int		tracelinetoplane_behindplane;
vector TraceLineToPlane(vector line_start, vector line_end, vector plane_normal, vector plane_point)
{
	tracelinetoplane_behindplane = FALSE;

    vector v = line_end-line_start;
    vector n = plane_normal;
    float d = -(plane_normal*plane_point);

    // dot products
    float dot1 = n*v;
    float dot2 = n*line_start;

	if(plane_normal*(line_end-plane_point) > 0) // the end isn't on or behind the plane (ignores reverse intersection, and non-intersections)
		return line_end;
	else
	if(plane_normal*(line_start-plane_point) <= 0) // both ends are behind the plane (or on it)
	{
		tracelinetoplane_behindplane = TRUE;
		return line_end;
	}

	// line is parallel with plane
     if(dot1 == 0)
        return line_end; // return original end point

    float t = -(dot2 + d) / dot1;
    return line_start + (t * v);
}