Alter layer hoisting to only hoist layers for one canvas at a time

src/gpu/GrLayerHoister.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.
  */
 
 #include "GrLayerCache.h"
 #include "GrLayerHoister.h"
 #include "GrRecordReplaceDraw.h"
 
 #include "SkCanvas.h"
 #include "SkGrPixelRef.h"
 #include "SkRecordDraw.h"
 #include "SkSurface.h"
 
 // Create the layer information for the hoisted layer and secure the
 // required texture/render target resources.
 static void prepare_for_hoisting(GrLayerCache* layerCache, 
                                  const SkPicture* topLevelPicture,
                                  const GrAccelData::SaveLayerInfo& info,
                                  const SkIRect& layerRect,
-                                 SkTDArray<GrHoistedLayer>* atlased,
-                                 SkTDArray<GrHoistedLayer>* nonAtlased,
-                                 SkTDArray<GrHoistedLayer>* recycled) {
+                                 SkTDArray<GrHoistedLayer>* needRendering,
+                                 SkTDArray<GrHoistedLayer>* recycled,
+                                 bool attemptToAtlas) {
     const SkPicture* pict = info.fPicture ? info.fPicture : topLevelPicture;
 
     SkMatrix combined = SkMatrix::Concat(info.fPreMat, info.fLocalMat);
 
     GrCachedLayer* layer = layerCache->findLayerOrCreate(pict->uniqueID(),
                                                          info.fSaveLayerOpID,
                                                          info.fRestoreOpID,
                                                          layerRect,
                                                          combined,
                                                          info.fPaint);
     GrTextureDesc desc;
     desc.fFlags = kRenderTarget_GrTextureFlagBit;
     desc.fWidth = layerRect.width();
     desc.fHeight = layerRect.height();
     desc.fConfig = kSkia8888_GrPixelConfig;
     // TODO: need to deal with sample count
 
-
-    bool disallowAtlasing = info.fHasNestedLayers || info.fIsNested ||
-                            (layer->paint() && layer->paint()->getImageFilter());
-
-    bool needsRendering = layerCache->lock(layer, desc, disallowAtlasing);
-    if (NULL == layer->texture()) {
+    bool locked, needsRendering;
+    if (attemptToAtlas) {
+        locked = layerCache->tryToAtlas(layer, desc, &needsRendering);
+    } else {
+        locked = layerCache->lock(layer, desc, &needsRendering);
+    }
+    if (!locked) {
         // GPU resources could not be secured for the hoisting of this layer
         return;
     }
 
+    if (attemptToAtlas) {
+        SkASSERT(layer->isAtlased());
+    }
+
     GrHoistedLayer* hl;
 
     if (needsRendering) {
-        if (layer->isAtlased()) {
-            hl = atlased->append();
-        } else {
-            hl = nonAtlased->append();
+        if (!attemptToAtlas) {
+            SkASSERT(!layer->isAtlased());
         }
+        hl = needRendering->append();
     } else {
         hl = recycled->append();
     }
     
     layerCache->addUse(layer);
     hl->fLayer = layer;
     hl->fPicture = pict;
     hl->fOffset = SkIPoint::Make(layerRect.fLeft, layerRect.fTop);
     hl->fLocalMat = info.fLocalMat;
     hl->fPreMat = info.fPreMat;
 }
 
-// Return true if any layers are suitable for hoisting
-bool GrLayerHoister::FindLayersToHoist(GrContext* context,
+// Atlased layers must be small enough to fit in the atlas, not have a
+// paint with an image filter and be neither nested nor nesting.
+// TODO: allow leaf nested layers to appear in the atlas.
+void GrLayerHoister::FindLayersToAtlas(GrContext* context,
                                        const SkPicture* topLevelPicture,
                                        const SkRect& query,
                                        SkTDArray<GrHoistedLayer>* atlased,
-                                       SkTDArray<GrHoistedLayer>* nonAtlased,
                                        SkTDArray<GrHoistedLayer>* recycled) {
     GrLayerCache* layerCache = context->getLayerCache();
 
     layerCache->processDeletedPictures();
 
