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 * Copyright (c) 2003 Sun Microsystems, Inc. All Rights Reserved.
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 * contributors may be used to endorse or promote products derived from
 * this software without specific prior written permission.
 * 
 * This software is provided "AS IS," without a warranty of any kind. ALL
 * EXPRESS OR IMPLIED CONDITIONS, REPRESENTATIONS AND WARRANTIES,
 * INCLUDING ANY IMPLIED WARRANTY OF MERCHANTABILITY, FITNESS FOR A
 * PARTICULAR PURPOSE OR NON-INFRINGEMENT, ARE HEREBY EXCLUDED. SUN
 * MICROSYSTEMS, INC. ("SUN") AND ITS LICENSORS SHALL NOT BE LIABLE FOR
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 * You acknowledge that this software is not designed or intended for use
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 * Sun gratefully acknowledges that this software was originally authored
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 */

package javax.media.opengl;

// FIXME: We need some way to tell when the device upon which the canvas is
// being displayed has changed (e.g., the user drags the canvas's parent
// window from one screen on multi-screen environment to another, when the
// user changes the display bit depth or screen resolution, etc). When this
// occurs, we need the canvas to reset the gl function pointer tables for the
// canvas, because the new device may have different capabilities (e.g.,
// doesn't support as many opengl extensions) from the original device. This
// hook would also be useful in other GLDrawables (for example, offscreen
// buffers such as pbuffers, whose contents may or may not be invalidated when
// the display mode changes, depending on the vendor's GL implementation).
//
// Right now I'm not sure how hook into when this change occurs. There isn't
// any AWT event corresponding to a device change (as far as I can
// tell). We could constantly check the GraphicsConfiguration of the canvas's top-level
// parent to see if it has changed, but this would be very slow (we'd have to
// do it every time the context is made current). There has got to be a better
// solution, but I'm not sure what it is.

// FIXME: Subclasses need to call resetGLFunctionAvailability() on their
// context whenever the displayChanged() function is called on our
// GLEventListeners

/** An abstraction for an OpenGL rendering target. A GLDrawable's
    primary functionality is to create OpenGL contexts which can be
    used to perform rendering. A GLDrawable does not automatically
    create an OpenGL context, but all implementations of {@link
    GLAutoDrawable} do so upon creation. */

public interface GLDrawable {
  /**
   * Creates a new context for drawing to this drawable that will
   * optionally share display lists and other server-side OpenGL
   * objects with the specified GLContext. <P>
   *
   * The GLContext <code>share</code> need not be associated with this
   * GLDrawable and may be null if sharing of display lists and other
   * objects is not desired. See the note in the overview
   * documentation on
   * <a href="../../../overview-summary.html#SHARING">context sharing</a>.
   */
  public GLContext createContext(GLContext shareWith);

  /**
   * Indicates to on-screen GLDrawable implementations whether the
   * underlying window has been created and can be drawn into. End
   * users do not need to call this method; it is not necessary to
   * call <code>setRealized</code> on a GLCanvas, a GLJPanel, or a
   * GLPbuffer, as these perform the appropriate calls on their
   * underlying GLDrawables internally.
   *
   * <P>
   *
   * Developers implementing new OpenGL components for various window
   * toolkits need to call this method against GLDrawables obtained
   * from the GLDrawableFactory via the {@link
   * GLDrawableFactory#getGLDrawable
   * GLDrawableFactory.getGLDrawable()} method. It must typically be
   * called with an argument of <code>true</code> when the component
   * associated with the GLDrawable is realized and with an argument
   * of <code>false</code> just before the component is unrealized.
   * For the AWT, this means calling <code>setRealized(true)</code> in
   * the <code>addNotify</code> method and with an argument of
   * <code>false</code> in the <code>removeNotify</code> method.
   *
   * <P>
   *
   * <code>GLDrawable</code> implementations should handle multiple
   * cycles of <code>setRealized(true)</code> /
   * <code>setRealized(false)</code> calls. Most, if not all, Java
   * window toolkits have a persistent object associated with a given
   * component, regardless of whether that component is currently
   * realized. The <CODE>GLDrawable</CODE> object associated with a
   * particular component is intended to be similarly persistent. A
   * <CODE>GLDrawable</CODE> is intended to be created for a given
   * component when it is constructed and live as long as that
   * component. <code>setRealized</code> allows the
   * <code>GLDrawable</code> to re-initialize and destroy any
   * associated resources as the component becomes realized and
   * unrealized, respectively.
   *
   * <P>
   *
   * Calling this method has no other effects. For example, if
   * <code>removeNotify</code> is called on a Canvas implementation
   * for which a GLDrawable has been created, it is also necessary to
   * destroy all OpenGL contexts associated with that GLDrawable. This
   * is not done automatically by the implementation.
   */
  public void setRealized(boolean realized);

  /** Returns the current width of this GLDrawable. */
  public int getWidth();

  /** Returns the current height of this GLDrawable. */
  public int getHeight();

  /** Swaps the front and back buffers of this drawable. For {@link
      GLAutoDrawable} implementations, when automatic buffer swapping
      is enabled (as is the default), this method is called
      automatically and should not be called by the end user. */
  public void swapBuffers() throws GLException;

  /** Fetches the {@link GLCapabilities} corresponding to the chosen
      OpenGL capabilities (pixel format / visual) for this drawable.
      Some drawables, in particular on-screen drawables, may be
      created lazily; null is returned if the drawable is not
      currently created or if its pixel format has not been set yet.
      On some platforms, the pixel format is not directly associated
      with the drawable; a best attempt is made to return a reasonable
      value in this case. 
      Returns a copy of the passed object.
    */
  public GLCapabilities getChosenGLCapabilities();

  public NativeWindow getNativeWindow();

  public GLDrawableFactory getFactory();

  public String toString();
}