blob: 1d203f3ff1ea3081ee22d4580f802b5303b00e84 [file] [log] [blame]
// 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 <memory>
#include <vector>
#include "base/memory/ptr_util.h"
#include "cc/base/container_util.h"
#include "cc/output/bsp_compare_result.h"
#include "cc/quads/draw_polygon.h"
namespace cc {
BspNode::BspNode(std::unique_ptr<DrawPolygon> data)
: node_data(std::move(data)) {}
BspNode::~BspNode() {
BspTree::BspTree(std::deque<std::unique_ptr<DrawPolygon>>* list) {
if (list->size() == 0)
root_ = base::MakeUnique<BspNode>(PopFront(list));
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,
std::deque<std::unique_ptr<DrawPolygon>>* polygon_list) {
std::deque<std::unique_ptr<DrawPolygon>> front_list;
std::deque<std::unique_ptr<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->empty()) {
std::unique_ptr<DrawPolygon> polygon;
std::unique_ptr<DrawPolygon> new_front;
std::unique_ptr<DrawPolygon> new_back;
// Time to split this geometry, *it needs to be split by node_data.
polygon = PopFront(polygon_list);
bool is_coplanar;
node->node_data->SplitPolygon(std::move(polygon), &new_front, &new_back,
if (is_coplanar) {
if (new_front)
if (new_back)
} else {
if (new_front)
if (new_back)
// Build the back subtree using the front of the back_list as our splitter.
if (back_list.size() > 0) {
node->back_child = base::MakeUnique<BspNode>(PopFront(&back_list));
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 = base::MakeUnique<BspNode>(PopFront(&front_list));
BuildTree(node->front_child.get(), &front_list);
// 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