cc/tiled_layer.cc

   1 // Copyright 2011 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "cc/tiled_layer.h"
   6
   7 #include "base/auto_reset.h"
   8 #include "base/basictypes.h"
   9 #include "build/build_config.h"
  10 #include "cc/layer_impl.h"
  11 #include "cc/layer_tree_host.h"
  12 #include "cc/layer_updater.h"
  13 #include "cc/overdraw_metrics.h"
  14 #include "cc/prioritized_resource.h"
  15 #include "cc/priority_calculator.h"
  16 #include "cc/tiled_layer_impl.h"
  17 #include "third_party/khronos/GLES2/gl2.h"
  18 #include "ui/gfx/rect_conversions.h"
  19
  20 namespace cc {
  21
  22 // Maximum predictive expansion of the visible area.
  23 static const int maxPredictiveTilesCount = 2;
  24
  25 // Number of rows/columns of tiles to pre-paint.
  26 // We should increase these further as all textures are
  27 // prioritized and we insure performance doesn't suffer.
  28 static const int prepaintRows = 4;
  29 static const int prepaintColumns = 2;
  30
  31
  32 class UpdatableTile : public LayerTilingData::Tile {
  33 public:
  34     static scoped_ptr<UpdatableTile> create(scoped_ptr<LayerUpdater::Resource> updaterResource)
  35     {
  36         return make_scoped_ptr(new UpdatableTile(updaterResource.Pass()));
  37     }
  38
  39     LayerUpdater::Resource* updaterResource() { return m_updaterResource.get(); }
  40     PrioritizedResource* managedResource() { return m_updaterResource->texture(); }
  41
  42     bool isDirty() const { return !dirtyRect.IsEmpty(); }
  43
  44     // Reset update state for the current frame. This should occur before painting
  45     // for all layers. Since painting one layer can invalidate another layer
  46     // after it has already painted, mark all non-dirty tiles as valid before painting
  47     // such that invalidations during painting won't prevent them from being pushed.
  48     void resetUpdateState()
  49     {
  50         updateRect = gfx::Rect();
  51         occluded = false;
  52         partialUpdate = false;
  53         validForFrame = !isDirty();
  54     }
  55
  56     // This promises to update the tile and therefore also guarantees the tile
  57     // will be valid for this frame. dirtyRect is copied into updateRect so
  58     // we can continue to track re-entrant invalidations that occur during painting.
  59     void markForUpdate()
  60     {
  61         validForFrame = true;
  62         updateRect = dirtyRect;
  63         dirtyRect = gfx::Rect();
  64     }
  65
  66     gfx::Rect dirtyRect;
  67     gfx::Rect updateRect;
  68     bool partialUpdate;
  69     bool validForFrame;
  70     bool occluded;
  71
  72 private:
  73     explicit UpdatableTile(scoped_ptr<LayerUpdater::Resource> updaterResource)
  74         : partialUpdate(false)
  75         , validForFrame(false)
  76         , occluded(false)
  77         , m_updaterResource(updaterResource.Pass())
  78     {
  79     }
  80
  81     scoped_ptr<LayerUpdater::Resource> m_updaterResource;
  82
  83     DISALLOW_COPY_AND_ASSIGN(UpdatableTile);
  84 };
  85
  86 TiledLayer::TiledLayer()
  87     : ContentsScalingLayer()
  88     , m_textureFormat(GL_INVALID_ENUM)
  89     , m_skipsDraw(false)
  90     , m_failedUpdate(false)
  91     , m_tilingOption(AutoTile)
  92 {
  93     m_tiler = LayerTilingData::create(gfx::Size(), LayerTilingData::HasBorderTexels);
  94 }
  95
  96 TiledLayer::~TiledLayer()
  97 {
  98 }
  99
 100 scoped_ptr<LayerImpl> TiledLayer::createLayerImpl(LayerTreeImpl* treeImpl)
 101 {
 102     return TiledLayerImpl::create(treeImpl, id()).PassAs<LayerImpl>();
 103 }
 104
 105 void TiledLayer::updateTileSizeAndTilingOption()
 106 {
 107     DCHECK(layerTreeHost());
 108
 109     gfx::Size defaultTileSize = layerTreeHost()->settings().defaultTileSize;
 110     gfx::Size maxUntiledLayerSize = layerTreeHost()->settings().maxUntiledLayerSize;
 111     int layerWidth = contentBounds().width();
 112     int layerHeight = contentBounds().height();
 113
 114     gfx::Size tileSize(std::min(defaultTileSize.width(), layerWidth), std::min(defaultTileSize.height(), layerHeight));
 115
 116     // Tile if both dimensions large, or any one dimension large and the other
 117     // extends into a second tile but the total layer area isn't larger than that
 118     // of the largest possible untiled layer. This heuristic allows for long skinny layers
 119     // (e.g. scrollbars) that are Nx1 tiles to minimize wasted texture space but still avoids
 120     // creating very large tiles.
