diff -r fc18ac4833f2 -r a0a3e334744f src/kdtree.cc
--- a/src/kdtree.cc	Sun Nov 25 15:50:01 2007 +0100
+++ b/src/kdtree.cc	Sun Nov 25 17:58:29 2007 +0100
@@ -23,10 +23,10 @@
 class SortableShapeList: public vector<SortableShape>
 {
 public:
-	SortableShapeList(ShapeList &shapes, short axis)
+	SortableShapeList(ShapeList *shapes, short axis)
 	{
 		ShapeList::iterator shape;
-		for (shape = shapes.begin(); shape != shapes.end(); shape++)
+		for (shape = shapes->begin(); shape != shapes->end(); shape++)
 			push_back(SortableShape(*shape, axis));
 	};
 };
@@ -89,9 +89,9 @@
 
 void KdNode::subdivide(BBox bbox, int depth)
 {
-	if (depth >= 20 || shapes.size() <= 4)
+	if (depth >= 20 || shapes->size() <= 4)
 	{
-		leaf = true;
+		setLeaf();
 		return;
 	}
 
@@ -173,9 +173,9 @@
 	// choose best split pos
 	const float K = 1.4; // constant, K = cost of traversal / cost of ray-triangle intersection
 	float SAV = 2*(bbox.w()*bbox.h() + bbox.w()*bbox.d() + bbox.h()*bbox.d()); // surface area of node
-	float cost = SAV * (K + shapes.size()); // initial cost = non-split cost
+	float cost = SAV * (K + shapes->size()); // initial cost = non-split cost
 	SplitPos *splitpos = NULL;
-	leaf = true;
+	bool leaf = true;
 	BBox lbb = bbox;
 	BBox rbb = bbox;
 	for (spl = splitlist.begin(); spl != splitlist.end(); spl++)
@@ -196,9 +196,12 @@
 	}
 
 	if (leaf)
+	{
+		setLeaf();
 		return;
+	}
 
-#if 1
+#if 0
 // export kd-tree as .obj for visualization
 // this would be hard to reconstruct later
 	static ofstream F("kdtree.obj");
@@ -289,7 +292,7 @@
 void KdTree::build()
 {
 	root = new KdNode();
-	root->shapes = shapes;
+	root->shapes = &shapes;
 	root->subdivide(bbox, 0);
 	built = true;
 }
@@ -320,14 +323,14 @@
 
 	/* distinguish between internal and external origin */
 	if (a >= 0.0) /* a ray with external origin */
-		enPt->pb = ray.a + ray.dir * a;
+		enPt->pb = ray.o + ray.dir * a;
 	else /* a ray with internal origin */
-		enPt->pb = ray.a;
+		enPt->pb = ray.o;
 
 	/* setup initial exit point in the stack */
 	StackElem *exPt = new StackElem();
 	exPt->t = b;
-	exPt->pb = ray.a + ray.dir * b;
+	exPt->pb = ray.o + ray.dir * b;
 	exPt->node = NULL; /* set termination flag */
 
 	st.push(enPt);
@@ -374,7 +377,7 @@
 			/* case P4 or N4 . . . traverse both children */
 
 			/* signed distance to the splitting plane */
-			t = (splitVal - ray.a.cell[axis]) / ray.dir.cell[axis];
+			t = (splitVal - ray.o.cell[axis]) / ray.dir.cell[axis];
 
 			/* setup the new exit point */
 			st.push(exPt);
@@ -384,8 +387,8 @@
 			exPt->t = t;
 			exPt->node = farchild;
 			exPt->pb[axis] = splitVal;
-			exPt->pb[(axis+1)%3] = ray.a.cell[(axis+1)%3] + t * ray.dir.cell[(axis+1)%3];
-			exPt->pb[(axis+2)%3] = ray.a.cell[(axis+2)%3] + t * ray.dir.cell[(axis+2)%3];
+			exPt->pb[(axis+1)%3] = ray.o.cell[(axis+1)%3] + t * ray.dir.cell[(axis+1)%3];
+			exPt->pb[(axis+2)%3] = ray.o.cell[(axis+2)%3] + t * ray.dir.cell[(axis+2)%3];
 		} /* while */
 
 		/* current node is the leaf . . . empty or full */
@@ -394,7 +397,7 @@
 		Shape *nearest_shape = NULL;
 		float dist = exPt->t;
 		ShapeList::iterator shape;
-		for (shape = node->shapes.begin(); shape != node->shapes.end(); shape++)
+		for (shape = node->shapes->begin(); shape != node->shapes->end(); shape++)
 			if (*shape != origin_shape && (*shape)->intersect(ray, dist)
 			&& dist >= enPt->t)
 				nearest_shape = *shape;
@@ -431,7 +434,7 @@
 	if (node == NULL)
 		node = root;
 	if (node->isLeaf())
-		str << "(leaf: " << node->shapes.size() << " shapes)";
+		str << "(leaf: " << node->shapes->size() << " shapes)";
 	else
 	{
 		str << "(split " << (char)('x'+node->getAxis()) << " at " << node->getSplit() << "; L=";