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 // This happens for a tile specific lower priority tree eviction queue
  65 // (because eviction priority the combined priority).
  66 // Those skipped shared out of order tiles are when returned only by the twin
  67 // eviction queue.
  68 class CC_EXPORT TilingSetEvictionQueue {
  69  public:
  70   TilingSetEvictionQueue(PictureLayerTilingSet* tiling_set,
  71                          bool skip_shared_out_of_order_tiles);
  72   ~TilingSetEvictionQueue();
  73
  74   Tile* Top();
  75   const Tile* Top() const;
  76   void Pop();
  77   bool IsEmpty() const;
  78
  79  private:
  80   bool AdvanceToNextEvictionTile();
  81   bool AdvanceToNextPriorityBin();
  82   bool AdvanceToNextTilingRangeType();
  83   bool AdvanceToNextValidTiling();
  84
  85   PictureLayerTilingSet::TilingRange CurrentTilingRange() const;
  86   size_t CurrentTilingIndex() const;
  87
  88   PictureLayerTilingSet* tiling_set_;
  89   WhichTree tree_;
  90   bool skip_shared_out_of_order_tiles_;
  91   bool processing_soon_border_rect_;
  92   bool processing_required_for_activation_tiles_;
  93
  94   TilePriority::PriorityBin current_priority_bin_;
  95   PictureLayerTiling* current_tiling_;
  96   size_t current_tiling_index_;
  97   PictureLayerTilingSet::TilingRangeType current_tiling_range_type_;
  98   Tile* current_eviction_tile_;
  99
 100   TilingData::ReverseSpiralDifferenceIterator spiral_iterator_;
 101   TilingData::Iterator visible_iterator_;
 102   std::vector<Tile*> unoccluded_now_tiles_;
 103 };
 104
 105 }  // namespace cc
 106
 107 #endif  // CC_RESOURCES_TILING_SET_EVICTION_QUEUE_H_