 121     bool anyDimensionLarge = layerWidth > maxUntiledLayerSize.width() || layerHeight > maxUntiledLayerSize.height();
 122     bool anyDimensionOneTile = (layerWidth <= defaultTileSize.width() || layerHeight <= defaultTileSize.height())
 123                                       && (layerWidth * layerHeight) <= (maxUntiledLayerSize.width() * maxUntiledLayerSize.height());
 124     bool autoTiled = anyDimensionLarge && !anyDimensionOneTile;
 125
 126     bool isTiled;
 127     if (m_tilingOption == AlwaysTile)
 128         isTiled = true;
 129     else if (m_tilingOption == NeverTile)
 130         isTiled = false;
 131     else
 132         isTiled = autoTiled;
 133
 134     gfx::Size requestedSize = isTiled ? tileSize : contentBounds();
 135     const int maxSize = layerTreeHost()->rendererCapabilities().maxTextureSize;
 136     requestedSize.ClampToMax(gfx::Size(maxSize, maxSize));
 137     setTileSize(requestedSize);
 138 }
 139
 140 void TiledLayer::updateBounds()
 141 {
 142     gfx::Size oldBounds = m_tiler->bounds();
 143     gfx::Size newBounds = contentBounds();
 144     if (oldBounds == newBounds)
 145         return;
 146     m_tiler->setBounds(newBounds);
 147
 148     // Invalidate any areas that the new bounds exposes.
 149     Region oldRegion = gfx::Rect(gfx::Point(), oldBounds);
 150     Region newRegion = gfx::Rect(gfx::Point(), newBounds);
 151     newRegion.Subtract(oldRegion);
 152     for (Region::Iterator newRects(newRegion); newRects.has_rect(); newRects.next())
 153         invalidateContentRect(newRects.rect());
 154 }
 155
 156 void TiledLayer::setTileSize(const gfx::Size& size)
 157 {
 158     m_tiler->setTileSize(size);
 159 }
 160
 161 void TiledLayer::setBorderTexelOption(LayerTilingData::BorderTexelOption borderTexelOption)
 162 {
 163     m_tiler->setBorderTexelOption(borderTexelOption);
 164 }
 165
 166 bool TiledLayer::drawsContent() const
 167 {
 168     if (!ContentsScalingLayer::drawsContent())
 169         return false;
 170
 171     bool hasMoreThanOneTile = m_tiler->numTilesX() > 1 || m_tiler->numTilesY() > 1;
 172     if (m_tilingOption == NeverTile && hasMoreThanOneTile)
 173         return false;
 174
 175     return true;
 176 }
 177
 178 void TiledLayer::setTilingOption(TilingOption tilingOption)
 179 {
 180     m_tilingOption = tilingOption;
 181 }
 182
 183 void TiledLayer::setIsMask(bool isMask)
 184 {
 185     setTilingOption(isMask ? NeverTile : AutoTile);
 186 }
 187
 188 void TiledLayer::pushPropertiesTo(LayerImpl* layer)
 189 {
 190     ContentsScalingLayer::pushPropertiesTo(layer);
 191
 192     TiledLayerImpl* tiledLayer = static_cast<TiledLayerImpl*>(layer);
 193
 194     tiledLayer->setSkipsDraw(m_skipsDraw);
 195     tiledLayer->setTilingData(*m_tiler);
 196     std::vector<UpdatableTile*> invalidTiles;
 197
 198     for (LayerTilingData::TileMap::const_iterator iter = m_tiler->tiles().begin(); iter != m_tiler->tiles().end(); ++iter) {
 199         int i = iter->first.first;
 200         int j = iter->first.second;
 201         UpdatableTile* tile = static_cast<UpdatableTile*>(iter->second);
 202         // FIXME: This should not ever be null.
 203         if (!tile)
 204             continue;
 205
 206         if (!tile->managedResource()->haveBackingTexture()) {
 207             // Evicted tiles get deleted from both layers
 208             invalidTiles.push_back(tile);
 209             continue;
 210         }
 211
 212         if (!tile->validForFrame) {
 213             // Invalidated tiles are set so they can get different debug colors.
