| // Copyright 2014 The Chromium Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| #include "cc/output/bsp_tree.h" |
| |
| #include <list> |
| #include <vector> |
| |
| #include "base/memory/scoped_ptr.h" |
| #include "cc/base/scoped_ptr_deque.h" |
| #include "cc/base/scoped_ptr_vector.h" |
| #include "cc/output/bsp_compare_result.h" |
| #include "cc/quads/draw_polygon.h" |
| |
| namespace cc { |
| |
| BspNode::BspNode(scoped_ptr<DrawPolygon> data) : node_data(data.Pass()) { |
| } |
| |
| BspNode::~BspNode() { |
| } |
| |
| BspTree::BspTree(ScopedPtrDeque<DrawPolygon>* list) { |
| if (list->size() == 0) |
| return; |
| |
| root_ = make_scoped_ptr(new BspNode(list->take_front())); |
| BuildTree(root_.get(), list); |
| } |
| |
| // The idea behind using a deque for BuildTree's input is that we want to be |
| // able to place polygons that we've decided aren't splitting plane candidates |
| // at the back of the queue while moving the candidate splitting planes to the |
| // front when the heuristic decides that they're a better choice. This way we |
| // can always simply just take from the front of the deque for our node's |
| // data. |
| void BspTree::BuildTree(BspNode* node, |
| ScopedPtrDeque<DrawPolygon>* polygon_list) { |
| ScopedPtrDeque<DrawPolygon> front_list; |
| ScopedPtrDeque<DrawPolygon> back_list; |
| |
| // We take in a list of polygons at this level of the tree, and have to |
| // find a splitting plane, then classify polygons as either in front of |
| // or behind that splitting plane. |
| while (polygon_list->size() > 0) { |
| // Is this particular polygon in front of or behind our splitting polygon. |
| BspCompareResult comparer_result = |
| GetNodePositionRelative(*polygon_list->front(), *(node->node_data)); |
| |
| // If it's clearly behind or in front of the splitting plane, we use the |
| // heuristic to decide whether or not we should put it at the back |
| // or front of the list. |
| switch (comparer_result) { |
| case BSP_FRONT: |
| front_list.push_back(polygon_list->take_front().Pass()); |
| break; |
| case BSP_BACK: |
| back_list.push_back(polygon_list->take_front().Pass()); |
| break; |
| case BSP_SPLIT: |
| { |
| scoped_ptr<DrawPolygon> polygon; |
| scoped_ptr<DrawPolygon> new_front; |
| scoped_ptr<DrawPolygon> new_back; |
| bool split_result = false; |
| // Time to split this geometry, *it needs to be split by node_data. |
| polygon = polygon_list->take_front(); |
| split_result = |
| polygon->Split(*(node->node_data), &new_front, &new_back); |
| DCHECK(split_result); |
| if (!split_result) { |
| break; |
| } |
| front_list.push_back(new_front.Pass()); |
| back_list.push_back(new_back.Pass()); |
| break; |
| } |
| case BSP_COPLANAR_FRONT: |
| node->coplanars_front.push_back(polygon_list->take_front()); |
| break; |
| case BSP_COPLANAR_BACK: |
| node->coplanars_back.push_back(polygon_list->take_front()); |
| break; |
| default: |
| NOTREACHED(); |
| break; |
| } |
| } |
| |
| // Build the back subtree using the front of the back_list as our splitter. |
| if (back_list.size() > 0) { |
| node->back_child = make_scoped_ptr(new BspNode(back_list.take_front())); |
| BuildTree(node->back_child.get(), &back_list); |
| } |
| |
| // Build the front subtree using the front of the front_list as our splitter. |
| if (front_list.size() > 0) { |
| node->front_child = |
| scoped_ptr<BspNode>(new BspNode(front_list.take_front())); |
| BuildTree(node->front_child.get(), &front_list); |
| } |
| } |
| |
| BspCompareResult BspTree::GetNodePositionRelative(const DrawPolygon& node_a, |
| const DrawPolygon& node_b) { |
| return DrawPolygon::SideCompare(node_a, node_b); |
| } |
| |
| // The base comparer with 0,0,0 as camera position facing forward |
| BspCompareResult BspTree::GetCameraPositionRelative(const DrawPolygon& node) { |
| if (node.normal().z() > 0.0f) { |
| return BSP_FRONT; |
| } |
| return BSP_BACK; |
| } |
| |
| BspTree::~BspTree() { |
| } |
| |
| } // namespace cc |