path: root/src/jogl/classes/javax/media/opengl/GLAutoDrawable.java

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package javax.media.opengl;

import javax.media.opengl.glu.*;
import com.jogamp.opengl.impl.Debug;
import java.security.*;

/** A higher-level abstraction than {@link GLDrawable} which supplies
    an event based mechanism ({@link GLEventListener}) for performing
    OpenGL rendering. A GLAutoDrawable automatically creates a primary
    rendering context which is associated with the GLAutoDrawable for
    the lifetime of the object. This context has the {@link
    GLContext#setSynchronized synchronized} property enabled so that
    calls to {@link GLContext#makeCurrent makeCurrent} will block if
    the context is current on another thread. This allows the internal
    GLContext for the GLAutoDrawable to be used both by the event
    based rendering mechanism as well by end users directly.<P>

    The implementation shall initialize itself as soon as possible,
    ie if the attached {@link javax.media.nativewindow.NativeWindow NativeWindow} is become visible. 
    The following protocol shall be satisfied:
    <ul>
        <li> Create the  {@link GLDrawable} with the requested {@link GLCapabilities}</li>
        <li> Notify {@link GLDrawable} to validate the {@link GLCapabilities} by calling {@link GLDrawable#setRealized setRealized(true)}.</li>
        <li> Create the new {@link GLContext}.</li>
        <li> Initialize all OpenGL resources by calling {@link GLEventListener#init init(..)} for all
             registered {@link GLEventListener}s. This can be done immediatly, or with the followup {@link #display display(..)} call.</li>
        <li> Send a reshape event by calling {@link GLEventListener#reshape reshape(..)} for all
             registered {@link GLEventListener}s. This shall be done after the {@link GLEventListener#init init(..)} calls.</li>
    </ul><P>

    Another implementation detail is the drawable reconfiguration. One use case is where a window is being 
    dragged to another screen with a different pixel configuration, ie {@link GLCapabilities}. The implementation 
    shall be able to detect such cases in conjunction with the associated {@link javax.media.nativewindow.NativeWindow NativeWindow}.<br>
    For example, AWT's {@link java.awt.Canvas} 's {@link java.awt.Canvas#getGraphicsConfiguration getGraphicsConfiguration()}
    is capable to determine a display device change. This is demonstrated within {@link javax.media.opengl.awt.GLCanvas}'s 
    and NEWT's <code>AWTCanvas</code> {@link javax.media.opengl.awt.GLCanvas#getGraphicsConfiguration getGraphicsConfiguration()} 
    specialization. Another demonstration is NEWT's {@link javax.media.nativewindow.NativeWindow NativeWindow} 
    implementation on the the Windows platform, which utilizes the native platform's <i>MonitorFromWindow(HWND)</i> function.<br>
    All OpenGL resources shall be regenerated, while the drawable's {@link GLCapabilities} has 
    to be choosen again. The following protocol shall be satisfied.
    <ul>
        <li> Controlled disposal:</li>
        <ul>
            <li> Dispose all OpenGL resources by calling {@link GLEventListener#dispose dispose(..)} for all
                 registered {@link GLEventListener}s.</li>
            <li> Destroy the {@link GLContext}.</li>
            <li> Notify {@link GLDrawable} of the invalid state by calling {@link GLDrawable#setRealized setRealized(false)}.</li>
        </ul>
        <li> Controlled regeneration:</li>
        <ul>
            <li> Create the new {@link GLDrawable} with the requested {@link GLCapabilities}
            <li> Notify {@link GLDrawable} to revalidate the {@link GLCapabilities} by calling {@link GLDrawable#setRealized setRealized(true)}.</li>
            <li> Create the new {@link GLContext}.</li>
            <li> Initialize all OpenGL resources by calling {@link GLEventListener#init init(..)} for all
                 registered {@link GLEventListener}s. This can be done immediatly, or with the followup {@link #display display(..)} call.</li>
            <li> Send a reshape event by calling {@link GLEventListener#reshape reshape(..)} for all
                 registered {@link GLEventListener}s. This shall be done after the {@link GLEventListener#init init(..)} calls.</li>
        </ul>
    </ul>
    Note: Current graphics driver keep the surface configuration for a given window, even if the window is moved to 
    a monitor with a different pixel configuration, ie 32bpp to 16bpp. However, it is best to not assume such behavior
    and make your application comply with the above protocol.<P>

    However, to not introduce to much breakage with older applications and because of the situation 
    mentioned above, the <code>boolean</code> system property <code>jogl.screenchange.action</code> will control the 
    screen change action as follows:<br>

    <PRE>
    -Djogl.screenchange.action=false Disable the drawable reconfiguration (the default)
    -Djogl.screenchange.action=true  Enable  the drawable reconfiguration
    </PRE>    
  */
public interface GLAutoDrawable extends GLDrawable {
  /** Flag reflecting wheather the drawable reconfiguration will be issued in 
    * case a screen device change occured, e.g. in a multihead environment,
    * where you drag the window to another monitor. */
  public static final boolean SCREEN_CHANGE_ACTION_ENABLED = Debug.getBooleanProperty("jogl.screenchange.action", true, AccessController.getContext());

  /** FIXME:
  ** Invalid state, the resources are not yet ready to render. *
  public static final int STATE_INVALID = 0;

