Minimize texture binds when drawing text

When several CacheTextures are used to draw text, sort the
draw batches by texture ID to minimize state changes in the
driver.

This change also tweaks the font cache size and renames
a property that was too long to be set using setprop.

Change-Id: I0a36dfffe58c9e75dd7384592d3343c192d042b1

1 files changed, 15 insertions, 14 deletions

diff --git a/libs/hwui/FontRenderer.cpp b/libs/hwui/FontRenderer.cpp
index f0dcb30db549..0c70e272d0a5 100644
--- a/libs/hwui/FontRenderer.cpp
+++ b/libs/hwui/FontRenderer.cpp
@@ -378,9 +378,9 @@ void FontRenderer::checkInit() {
 
 void FontRenderer::updateDrawParams() {
     if (mCurrentQuadIndex != mLastQuadIndex) {
-        mDrawOffsets.add((uint16_t*)(mLastQuadIndex * sizeof(uint16_t) * 6));
-        mDrawCounts.add(mCurrentQuadIndex - mLastQuadIndex);
-        mDrawCacheTextures.add(mCurrentCacheTexture);
+        uint16_t* offset = (uint16_t*)(mLastQuadIndex * sizeof(uint16_t) * 6);
+        uint32_t count = mCurrentQuadIndex - mLastQuadIndex;
+        mDrawBatch.add(TextBatch(offset, count, mCurrentCacheTexture));
         mLastQuadIndex = mCurrentQuadIndex;
     }
 }
@@ -438,26 +438,27 @@ void FontRenderer::issueDrawCommand() {
         caches.bindTexCoordsVertexPointer(force, buffer + offset);
     }
 
-    for (uint32_t i = 0; i < mDrawOffsets.size(); i++) {
-        uint16_t* offset = mDrawOffsets[i];
-        uint32_t count = mDrawCounts[i];
-        CacheTexture* texture = mDrawCacheTextures[i];
+    caches.activeTexture(0);
+    GLuint lastId = 0;
 
-        caches.activeTexture(0);
-        glBindTexture(GL_TEXTURE_2D, texture->getTextureId());
+    for (uint32_t i = 0; i < mDrawBatch.size(); i++) {
+        const TextBatch& batch = mDrawBatch[i];
 
-        texture->setLinearFiltering(mLinearFiltering, false);
+        GLuint id = batch.texture->getTextureId();
+        if (id != lastId) {
+            glBindTexture(GL_TEXTURE_2D, id);
+            batch.texture->setLinearFiltering(mLinearFiltering, false);
+            lastId = id;
+        }
 
-        glDrawElements(GL_TRIANGLES, count * 6, GL_UNSIGNED_SHORT, offset);
+        glDrawElements(GL_TRIANGLES, batch.count * 6, GL_UNSIGNED_SHORT, batch.offset);
     }
 
     mDrawn = true;
 
     mCurrentQuadIndex = 0;
     mLastQuadIndex = 0;
-    mDrawOffsets.clear();
-    mDrawCounts.clear();
-    mDrawCacheTextures.clear();
+    mDrawBatch.clear();
 }
 
 void FontRenderer::appendMeshQuadNoClip(float x1, float y1, float u1, float v1,