Full-Screen Exclusive Graphics

Full-Screen Exclusive Graphics
An Introduction with Examples in Java

Prof. David Bernstein
James Madison University

Computer Science Department

bernstdh@jmu.edu

Motivation

Graphics is complicated considerably by "windowing"
As a result, the performance of graphical systems is hampered by "windowing"
One way around this problem is for a single graphical application to take control of the entire screen

Concepts

Environment:
- A description of the overall capabilities of the system. In Java, an environment is encapsulated by the GraphicsEnvironment class
Device:
- A display device (usually a monitor, printer, or plotter). In Java, a device is encapsulated by the GraphicsDevice class.
Configuration:
- The settings for a particular device (e.g., resolution, color depth). In Java, a configuration is encapsulated by the GraphicsConfiguration class.

Issues

Display Mode:
- It is not always possible to change the display mode on the fly, and this makes full-screen graphics cumbersome
- If the display mode is the same color depth as the screen then the colors will not have to be dithered, and this is usually much more efficient
Page Flipping:
- The screen has a video pointer and there are two (or more in the case of a multi-buffered system) images
- This group of images is sometimes called a flip chain

Issues (cont.)

Image Acceleration:
- In some system, an image can be accelerated in a variety of ways including including pixmaps, Video RAM (VRAM), and Accelerated Graphics Port (AGP)
Volatility of Images:
- A "volatile image" (which is encapsulated in Java by the VolatileImage class) is subject to losing its contents at any time in ways that are beyond the control of the application (e.g., situations caused by the operating system or by other applications).
- Volatile images are required by some kinds of acceleration.

Capabilities

javaexamples/fullscreen/ShowCapabilities.java

Animation

Up until now, the "rendering" loop was under the control of the OS.
With full-screen exclusive mode graphics, it is completely controlled by the application.

Animation (cont.)

Without a Buffer Strategy

Graphics g = getPaintGraphics(); while (!done) { // Rendering using g } g.dispose();

Animation (cont.)

With a Buffer Strategy

BufferStrategy strategy; Window window; // Construct the Window // Create the BufferStrategy window.createBufferStrategy(2); strategy = window.getBufferStrategy(); Graphics g = strategy.getDrawGraphics(); while (!done) { // Rendering using g strategy.show(); } g.dispose();

An Example

The Stage Revisited

javaexamples/fullscreen/FullScreenStage.java

There's Always More to Learn