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Unified Diff: cc/output/bsp_tree.cc

Issue 384083002: WIP BSP Tree for 3D Layer Sorting (Closed) Base URL: https://chromium.googlesource.com/chromium/src.git@master
Patch Set: Small fixes to style/formatting, minor cleanup. Created 6 years, 5 months ago
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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..aa1dffbea893837a72be7aa247cf0c87551e5e91
--- /dev/null
+++ b/cc/output/bsp_tree.cc
@@ -0,0 +1,151 @@
+// 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/output/bsp_controller.h"
+#include "cc/quads/draw_polygon.h"
+
+namespace cc {
+
+BspNode::BspNode(scoped_ptr<DrawPolygon> data) {
+ node_data = data.Pass();
+}
+
+BspNode::~BspNode() {
+}
+
+BspTree::BspTree(BspController* bsp_controller,
+ ScopedPtrVector<DrawPolygon>* list)
+ : controller_(bsp_controller) {
+ FromList(list);
+}
+
+void BspTree::FromList(ScopedPtrVector<DrawPolygon>* list) {
+ if (list->size() <= 0)
Ian Vollick 2014/07/16 20:54:32 Can size < 0?
troyhildebrandt 2014/07/18 21:48:26 Nope, it's unsigned, changed to == 0.
+ return;
+
+ float split_weight = 0.0f;
Ian Vollick 2014/07/16 20:54:33 nit: max_weight or max_split_weight conveys a bit
troyhildebrandt 2014/07/18 21:48:25 Done.
+ ScopedPtrDeque<DrawPolygon> list_data;
+ for (ScopedPtrVector<DrawPolygon>::iterator it = list->begin();
+ it != list->end();
+ ++it) {
+ float poly_weight = controller_->SplitWeight(*list->back());
+ if (poly_weight > split_weight) {
+ list_data.push_front(list->take(it));
+ split_weight = poly_weight;
+ } else {
+ list_data.push_back(list->take(it));
+ }
+ }
+
+ root_ = scoped_ptr<BspNode>(new BspNode(list_data.take_front()));
+ BuildTree(root_, &list_data);
+}
+
+void BspTree::BuildTree(const scoped_ptr<BspNode>& node,
+ ScopedPtrDeque<DrawPolygon>* data) {
+ ScopedPtrDeque<DrawPolygon> front_list;
+ ScopedPtrDeque<DrawPolygon> back_list;
+ // We keep track of the splitting weights (the "score" of a polygon that
+ // chooses whether or not it's the splitting plane of a new node) for both
+ // the front and back list independently so the better splitting plane is
+ // chosen for both sides.
+ float front_weight = 0.0f;
Ian Vollick 2014/07/16 20:54:32 Could you choose names for these that involve "max
troyhildebrandt 2014/07/18 21:48:26 Done.
+ float back_weight = 0.0f;
+
+ // 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 (data->size() > 0) {
+ // Is this particular polygon in front of or behind our splitting polygon.
+ BspCompareResult comparer_result = controller_->GetNodePositionRelative(
+ *data->front(), *(node->node_data));
+ float poly_weight = controller_->SplitWeight(*data->front());
+
+ // 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.
+ if (comparer_result == BSP_FRONT) {
Ian Vollick 2014/07/16 20:54:32 switch?
troyhildebrandt 2014/07/18 21:48:26 Done.
+ if (poly_weight > front_weight) {
+ front_list.push_front(data->take_front());
+ front_weight = poly_weight;
+ } else {
+ front_list.push_back(data->take_front());
+ }
+
+ } else if (comparer_result == BSP_BACK) {
+ if (poly_weight > back_weight) {
+ back_list.push_front(data->take_front());
+ back_weight = poly_weight;
+ } else {
+ back_list.push_back(data->take_front());
Ian Vollick 2014/07/16 20:54:33 The front and back behavior is so symmetric that i
troyhildebrandt 2014/07/18 21:48:26 Done.
+ }
+
+ } else if (comparer_result == BSP_SPLIT) {
+ // Time to split this geometry, *it needs to be split by node_data.
+ scoped_ptr<DrawPolygon> new_front;
+ scoped_ptr<DrawPolygon> new_back;
+ if (controller_->SplitPolygon(
+ data->take_front(), *(node->node_data), &new_front, &new_back)) {
+ // Now add new_front and new_back to their respective lists, again
+ // using the heuristic in an attempt to choose the best splitting
+ // plane, and keep track of the highest weighted polygon known so far
+ // so if we find something better we can use that instead.
+ float front_poly_weight = controller_->SplitWeight(*new_front);
+ float back_poly_weight = controller_->SplitWeight(*new_back);
+
+ if (front_poly_weight > front_weight) {
+ front_list.push_front(new_front.Pass());
+ front_weight = front_poly_weight;
+ } else {
+ front_list.push_back(new_front.Pass());
Ian Vollick 2014/07/16 20:54:32 These two bits could use that helper, too.
troyhildebrandt 2014/07/18 21:48:26 Done.
+ }
+
+ if (back_poly_weight > back_weight) {
+ back_list.push_front(new_back.Pass());
+ back_weight = back_poly_weight;
+ } else {
+ back_list.push_back(new_back.Pass());
+ }
+ }
+ } else if (comparer_result == BSP_COPLANAR_FRONT) {
+ node->coplanars_front.push_back(data->take_front());
+ } else if (comparer_result == BSP_COPLANAR_BACK) {
+ node->coplanars_back.push_back(data->take_front());
+ }
Ian Vollick 2014/07/16 20:54:33 else { NOTREACHED(); // or equivalent for the de
troyhildebrandt 2014/07/18 21:48:26 Done.
+ }
+
+ // 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, &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, &front_list);
+ }
+}
+
+void BspTree::Clear() {
+ if (root_) {
+ root_.reset();
+ }
+}
+
+BspTree::~BspTree() {
+ Clear();
+}
+
+} // namespace cc

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