Index: cc/output/bsp_tree.cc |
diff --git a/cc/output/bsp_tree.cc b/cc/output/bsp_tree.cc |
new file mode 100644 |
index 0000000000000000000000000000000000000000..2755c0b77971aa407c96a20638a399380bb87329 |
--- /dev/null |
+++ b/cc/output/bsp_tree.cc |
@@ -0,0 +1,121 @@ |
+// 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_ = scoped_ptr<BspNode>(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 = scoped_ptr<BspNode>(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 |