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/*
* BSPTree.cpp
*
* Copyright (C) 2009 Matthias Schiffer <matthias@gamezock.de>
*
* This program is free software: you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as published by the
* Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
* See the GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License along
* with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include "BSPTree.h"
namespace Zoom {
void BSPTree::partition(const TriangleRecord &t, std::list<TriangleRecord> *front, std::list<TriangleRecord> *back) const {
for(int i = 0; i < 3; ++i) {
if(plane.contains(t.getTriangle().getVertex(i))) {
const vmml::vec3f *v[3] = {&t.getTriangle().getVertex(i), &t.getTriangle().getVertex((i+1)%3), &t.getTriangle().getVertex((i+2)%3)};
vmml::vec3f is = plane.intersection(MathUtil::Ray(*v[1], *v[2]-*v[1]));
if(plane.isInFront(*v[1])) {
front->push_back(TriangleRecord(Triangle(*v[0], *v[1], is, t.getTriangle().getColor()), t.getData()));
back->push_back(TriangleRecord(Triangle(*v[0], is, *v[2], t.getTriangle().getColor()), t.getData()));
}
else {
back->push_back(TriangleRecord(Triangle(*v[0], *v[1], is, t.getTriangle().getColor()), t.getData()));
front->push_back(TriangleRecord(Triangle(*v[0], is, *v[2], t.getTriangle().getColor()), t.getData()));
}
return;
}
}
for(int i = 0; i < 3; ++i) {
const vmml::vec3f *v[3] = {&t.getTriangle().getVertex(i), &t.getTriangle().getVertex((i+1)%3), &t.getTriangle().getVertex((i+2)%3)};
if((plane.isInFront(*v[0]) && plane.isBehind(*v[1]) && plane.isBehind(*v[2]))
|| (plane.isBehind(*v[0]) && plane.isInFront(*v[1]) && plane.isInFront(*v[2]))) {
vmml::vec3f is1 = plane.intersection(MathUtil::Ray(*v[0], *v[1]-*v[0]));
vmml::vec3f is2 = plane.intersection(MathUtil::Ray(*v[0], *v[2]-*v[0]));
if(plane.isInFront(*v[0])) {
front->push_back(TriangleRecord(Triangle(*v[0], is1, is2, t.getTriangle().getColor()), t.getData()));
back->push_back(TriangleRecord(Triangle(is1, *v[1], is2, t.getTriangle().getColor()), t.getData()));
back->push_back(TriangleRecord(Triangle(*v[1], *v[2], is2, t.getTriangle().getColor()), t.getData()));
}
else {
back->push_back(TriangleRecord(Triangle(*v[0], is1, is2, t.getTriangle().getColor()), t.getData()));
front->push_back(TriangleRecord(Triangle(is1, *v[1], is2, t.getTriangle().getColor()), t.getData()));
front->push_back(TriangleRecord(Triangle(*v[1], *v[2], is2, t.getTriangle().getColor()), t.getData()));
}
return;
}
}
}
BSPTree::BSPTree(const std::list<TriangleRecord> &triangles) : frontTree(0), backTree(0) {
const Triangle *planeT = findNearestTriangle(triangles, findCenter(triangles));
if(!planeT)
return;
plane = MathUtil::Plane(*planeT);
std::list<TriangleRecord> front, back;
for(std::list<TriangleRecord>::const_iterator t = triangles.begin(); t != triangles.end(); ++t) {
if(t->getTriangle().isDegenerate())
continue;
if(plane.contains(t->getTriangle())) {
this->triangles.push_back(*t);
continue;
}
else if(plane.isInFront(t->getTriangle())) {
front.push_back(*t);
continue;
}
else if(plane.isBehind(t->getTriangle())) {
back.push_back(*t);
continue;
}
partition(*t, &front, &back);
}
if(!front.empty())
frontTree = new BSPTree(front);
if(!back.empty())
backTree = new BSPTree(back);
}
BSPTree& BSPTree::operator=(const BSPTree &tree) {
if(frontTree) {
delete frontTree;
frontTree = 0;
}
if(backTree) {
delete backTree;
backTree = 0;
}
plane = tree.plane;
triangles = tree.triangles;
if(tree.frontTree)
frontTree = new BSPTree(*tree.frontTree);
if(tree.backTree)
backTree = new BSPTree(*tree.backTree);
return *this;
}
vmml::vec3f BSPTree::findCenter(const std::list<TriangleRecord> &triangles) {
vmml::vec3f v;
for(std::list<TriangleRecord>::const_iterator t = triangles.begin(); t != triangles.end(); ++t) {
v += t->getTriangle().getCenter();
}
return v/triangles.size();
}
const Triangle* BSPTree::findNearestTriangle(const std::list<TriangleRecord> &triangles, const vmml::vec3f &v) {
const Triangle *current = 0;
float distanceSq;
for(std::list<TriangleRecord>::const_iterator t = triangles.begin(); t != triangles.end(); ++t) {
if(t->getTriangle().isDegenerate())
continue;
float d = t->getTriangle().getCenter().squared_distance(v);
if(!current || d < distanceSq) {
current = &t->getTriangle();
distanceSq = d;
}
}
return current;
}
}
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