 214             tiledLayer->pushInvalidTile(i, j);
 215             continue;
 216         }
 217
 218         tiledLayer->pushTileProperties(i, j, tile->managedResource()->resourceId(), tile->opaqueRect(), tile->managedResource()->contentsSwizzled());
 219     }
 220     for (std::vector<UpdatableTile*>::const_iterator iter = invalidTiles.begin(); iter != invalidTiles.end(); ++iter)
 221         m_tiler->takeTile((*iter)->i(), (*iter)->j());
 222 }
 223
 224 bool TiledLayer::blocksPendingCommit() const
 225 {
 226     return true;
 227 }
 228
 229 PrioritizedResourceManager* TiledLayer::resourceManager() const
 230 {
 231     if (!layerTreeHost())
 232         return 0;
 233     return layerTreeHost()->contentsTextureManager();
 234 }
 235
 236 const PrioritizedResource* TiledLayer::resourceAtForTesting(int i, int j) const
 237 {
 238     UpdatableTile* tile = tileAt(i, j);
 239     if (!tile)
 240         return 0;
 241     return tile->managedResource();
 242 }
 243
 244 void TiledLayer::setLayerTreeHost(LayerTreeHost* host)
 245 {
 246     if (host && host != layerTreeHost()) {
 247         for (LayerTilingData::TileMap::const_iterator iter = m_tiler->tiles().begin(); iter != m_tiler->tiles().end(); ++iter) {
 248             UpdatableTile* tile = static_cast<UpdatableTile*>(iter->second);
 249             // FIXME: This should not ever be null.
 250             if (!tile)
 251                 continue;
 252             tile->managedResource()->setTextureManager(host->contentsTextureManager());
 253         }
 254     }
 255     ContentsScalingLayer::setLayerTreeHost(host);
 256 }
 257
 258 UpdatableTile* TiledLayer::tileAt(int i, int j) const
 259 {
 260     return static_cast<UpdatableTile*>(m_tiler->tileAt(i, j));
 261 }
 262
 263 UpdatableTile* TiledLayer::createTile(int i, int j)
 264 {
 265     createUpdaterIfNeeded();
 266
 267     scoped_ptr<UpdatableTile> tile(UpdatableTile::create(updater()->createResource(resourceManager())));
 268     tile->managedResource()->setDimensions(m_tiler->tileSize(), m_textureFormat);
 269
 270     UpdatableTile* addedTile = tile.get();
 271     m_tiler->addTile(tile.PassAs<LayerTilingData::Tile>(), i, j);
 272
 273     addedTile->dirtyRect = m_tiler->tileRect(addedTile);
 274
 275     // Temporary diagnostic crash.
 276     CHECK(addedTile);
 277     CHECK(tileAt(i, j));
 278
 279     return addedTile;
 280 }
 281
 282 void TiledLayer::setNeedsDisplayRect(const gfx::RectF& dirtyRect)
 283 {
 284     invalidateContentRect(layerRectToContentRect(dirtyRect));
 285     ContentsScalingLayer::setNeedsDisplayRect(dirtyRect);
 286 }
 287
 288 void TiledLayer::invalidateContentRect(const gfx::Rect& contentRect)
 289 {
 290     updateBounds();
 291     if (m_tiler->isEmpty() || contentRect.IsEmpty() || m_skipsDraw)
 292         return;
 293
 294     for (LayerTilingData::TileMap::const_iterator iter = m_tiler->tiles().begin(); iter != m_tiler->tiles().end(); ++iter) {
 295         UpdatableTile* tile = static_cast<UpdatableTile*>(iter->second);
 296         DCHECK(tile);
 297         // FIXME: This should not ever be null.
 298         if (!tile)
 299             continue;
 300         gfx::Rect bound = m_tiler->tileRect(tile);
 301         bound.Intersect(contentRect);
 302         tile->dirtyRect.Union(bound);
 303     }
 304 }
 305
 306 // Returns true if tile is dirty and only part of it needs to be updated.
 307 bool TiledLayer::tileOnlyNeedsPartialUpdate(UpdatableTile* tile)
 308 {
 309     return !tile->dirtyRect.Contains(m_tiler->tileRect(tile)) && tile->managedResource()->haveBackingTexture();
 310 }
 311
 312 bool TiledLayer::updateTiles(int left, int top, int right, int bottom, ResourceUpdateQueue& queue, const OcclusionTracker* occlusion, RenderingStats* stats, bool& didPaint)
 313 {
 314     didPaint = false;
 315     createUpdaterIfNeeded();
 316
 317     bool ignoreOcclusions = !occlusion;
 318     if (!haveTexturesForTiles(left, top, right, bottom, ignoreOcclusions)) {
 319         m_failedUpdate = true;
 320         return false;
 321     }
 322
 323     gfx::Rect paintRect = markTilesForUpdate(left, top, right, bottom, ignoreOcclusions);
 324
 325     if (occlusion)
 326         occlusion->overdrawMetrics().didPaint(paintRect);
 327
 328     if (paintRect.IsEmpty())
 329         return true;
 330
 331     didPaint = true;
 332     updateTileTextures(paintRect, left, top, right, bottom, queue, occlusion, stats);
 333     return true;
 334 }
 335
 336 void TiledLayer::markOcclusionsAndRequestTextures(int left, int top, int right, int bottom, const OcclusionTracker* occlusion)
 337 {
 338     // There is some difficult dependancies between occlusions, recording occlusion metrics
 339     // and requesting memory so those are encapsulated in this function:
 340     // - We only want to call requestLate on unoccluded textures (to preserve
 341     //   memory for other layers when near OOM).
