First BSP Example

You'll encapsulate the BSP drawing in the SimpleBSPRenderer class, which is a subclass of ShadedSurfacePolygonRenderer. This new class has one method for drawing polygons in a tree and also is a BSPTraverseListener, as shown here:

 Draws the visible polygons in a BSP tree based on
 the camera location. The polygons are drawn front to back.
public void draw(Graphics2D g, BSPTree tree) {
 currentGraphics2D = g;
 traverser.traverse(tree, camera.getLocation());
// from the BSPTreeTraverseListener interface public boolean visitPolygon(BSPPolygon poly, boolean isBack) {
 draw(currentGraphics2D, poly);
 return !((SortedScanConverter)scanConverter).isFilled();

Next, create the basic demo in a class called BSPTest3D. The BSPTest3D class is similar to BSPTest2D, except that it draws polygons using the SimpleBSPRenderer:

public void draw(Graphics2D g) {
 // draw polygons
 ((SimpleBSPRenderer)polygonRenderer).draw(g, bspTree);

That's it for the demo. Finally, you can see your example floor plan in 3D. Check out the screenshot in Screenshot.

Screenshot Screenshot of BSPTest3D.

Java graphics 10fig18.gif

This demo works fine, but there are a couple problems:

  • You can draw 3D objects such as monsters and treasures, but they won't be merged correctly with the scene because object drawing relies on z-buffering.
  • Creating polygons in code will quickly become a drag. You need an easier way.

So, let's work on solving these issues, shall we?