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| 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 #include "cc/output/bsp_tree.h" |
| 6 |
| 7 #include <list> |
| 8 #include <vector> |
| 9 |
| 10 #include "base/memory/scoped_ptr.h" |
| 11 #include "cc/base/scoped_ptr_deque.h" |
| 12 #include "cc/base/scoped_ptr_vector.h" |
| 13 #include "cc/output/bsp_compare_result.h" |
| 14 #include "cc/quads/draw_polygon.h" |
| 15 |
| 16 namespace cc { |
| 17 |
| 18 BspNode::BspNode(scoped_ptr<DrawPolygon> data) : node_data(data.Pass()) { |
| 19 } |
| 20 |
| 21 BspNode::~BspNode() { |
| 22 } |
| 23 |
| 24 BspTree::BspTree(ScopedPtrDeque<DrawPolygon>* list) { |
| 25 if (list->size() == 0) |
| 26 return; |
| 27 |
| 28 root_ = scoped_ptr<BspNode>(new BspNode(list->take_front())); |
| 29 BuildTree(root_.get(), list); |
| 30 } |
| 31 |
| 32 // The idea behind using a deque for BuildTree's input is that we want to be |
| 33 // able to place polygons that we've decided aren't splitting plane candidates |
| 34 // at the back of the queue while moving the candidate splitting planes to the |
| 35 // front when the heuristic decides that they're a better choice. This way we |
| 36 // can always simply just take from the front of the deque for our node's |
| 37 // data. |
| 38 void BspTree::BuildTree(BspNode* node, |
| 39 ScopedPtrDeque<DrawPolygon>* polygon_list) { |
| 40 ScopedPtrDeque<DrawPolygon> front_list; |
| 41 ScopedPtrDeque<DrawPolygon> back_list; |
| 42 |
| 43 // We take in a list of polygons at this level of the tree, and have to |
| 44 // find a splitting plane, then classify polygons as either in front of |
| 45 // or behind that splitting plane. |
| 46 while (polygon_list->size() > 0) { |
| 47 // Is this particular polygon in front of or behind our splitting polygon. |
| 48 BspCompareResult comparer_result = |
| 49 GetNodePositionRelative(*polygon_list->front(), *(node->node_data)); |
| 50 |
| 51 // If it's clearly behind or in front of the splitting plane, we use the |
| 52 // heuristic to decide whether or not we should put it at the back |
| 53 // or front of the list. |
| 54 switch (comparer_result) { |
| 55 case BSP_FRONT: |
| 56 front_list.push_back(polygon_list->take_front().Pass()); |
| 57 break; |
| 58 case BSP_BACK: |
| 59 back_list.push_back(polygon_list->take_front().Pass()); |
| 60 break; |
| 61 case BSP_SPLIT: |
| 62 { |
| 63 scoped_ptr<DrawPolygon> polygon; |
| 64 scoped_ptr<DrawPolygon> new_front; |
| 65 scoped_ptr<DrawPolygon> new_back; |
| 66 bool split_result = false; |
| 67 // Time to split this geometry, *it needs to be split by node_data. |
| 68 polygon = polygon_list->take_front(); |
| 69 split_result = |
| 70 polygon->Split(*(node->node_data), &new_front, &new_back); |
| 71 DCHECK(split_result); |
| 72 if (!split_result) { |
| 73 break; |
| 74 } |
| 75 front_list.push_back(new_front.Pass()); |
| 76 back_list.push_back(new_back.Pass()); |
| 77 break; |
| 78 } |
| 79 case BSP_COPLANAR_FRONT: |
| 80 node->coplanars_front.push_back(polygon_list->take_front()); |
| 81 break; |
| 82 case BSP_COPLANAR_BACK: |
| 83 node->coplanars_back.push_back(polygon_list->take_front()); |
| 84 break; |
| 85 default: |
| 86 NOTREACHED(); |
| 87 break; |
| 88 } |
| 89 } |
| 90 |
| 91 // Build the back subtree using the front of the back_list as our splitter. |
| 92 if (back_list.size() > 0) { |
| 93 node->back_child = scoped_ptr<BspNode>(new BspNode(back_list.take_front())); |
| 94 BuildTree(node->back_child.get(), &back_list); |
| 95 } |
| 96 |
| 97 // Build the front subtree using the front of the front_list as our splitter. |
| 98 if (front_list.size() > 0) { |
| 99 node->front_child = |
| 100 scoped_ptr<BspNode>(new BspNode(front_list.take_front())); |
| 101 BuildTree(node->front_child.get(), &front_list); |
| 102 } |
| 103 } |
| 104 |
| 105 BspCompareResult BspTree::GetNodePositionRelative(const DrawPolygon& node_a, |
| 106 const DrawPolygon& node_b) { |
| 107 return DrawPolygon::SideCompare(node_a, node_b); |
| 108 } |
| 109 |
| 110 // The base comparer with 0,0,0 as camera position facing forward |
| 111 BspCompareResult BspTree::GetCameraPositionRelative(const DrawPolygon& node) { |
| 112 if (node.normal().z() > 0.0f) { |
| 113 return BSP_FRONT; |
| 114 } |
| 115 return BSP_BACK; |
| 116 } |
| 117 |
| 118 BspTree::~BspTree() { |
| 119 } |
| 120 |
| 121 } // namespace cc |
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