 342     // - We only want to record occlusion metrics if all memory requests succeed.
 343
 344     int occludedTileCount = 0;
 345     bool succeeded = true;
 346     for (int j = top; j <= bottom; ++j) {
 347         for (int i = left; i <= right; ++i) {
 348             UpdatableTile* tile = tileAt(i, j);
 349             DCHECK(tile); // Did setTexturePriorities get skipped?
 350             // FIXME: This should not ever be null.
 351             if (!tile)
 352                 continue;
 353             DCHECK(!tile->occluded); // Did resetUpdateState get skipped? Are we doing more than one occlusion pass?
 354             gfx::Rect visibleTileRect = gfx::IntersectRects(m_tiler->tileBounds(i, j), visibleContentRect());
 355             if (occlusion && occlusion->occluded(renderTarget(), visibleTileRect, drawTransform(), drawTransformIsAnimating(), isClipped(), clipRect())) {
 356                 tile->occluded = true;
 357                 occludedTileCount++;
 358             } else {
 359                 succeeded &= tile->managedResource()->requestLate();
 360             }
 361         }
 362     }
 363
 364     if (!succeeded)
 365         return;
 366     if (occlusion)
 367         occlusion->overdrawMetrics().didCullTilesForUpload(occludedTileCount);
 368 }
 369
 370 bool TiledLayer::haveTexturesForTiles(int left, int top, int right, int bottom, bool ignoreOcclusions)
 371 {
 372     for (int j = top; j <= bottom; ++j) {
 373         for (int i = left; i <= right; ++i) {
 374             UpdatableTile* tile = tileAt(i, j);
 375             DCHECK(tile); // Did setTexturePriorites get skipped?
 376             // FIXME: This should not ever be null.
 377             if (!tile)
 378                 continue;
 379
 380             // Ensure the entire tile is dirty if we don't have the texture.
 381             if (!tile->managedResource()->haveBackingTexture())
 382                 tile->dirtyRect = m_tiler->tileRect(tile);
 383
 384             // If using occlusion and the visible region of the tile is occluded,
 385             // don't reserve a texture or update the tile.
 386             if (tile->occluded && !ignoreOcclusions)
 387                 continue;
 388
 389             if (!tile->managedResource()->canAcquireBackingTexture())
 390                 return false;
 391         }
 392     }
 393     return true;
 394 }
 395
 396 gfx::Rect TiledLayer::markTilesForUpdate(int left, int top, int right, int bottom, bool ignoreOcclusions)
 397 {
 398   gfx::Rect paintRect;
 399     for (int j = top; j <= bottom; ++j) {
 400         for (int i = left; i <= right; ++i) {
 401             UpdatableTile* tile = tileAt(i, j);
 402             DCHECK(tile); // Did setTexturePriorites get skipped?
 403             // FIXME: This should not ever be null.
 404             if (!tile)
 405                 continue;
 406             if (tile->occluded && !ignoreOcclusions)
 407                 continue;
 408             // FIXME: Decide if partial update should be allowed based on cost
 409             // of update. https://bugs.webkit.org/show_bug.cgi?id=77376
 410             if (tile->isDirty() && layerTreeHost() && layerTreeHost()->bufferedUpdates()) {
 411                 // If we get a partial update, we use the same texture, otherwise return the
 412                 // current texture backing, so we don't update visible textures non-atomically.
 413                 // If the current backing is in-use, it won't be deleted until after the commit
 414                 // as the texture manager will not allow deletion or recycling of in-use textures.
