Begin atlasing

This CL makes it possible for pulled-forward-layers to be atlased. It currently has a couple glaring limitations (which is why it is disabled):

1) the atlased layers cannot be purged nor aged out
2) the texture backing the atlas is not pulled from (or returned to) the resource cache

#1 is on hold until we have a recycling rectanizer

A separate major limitation (the non-atlased layers aren't cached) is blocked until we can transmute entries in the resource cache from scratch to non-scratch while potentially preserving their contents.

Committed: https://skia.googlesource.com/skia/+/55e61f0ef4e5c8c34ac107deaadc9b4ffef3111b

R=bsalomon@google.com

Author: robertphillips@google.com

Review URL: https://codereview.chromium.org/354533004

1 files changed, 85 insertions, 12 deletions

diff --git a/src/gpu/GrLayerCache.cpp b/src/gpu/GrLayerCache.cpp
index c20d809062..62c97208cc 100644
--- a/src/gpu/GrLayerCache.cpp
+++ b/src/gpu/GrLayerCache.cpp
@@ -42,14 +42,23 @@ private:
 };
 
 GrLayerCache::GrLayerCache(GrContext* context)
-    : fContext(context)
-    , fLayerPool(16) {      // TODO: may need to increase this later
+    : fContext(context) {
+    this->initAtlas();
 }
 
 GrLayerCache::~GrLayerCache() {
+    SkTDArray<GrCachedLayer*>& layerArray = fLayerHash.getArray();
+    for (int i = 0; i < fLayerHash.count(); ++i) {
+        this->unlock(layerArray[i]);
+    }
+
+    fLayerHash.deleteAll();
+
+    // The atlas only lets go of its texture when the atlas is deleted. 
+    fAtlas.free();    
 }
 
-void GrLayerCache::init() {
+void GrLayerCache::initAtlas() {
     static const int kAtlasTextureWidth = 1024;
     static const int kAtlasTextureHeight = 1024;
 
@@ -58,19 +67,31 @@ void GrLayerCache::init() {
     // The layer cache only gets 1 plot
     SkISize textureSize = SkISize::Make(kAtlasTextureWidth, kAtlasTextureHeight);
     fAtlas.reset(SkNEW_ARGS(GrAtlas, (fContext->getGpu(), kSkia8888_GrPixelConfig,
+                                      kRenderTarget_GrTextureFlagBit,
                                       textureSize, 1, 1, false)));
 }
 
 void GrLayerCache::freeAll() {
+    SkTDArray<GrCachedLayer*>& layerArray = fLayerHash.getArray();
+    for (int i = 0; i < fLayerHash.count(); ++i) {
+        this->unlock(layerArray[i]);
+    }
+
     fLayerHash.deleteAll();
+
+    // The atlas only lets go of its texture when the atlas is deleted. 
     fAtlas.free();
+    // GrLayerCache always assumes an atlas exists so recreate it. The atlas 
+    // lazily allocates a replacement texture so reallocating a new 
+    // atlas here won't disrupt a GrContext::contextDestroyed or freeGpuResources.
+    // TODO: Make GrLayerCache lazily allocate the atlas manager?
+    this->initAtlas();
 }
 
 GrCachedLayer* GrLayerCache::createLayer(const SkPicture* picture, int layerID) {
-    GrCachedLayer* layer = fLayerPool.alloc();
-
     SkASSERT(picture->uniqueID() != SK_InvalidGenID);
-    layer->init(picture->uniqueID(), layerID);
+
+    GrCachedLayer* layer = SkNEW_ARGS(GrCachedLayer, (picture->uniqueID(), layerID));
     fLayerHash.insert(PictureLayerKey(picture->uniqueID(), layerID), layer);
     return layer;
 }
@@ -91,19 +112,71 @@ GrCachedLayer* GrLayerCache::findLayerOrCreate(const SkPicture* picture, int lay
 }
 
 bool GrLayerCache::lock(GrCachedLayer* layer, const GrTextureDesc& desc) {
-    SkASSERT(NULL == layer->getTexture());
 
-    // This just uses scratch textures and doesn't cache the texture.
+    if (NULL != layer->texture()) {
+        // This layer is already locked
+#ifdef SK_DEBUG
+        if (!layer->rect().isEmpty()) {
+            // It claims to be atlased
+            SkASSERT(layer->rect().width() == desc.fWidth);
+            SkASSERT(layer->rect().height() == desc.fHeight);
+        }
+#endif
+        return true;
+    }
+
+#if USE_ATLAS
+    SkIPoint16 loc;
+    GrPlot* plot = fAtlas->addToAtlas(&fPlotUsage, desc.fWidth, desc.fHeight, NULL, &loc);
+    if (NULL != plot) {
+        GrIRect16 bounds = GrIRect16::MakeXYWH(loc.fX, loc.fY, 
+                                               SkToS16(desc.fWidth), SkToS16(desc.fHeight));
+        layer->setTexture(fAtlas->getTexture(), bounds);
+        return false;
+    }
+#endif
+
+    // This path always uses a new scratch texture and (thus) doesn't cache anything.
     // This can yield a lot of re-rendering
-    layer->setTexture(fContext->lockAndRefScratchTexture(desc, GrContext::kApprox_ScratchTexMatch));
+    layer->setTexture(fContext->lockAndRefScratchTexture(desc, GrContext::kApprox_ScratchTexMatch),
+                      GrIRect16::MakeEmpty());
     return false;
 }
 
 void GrLayerCache::unlock(GrCachedLayer* layer) {
-    if (NULL == layer || NULL == layer->getTexture()) {
+    if (NULL == layer || NULL == layer->texture()) {
         return;
     }
 
-    fContext->unlockScratchTexture(layer->getTexture());
-    layer->setTexture(NULL);
+    // The atlas doesn't currently use a scratch texture (and we would have
+    // to free up space differently anyways)
+    // TODO: unlock atlas space when a recycling rectanizer is available
+    if (layer->texture() != fAtlas->getTexture()) {
+        fContext->unlockScratchTexture(layer->texture());
+        layer->setTexture(NULL, GrIRect16::MakeEmpty());
+    }
+}
+
+void GrLayerCache::purge(const SkPicture* picture) {
+    // This is somewhat of an abuse of GrTHashTable. We need to find all the
+    // layers associated with 'picture' but the usual hash calls only look for
+    // exact key matches. This code peeks into the hash table's innards to
+    // find all the 'picture'-related layers.
+    // TODO: use a different data structure for the layer hash?
+    SkTDArray<GrCachedLayer*> toBeRemoved;
+
+    const SkTDArray<GrCachedLayer*>& layerArray = fLayerHash.getArray();
+    for (int i = 0; i < fLayerHash.count(); ++i) {
+        if (picture->uniqueID() == layerArray[i]->pictureID()) {
+            *toBeRemoved.append() = layerArray[i];
+        }
+    }
+
+    for (int i = 0; i < toBeRemoved.count(); ++i) {
+        this->unlock(toBeRemoved[i]);
+
+        PictureLayerKey key(picture->uniqueID(), toBeRemoved[i]->layerID());
+        fLayerHash.remove(key, toBeRemoved[i]);
+        SkDELETE(toBeRemoved[i]);
+    }
 }