Java Doc for BufferStrategy.java in  » 6.0-JDK-Core » AWT » java » awt » image » Java Source Code / Java DocumentationJava Source Code and Java Documentation

It is worth noting that the terms buffer and surface are meant to be synonymous: an area of contiguous memory, either in video device memory or in system memory.

There are several types of complex buffer strategies, including sequential ring buffering and blit buffering. Sequential ring buffering (i.e., double or triple buffering) is the most common; an application draws to a single back buffer and then moves the contents to the front (display) in a single step, either by copying the data or moving the video pointer. Moving the video pointer exchanges the buffers so that the first buffer drawn becomes the front buffer, or what is currently displayed on the device; this is called page flipping.

Alternatively, the contents of the back buffer can be copied, or blitted forward in a chain instead of moving the video pointer.

 Double buffering:
 ------> *         *
 [To display] <---- * Front B *   Show  * Back B. * <---- Rendering
 <------ *         *
 Triple buffering:
 [To      ***********         ***********        ***********
 display] *         * --------+---------+------> *         *
 <---- * Front B *   Show  * Mid. B. *        * Back B. * <---- Rendering
 <------ *         * <----- *         *
 

Here is an example of how buffer strategies can be created and used:

 // Check the capabilities of the GraphicsConfiguration
 ...
 // Create our component
 Window w = new Window(gc);
 // Show our window
 w.setVisible(true);
 // Create a general double-buffering strategy
 w.createBufferStrategy(2);
 BufferStrategy strategy = w.getBufferStrategy();
 // Main loop
 while (!done) {
 // Prepare for rendering the next frame
 // ...
 // Render single frame
 do {
 // The following loop ensures that the contents of the drawing buffer
 // are consistent in case the underlying surface was recreated
 do {
 // Get a new graphics context every time through the loop
 // to make sure the strategy is validated
 Graphics graphics = strategy.getDrawGraphics();
 // Render to graphics
 // ...
 // Dispose the graphics
 graphics.dispose();
 // Repeat the rendering if the drawing buffer contents 
 // were restored
 } while (strategy.contentsRestored());
 // Display the buffer
 strategy.show();
 // Repeat the rendering if the drawing buffer was lost
 } while (strategy.contentsLost());
 }
 // Dispose the window
 w.setVisible(false);
 w.dispose();