  ** Valid state, all resources are ready to render, 
      and all registered {@link GLEventListener#init init(..)} are called. *
  public static final int STATE_VALID = 1;

  ** Destroying state, currently executing the {@link #destroy()} method. *
  public static final int STATE_DESTROYING = 2; */

  /**
   * Returns the context associated with this drawable. The returned
   * context will be synchronized.
   * Don't rely on it's identity, the context may change.
   */
  public GLContext getContext();

  /**
   * Associate a new context to this drawable.
   */
  public void setContext(GLContext context);

  /** Adds a {@link GLEventListener} to the end of this drawable queue.
      The listeners are notified of events in the order of the queue. */
  public void addGLEventListener(GLEventListener listener);

  /** 
   * Adds a {@link GLEventListener} at the given index of this drawable queue.
   * The listeners are notified of events in the order of the queue.
   * @param index Position where the listener will be inserted. 
   *              Should be within (0 <= index && index <= size()).
   *              An index value of -1 is interpreted as the end of the list, size().
   * @param listener The GLEventListener object to be inserted
   * @throws IndexOutOfBoundsException If the index is not within (0 <= index && index <= size()), or -1
   */
  public void addGLEventListener(int index, GLEventListener listener)
    throws IndexOutOfBoundsException;

  /** Removes a {@link GLEventListener} from this drawable. Note that
      if this is done from within a particular drawable's {@link
      GLEventListener} handler (reshape, display, etc.) that it is not
      guaranteed that all other listeners will be evaluated properly
      during this update cycle. */
  public void removeGLEventListener(GLEventListener listener);

  /** 
   * Enqueues the one-shot {@link javax.media.opengl.GLRunnable} into the queue,
   * which will be executed at the next {@link #display()} call.
   * <p>
   * Warning: We cannot verify if the caller runs in the same thread 
   * as the display caller, hence we cannot avoid a deadlock
   * in such case. You have to know what you are doing, 
   * ie call this only in a I/O event listener, or such.<br></p>
   * @see #display()
   * @see javax.media.opengl.GLRunnable
   */   
  public void invoke(boolean wait, GLRunnable glRunnable);

  /** FIXME: Returns the current state, 
      {@link #STATE_INVALID}, {@link #STATE_VALID} or {@link #STATE_DESTROYING}.
      Tool to determine, e.g. if a {@link GLEventListener#dispose dispose(..)}
      event is send in the context of the destruction of this GLAutoDrawable.
  public int getCurrentState(); */

  /** Destroys all resources associated with this GLAutoDrawable,
      inclusive the GLContext.
      If a window is attached to it's implementation, it shall be closed.
      Causes disposing of all OpenGL resources
      by calling {@link GLEventListener#dispose dispose(..)} for all
      registered {@link GLEventListener}s. Called automatically by the
      window system toolkit upon receiving a destroy notification. This
      routine may be called manually. */
  public void destroy();

  /** <p>Causes OpenGL rendering to be performed for this GLAutoDrawable
      in the following order:
      <ul>
        <li> Calling {@link GLEventListener#display display(..)} for all
             registered {@link GLEventListener}s. </li>
        <li> Execute and dismiss all one-shot {@link javax.media.opengl.GLRunnable},
             enqueued via {@link #invoke(boolean, GLRunnable)}.</li>
      </ul></p>
      <p> 
      Called automatically by the
      window system toolkit upon receiving a repaint() request.</p> 
      <p> 
      This routine may be called manually for better control over the
      rendering process. It is legal to call another GLAutoDrawable's
      display method from within the {@link GLEventListener#display
      display(..)} callback.</p>
      <p>
      In case of a new generated OpenGL context, 
      the implementation shall call {@link GLEventListener#init init(..)} for all
      registered {@link GLEventListener}s <i>before</i> making the 
      actual {@link GLEventListener#display display(..)} calls,
      in case this has not been done yet.</p> */
  public void display();

  /** Enables or disables automatic buffer swapping for this drawable.
      By default this property is set to true; when true, after all
      GLEventListeners have been called for a display() event, the
      front and back buffers are swapped, displaying the results of
      the render. When disabled, the user is responsible for calling
      {@link #swapBuffers(..)} manually. */
  public void setAutoSwapBufferMode(boolean onOrOff);

  /** Indicates whether automatic buffer swapping is enabled for this
      drawable. See {@link #setAutoSwapBufferMode}. */
  public boolean getAutoSwapBufferMode();

  /** Returns the {@link GL} pipeline object this GLAutoDrawable uses.
      If this method is called outside of the {@link
      GLEventListener}'s callback methods (init, display, etc.) it may
      return null. Users should not rely on the identity of the
      returned GL object; for example, users should not maintain a
      hash table with the GL object as the key. Additionally, the GL
      object should not be cached in client code, but should be
      re-fetched from the GLAutoDrawable at the beginning of each call
      to init, display, etc. */
  public GL getGL();

  /** Sets the {@link GL} pipeline object this GLAutoDrawable uses.
      This should only be called from within the GLEventListener's
      callback methods, and usually only from within the init()
      method, in order to install a composable pipeline. See the JOGL
      demos for examples.
      @return the set GL pipeline or null if not successful */
  public GL setGL(GL gl);

}