This applet is a demonstration of physics-based modeling. This applet models a chain of balls connected by springs. The two ends are fixed; the balls in the middle are initially assigned random positions, and the forces of the springs and of gravity then act on them. Click on the applet with your mouse to restart the process. Physics-based modeling was once purely the domain of academia, but there is increasing interest in it among games developers, who are striving for ever-increasing levels of realism in their virtual worlds. (For example, note that the balls eventually settle into a curved shape, rather than a straight line; this is due to the interaction of gravity with the mass of the balls and the force applied by the springs. Pretty cool, eh?).

This applet is essentially a Java port of an example program by Dr. Jim X. Chen. The program was originally written in SGI GL. I first ported it to OpenGL, and then, for grins, to Java.

This applet makes use of double buffering. There is no built-in support for double buffering in Java, as there is in OpenGL (that is, there is nothing analogous to auxSwapBuffers() in Java). However, you can get the same effect by doing all your drawing to an offscreen Image and then responding to paint() messages by simply drawing the image onscreen.