 415                 if (tileOnlyNeedsPartialUpdate(tile) && layerTreeHost()->requestPartialTextureUpdate())
 416                     tile->partialUpdate = true;
 417                 else {
 418                     tile->dirtyRect = m_tiler->tileRect(tile);
 419                     tile->managedResource()->returnBackingTexture();
 420                 }
 421             }
 422
 423             paintRect.Union(tile->dirtyRect);
 424             tile->markForUpdate();
 425         }
 426     }
 427     return paintRect;
 428 }
 429
 430 void TiledLayer::updateTileTextures(const gfx::Rect& paintRect, int left, int top, int right, int bottom, ResourceUpdateQueue& queue, const OcclusionTracker* occlusion, RenderingStats* stats)
 431 {
 432     // The updateRect should be in layer space. So we have to convert the paintRect from content space to layer space.
 433     float widthScale = bounds().width() / static_cast<float>(contentBounds().width());
 434     float heightScale = bounds().height() / static_cast<float>(contentBounds().height());
 435     m_updateRect = gfx::ScaleRect(paintRect, widthScale, heightScale);
 436
 437     // Calling prepareToUpdate() calls into WebKit to paint, which may have the side
 438     // effect of disabling compositing, which causes our reference to the texture updater to be deleted.
 439     // However, we can't free the memory backing the SkCanvas until the paint finishes,
 440     // so we grab a local reference here to hold the updater alive until the paint completes.
 441     scoped_refptr<LayerUpdater> protector(updater());
 442     gfx::Rect paintedOpaqueRect;
 443     updater()->prepareToUpdate(paintRect, m_tiler->tileSize(), 1 / widthScale, 1 / heightScale, paintedOpaqueRect, stats);
 444
 445     for (int j = top; j <= bottom; ++j) {
 446         for (int i = left; i <= right; ++i) {
 447             UpdatableTile* tile = tileAt(i, j);
 448             DCHECK(tile); // Did setTexturePriorites get skipped?
 449             // FIXME: This should not ever be null.
 450             if (!tile)
 451                 continue;
 452
 453             gfx::Rect tileRect = m_tiler->tileBounds(i, j);
 454
 455             // Use updateRect as the above loop copied the dirty rect for this frame to updateRect.
 456             const gfx::Rect& dirtyRect = tile->updateRect;
 457             if (dirtyRect.IsEmpty())
 458                 continue;
 459
 460             // Save what was painted opaque in the tile. Keep the old area if the paint didn't touch it, and didn't paint some
 461             // other part of the tile opaque.
 462             gfx::Rect tilePaintedRect = gfx::IntersectRects(tileRect, paintRect);
 463             gfx::Rect tilePaintedOpaqueRect = gfx::IntersectRects(tileRect, paintedOpaqueRect);
 464             if (!tilePaintedRect.IsEmpty()) {
 465                 gfx::Rect paintInsideTileOpaqueRect = gfx::IntersectRects(tile->opaqueRect(), tilePaintedRect);
 466                 bool paintInsideTileOpaqueRectIsNonOpaque = !tilePaintedOpaqueRect.Contains(paintInsideTileOpaqueRect);
 467                 bool opaquePaintNotInsideTileOpaqueRect = !tilePaintedOpaqueRect.IsEmpty() && !tile->opaqueRect().Contains(tilePaintedOpaqueRect);
 468
 469                 if (paintInsideTileOpaqueRectIsNonOpaque || opaquePaintNotInsideTileOpaqueRect)
 470                     tile->setOpaqueRect(tilePaintedOpaqueRect);
 471             }
 472
 473             // sourceRect starts as a full-sized tile with border texels included.
 474             gfx::Rect sourceRect = m_tiler->tileRect(tile);
 475             sourceRect.Intersect(dirtyRect);
 476             // Paint rect not guaranteed to line up on tile boundaries, so
 477             // make sure that sourceRect doesn't extend outside of it.
 478             sourceRect.Intersect(paintRect);
 479
 480             tile->updateRect = sourceRect;
 481
 482             if (sourceRect.IsEmpty())
 483                 continue;
 484
 485             const gfx::Point anchor = m_tiler->tileRect(tile).origin();
 486
 487             // Calculate tile-space rectangle to upload into.
 488             gfx::Vector2d destOffset = sourceRect.origin() - anchor;
 489             CHECK(destOffset.x() >= 0);
 490             CHECK(destOffset.y() >= 0);
 491
 492             // Offset from paint rectangle to this tile's dirty rectangle.
