Allocate only the vertices we need for text.

src/gpu/GrDistanceFieldTextContext.cpp

 /*
  * Copyright 2013 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "GrDistanceFieldTextContext.h"
 #include "GrAtlas.h"
 #include "GrBitmapTextContext.h"
@@ skipping 38 matching lines @@
 
 // position + color + texture coord
 extern const GrVertexAttrib gTextVertexWithColorAttribs[] = {
     {kVec2f_GrVertexAttribType,  0,                                 kPosition_GrVertexAttribBinding},
     {kVec4ub_GrVertexAttribType, sizeof(SkPoint),                   kColor_GrVertexAttribBinding},
     {kVec2f_GrVertexAttribType,  sizeof(SkPoint) + sizeof(GrColor), kGeometryProcessor_GrVertexAttribBinding}
 };
     
 static const size_t kTextVAColorSize = 2 * sizeof(SkPoint) + sizeof(GrColor); 
 
+static const int kVerticesPerGlyph = 4;
+static const int kIndicesPerGlyph = 6;
 };
 
 GrDistanceFieldTextContext::GrDistanceFieldTextContext(GrContext* context,
                                                        const SkDeviceProperties& properties,
                                                        bool enable)
                                                     : GrTextContext(context, properties) {
 #if SK_FORCE_DISTANCEFIELD_FONTS
     fEnableDFRendering = true;
 #else
     fEnableDFRendering = enable;
 #endif
     fStrike = NULL;
     fGammaTexture = NULL;
 
-    fCurrTexture = NULL;
-    fCurrVertex = 0;
     fEffectTextureUniqueID = SK_InvalidUniqueID;
     fEffectColor = GrColor_ILLEGAL;
     fEffectFlags = 0;
 
     fVertices = NULL;
-    fMaxVertices = 0;
+    fCurrVertex = 0;
+    fAllocVertexCount = 0;
+    fTotalVertexCount = 0;
+    fCurrTexture = NULL;
 
     fVertexBounds.setLargestInverted();
 }
 
 GrDistanceFieldTextContext* GrDistanceFieldTextContext::Create(GrContext* context,
                                                                const SkDeviceProperties& props,
                                                                bool enable) {
     GrDistanceFieldTextContext* textContext = SkNEW_ARGS(GrDistanceFieldTextContext, 
                                                          (context, props, enable));
     textContext->fFallbackTextContext = GrBitmapTextContext::Create(context, props);
 
     return textContext;
 }
 
 GrDistanceFieldTextContext::~GrDistanceFieldTextContext() {
-    this->flush();
+    this->finish();
     SkSafeSetNull(fGammaTexture);
 }
 
 bool GrDistanceFieldTextContext::canDraw(const SkPaint& paint) {
     if (!fEnableDFRendering && !paint.isDistanceFieldTextTEMP()) {
         return false;
     }
 
     // rasterizers and mask filters modify alpha, which doesn't
     // translate well to distance
@@ skipping 31 matching lines @@
     SkScalar maxScale = ctm.getMaxScale();
     SkScalar textSize = fSkPaint.getTextSize();
     SkScalar scaledTextSize = textSize;
     // if we have non-unity scale, we need to choose our base text size
     // based on the SkPaint's text size multiplied by the max scale factor
     // TODO: do we need to do this if we're scaling down (i.e. maxScale < 1)?
     if (maxScale > 0 && !SkScalarNearlyEqual(maxScale, SK_Scalar1)) {
         scaledTextSize *= maxScale;
     }
 
+    fVertices = NULL;
     fCurrVertex = 0;
-
-    fVertices = NULL;
+    fAllocVertexCount = 0;
+    fTotalVertexCount = 0;
 
     if (scaledTextSize <= kSmallDFFontLimit) {
         fTextRatio = textSize / kSmallDFFontSize;
         fSkPaint.setTextSize(SkIntToScalar(kSmallDFFontSize));
     } else if (scaledTextSize <= kMediumDFFontLimit) {
         fTextRatio = textSize / kMediumDFFontSize;
         fSkPaint.setTextSize(SkIntToScalar(kMediumDFFontSize));
     } else {
         fTextRatio = textSize / kLargeDFFontSize;
         fSkPaint.setTextSize(SkIntToScalar(kLargeDFFontSize));
     }
 
     fUseLCDText = fSkPaint.isLCDRenderText();
 
     fSkPaint.setLCDRenderText(false);
     fSkPaint.setAutohinted(false);
     fSkPaint.setHinting(SkPaint::kNormal_Hinting);
     fSkPaint.setSubpixelText(true);
-
 }
 
 static void setup_gamma_texture(GrContext* context, const SkGlyphCache* cache,
                                 const SkDeviceProperties& deviceProperties,
                                 GrTexture** gammaTexture) {
     if (NULL == *gammaTexture) {
         int width, height;
         size_t size;
 
 #ifdef SK_GAMMA_CONTRAST
@@ skipping 106 matching lines @@
     this->init(paint, skPaint);
 
     SkDrawCacheProc glyphCacheProc = fSkPaint.getDrawCacheProc();
 
     SkAutoGlyphCacheNoGamma    autoCache(fSkPaint, &fDeviceProperties, NULL);
     SkGlyphCache*              cache = autoCache.getCache();
     GrFontScaler*              fontScaler = GetGrFontScaler(cache);
 
     setup_gamma_texture(fContext, cache, fDeviceProperties, &fGammaTexture);
 