     SkPicture::AccelData::Key key = GrAccelData::ComputeAccelDataKey();
 
     const SkPicture::AccelData* topLevelData = topLevelPicture->EXPERIMENTAL_getAccelData(key);
     if (!topLevelData) {
-        return false;
+        return;
     }
 
     const GrAccelData *topLevelGPUData = static_cast<const GrAccelData*>(topLevelData);
     if (0 == topLevelGPUData->numSaveLayers()) {
-        return false;
+        return;
     }
 
-    bool anyHoisted = false;
-
-    // The layer hoisting code will pre-render and cache an entire layer if most
-    // of it is being used (~70%) and it will fit in a texture. This is to allow
-    // such layers to be re-used for different clips/tiles. 
-    // Small layers will additionally be atlased.
-    // The only limitation right now is that nested layers are currently not hoisted.
-    // Parent layers are hoisted but are never atlased (so that we never swap
-    // away from the atlas rendertarget when generating the hoisted layers).
-
     atlased->setReserve(atlased->count() + topLevelGPUData->numSaveLayers());
 
-    // Find and prepare for hoisting all the layers that intersect the query rect
     for (int i = 0; i < topLevelGPUData->numSaveLayers(); ++i) {
+        const GrAccelData::SaveLayerInfo& info = topLevelGPUData->saveLayerInfo(i);
 
-        const GrAccelData::SaveLayerInfo& info = topLevelGPUData->saveLayerInfo(i);
+        // TODO: ignore perspective projected layers here?
+        bool disallowAtlasing = info.fHasNestedLayers || info.fIsNested ||
+                                (info.fPaint && info.fPaint->getImageFilter());
+
+        if (disallowAtlasing) {
+            continue;
+        }
 
         SkRect layerRect = SkRect::Make(info.fBounds);
         if (!layerRect.intersect(query)) {
             continue;
         }
 
         SkIRect ir;
         layerRect.roundOut(&ir);
 
-        // TODO: ignore perspective projected layers here!
-        // TODO: once this code is more stable unsuitable layers can
-        // just be omitted during the optimization stage
-        if (info.fIsNested) {
+        if (!GrLayerCache::PlausiblyAtlasable(ir.width(), ir.height())) {
             continue;
         }
 
-        prepare_for_hoisting(layerCache, topLevelPicture, info, ir, atlased, nonAtlased, recycled);
-        anyHoisted = true;
+        prepare_for_hoisting(layerCache, topLevelPicture, info, ir, atlased, recycled, true);
     }
 
-    return anyHoisted;
+}
+
+void GrLayerHoister::FindLayersToHoist(GrContext* context,
+                                       const SkPicture* topLevelPicture,
+                                       const SkRect& query,
+                                       SkTDArray<GrHoistedLayer>* needRendering,
+                                       SkTDArray<GrHoistedLayer>* recycled) {
+    GrLayerCache* layerCache = context->getLayerCache();
+
+    layerCache->processDeletedPictures();
+
+    SkPicture::AccelData::Key key = GrAccelData::ComputeAccelDataKey();
+
+    const SkPicture::AccelData* topLevelData = topLevelPicture->EXPERIMENTAL_getAccelData(key);
+    if (!topLevelData) {
+        return;
+    }
+
+    const GrAccelData *topLevelGPUData = static_cast<const GrAccelData*>(topLevelData);
+    if (0 == topLevelGPUData->numSaveLayers()) {
+        return;
+    }
+
+    // Find and prepare for hoisting all the layers that intersect the query rect
+    for (int i = 0; i < topLevelGPUData->numSaveLayers(); ++i) {
+        const GrAccelData::SaveLayerInfo& info = topLevelGPUData->saveLayerInfo(i);
+        if (info.fIsNested) {
+            // Parent layers are currently hoisted while nested layers are not.
+            continue;
+        }
+
+        SkRect layerRect = SkRect::Make(info.fBounds);
+        if (!layerRect.intersect(query)) {
+            continue;
+        }
+
+        SkIRect ir;
+        layerRect.roundOut(&ir);
+
+        prepare_for_hoisting(layerCache, topLevelPicture, info, ir, 
+                             needRendering, recycled, false);
+    }
 }
 
 static void wrap_texture(GrTexture* texture, int width, int height, SkBitmap* result) {
     SkImageInfo info = SkImageInfo::MakeN32Premul(width, height);
     result->setInfo(info);
     result->setPixelRef(SkNEW_ARGS(SkGrPixelRef, (info, texture)))->unref();
 }
 