 493             gfx::Vector2d paintOffset = sourceRect.origin() - paintRect.origin();
 494             CHECK(paintOffset.x() >= 0);
 495             CHECK(paintOffset.y() >= 0);
 496             CHECK(paintOffset.x() + sourceRect.width() <= paintRect.width());
 497             CHECK(paintOffset.y() + sourceRect.height() <= paintRect.height());
 498
 499             tile->updaterResource()->update(queue, sourceRect, destOffset, tile->partialUpdate, stats);
 500             if (occlusion)
 501                 occlusion->overdrawMetrics().didUpload(gfx::Transform(), sourceRect, tile->opaqueRect());
 502
 503         }
 504     }
 505 }
 506
 507 // This picks a small animated layer to be anything less than one viewport. This
 508 // is specifically for page transitions which are viewport-sized layers. The extra
 509 // tile of padding is due to these layers being slightly larger than the viewport
 510 // in some cases.
 511 bool TiledLayer::isSmallAnimatedLayer() const
 512 {
 513     if (!drawTransformIsAnimating() && !screenSpaceTransformIsAnimating())
 514         return false;
 515     gfx::Size viewportSize = layerTreeHost() ? layerTreeHost()->deviceViewportSize() : gfx::Size();
 516     gfx::Rect contentRect(gfx::Point(), contentBounds());
 517     return contentRect.width() <= viewportSize.width() + m_tiler->tileSize().width()
 518         && contentRect.height() <= viewportSize.height() + m_tiler->tileSize().height();
 519 }
 520
 521 namespace {
 522 // FIXME: Remove this and make this based on distance once distance can be calculated
 523 // for offscreen layers. For now, prioritize all small animated layers after 512
 524 // pixels of pre-painting.
 525 void setPriorityForTexture(const gfx::Rect& visibleRect,
 526                            const gfx::Rect& tileRect,
 527                            bool drawsToRoot,
 528                            bool isSmallAnimatedLayer,
 529                            PrioritizedResource* texture)
 530 {
 531     int priority = PriorityCalculator::lowestPriority();
 532     if (!visibleRect.IsEmpty())
 533         priority = PriorityCalculator::priorityFromDistance(visibleRect, tileRect, drawsToRoot);
 534     if (isSmallAnimatedLayer)
 535         priority = PriorityCalculator::maxPriority(priority, PriorityCalculator::smallAnimatedLayerMinPriority());
 536     if (priority != PriorityCalculator::lowestPriority())
 537         texture->setRequestPriority(priority);
 538 }
 539 } // namespace
 540
 541 void TiledLayer::setTexturePriorities(const PriorityCalculator& priorityCalc)
 542 {
 543     updateBounds();
 544     resetUpdateState();
 545     updateScrollPrediction();
 546
 547     if (m_tiler->hasEmptyBounds())
 548         return;
 549
 550     bool drawsToRoot = !renderTarget()->parent();
 551     bool smallAnimatedLayer = isSmallAnimatedLayer();
 552
 553     // Minimally create the tiles in the desired pre-paint rect.
 554     gfx::Rect createTilesRect = idlePaintRect();
 555     if (smallAnimatedLayer)
 556         createTilesRect = gfx::Rect(gfx::Point(), contentBounds());
 557     if (!createTilesRect.IsEmpty()) {
 558         int left, top, right, bottom;
 559         m_tiler->contentRectToTileIndices(createTilesRect, left, top, right, bottom);
 560         for (int j = top; j <= bottom; ++j) {
 561             for (int i = left; i <= right; ++i) {
 562                 if (!tileAt(i, j))
 563                     createTile(i, j);
 564             }
 565         }
 566     }
 567
 568     // Now update priorities on all tiles we have in the layer, no matter where they are.
 569     for (LayerTilingData::TileMap::const_iterator iter = m_tiler->tiles().begin(); iter != m_tiler->tiles().end(); ++iter) {
 570         UpdatableTile* tile = static_cast<UpdatableTile*>(iter->second);
 571         // FIXME: This should not ever be null.
 572         if (!tile)
 573             continue;
 574         gfx::Rect tileRect = m_tiler->tileRect(tile);
 575         setPriorityForTexture(m_predictedVisibleRect, tileRect, drawsToRoot, smallAnimatedLayer, tile->managedResource());
 576     }
 577 }
 578
 579 Region TiledLayer::visibleContentOpaqueRegion() const
 580 {
 581     if (m_skipsDraw)
 582         return Region();
 583     if (contentsOpaque())
 584         return visibleContentRect();
 585     return m_tiler->opaqueRegionInContentRect(visibleContentRect());
 586 }
 587
 588 void TiledLayer::resetUpdateState()
 589 {
 590     m_skipsDraw = false;
 591     m_failedUpdate = false;
 592
 593     LayerTilingData::TileMap::const_iterator end = m_tiler->tiles().end();
 594     for (LayerTilingData::TileMap::const_iterator iter = m_tiler->tiles().begin(); iter != end; ++iter) {
 595         UpdatableTile* tile = static_cast<UpdatableTile*>(iter->second);
 596         // FIXME: This should not ever be null.
