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// 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.
#ifndef CC_OUTPUT_BSP_TREE_H_
#define CC_OUTPUT_BSP_TREE_H_
#include <stddef.h>
#include <deque>
#include <vector>
#include "base/memory/scoped_ptr.h"
#include "cc/output/bsp_compare_result.h"
#include "cc/quads/draw_polygon.h"
namespace cc {
struct BspNode {
// This represents the splitting plane.
scoped_ptr<DrawPolygon> node_data;
// This represents any coplanar geometry we found while building the BSP.
std::vector<scoped_ptr<DrawPolygon>> coplanars_front;
std::vector<scoped_ptr<DrawPolygon>> coplanars_back;
scoped_ptr<BspNode> back_child;
scoped_ptr<BspNode> front_child;
explicit BspNode(scoped_ptr<DrawPolygon> data);
~BspNode();
};
class CC_EXPORT BspTree {
public:
explicit BspTree(std::deque<scoped_ptr<DrawPolygon>>* list);
scoped_ptr<BspNode>& root() { return root_; }
template <typename ActionHandlerType>
void TraverseWithActionHandler(ActionHandlerType* action_handler) const {
if (root_) {
WalkInOrderRecursion<ActionHandlerType>(action_handler, root_.get());
}
}
~BspTree();
private:
scoped_ptr<BspNode> root_;
void FromList(std::vector<scoped_ptr<DrawPolygon>>* list);
void BuildTree(BspNode* node, std::deque<scoped_ptr<DrawPolygon>>* data);
template <typename ActionHandlerType>
void WalkInOrderAction(ActionHandlerType* action_handler,
DrawPolygon* item) const {
(*action_handler)(item);
}
template <typename ActionHandlerType>
void WalkInOrderVisitNodes(
ActionHandlerType* action_handler,
const BspNode* node,
const BspNode* first_child,
const BspNode* second_child,
const std::vector<scoped_ptr<DrawPolygon>>& first_coplanars,
const std::vector<scoped_ptr<DrawPolygon>>& second_coplanars) const {
if (first_child) {
WalkInOrderRecursion(action_handler, first_child);
}
for (size_t i = 0; i < first_coplanars.size(); i++) {
WalkInOrderAction(action_handler, first_coplanars[i].get());
}
WalkInOrderAction(action_handler, node->node_data.get());
for (size_t i = 0; i < second_coplanars.size(); i++) {
WalkInOrderAction(action_handler, second_coplanars[i].get());
}
if (second_child) {
WalkInOrderRecursion(action_handler, second_child);
}
}
template <typename ActionHandlerType>
void WalkInOrderRecursion(ActionHandlerType* action_handler,
const BspNode* node) const {
// If our view is in front of the the polygon
// in this node then walk back then front.
if (GetCameraPositionRelative(*(node->node_data)) == BSP_FRONT) {
WalkInOrderVisitNodes<ActionHandlerType>(action_handler,
node,
node->back_child.get(),
node->front_child.get(),
node->coplanars_front,
node->coplanars_back);
} else {
WalkInOrderVisitNodes<ActionHandlerType>(action_handler,
node,
node->front_child.get(),
node->back_child.get(),
node->coplanars_back,
node->coplanars_front);
}
}
// Returns whether or not nodeA is on one or the other side of nodeB,
// coplanar, or whether it crosses nodeB's plane and needs to be split
static BspCompareResult GetNodePositionRelative(const DrawPolygon& node_a,
const DrawPolygon& node_b);
// Returns whether or not our viewer is in front of or behind the plane
// defined by this polygon/node
static BspCompareResult GetCameraPositionRelative(const DrawPolygon& node);
};
} // namespace cc
#endif // CC_OUTPUT_BSP_TREE_H_
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