-static void convert_layers_to_replacements(const SkTDArray<GrHoistedLayer>& layers,
-                                           GrReplacements* replacements) {
+void GrLayerHoister::ConvertLayersToReplacements(const SkTDArray<GrHoistedLayer>& layers,
+                                                 GrReplacements* replacements) {
     // TODO: just replace GrReplacements::ReplacementInfo with GrCachedLayer?
     for (int i = 0; i < layers.count(); ++i) {
         GrCachedLayer* layer = layers[i].fLayer;
         const SkPicture* picture = layers[i].fPicture;
 
         SkMatrix combined = SkMatrix::Concat(layers[i].fPreMat, layers[i].fLocalMat);
 
         GrReplacements::ReplacementInfo* layerInfo =
                     replacements->newReplacement(picture->uniqueID(),
                                                  layer->start(),
@@ skipping 14 matching lines @@
                                 ? SkNEW_ARGS(SkPaint, (*layers[i].fLayer->paint()))
                                 : NULL;
 
         layerInfo->fSrcRect = SkIRect::MakeXYWH(layers[i].fLayer->rect().fLeft,
                                                 layers[i].fLayer->rect().fTop,
                                                 layers[i].fLayer->rect().width(),
                                                 layers[i].fLayer->rect().height());
     }
 }
 
-void GrLayerHoister::DrawLayers(GrContext* context,
-                                const SkTDArray<GrHoistedLayer>& atlased,
-                                const SkTDArray<GrHoistedLayer>& nonAtlased,
-                                const SkTDArray<GrHoistedLayer>& recycled,
-                                GrReplacements* replacements) {
-    // Render the atlased layers that require it
+void GrLayerHoister::DrawLayersToAtlas(GrContext* context,
+                                       const SkTDArray<GrHoistedLayer>& atlased) {
     if (atlased.count() > 0) {
         // All the atlased layers are rendered into the same GrTexture
         SkAutoTUnref<SkSurface> surface(SkSurface::NewRenderTargetDirect(
                                         atlased[0].fLayer->texture()->asRenderTarget(), NULL));
 
         SkCanvas* atlasCanvas = surface->getCanvas();
 
         SkPaint clearPaint;
         clearPaint.setColor(SK_ColorTRANSPARENT);
         clearPaint.setXfermode(SkXfermode::Create(SkXfermode::kSrc_Mode))->unref();
@@ skipping 10 matching lines @@
 
             // Add a rect clip to make sure the rendering doesn't
             // extend beyond the boundaries of the atlased sub-rect
             SkRect bound = SkRect::MakeXYWH(SkIntToScalar(layer->rect().fLeft),
                                             SkIntToScalar(layer->rect().fTop),
                                             SkIntToScalar(layer->rect().width()),
                                             SkIntToScalar(layer->rect().height()));
             atlasCanvas->clipRect(bound);
 
             // Since 'clear' doesn't respect the clip we need to draw a rect
-            // TODO: ensure none of the atlased layers contain a clear call!
             atlasCanvas->drawRect(bound, clearPaint);
 
-            // info.fCTM maps the layer's top/left to the origin.
+            // '-offset' maps the layer's top/left to the origin.
             // Since this layer is atlased, the top/left corner needs
             // to be offset to the correct location in the backing texture.
             SkMatrix initialCTM;
-            initialCTM.setTranslate(SkIntToScalar(-offset.fX), 
-                                    SkIntToScalar(-offset.fY));
-            initialCTM.postTranslate(bound.fLeft, bound.fTop);
-            initialCTM.postConcat(atlased[i].fPreMat);
+            initialCTM.setTranslate(SkIntToScalar(-offset.fX), SkIntToScalar(-offset.fY));
+            initialCTM.preTranslate(bound.fLeft, bound.fTop);
+            initialCTM.preConcat(atlased[i].fPreMat);
 
-            atlasCanvas->translate(SkIntToScalar(-offset.fX), 
-                                   SkIntToScalar(-offset.fY));
-            atlasCanvas->translate(bound.fLeft, bound.fTop);
-            atlasCanvas->concat(atlased[i].fPreMat);
+            atlasCanvas->setMatrix(initialCTM);
             atlasCanvas->concat(atlased[i].fLocalMat);
 
