1 files changed, 164 insertions, 0 deletions
diff --git a/src/BSPTree.cpp b/src/BSPTree.cpp
new file mode 100644
index 0000000..a94c77a
--- /dev/null
+++ b/src/BSPTree.cpp
@@ -0,0 +1,164 @@
+/*
+ * 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 {
+
+vmml::vec3f BSPTree::Plane::intersection(const vmml::vec3f &p, const vmml::vec3f &dir) const {
+  float r = (d - p.dot(normal))/dir.dot(normal);
+
+  return p + r*dir;
+}
+
+void BSPTree::Plane::partition(const TriangleRecord &t, std::list<TriangleRecord> *front, std::list<TriangleRecord> *back) const {
+  for(int i = 0; i < 3; ++i) {
+    if(contains(t.triangle.getVertex(i))) {
+      const vmml::vec3f *v[3] = {&t.triangle.getVertex(i), &t.triangle.getVertex((i+1)%3), &t.triangle.getVertex((i+2)%3)};
+
+      vmml::vec3f is = intersection(*v[1], *v[2]-*v[1]);
+
+      if(isInFront(*v[1])) {
+        front->push_back(TriangleRecord(Triangle(*v[0], *v[1], is, t.triangle.getColor()), t.data));
+        back->push_back(TriangleRecord(Triangle(*v[0], is, *v[2], t.triangle.getColor()), t.data));
+      }
+      else {
+        back->push_back(TriangleRecord(Triangle(*v[0], *v[1], is, t.triangle.getColor()), t.data));
+        front->push_back(TriangleRecord(Triangle(*v[0], is, *v[2], t.triangle.getColor()), t.data));
+      }
+
+      return;
+    }
+  }
+
+  for(int i = 0; i < 3; ++i) {
+    const vmml::vec3f *v[3] = {&t.triangle.getVertex(i), &t.triangle.getVertex((i+1)%3), &t.triangle.getVertex((i+2)%3)};
+
+    if((isInFront(*v[0]) && isBehind(*v[1]) && isBehind(*v[2]))
+        || (isBehind(*v[0]) && isInFront(*v[1]) && isInFront(*v[2]))) {
+      vmml::vec3f is1 = intersection(*v[0], *v[1]-*v[0]);
+      vmml::vec3f is2 = intersection(*v[0], *v[2]-*v[0]);
+
+      if(isInFront(*v[0])) {
+        front->push_back(TriangleRecord(Triangle(*v[0], is1, is2, t.triangle.getColor()), t.data));
+        back->push_back(TriangleRecord(Triangle(is1, *v[1], is2, t.triangle.getColor()), t.data));
+        back->push_back(TriangleRecord(Triangle(*v[1], *v[2], is2, t.triangle.getColor()), t.data));
+      }
+      else {
+        back->push_back(TriangleRecord(Triangle(*v[0], is1, is2, t.triangle.getColor()), t.data));
+        front->push_back(TriangleRecord(Triangle(is1, *v[1], is2, t.triangle.getColor()), t.data));
+        front->push_back(TriangleRecord(Triangle(*v[1], *v[2], is2, t.triangle.getColor()), t.data));
+      }
+
+      return;
+    }
+  }
+}
+
+
+BSPTree::BSPTree(const std::list<TriangleRecord> &triangles) : frontTree(0), backTree(0) {
+  const Triangle *planeT = findNearestTriangle(triangles, findCenter(triangles));
+
+  if(!planeT)
+    return;
+
+  plane = Plane(*planeT);
+
+  std::list<TriangleRecord> front, back;
+
+  for(std::list<TriangleRecord>::const_iterator t = triangles.begin(); t != triangles.end(); ++t) {
+    if(t->triangle.isDegenerate())
+      continue;
+
+    if(plane.contains(t->triangle)) {
+      this->triangles.push_back(*t);
+      continue;
+    }
+    else if(plane.isInFront(t->triangle)) {
+      front.push_back(*t);
+      continue;
+    }
+    else if(plane.isBehind(t->triangle)) {
+      back.push_back(*t);
+      continue;
+    }
+
+    plane.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->triangle.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->triangle.isDegenerate())
+      continue;
+
+    float d = t->triangle.getCenter().squared_distance(v);
+
+    if(!current || d < distanceSq) {
+      current = &t->triangle;
+      distanceSq = d;
+    }
+  }
+
+  return current;
+}
+
+}