Make GrLayerCache use multiple plots in its atlas

Until we have a recycling Rectanizer the atlas purging must occur at the GrPlot level. This CL breaks the atlas into four plots to give some room for purging (without trashing the entire atlas).

This is calved off of (Add atlased layer purging - https://codereview.chromium.org/367073002/)

R=jvanverth@google.com

Author: robertphillips@google.com

Review URL: https://codereview.chromium.org/397873004

1 files changed, 73 insertions, 14 deletions

diff --git a/src/gpu/GrLayerCache.cpp b/src/gpu/GrLayerCache.cpp
index 9688cac650..ff26750df7 100644
--- a/src/gpu/GrLayerCache.cpp
+++ b/src/gpu/GrLayerCache.cpp
@@ -41,8 +41,33 @@ private:
     int      fLayerID;
 };
 
+/**
+ *  PictureKey just wraps a picture's unique ID for GrTHashTable. It is used to
+ *  look up a picture's GrPictureInfo (i.e., its GrPlot usage).
+ */
+class GrLayerCache::PictureKey {
+public:
+    PictureKey(uint32_t pictureID) : fPictureID(pictureID) { }
+
+    uint32_t pictureID() const { return fPictureID; }
+
+    uint32_t getHash() const { return fPictureID; }
+
+    static bool LessThan(const GrPictureInfo& pictInfo, const PictureKey& key) {
+        return pictInfo.fPictureID < key.pictureID();
+    }
+
+    static bool Equals(const GrPictureInfo& pictInfo, const PictureKey& key) {
+        return pictInfo.fPictureID == key.pictureID();
+
+    }
+
+private:
+    uint32_t fPictureID;
+};
+
 #ifdef SK_DEBUG
-void GrCachedLayer::validate(GrTexture* backingTexture) const {
+void GrCachedLayer::validate(const GrTexture* backingTexture) const {
     SkASSERT(SK_InvalidGenID != fPictureID);
     SkASSERT(-1 != fLayerID);
 
@@ -55,6 +80,14 @@ void GrCachedLayer::validate(GrTexture* backingTexture) const {
         }
     } else {
         SkASSERT(fRect.isEmpty());
+        SkASSERT(NULL == fPlot);
+    }
+
+    if (NULL != fPlot) {
+        // If a layer has a plot (i.e., is atlased) then it must point to
+        // the backing texture. Additionally, its rect should be non-empty.
+        SkASSERT(NULL != fTexture && backingTexture == fTexture);
+        SkASSERT(!fRect.isEmpty());
     }
 }
 
@@ -72,9 +105,13 @@ public:
             fLayer->validate(fBackingTexture);
         }
     }
+    void setBackingTexture(GrTexture* backingTexture) {
+        SkASSERT(NULL == fBackingTexture || fBackingTexture == backingTexture);
+        fBackingTexture = backingTexture;
+    }
 
 private:
-    GrTexture* fBackingTexture;
+    const GrTexture* fBackingTexture;
     const GrCachedLayer* fLayer;
 };
 #endif
@@ -106,7 +143,7 @@ void GrLayerCache::initAtlas() {
     SkISize textureSize = SkISize::Make(kAtlasTextureWidth, kAtlasTextureHeight);
     fAtlas.reset(SkNEW_ARGS(GrAtlas, (fContext->getGpu(), kSkia8888_GrPixelConfig,
                                       kRenderTarget_GrTextureFlagBit,
-                                      textureSize, 1, 1, false)));
+                                      textureSize, kNumPlotsX, kNumPlotsY, false)));
 }
 
 void GrLayerCache::freeAll() {
@@ -165,14 +202,26 @@ bool GrLayerCache::lock(GrCachedLayer* layer, const GrTextureDesc& desc) {
     }
 
 #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);
-        layer->setAtlased(true);
-        return false;
+    {
+        GrPictureInfo* pictInfo = fPictureHash.find(PictureKey(layer->pictureID()));
+        if (NULL == pictInfo) {
+            pictInfo = SkNEW_ARGS(GrPictureInfo, (layer->pictureID()));
+            fPictureHash.insert(PictureKey(layer->pictureID()), pictInfo);
+        }
+
+        SkIPoint16 loc;
+        GrPlot* plot = fAtlas->addToAtlas(&pictInfo->fPlotUsage, 
+                                          desc.fWidth, desc.fHeight, 
+                                          NULL, &loc);
+        // addToAtlas can allocate the backing texture
+        SkDEBUGCODE(avl.setBackingTexture(fAtlas->getTexture()));
+        if (NULL != plot) {
+            GrIRect16 bounds = GrIRect16::MakeXYWH(loc.fX, loc.fY,
+                                                   SkToS16(desc.fWidth), SkToS16(desc.fHeight));
+            layer->setTexture(fAtlas->getTexture(), bounds);
+            layer->setPlot(plot);
+            return false;
+        }
     }
 #endif
 
@@ -192,9 +241,13 @@ void GrLayerCache::unlock(GrCachedLayer* layer) {
     }
 
     if (layer->isAtlased()) {
-        // 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
+        SkASSERT(layer->texture() == fAtlas->getTexture());
+
+        GrPictureInfo* pictInfo = fPictureHash.find(PictureKey(layer->pictureID()));
+        SkASSERT(NULL != pictInfo);
+        pictInfo->fPlotUsage.isEmpty(); // just to silence compiler warnings for the time being
+
+        // TODO: purging from atlas goes here
     } else {
         fContext->unlockScratchTexture(layer->texture());
         layer->setTexture(NULL, GrIRect16::MakeEmpty());
@@ -247,4 +300,10 @@ void GrLayerCache::purge(const SkPicture* picture) {
         fLayerHash.remove(key, toBeRemoved[i]);
         SkDELETE(toBeRemoved[i]);
     }
+
+    GrPictureInfo* pictInfo = fPictureHash.find(PictureKey(picture->uniqueID()));
+    if (NULL != pictInfo) {
+        fPictureHash.remove(PictureKey(picture->uniqueID()), pictInfo);
+        SkDELETE(pictInfo);
+    }
 }