             SkRecordPartialDraw(*pict->fRecord.get(), atlasCanvas, bound,
-                                layer->start()+1, layer->stop(), initialCTM);
+                                layer->start() + 1, layer->stop(), initialCTM);
 
             atlasCanvas->restore();
         }
 
         atlasCanvas->flush();
     }
+}
 
-    // Render the non-atlased layers that require it
-    for (int i = 0; i < nonAtlased.count(); ++i) {
-        GrCachedLayer* layer = nonAtlased[i].fLayer;
-        const SkPicture* pict = nonAtlased[i].fPicture;
-        const SkIPoint& offset = nonAtlased[i].fOffset;
+void GrLayerHoister::DrawLayers(GrContext* context, const SkTDArray<GrHoistedLayer>& layers) {
+    for (int i = 0; i < layers.count(); ++i) {
+        GrCachedLayer* layer = layers[i].fLayer;
+        const SkPicture* pict = layers[i].fPicture;
+        const SkIPoint& offset = layers[i].fOffset;
 
         // Each non-atlased layer has its own GrTexture
         SkAutoTUnref<SkSurface> surface(SkSurface::NewRenderTargetDirect(
                                         layer->texture()->asRenderTarget(), NULL));
 
         SkCanvas* layerCanvas = surface->getCanvas();
 
         SkASSERT(0 == layer->rect().fLeft && 0 == layer->rect().fTop);
 
         // Add a rect clip to make sure the rendering doesn't
-        // extend beyond the boundaries of the atlased sub-rect
+        // extend beyond the boundaries of the layer
         SkRect bound = SkRect::MakeXYWH(SkIntToScalar(layer->rect().fLeft),
                                         SkIntToScalar(layer->rect().fTop),
                                         SkIntToScalar(layer->rect().width()),
                                         SkIntToScalar(layer->rect().height()));
 
-        layerCanvas->clipRect(bound); // TODO: still useful?
+        layerCanvas->clipRect(bound);
 
         layerCanvas->clear(SK_ColorTRANSPARENT);
 
         SkMatrix initialCTM;
         initialCTM.setTranslate(SkIntToScalar(-offset.fX), SkIntToScalar(-offset.fY));
-        initialCTM.postConcat(nonAtlased[i].fPreMat);
+        initialCTM.preConcat(layers[i].fPreMat);
 
-        layerCanvas->translate(SkIntToScalar(-offset.fX), SkIntToScalar(-offset.fY));
-        layerCanvas->concat(nonAtlased[i].fPreMat);
-        layerCanvas->concat(nonAtlased[i].fLocalMat);
+        layerCanvas->setMatrix(initialCTM);
+        layerCanvas->concat(layers[i].fLocalMat);
 
         SkRecordPartialDraw(*pict->fRecord.get(), layerCanvas, bound,
                             layer->start()+1, layer->stop(), initialCTM);
 
         layerCanvas->flush();
     }
-
-    convert_layers_to_replacements(atlased, replacements);
-    convert_layers_to_replacements(nonAtlased, replacements);
-    convert_layers_to_replacements(recycled, replacements);
 }
 
 void GrLayerHoister::UnlockLayers(GrContext* context,
-                                  const SkTDArray<GrHoistedLayer>& atlased,
-                                  const SkTDArray<GrHoistedLayer>& nonAtlased,
-                                  const SkTDArray<GrHoistedLayer>& recycled) {
+                                  const SkTDArray<GrHoistedLayer>& layers) {
     GrLayerCache* layerCache = context->getLayerCache();
 
-    for (int i = 0; i < atlased.count(); ++i) {
-        layerCache->removeUse(atlased[i].fLayer);
-    }
-
-    for (int i = 0; i < nonAtlased.count(); ++i) {
-        layerCache->removeUse(nonAtlased[i].fLayer);
-    }
-
-    for (int i = 0; i < recycled.count(); ++i) {
-        layerCache->removeUse(recycled[i].fLayer);
+    for (int i = 0; i < layers.count(); ++i) {
+        layerCache->removeUse(layers[i].fLayer);
     }
 
 #if DISABLE_CACHING
     // This code completely clears out the atlas. It is required when
     // caching is disabled so the atlas doesn't fill up and force more
     // free floating layers
     layerCache->purgeAll();
 #endif
 
     SkDEBUGCODE(layerCache->validate();)
 }