cc/resources/tiling_set_eviction_queue.h

   1 // Copyright 2014 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 #ifndef CC_RESOURCES_TILING_SET_EVICTION_QUEUE_H_
   6 #define CC_RESOURCES_TILING_SET_EVICTION_QUEUE_H_
   7
   8 #include <vector>
   9
  10 #include "cc/base/cc_export.h"
  11 #include "cc/resources/picture_layer_tiling_set.h"
  12
  13 namespace cc {
  14
  15 // This eviction queue returned tiles from all tilings in a tiling set in
  16 // the following order:
  17 // 1) Eventually rect tiles (EVENTUALLY tiles).
  18 //    1) Eventually rect tiles not required for activation from each tiling in
  19 //       the tiling set, in turn, in the following order:
  20 //       1) the first higher than high res tiling, the second one and so on
  21 //       2) the first lower than low res tiling, the second one and so on
  22 //       3) the first between high and low res tiling, the second one and so on
  23 //       4) low res tiling
  24 //       5) high res tiling
  25 //    2) Eventually rect tiles required for activation from the tiling with
  26 //       required for activation tiles. In the case of a pending tree tiling
  27 //       set that is the high res tiling. In the case of an active tree tiling
  28 //       set that is a tiling whose twin tiling is a pending tree high res
  29 //       tiling.
  30 // 2) Soon border rect and skewport rect tiles (whose priority bin is SOON
  31 //    unless the max tile priority bin is lowered by PictureLayerTilingClient).
  32 //    1) Soon border rect and skewport rect tiles not required for activation
  33 //       from each tiling in the tiling set.
  34 //        * Tilings are iterated in the same order as in the case of eventually
  35 //          rect tiles not required for activation.
  36 //        * For each tiling, first soon border rect tiles and then skewport
  37 //          rect tiles are returned.
  38 //    2) Soon border rect and skewport rect tiles required for activation from
  39 //       the tiling with required for activation tiles.
  40 //        * First soon border rect tiles and then skewport rect tiles are
  41 //          returned.
  42 // 3) Visible rect tiles (whose priority bin is NOW unless the max tile
  43 //    priority bin is lowered by PictureLayerTilingClient).
  44 //    1) Visible rect tiles not required for activation from each tiling in
  45 //       the tiling set.
  46 //        * Tilings are iterated in the same order as in the case of eventually
  47 //          rect tiles not required for activation.
  48 //        * For each tiling, first occluded tiles and then unoccluded tiles
  49 //          are returned.
  50 //    2) Visible rect tiles required for activation from the tiling with
  51 //       required for activation tiles.
  52 //        * First occluded tiles and then unoccluded tiles are returned.
  53 //    If the max tile priority bin is lowered by PictureLayerTilingClient,
  54 //    occlusion is not taken into account as occlusion is meaningful only for
  55 //    NOW tiles.
  56 //
  57 // Within each tiling and tile priority rect, tiles are returned in reverse
  58 // spiral order i.e. in (mostly) decreasing distance-to-visible order.
  59 //
  60 // If the skip_shared_out_of_order_tiles value passed to the constructor is
  61 // true (like it should be when there is a twin layer with a twin tiling set),
  62 // eviction queue does not return shared which are out of order because their
  63 // priority for tree priority is lowered or raised by a twin layer.
  64 //  * If tree_priority is SAME_PRIORITY_FOR_BOTH_TREES, this happens for
  65 //    a tile specific lower priority tree eviction queue (because priority for
  66 //    tree priority is a merged priority).
  67 //  * If tree priority is NEW_CONTENT_TAKES_PRIORITY, this happens for
  68 //    an active tree eviction queue (because priority for tree priority is
  69 //    the pending priority).
  70 //  * If tree_priority is SMOOTHNESS_TAKES_PRIORITY, this happens for a pending
  71 //    tree eviction queue (because priority for tree priority is the active
  72 //    priority).
  73 // Those skipped shared out of order tiles are when returned only by the twin
  74 // eviction queue.
  75 class CC_EXPORT TilingSetEvictionQueue {
  76  public:
  77   TilingSetEvictionQueue(PictureLayerTilingSet* tiling_set,
  78                          TreePriority tree_priority,
  79                          bool skip_shared_out_of_order_tiles);
  80   ~TilingSetEvictionQueue();
  81
  82   Tile* Top();
  83   const Tile* Top() const;
  84   void Pop();
  85   bool IsEmpty() const;
  86
  87  private:
  88   bool AdvanceToNextEvictionTile();
  89   bool AdvanceToNextPriorityBin();
  90   bool AdvanceToNextTilingRangeType();
  91   bool AdvanceToNextValidTiling();
  92
  93   PictureLayerTilingSet::TilingRange CurrentTilingRange() const;
  94   size_t CurrentTilingIndex() const;
  95   bool IsSharedOutOfOrderTile(const Tile* tile) const;
  96   size_t TilingIndexWithRequiredForActivationTiles() const;
  97
  98   PictureLayerTilingSet* tiling_set_;
  99   WhichTree tree_;
 100   TreePriority tree_priority_;
 101   bool skip_all_shared_tiles_;
 102   bool skip_shared_out_of_order_tiles_;
 103   bool processing_soon_border_rect_;
 104   bool processing_tiling_with_required_for_activation_tiles_;
 105   size_t tiling_index_with_required_for_activation_tiles_;
 106
 107   TilePriority::PriorityBin current_priority_bin_;
 108   PictureLayerTiling* current_tiling_;
 109   size_t current_tiling_index_;
 110   PictureLayerTilingSet::TilingRangeType current_tiling_range_type_;
 111   Tile* current_eviction_tile_;
 112
 113   TilingData::ReverseSpiralDifferenceIterator spiral_iterator_;
 114   TilingData::Iterator visible_iterator_;
 115   std::vector<Tile*> unoccluded_now_tiles_;
 116 };
 117
 118 }  // namespace cc
 119
 120 #endif  // CC_RESOURCES_TILING_SET_EVICTION_QUEUE_H_