 597         if (!tile)
 598             continue;
 599         tile->resetUpdateState();
 600     }
 601 }
 602
 603 namespace {
 604 gfx::Rect expandRectByDelta(gfx::Rect rect, gfx::Vector2d delta) {
 605     int width  = rect.width() + abs(delta.x());
 606     int height = rect.height() + abs(delta.y());
 607     int x = rect.x() + ((delta.x() < 0)  ? delta.x()  : 0);
 608     int y = rect.y() + ((delta.y() < 0) ? delta.y() : 0);
 609     return gfx::Rect(x, y, width, height);
 610 }
 611 }
 612
 613 void TiledLayer::updateScrollPrediction()
 614 {
 615     // This scroll prediction is very primitive and should be replaced by a
 616     // a recursive calculation on all layers which uses actual scroll/animation
 617     // velocities. To insure this doesn't miss-predict, we only use it to predict
 618     // the visibleRect if:
 619     // - contentBounds() hasn't changed.
 620     // - visibleRect.size() hasn't changed.
 621     // These two conditions prevent rotations, scales, pinch-zooms etc. where
 622     // the prediction would be incorrect.
 623     gfx::Vector2d delta = visibleContentRect().CenterPoint() - m_previousVisibleRect.CenterPoint();
 624     m_predictedScroll = -delta;
 625     m_predictedVisibleRect = visibleContentRect();
 626     if (m_previousContentBounds == contentBounds() && m_previousVisibleRect.size() == visibleContentRect().size()) {
 627         // Only expand the visible rect in the major scroll direction, to prevent
 628         // massive paints due to diagonal scrolls.
 629         gfx::Vector2d majorScrollDelta = (abs(delta.x()) > abs(delta.y())) ? gfx::Vector2d(delta.x(), 0) : gfx::Vector2d(0, delta.y());
 630         m_predictedVisibleRect = expandRectByDelta(visibleContentRect(), majorScrollDelta);
 631
 632         // Bound the prediction to prevent unbounded paints, and clamp to content bounds.
 633         gfx::Rect bound = visibleContentRect();
 634         bound.Inset(-m_tiler->tileSize().width() * maxPredictiveTilesCount,
 635                     -m_tiler->tileSize().height() * maxPredictiveTilesCount);
 636         bound.Intersect(gfx::Rect(gfx::Point(), contentBounds()));
 637         m_predictedVisibleRect.Intersect(bound);
 638     }
 639     m_previousContentBounds = contentBounds();
 640     m_previousVisibleRect = visibleContentRect();
 641 }
 642
 643 void TiledLayer::update(ResourceUpdateQueue& queue, const OcclusionTracker* occlusion, RenderingStats* stats)
 644 {
 645     DCHECK(!m_skipsDraw && !m_failedUpdate); // Did resetUpdateState get skipped?
 646
 647     {
 648         base::AutoReset<bool> ignoreSetNeedsCommit(&m_ignoreSetNeedsCommit, true);
 649
 650         ContentsScalingLayer::update(queue, occlusion, stats);
 651         updateBounds();
 652     }
 653
 654     if (m_tiler->hasEmptyBounds() || !drawsContent())
 655         return;
 656
 657     bool didPaint = false;
 658
 659     // Animation pre-paint. If the layer is small, try to paint it all
 660     // immediately whether or not it is occluded, to avoid paint/upload
 661     // hiccups while it is animating.
 662     if (isSmallAnimatedLayer()) {
 663         int left, top, right, bottom;
 664         m_tiler->contentRectToTileIndices(gfx::Rect(gfx::Point(), contentBounds()), left, top, right, bottom);
 665         updateTiles(left, top, right, bottom, queue, 0, stats, didPaint);
 666         if (didPaint)
 667             return;
 668         // This was an attempt to paint the entire layer so if we fail it's okay,
 669         // just fallback on painting visible etc. below.
 670         m_failedUpdate = false;
 671     }
 672
 673     if (m_predictedVisibleRect.IsEmpty())
 674         return;
 675
 676     // Visible painting. First occlude visible tiles and paint the non-occluded tiles.
 677     int left, top, right, bottom;
 678     m_tiler->contentRectToTileIndices(m_predictedVisibleRect, left, top, right, bottom);
 679     markOcclusionsAndRequestTextures(left, top, right, bottom, occlusion);
 680     m_skipsDraw = !updateTiles(left, top, right, bottom, queue, occlusion, stats, didPaint);
 681     if (m_skipsDraw)
 682         m_tiler->reset();
 683     if (m_skipsDraw || didPaint)
 684         return;
 685
 686     // If we have already painting everything visible. Do some pre-painting while idle.
