGlyph* glyph = fStrike->getGlyph(packed, scaler);
     if (NULL == glyph || glyph->fBounds.isEmpty()) {
         return;
@@ -293,10 +282,19 @@
 #endif
         }
 
-        // before we purge the cache, we must flush any accumulated draws
+        // flush any accumulated draws to allow us to free up a plot
+        int remainingVertexCount = fVertexCount - fCurrVertex;
         this->flushGlyphs();
         fContext->flush();
 
+        // need to reallocate the vertex buffer for the remaining glyphs
+        fVertexCount = remainingVertexCount;
+        bool success = fDrawTarget->reserveVertexAndIndexSpace(fVertexCount,
+                                                               0,
+                                                               &fVertices,
+                                                               NULL);
+        GrAlwaysAssert(success);
+
         // we should have an unused plot now
         if (fContext->getFontCache()->freeUnusedPlot(fStrike) &&
             fStrike->addGlyphToAtlas(glyph, scaler)) {
@@ -332,59 +330,6 @@
     GrTexture* texture = glyph->fPlot->texture();
     SkASSERT(texture);
 
-    if (fCurrTexture != texture || fCurrVertex + 4 > fMaxVertices) {
-        this->flushGlyphs();
-        fCurrTexture = texture;
-        fCurrTexture->ref();
-    }
-
-    bool useColorVerts = !fUseLCDText;
-    
-    if (NULL == fVertices) {
-        // If we need to reserve vertices allow the draw target to suggest
-        // a number of verts to reserve and whether to perform a flush.
-        fMaxVertices = kMinRequestedVerts;
-        if (useColorVerts) {
-            fDrawTarget->drawState()->setVertexAttribs<gTextVertexWithColorAttribs>(
-                                                    SK_ARRAY_COUNT(gTextVertexWithColorAttribs),
-                                                    kTextVAColorSize);
-        } else {
-            fDrawTarget->drawState()->setVertexAttribs<gTextVertexAttribs>(
-                                                    SK_ARRAY_COUNT(gTextVertexAttribs),
-                                                    kTextVASize);
-        }
-        bool flush = fDrawTarget->geometryHints(&fMaxVertices, NULL);
-        if (flush) {
-            this->flushGlyphs();
-            fContext->flush();
-            if (useColorVerts) {
-                fDrawTarget->drawState()->setVertexAttribs<gTextVertexWithColorAttribs>(
-                                                    SK_ARRAY_COUNT(gTextVertexWithColorAttribs),
-                                                    kTextVAColorSize);
-            } else {
-                fDrawTarget->drawState()->setVertexAttribs<gTextVertexAttribs>(
-                                                    SK_ARRAY_COUNT(gTextVertexAttribs),
-                                                    kTextVASize);
-            }
-        }
-        fMaxVertices = kDefaultRequestedVerts;
-        // ignore return, no point in flushing again.
-        fDrawTarget->geometryHints(&fMaxVertices, NULL);
-        
-        int maxQuadVertices = 4 * fContext->getQuadIndexBuffer()->maxQuads();
-        if (fMaxVertices < kMinRequestedVerts) {
-            fMaxVertices = kDefaultRequestedVerts;
-        } else if (fMaxVertices > maxQuadVertices) {
-            // don't exceed the limit of the index buffer
-            fMaxVertices = maxQuadVertices;
-        }
-        bool success = fDrawTarget->reserveVertexAndIndexSpace(fMaxVertices,
-                                                               0,
-                                                               &fVertices,
-                                                               NULL);
-        GrAlwaysAssert(success);
-    }
-    
     SkScalar dx = SkIntToScalar(glyph->fBounds.fLeft + SK_DistanceFieldInset);
     SkScalar dy = SkIntToScalar(glyph->fBounds.fTop + SK_DistanceFieldInset);
     SkScalar width = SkIntToScalar(glyph->fBounds.width() - 2*SK_DistanceFieldInset);
@@ -397,7 +342,7 @@
     sy += dy;
     width *= scale;
     height *= scale;
-    
+
     SkFixed tx = SkIntToFixed(glyph->fAtlasLocation.fX + SK_DistanceFieldInset);
     SkFixed ty = SkIntToFixed(glyph->fAtlasLocation.fY + SK_DistanceFieldInset);
     SkFixed tw = SkIntToFixed(glyph->fBounds.width() - 2*SK_DistanceFieldInset);
@@ -428,7 +373,7 @@
                               SkFixedToFloat(texture->normalizeFixedX(tx + tw)),
                               SkFixedToFloat(texture->normalizeFixedY(ty + th)),
                               vertSize);
-    if (useColorVerts) {
+    if (!fUseLCDText) {
         if (0xFF == GrColorUnpackA(fPaint.getColor())) {
             fDrawTarget->drawState()->setHint(GrDrawState::kVertexColorsAreOpaque_Hint, true);
         }
@@ -518,6 +463,25 @@
     }
 }
 
