Add CTM to the cached layers' key and reduce render target pingponging in layer pre-rendering

tests/GpuLayerCacheTest.cpp

 /*
 * Copyright 2014 Google Inc.
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */
 
 #if SK_SUPPORT_GPU
 
 #include "GrContext.h"
@@ skipping 13 matching lines @@
 };
 
 // Add several layers to the cache
 static void create_layers(skiatest::Reporter* reporter,
                           GrLayerCache* cache,
                           const SkPicture& picture,
                           int numToAdd,
                           int idOffset) {
 
     for (int i = 0; i < numToAdd; ++i) {
-        GrCachedLayer* layer = cache->findLayerOrCreate(&picture, idOffset+i);
+        GrCachedLayer* layer = cache->findLayerOrCreate(&picture, 
+                                                        idOffset+i+1, idOffset+i+2, 
+                                                        SkMatrix::I());
         REPORTER_ASSERT(reporter, NULL != layer);
-        GrCachedLayer* temp = cache->findLayer(&picture, idOffset+i);
+        GrCachedLayer* temp = cache->findLayer(&picture, idOffset+i+1, idOffset+i+2, SkMatrix::I());
         REPORTER_ASSERT(reporter, temp == layer);
 
         REPORTER_ASSERT(reporter, TestingAccess::NumLayers(cache) == idOffset + i + 1);
 
         REPORTER_ASSERT(reporter, picture.uniqueID() == layer->pictureID());
-        REPORTER_ASSERT(reporter, layer->layerID() == idOffset + i);
+        REPORTER_ASSERT(reporter, layer->start() == idOffset + i + 1);
+        REPORTER_ASSERT(reporter, layer->stop() == idOffset + i + 2);
+        REPORTER_ASSERT(reporter, layer->ctm() == SkMatrix::I());
         REPORTER_ASSERT(reporter, NULL == layer->texture());
         REPORTER_ASSERT(reporter, !layer->isAtlased());
     }
 
     cache->trackPicture(&picture);
 }
 
 static void lock_layer(skiatest::Reporter* reporter,
                        GrLayerCache* cache,
                        GrCachedLayer* layer) {
@@ skipping 35 matching lines @@
 
         SkPictureRecorder recorder;
         recorder.beginRecording(1, 1);
         SkAutoTUnref<const SkPicture> picture(recorder.endRecording());
 
         GrLayerCache cache(context);
 
         create_layers(reporter, &cache, *picture, kInitialNumLayers, 0);
 
         for (int i = 0; i < kInitialNumLayers; ++i) {
-            GrCachedLayer* layer = cache.findLayer(picture, i);
+            GrCachedLayer* layer = cache.findLayer(picture, i+1, i+2, SkMatrix::I());
             REPORTER_ASSERT(reporter, NULL != layer);
 
             lock_layer(reporter, &cache, layer);
 
             // The first 4 layers should be in the atlas (and thus have non-empty
             // rects)
             if (i < 4) {
                 REPORTER_ASSERT(reporter, layer->isAtlased());
             } else {
                 // The 5th layer couldn't fit in the atlas
                 REPORTER_ASSERT(reporter, !layer->isAtlased());
             }
         }
 
         // Unlock the textures
         for (int i = 0; i < kInitialNumLayers; ++i) {
-            GrCachedLayer* layer = cache.findLayer(picture, i);
+            GrCachedLayer* layer = cache.findLayer(picture, i+1, i+2, SkMatrix::I());
             REPORTER_ASSERT(reporter, NULL != layer);
 
             cache.unlock(layer);
         }
 
         for (int i = 0; i < kInitialNumLayers; ++i) {
-            GrCachedLayer* layer = cache.findLayer(picture, i);
+            GrCachedLayer* layer = cache.findLayer(picture, i+1, i+2, SkMatrix::I());
             REPORTER_ASSERT(reporter, NULL != layer);
 
             REPORTER_ASSERT(reporter, !layer->locked());
             // The first 4 layers should still be in the atlas.
             if (i < 4) {
                 REPORTER_ASSERT(reporter, NULL != layer->texture());
                 REPORTER_ASSERT(reporter, layer->isAtlased());
             } else {
                 // The final layer should be unlocked.
                 REPORTER_ASSERT(reporter, NULL == layer->texture());
                 REPORTER_ASSERT(reporter, !layer->isAtlased());
             }
         }
 
         {
             // Add an additional layer. Since all the layers are unlocked this 
             // will force out the first atlased layer
             create_layers(reporter, &cache, *picture, 1, kInitialNumLayers);
-            GrCachedLayer* layer = cache.findLayer(picture, kInitialNumLayers);
+            GrCachedLayer* layer = cache.findLayer(picture, 
+                                                   kInitialNumLayers+1, kInitialNumLayers+2, 
+                                                   SkMatrix::I());
             REPORTER_ASSERT(reporter, NULL != layer);
 
             lock_layer(reporter, &cache, layer);
             cache.unlock(layer);
         }
 
         for (int i = 0; i < kInitialNumLayers+1; ++i) {
-            GrCachedLayer* layer = cache.findLayer(picture, i);
+            GrCachedLayer* layer = cache.findLayer(picture, i+1, i+2, SkMatrix::I());
             // 3 old layers plus the new one should be in the atlas.
             if (1 == i || 2 == i || 3 == i || 5 == i) {
                 REPORTER_ASSERT(reporter, NULL != layer);
                 REPORTER_ASSERT(reporter, !layer->locked());
                 REPORTER_ASSERT(reporter, NULL != layer->texture());
                 REPORTER_ASSERT(reporter, layer->isAtlased());
             } else if (4 == i) {
                 // The one that was never atlased should still be around
                 REPORTER_ASSERT(reporter, NULL != layer);
 
@@ skipping 32 matching lines @@
 
         picture.reset(NULL);
         cache.processDeletedPictures();
 
         REPORTER_ASSERT(reporter, TestingAccess::NumLayers(&cache) == 0);
         // TODO: add VRAM/resource cache check here
     }
 }
 
 #endif