 687     gfx::Rect idlePaintContentRect = idlePaintRect();
 688     if (idlePaintContentRect.IsEmpty())
 689         return;
 690
 691     // Prepaint anything that was occluded but inside the layer's visible region.
 692     if (!updateTiles(left, top, right, bottom, queue, 0, stats, didPaint) || didPaint)
 693         return;
 694
 695     int prepaintLeft, prepaintTop, prepaintRight, prepaintBottom;
 696     m_tiler->contentRectToTileIndices(idlePaintContentRect, prepaintLeft, prepaintTop, prepaintRight, prepaintBottom);
 697
 698     // Then expand outwards one row/column at a time until we find a dirty row/column
 699     // to update. Increment along the major and minor scroll directions first.
 700     gfx::Vector2d delta = -m_predictedScroll;
 701     delta = gfx::Vector2d(delta.x() == 0 ? 1 : delta.x(),
 702                           delta.y() == 0 ? 1 : delta.y());
 703     gfx::Vector2d majorDelta = (abs(delta.x()) >  abs(delta.y())) ? gfx::Vector2d(delta.x(), 0) : gfx::Vector2d(0, delta.y());
 704     gfx::Vector2d minorDelta = (abs(delta.x()) <= abs(delta.y())) ? gfx::Vector2d(delta.x(), 0) : gfx::Vector2d(0, delta.y());
 705     gfx::Vector2d deltas[4] = {majorDelta, minorDelta, -majorDelta, -minorDelta};
 706     for(int i = 0; i < 4; i++) {
 707         if (deltas[i].y() > 0) {
 708             while (bottom < prepaintBottom) {
 709                 ++bottom;
 710                 if (!updateTiles(left, bottom, right, bottom, queue, 0, stats, didPaint) || didPaint)
 711                     return;
 712             }
 713         }
 714         if (deltas[i].y() < 0) {
 715             while (top > prepaintTop) {
 716                 --top;
 717                 if (!updateTiles(left, top, right, top, queue, 0, stats, didPaint) || didPaint)
 718                     return;
 719             }
 720         }
 721         if (deltas[i].x() < 0) {
 722             while (left > prepaintLeft) {
 723                 --left;
 724                 if (!updateTiles(left, top, left, bottom, queue, 0, stats, didPaint) || didPaint)
 725                     return;
 726             }
 727         }
 728         if (deltas[i].x() > 0) {
 729             while (right < prepaintRight) {
 730                 ++right;
 731                 if (!updateTiles(right, top, right, bottom, queue, 0, stats, didPaint) || didPaint)
 732                     return;
 733             }
 734         }
 735     }
 736 }
 737
 738 bool TiledLayer::needsIdlePaint()
 739 {
 740     // Don't trigger more paints if we failed (as we'll just fail again).
 741     if (m_failedUpdate || visibleContentRect().IsEmpty() || m_tiler->hasEmptyBounds() || !drawsContent())
 742         return false;
 743
 744     gfx::Rect idlePaintContentRect = idlePaintRect();
 745     if (idlePaintContentRect.IsEmpty())
 746         return false;
 747
 748     int left, top, right, bottom;
 749     m_tiler->contentRectToTileIndices(idlePaintContentRect, left, top, right, bottom);
 750
 751     for (int j = top; j <= bottom; ++j) {
 752         for (int i = left; i <= right; ++i) {
 753             UpdatableTile* tile = tileAt(i, j);
 754             DCHECK(tile); // Did setTexturePriorities get skipped?
 755             if (!tile)
 756                 continue;
 757
 758             bool updated = !tile->updateRect.IsEmpty();
 759             bool canAcquire = tile->managedResource()->canAcquireBackingTexture();
 760             bool dirty = tile->isDirty() || !tile->managedResource()->haveBackingTexture();
 761             if (!updated && canAcquire && dirty)
 762                 return true;
 763         }
 764     }
 765     return false;
 766 }
 767
 768 gfx::Rect TiledLayer::idlePaintRect()
 769 {
 770     // Don't inflate an empty rect.
 771     if (visibleContentRect().IsEmpty())
 772       return gfx::Rect();
 773
 774     gfx::Rect prepaintRect = visibleContentRect();
 775     prepaintRect.Inset(-m_tiler->tileSize().width() * prepaintColumns,
 776                        -m_tiler->tileSize().height() * prepaintRows);
 777     gfx::Rect contentRect(gfx::Point(), contentBounds());
 778     prepaintRect.Intersect(contentRect);
 779
 780     return prepaintRect;
 781 }
 782
 783 }  // namespace cc