+void GrDistanceFieldTextContext::allocateVertices(const char text[], size_t byteLength) {
+    SkASSERT(NULL == fVertices);
+    if (!fUseLCDText) {
+        fDrawTarget->drawState()->setVertexAttribs<gTextVertexWithColorAttribs>(
+                                                    SK_ARRAY_COUNT(gTextVertexWithColorAttribs),
+                                                    kTextVAColorSize);
+    } else {
+        fDrawTarget->drawState()->setVertexAttribs<gTextVertexAttribs>(
+                                                    SK_ARRAY_COUNT(gTextVertexAttribs),
+                                                    kTextVASize);
+    }
+    fVertexCount = 4*fSkPaint.textToGlyphs(text, byteLength, NULL);
+    bool success = fDrawTarget->reserveVertexAndIndexSpace(fVertexCount,
+                                                           0,
+                                                           &fVertices,
+                                                           NULL);
+    GrAlwaysAssert(success);
+}
+
 void GrDistanceFieldTextContext::drawText(const GrPaint& paint, const SkPaint& skPaint,
                                           const char text[], size_t byteLength,
                                           SkScalar x, SkScalar y) {
@@ -531,6 +495,10 @@
 
     this->init(paint, skPaint);
 
+    if (NULL == fDrawTarget) {
+        return;
+    }
+    
     SkScalar sizeRatio = fTextRatio;
 
     SkDrawCacheProc glyphCacheProc = fSkPaint.getDrawCacheProc();
@@ -538,9 +506,14 @@
     SkAutoGlyphCacheNoGamma    autoCache(fSkPaint, &fDeviceProperties, NULL);
     SkGlyphCache*              cache = autoCache.getCache();
     GrFontScaler*              fontScaler = GetGrFontScaler(cache);
+    if (NULL == fStrike) {
+        fStrike = fContext->getFontCache()->getStrike(fontScaler, true);
+    }
 
     setup_gamma_texture(fContext, cache, fDeviceProperties, &fGammaTexture);
 
+    this->allocateVertices(text, byteLength);
+
     // need to measure first
     // TODO - generate positions and pre-load cache as well?
     const char* stop = text + byteLength;
@@ -608,14 +581,23 @@
 
     this->init(paint, skPaint);
 
+    if (NULL == fDrawTarget) {
+        return;
+    }
+    
     SkDrawCacheProc glyphCacheProc = fSkPaint.getDrawCacheProc();
 
     SkAutoGlyphCacheNoGamma    autoCache(fSkPaint, &fDeviceProperties, NULL);
     SkGlyphCache*              cache = autoCache.getCache();
     GrFontScaler*              fontScaler = GetGrFontScaler(cache);
+    if (NULL == fStrike) {
+        fStrike = fContext->getFontCache()->getStrike(fontScaler, true);
+    }
 
     setup_gamma_texture(fContext, cache, fDeviceProperties, &fGammaTexture);
 
+    this->allocateVertices(text, byteLength);
+
     const char*        stop = text + byteLength;
 
     if (SkPaint::kLeft_Align == fSkPaint.getTextAlign()) {