eu.mihosoft.vrl.v3d.ext.quickhull3d.VertexList Maven / Gradle / Ivy

Go to download

Show more of this group Show more artifacts with this name
Show all versions of jcsg Show documentation

Java implementation of BSP based CSG (Constructive Solid Geometry)

There is a newer version: 0.5.7

package eu.mihosoft.vrl.v3d.ext.quickhull3d;

/**
 * Maintains a double-linked list of vertices for use by QuickHull3D
 */
class VertexList
{
	private Vertex head;
	private Vertex tail;

	/**
	 * Clears this list.
	 */
	public void clear()
	 {
	   head = tail = null; 
	 }

	/**
	 * Adds a vertex to the end of this list.
	 */
	public void add (Vertex vtx)
	 { 
	   if (head == null)
	    { head = vtx;
	    }
	   else
	    { tail.next = vtx; 
	    }
	   vtx.prev = tail;
	   vtx.next = null;
	   tail = vtx;
	 }

	/**
	 * Adds a chain of vertices to the end of this list.
	 */
	public void addAll (Vertex vtx)
	 { 
	   if (head == null)
	    { head = vtx;
	    }
	   else
	    { tail.next = vtx; 
	    }
	   vtx.prev = tail;
	   while (vtx.next != null)
	    { vtx = vtx.next;
	    }
	   tail = vtx;
	 }

	/**
	 * Deletes a vertex from this list.
	 */
	public void delete (Vertex vtx)
	 {
	   if (vtx.prev == null)
	    { head = vtx.next;
	    }
	   else
	    { vtx.prev.next = vtx.next; 
	    }
	   if (vtx.next == null)
	    { tail = vtx.prev; 
	    }
	   else
	    { vtx.next.prev = vtx.prev; 
	    }
	 }

	/**
	 * Deletes a chain of vertices from this list.
	 */
	public void delete (Vertex vtx1, Vertex vtx2)
	 {
	   if (vtx1.prev == null)
	    { head = vtx2.next;
	    }
	   else
	    { vtx1.prev.next = vtx2.next; 
	    }
	   if (vtx2.next == null)
	    { tail = vtx1.prev; 
	    }
	   else
	    { vtx2.next.prev = vtx1.prev; 
	    }
	 }

	/**
	 * Inserts a vertex into this list before another
	 * specificed vertex.
	 */
	public void insertBefore (Vertex vtx, Vertex next)
	 {
	   vtx.prev = next.prev;
	   if (next.prev == null)
	    { head = vtx;
	    }
	   else
	    { next.prev.next = vtx; 
	    }
	   vtx.next = next;
	   next.prev = vtx;
	 }

	/**
	 * Returns the first element in this list.
	 */
	public Vertex first()
	 {
	   return head;
	 }

	/**
	 * Returns true if this list is empty.
	 */
	public boolean isEmpty()
	 {
	   return head == null;
	 }
}