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BarnesHutTree.cpp 1.69 KiB
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#include "BarnesHutTree.hpp"
#include "TreeNode.hpp"
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#include <iostream>
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	using namespace std;

	BarnesHutTree::BarnesHutTree() {
	}

	BarnesHutTree::~BarnesHutTree() {
	}

	vector<Box> BarnesHutTree::splitBB(TreeNode* node) {
		vector<Box> result;

		for (int i = 0; i < 8; i++) {
			Box current = node->getBB();

			for (int j = 0; j < 3; j++) {
				double middle = node->getBB().getMin(j) + (node->getBB().getMax(j) - node->getBB().getMin(j)) / 2.0;

				if (i & (1 >> j)) {
					current.setMin(j, middle);
				} else {
					current.setMax(j, middle);
				}
			}
			result.push_back(current);
		}
		return result;
	}

	void BarnesHutTree::build(vector<Body> bodies) {
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		TreeNode* current;
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		unsigned long nodes = 0;
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		if (bodies.empty()) return;
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		this->nodes->insertAfter(new TreeNode(this));
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		current = this->nodes->next;
		current->bodies = bodies;
		current->extendBBforBodies();
		current->extendBBtoCube();
		while (current != this->nodes) {
			if (current->isSplitable()) {
				vector<Box> subboxes = this->splitBB(current);
				vector<Body> localBodies = current->getBodies();
				TreeNode* after = current->next;

				for (vector<Box>::iterator bit = subboxes.begin(); bit != subboxes.end(); bit++) {
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					TreeNode* child = new TreeNode(this);
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					nodes++;
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					child->bb = *bit;
					child->bodies = bit->containedBodies(localBodies);
					current->next->insertBefore(child);
				}
				for (TreeNode* child = current->next; child != after->prev; child = child->next) {
					child->afterSubtree = child->next;
				}
				after->prev->afterSubtree = after->afterSubtree;
				current->bodies.clear();
			}

			current = current->next;
		}
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		cout << "nodes " << nodes << endl;