#define MAX_BOUNDS 16384    //this is the abs(max point in data set)

//Planes is an array of planes that define a convex area in space
//which has been loaded from the map file
//NumPlanes is the number of planes in the list

CFace* FacesFromPlaneList(CPlane *Planes, int NumPlanes)
{
    //you need at least 4 planes to make a solid
    if(NumPlanes < 4)
        return 0;

    //allocate some memory for the new faces
    CFace *NewFaces = new CFace[NumPlanes];

    //need to make faces that lie on the planes of the solid that
    //extend to the bounds of the data set. 
    for(int i = 0; i < NumPlanes; i++)
    {
        //the vertex count for each inital face will be 4
        NewFaces[i].VertexCount = 4;

        //check to see if the plane is x-axis oriented
        if(abs(Planes[i].x) >= abs(Planes[i].y) && abs(Planes[i].x) >= abs(Planes[i].z))
        {
            //set the bounds of the polygon, using y and z axis
            NewFaces[i].Vertex[0].Set(0, -MAX_BOUNDS, -MAX_BOUNDS);
            NewFaces[i].Vertex[1].Set(0, -MAX_BOUNDS, MAX_BOUNDS);
            NewFaces[i].Vertex[2].Set(0, MAX_BOUNDS, MAX_BOUNDS);
            NewFaces[i].Vertex[3].Set(0, MAX_BOUNDS, -MAX_BOUNDS);

            //calculate the x value of each vertex on the plane
            for(int j = 0; j < 4; j++)
            {
                NewFaces[i].Vertex[j].x = Planes[i].d - 
                    Planes[i].z * NewFaces[i].Vertex[j].z -
                    Planes[i].y * NewFaces[i].Vertex[j].y ) / 
                    Planes[i].x;
            }
        }
        //check to see if the plane is y-axis oriented
        else if(abs(Planes[i].y) >= abs(Planes[i].x) && abs(Planes[i].y) >= abs(Planes[i].z))
        {
            //set the bounds of the polygon using the x and z axis
            NewFaces[i].Vertex[0].Set(-MAX_BOUNDS, 0, -MAX_BOUNDS);
            NewFaces[i].Vertex[1].Set(-MAX_BOUNDS, 0, MAX_BOUNDS);
            NewFaces[i].Vertex[2].Set(MAX_BOUNDS, 0, MAX_BOUNDS);
            NewFaces[i].Vertex[3].Set(MAX_BOUNDS, 0, -MAX_BOUNDS);
             
            //calculate the y value of each vertex on the plane
            for(int j = 0; j < 4; j++)
            {
                NewFaces[i].Vertex[j].y = ( Planes[i].d - 
                    Planes[i].z * NewFaces[i].Vertex[j].z -
                    Planes[i].x * NewFaces[i].Vertex[j].x ) /
                    Planes[i].y;
            }
        }
        //plane must be z-axis oriented
        else
        {
            //set the bounds of the polygon using the x and y axis
            NewFaces[i].Vertex[0].Set(-MAX_BOUNDS, -MAX_BOUNDS, 0);
            NewFaces[i].Vertex[1].Set(-MAX_BOUNDS, MAX_BOUNDS, 0);
            NewFaces[i].Vertex[2].Set(MAX_BOUNDS, MAX_BOUNDS, 0);
            NewFaces[i].Vertex[3].Set(MAX_BOUNDS, -MAX_BOUNDS, 0);

            //calculate the z of each vertex on the plane
            for(int j = 0; j < 4; j++)
            {
                NewFaces[i].Vertex[i].z = ( Planes[i].d - 
                    Planes[i].y * NewFaces[i].Vertex[j].y -
                    Planes[i].x * NewFaces[i].Vertex[j].x ) /
                    Planes[i].z;
            }
        }
    }

    //now for each face, we clip it against the planes of all the other faces
    //since it is convex, after all the clipping the face will be the original
    //as seen in the editor
    //NOTE: Depending on how you calculated your plane equations, you may need
    //to flip the plane before you clip the faces, since the wrong side of the 
    //face will be clipped. And you will end up with faces with no vertices.
    for(i = 0; i < NumPlanes; i++)
        for(int j = 0; j < NumPlanes; j++)
             if(i != j)
                 ClipFaceWithPlane(NewFaces[i], Planes[j]);

    return NewFaces;
}