com.sun.opengl.util.awt
Class Overlay

java.lang.Object
  com.sun.opengl.util.awt.Overlay

public class Overlay
extends Object

Provides a Java 2D overlay on top of an arbitrary GLDrawable, making it easier to do things like draw text and images on top of an OpenGL scene while still maintaining reasonably good efficiency.

Constructor Summary

Overlay(GLDrawable drawable)
Creates a new Java 2D overlay on top of the specified GLDrawable.

Method Summary

void	beginRendering() Begins the OpenGL rendering process for the overlay.
boolean	contentsLost() Indicates whether the Java 2D contents of the overlay were lost since the last time createGraphics() was called.
Graphics2D	createGraphics() Creates a Graphics2D instance for rendering into the overlay.
void	draw(int x, int y, int width, int height) Draws the specified sub-rectangle of the overlay on top of the OpenGL drawable.
void	draw(int screenx, int screeny, int overlayx, int overlayy, int width, int height) Draws the specified sub-rectangle of the overlay at the specified x and y coordinate on top of the OpenGL drawable.
void	drawAll() Draws the entire contents of the overlay on top of the OpenGL drawable.
void	endRendering() Ends the OpenGL rendering process for the overlay.
void	markDirty(int x, int y, int width, int height) Marks the given region of the overlay as dirty.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

Overlay

public Overlay(GLDrawable drawable)

Creates a new Java 2D overlay on top of the specified GLDrawable.

Method Detail

createGraphics

public Graphics2D createGraphics()

Creates a Graphics2D instance for rendering into the overlay. The returned object should be disposed of using the normal Graphics.dispose() method once it is no longer being used.

Returns:

a new Graphics2D object for rendering into the backing store of this renderer

contentsLost

public boolean contentsLost()

Indicates whether the Java 2D contents of the overlay were lost since the last time createGraphics() was called. This method should be called immediately after calling createGraphics() to see whether the entire contents of the overlay need to be redrawn or just the region the application is interested in updating.

Returns:

whether the contents of the overlay were lost since the last render

markDirty

public void markDirty(int x,
                      int y,
                      int width,
                      int height)

Marks the given region of the overlay as dirty. This region, and any previously set dirty regions, will be automatically synchronized with the underlying Texture during the next draw or drawAll operation, at which point the dirty region will be cleared. It is not necessary for an OpenGL context to be current when this method is called.

Parameters:

x - the x coordinate (in Java 2D coordinates -- relative to upper left) of the region to update

y - the y coordinate (in Java 2D coordinates -- relative to upper left) of the region to update

width - the width of the region to update

height - the height of the region to update

Throws:

GLException - If an OpenGL context is not current when this method is called

drawAll

public void drawAll()
             throws GLException

Draws the entire contents of the overlay on top of the OpenGL drawable. This is a convenience method which encapsulates all portions of the rendering process; if this method is used, beginRendering(), endRendering(), etc. should not be used. This method should be called while the OpenGL context for the drawable is current, and after your OpenGL scene has been rendered.

Throws:

GLException - If an OpenGL context is not current when this method is called

beginRendering

public void beginRendering()
                    throws GLException

Begins the OpenGL rendering process for the overlay. This is separated out so advanced applications can render independent pieces of the overlay to different portions of the drawable.

Throws:

GLException - If an OpenGL context is not current when this method is called

endRendering

public void endRendering()
                  throws GLException

Ends the OpenGL rendering process for the overlay. This is separated out so advanced applications can render independent pieces of the overlay to different portions of the drawable.

Throws:

GLException - If an OpenGL context is not current when this method is called

draw

public void draw(int x,
                 int y,
                 int width,
                 int height)
          throws GLException

Draws the specified sub-rectangle of the overlay on top of the OpenGL drawable. beginRendering() and endRendering() must be used in conjunction with this method to achieve proper rendering results. This method should be called while the OpenGL context for the drawable is current, and after your OpenGL scene has been rendered.

Parameters:

x - the lower-left x coordinate (relative to the lower left of the overlay) of the rectangle to draw

y - the lower-left y coordinate (relative to the lower left of the overlay) of the rectangle to draw

width - the width of the rectangle to draw

height - the height of the rectangle to draw

Throws:

GLException - If an OpenGL context is not current when this method is called

draw

public void draw(int screenx,
                 int screeny,
                 int overlayx,
                 int overlayy,
                 int width,
                 int height)
          throws GLException

Draws the specified sub-rectangle of the overlay at the specified x and y coordinate on top of the OpenGL drawable. beginRendering() and endRendering() must be used in conjunction with this method to achieve proper rendering results. This method should be called while the OpenGL context for the drawable is current, and after your OpenGL scene has been rendered.

Parameters:

screenx - the on-screen x coordinate at which to draw the rectangle

screeny - the on-screen y coordinate (relative to lower left) at which to draw the rectangle

overlayx - the x coordinate of the pixel in the overlay of the lower left portion of the rectangle to draw

overlayy - the y coordinate of the pixel in the overlay (relative to lower left) of the lower left portion of the rectangle to draw

width - the width of the rectangle to draw

height - the height of the rectangle to draw

Throws:

GLException - If an OpenGL context is not current when this method is called