Allocate only the vertices we need for text.

This restructures the vertex allocation for text rendering to compute
the max number of vertices we would need for a line of text, and then
only allocate that much. If this number exceeds the quad index limit,
then it will allocate for the max number of quads, and reallocate for
the rest later.

Review URL: https://codereview.chromium.org/663423003

1 files changed, 55 insertions, 52 deletions

diff --git a/src/gpu/GrBitmapTextContext.cpp b/src/gpu/GrBitmapTextContext.cpp
index fa70d3270b..afecead65d 100755
--- a/src/gpu/GrBitmapTextContext.cpp
+++ b/src/gpu/GrBitmapTextContext.cpp
@@ -47,8 +47,10 @@ extern const GrVertexAttrib gTextVertexWithColorAttribs[] = {
     {kVec2f_GrVertexAttribType,  sizeof(SkPoint) + sizeof(GrColor), kGeometryProcessor_GrVertexAttribBinding}
 };
 
-static const size_t kTextVAColorSize = 2 * sizeof(SkPoint) + sizeof(GrColor); 
+static const size_t kTextVAColorSize = 2 * sizeof(SkPoint) + sizeof(GrColor);
 
+static const int kVerticesPerGlyph = 4;
+static const int kIndicesPerGlyph = 6;
 };
 
 GrBitmapTextContext::GrBitmapTextContext(GrContext* context,
@@ -57,11 +59,12 @@ GrBitmapTextContext::GrBitmapTextContext(GrContext* context,
     fStrike = NULL;
 
     fCurrTexture = NULL;
-    fCurrVertex = 0;
     fEffectTextureUniqueID = SK_InvalidUniqueID;
 
     fVertices = NULL;
-    fMaxVertices = 0;
+    fCurrVertex = 0;
+    fAllocVertexCount = 0;
+    fTotalVertexCount = 0;
 
     fVertexBounds.setLargestInverted();
 }
@@ -72,7 +75,7 @@ GrBitmapTextContext* GrBitmapTextContext::Create(GrContext* context,
 }
 
 GrBitmapTextContext::~GrBitmapTextContext() {
-    this->flush();
+    this->finish();
 }
 
 bool GrBitmapTextContext::canDraw(const SkPaint& paint) {
@@ -88,7 +91,8 @@ inline void GrBitmapTextContext::init(const GrPaint& paint, const SkPaint& skPai
     fCurrVertex = 0;
 
     fVertices = NULL;
-    fMaxVertices = 0;
+    fAllocVertexCount = 0;
+    fTotalVertexCount = 0;
 }
 
 void GrBitmapTextContext::onDrawText(const GrPaint& paint, const SkPaint& skPaint,
@@ -118,13 +122,13 @@ void GrBitmapTextContext::onDrawText(const GrPaint& paint, const SkPaint& skPain
     }
 
     // need to measure first
+    int numGlyphs;
     if (fSkPaint.getTextAlign() != SkPaint::kLeft_Align) {
-        SkVector    stop;
-
-        MeasureText(cache, glyphCacheProc, text, byteLength, &stop);
+        SkVector    stopVector;
+        numGlyphs = MeasureText(cache, glyphCacheProc, text, byteLength, &stopVector);
 
-        SkScalar    stopX = stop.fX;
-        SkScalar    stopY = stop.fY;
+        SkScalar    stopX = stopVector.fX;
+        SkScalar    stopY = stopVector.fY;
 
         if (fSkPaint.getTextAlign() == SkPaint::kCenter_Align) {
             stopX = SkScalarHalf(stopX);
@@ -132,7 +136,10 @@ void GrBitmapTextContext::onDrawText(const GrPaint& paint, const SkPaint& skPain
         }
         x -= stopX;
         y -= stopY;
+    } else {
+        numGlyphs = fSkPaint.textToGlyphs(text, byteLength, NULL);
     }
+    fTotalVertexCount = kVerticesPerGlyph*numGlyphs;
 
     const char* stop = text + byteLength;
 
@@ -207,6 +214,9 @@ void GrBitmapTextContext::onDrawPosText(const GrPaint& paint, const SkPaint& skP
     GrContext::AutoMatrix  autoMatrix;
     autoMatrix.setIdentity(fContext, &fPaint);
 
+    int numGlyphs = fSkPaint.textToGlyphs(text, byteLength, NULL);
+    fTotalVertexCount = kVerticesPerGlyph*numGlyphs;
+
     const char*        stop = text + byteLength;
     SkTextAlignProc    alignProc(fSkPaint.getTextAlign());
     SkTextMapStateProc tmsProc(ctm, offset, scalarsPerPosition);
@@ -335,6 +345,28 @@ void GrBitmapTextContext::onDrawPosText(const GrPaint& paint, const SkPaint& skP
     this->finish();
 }
 
+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 GrBitmapTextContext::appendGlyph(GrGlyph::PackedID packed,
                                       SkFixed vx, SkFixed vy,
                                       GrFontScaler* scaler) {
@@ -418,6 +450,9 @@ void GrBitmapTextContext::appendGlyph(GrGlyph::PackedID packed,
         am.setPreConcat(fContext, translate, &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;
     }
 
@@ -434,7 +469,7 @@ HAS_ATLAS:
     GrTexture* texture = glyph->fPlot->texture();
     SkASSERT(texture);
 
-    if (fCurrTexture != texture || fCurrVertex + 4 > fMaxVertices) {
+    if (fCurrTexture != texture || fCurrVertex + kVerticesPerGlyph > fAllocVertexCount) {
         this->flush();
         fCurrTexture = texture;
         fCurrTexture->ref();
@@ -444,44 +479,9 @@ HAS_ATLAS:
     bool useColorVerts = kA8_GrMaskFormat == fCurrMaskFormat;
 
     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);
     }
 
     SkFixed tx = SkIntToFixed(glyph->fAtlasLocation.fX);
@@ -597,15 +597,17 @@ void GrBitmapTextContext::flush() {
             default:
                 SkFAIL("Unexpected mask format.");
         }
-        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;
+        fAllocVertexCount = 0;
+        // reset to be those that are left
+        fTotalVertexCount -= fCurrVertex;
         fCurrVertex = 0;
         fVertexBounds.setLargestInverted();
         SkSafeSetNull(fCurrTexture);
@@ -614,6 +616,7 @@ void GrBitmapTextContext::flush() {
 
 inline void GrBitmapTextContext::finish() {
     this->flush();
+    fTotalVertexCount = 0;
 
     GrTextContext::finish();
 }