+    int numGlyphs = fSkPaint.textToGlyphs(text, byteLength, NULL);
+    fTotalVertexCount = kVerticesPerGlyph*numGlyphs;
+
     const char*        stop = text + byteLength;
     SkTArray<char>     fallbackTxt;
     SkTArray<SkScalar> fallbackPos;
 
     if (SkPaint::kLeft_Align == fSkPaint.getTextAlign()) {
         while (text < stop) {
             const char* lastText = text;
             // the last 2 parameters are ignored
             const SkGlyph& glyph = glyphCacheProc(cache, &text, 0, 0);
 
@@ skipping 58 matching lines @@
     }
 }
 
 static inline GrColor skcolor_to_grcolor_nopremultiply(SkColor c) {
     unsigned r = SkColorGetR(c);
     unsigned g = SkColorGetG(c);
     unsigned b = SkColorGetB(c);
     return GrColorPackRGBA(r, g, b, 0xff);
 }
 
+static void* alloc_vertices(GrDrawTarget* drawTarget, int numVertices, bool useColorVerts) {
+    if (numVertices <= 0) {
+        return NULL;
+    }
+
+    // set up attributes
+    if (useColorVerts) {
+        drawTarget->drawState()->setVertexAttribs<gTextVertexWithColorAttribs>(
+                                    SK_ARRAY_COUNT(gTextVertexWithColorAttribs), kTextVAColorSize);
+    } else {
+        drawTarget->drawState()->setVertexAttribs<gTextVertexAttribs>(
+                                    SK_ARRAY_COUNT(gTextVertexAttribs), kTextVASize);
+    }
+    void* vertices = NULL;
+    bool success = drawTarget->reserveVertexAndIndexSpace(numVertices,
+                                                          0,
+                                                          &vertices,
+                                                          NULL);
+    GrAlwaysAssert(success);
+    return vertices;
+}
+
 void GrDistanceFieldTextContext::setupCoverageEffect(const SkColor& filteredColor) {
     GrTextureParams params(SkShader::kRepeat_TileMode, GrTextureParams::kBilerp_FilterMode);
     GrTextureParams gammaParams(SkShader::kClamp_TileMode, GrTextureParams::kNone_FilterMode);
     
     uint32_t textureUniqueID = fCurrTexture->getUniqueID();
     const SkMatrix& ctm = fContext->getMatrix();
     
     // set up any flags
     uint32_t flags = 0;
     flags |= ctm.isSimilarity() ? kSimilarity_DistanceFieldEffectFlag : 0;
@@ skipping 124 matching lines @@
         this->flush();
 
         GrContext::AutoMatrix am;
         SkMatrix ctm;
         ctm.setScale(fTextRatio, fTextRatio);
         ctm.postTranslate(sx, sy);
         GrPaint tmpPaint(fPaint);
         am.setPreConcat(fContext, ctm, &tmpPaint);
         GrStrokeInfo strokeInfo(SkStrokeRec::kFill_InitStyle);
         fContext->drawPath(tmpPaint, *glyph->fPath, strokeInfo);
+
+        // remove this glyph from the vertices we need to allocate
+        fTotalVertexCount -= kVerticesPerGlyph;
         return true;
     }
 
 HAS_ATLAS:
     SkASSERT(glyph->fPlot);
     GrDrawTarget::DrawToken drawToken = fDrawTarget->getCurrentDrawToken();
     glyph->fPlot->setDrawToken(drawToken);
 
     GrTexture* texture = glyph->fPlot->texture();
     SkASSERT(texture);
 
-    if (fCurrTexture != texture || fCurrVertex + 4 > fMaxVertices) {
+    if (fCurrTexture != texture || fCurrVertex + kVerticesPerGlyph > fTotalVertexCount) {
         this->flush();
         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->flush();
-            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);
+        int maxQuadVertices = kVerticesPerGlyph * fContext->getQuadIndexBuffer()->maxQuads();
+        fAllocVertexCount = SkMin32(fTotalVertexCount, maxQuadVertices);
+        fVertices = alloc_vertices(fDrawTarget, fAllocVertexCount, useColorVerts);
     }
 
     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);
     SkScalar height = SkIntToScalar(glyph->fBounds.height() - 2*SK_DistanceFieldInset);
 
     SkScalar scale = fTextRatio;
     dx *= scale;
     dy *= scale;
@@ skipping 94 matching lines @@
             drawState->setColor(SkColorSetARGB(a, a, a, a));
             // paintColor
             drawState->setBlendConstant(colorNoPreMul);
             drawState->setBlendFunc(kConstC_GrBlendCoeff, kISC_GrBlendCoeff);
         } else {
             // set back to normal in case we took LCD path previously.
             drawState->setBlendFunc(fPaint.getSrcBlendCoeff(), fPaint.getDstBlendCoeff());
             // We're using per-vertex color.
             SkASSERT(drawState->hasColorVertexAttribute());
         }
-        int nGlyphs = fCurrVertex / 4;
+        int nGlyphs = fCurrVertex / kVerticesPerGlyph;
         fDrawTarget->setIndexSourceToBuffer(fContext->getQuadIndexBuffer());
         fDrawTarget->drawIndexedInstances(kTriangles_GrPrimitiveType,
                                           nGlyphs,
-                                          4, 6, &fVertexBounds);
+                                          kVerticesPerGlyph, kIndicesPerGlyph, &fVertexBounds);
         fDrawTarget->resetVertexSource();
         fVertices = NULL;
-        fMaxVertices = 0;
+        fTotalVertexCount -= fCurrVertex;
         fCurrVertex = 0;
         SkSafeSetNull(fCurrTexture);
         fVertexBounds.setLargestInverted();
     }
 }
 
 inline void GrDistanceFieldTextContext::finish() {
     this->flush();
+    fTotalVertexCount = 0;
 
     GrTextContext::finish();
 }