#include "BarnesHutTree.hpp"
namespace nbody {
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) {
vector<TreeNode*>::iterator it;
this->clean();
this->nodes.push_back(new TreeNode());
std::copy(bodies.begin(), bodies.end(), this->nodes.front()->bodies.begin());
this->nodes.front()->extendBBforBodies();
this->nodes.front()->extendBBtoCube();
it = this->nodes.begin();
while (it != this->nodes.end()) {
(*it)->afterSubtree = it;
(*it)->afterSubtree++;
if ((*it)->isSplitable()) {
vector<Box> subboxes = this->splitBB(*it);
for (vector<Box>::iterator bit = subboxes.begin(); bit != subboxes.end(); bit++) {
TreeNode* current = new TreeNode();
current->bb = *bit;
current->bodies = bit->containedBodies((*it)->getBodies());
this->nodes.insert((*it)->afterSubtree, current);
}
(*it)->bodies.clear();
}
it++;
}
}
}