#include "BarnesHutTree.hpp"
#include "TreeNode.hpp"
#include <iostream>
namespace nbody {
using namespace std;
BarnesHutTree::BarnesHutTree() {
}
BarnesHutTree::~BarnesHutTree() {
}
vector<Box> BarnesHutTree::splitBB(TreeNode* node) {
vector<Box> result;
for (unsigned int i = 0; i < 8; i++) {
Box current = node->getBB();
for (unsigned int j = 0; j < 3; j++) {
double middle = current.getMin(j) + (current.getMax(j) - current.getMin(j)) / 2.0;
if (i & (1 << j)) {
current.setMin(j, middle);
} else {
current.setMax(j, middle);
}
}
result.push_back(current);
}
return result;
}
int BarnesHutTree::numberOfChildren() {
return 8;
}
void BarnesHutTree::build(vector<Body> bodies) {
TreeNode* current;
unsigned long nodes = 0;
this->clean();
if (bodies.empty()) return;
//insert root node
this->nodes->insertAfter(new TreeNode(this));
current = this->nodes->next;
//assign bodies to root node
current->bodies = bodies;
//setup proper bounding box
current->extendBBforBodies();
current->extendBBtoCube();
current->afterSubtree = current->next;
//iterate over existing boxes and split if it contains too much bodies
while (current != this->nodes) {
if (!current->isCorrect()) {
cout << "node before split incorrect" << endl;
return;
}
if (current->isSplitable()) {
vector<Box> subboxes = this->splitBB(current);
vector<Body> localBodies = current->getBodies();
TreeNode* after = current->next;
current->leaf = false;
for (vector<Box>::iterator bit = subboxes.begin(); bit != subboxes.end(); bit++) {
TreeNode* child = new TreeNode(this);
nodes++;
child->bb = *bit;
child->bodies = bit->containedBodies(localBodies);
current->next->insertBefore(child);
child->afterSubtree = (bit == subboxes.begin()) ? current->afterSubtree : child->next;
}
current->bodies.clear();
}
current = current->next;
}
cout << "nodes " << nodes << endl;
}
}