public CSG_Node(List <CSG_Polygon> list, CSG_Plane plane, CSG_Node front, CSG_Node back)
{
this.polygons = list;
this.plane = plane;
this.front = front;
this.back = back;
}
/**
* Return a new mesh by intersecting @lhs with @rhs. This operation
* is non-commutative, so set @lhs and @rhs accordingly.
*/
public static Mesh Intersect(CSG_Model csg_model_a, CSG_Model csg_model_b)
{
CSG_Node a = new CSG_Node(csg_model_a.ToPolygons());
CSG_Node b = new CSG_Node(csg_model_b.ToPolygons());
List <CSG_Polygon> polygons = CSG_Node.Intersect(a, b).AllPolygons();
CSG_Model result = new CSG_Model(polygons);
return(result.ToMesh());
}
/**
* Returns a new mesh by subtracting @rhs from @lhs.
*/
public static Mesh Subtract(GameObject lhs, GameObject rhs)
{
CSG_Model csg_model_a = new CSG_Model(lhs);
CSG_Model csg_model_b = new CSG_Model(rhs);
CSG_Node a = new CSG_Node(csg_model_a.ToPolygons());
CSG_Node b = new CSG_Node(csg_model_b.ToPolygons());
List <CSG_Polygon> polygons = CSG_Node.Subtract(a, b).AllPolygons();
CSG_Model result = new CSG_Model(polygons);
return(result.ToMesh());
}
// Remove all polygons in this BSP tree that are inside the other BSP tree
// `bsp`.
public void ClipTo(CSG_Node other)
{
this.polygons = other.ClipPolygons(this.polygons);
if (this.front != null)
{
this.front.ClipTo(other);
}
if (this.back != null)
{
this.back.ClipTo(other);
}
}
// Build a BSP tree out of `polygons`. When called on an existing tree, the
// new polygons are filtered down to the bottom of the tree and become new
// nodes there. Each set of polygons is partitioned using the first polygon
// (no heuristic is used to pick a good split).
public void Build(List <CSG_Polygon> list)
{
if (list.Count < 1)
{
return;
}
if (this.plane == null || !this.plane.Valid())
{
this.plane = new CSG_Plane();
this.plane.normal = list[0].plane.normal;
this.plane.w = list[0].plane.w;
}
if (this.polygons == null)
{
this.polygons = new List <CSG_Polygon>();
}
List <CSG_Polygon> list_front = new List <CSG_Polygon>();
List <CSG_Polygon> list_back = new List <CSG_Polygon>();
for (int i = 0; i < list.Count; i++)
{
this.plane.SplitPolygon(list[i], this.polygons, this.polygons, list_front, list_back);
}
if (list_front.Count > 0)
{
if (this.front == null)
{
this.front = new CSG_Node();
}
this.front.Build(list_front);
}
if (list_back.Count > 0)
{
if (this.back == null)
{
this.back = new CSG_Node();
}
this.back.Build(list_back);
}
}
// Return a new CSG solid representing space both this solid and in the
// solid `csg`. Neither this solid nor the solid `csg` are modified.
public static CSG_Node Intersect(CSG_Node a1, CSG_Node b1)
{
CSG_Node a = a1.Clone();
CSG_Node b = b1.Clone();
a.Invert();
b.ClipTo(a);
b.Invert();
a.ClipTo(b);
b.ClipTo(a);
a.Build(b.AllPolygons());
a.Invert();
CSG_Node ret = new CSG_Node(a.AllPolygons());
return(ret);
}
// Convert solid space to empty space and empty space to solid space.
public void Invert()
{
for (int i = 0; i < this.polygons.Count; i++)
{
this.polygons[i].Flip();
}
this.plane.Flip();
if (this.front != null)
{
this.front.Invert();
}
if (this.back != null)
{
this.back.Invert();
}
CSG_Node tmp = this.front;
this.front = this.back;
this.back = tmp;
}
public CSG_Node Clone()
{
CSG_Node clone = new CSG_Node(this.polygons, this.plane, this.front, this.back);
return(clone);
}
public CSG_Node()
{
this.front = null;
this.back = null;
}