/*
 * Copyright (c) 2003 Sun Microsystems, Inc. All Rights Reserved.
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met:
 * 
 * - Redistribution of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 * 
 * - Redistribution in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in the
 *   documentation and/or other materials provided with the distribution.
 * 
 * Neither the name of Sun Microsystems, Inc. or the names of
 * 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
 * ANY DAMAGES SUFFERED BY LICENSEE AS A RESULT OF USING, MODIFYING OR
 * DISTRIBUTING THIS SOFTWARE OR ITS DERIVATIVES. IN NO EVENT WILL SUN OR
 * ITS LICENSORS BE LIABLE FOR ANY LOST REVENUE, PROFIT OR DATA, OR FOR
 * DIRECT, INDIRECT, SPECIAL, CONSEQUENTIAL, INCIDENTAL OR PUNITIVE
 * DAMAGES, HOWEVER CAUSED AND REGARDLESS OF THE THEORY OF LIABILITY,
 * ARISING OUT OF THE USE OF OR INABILITY TO USE THIS SOFTWARE, EVEN IF
 * SUN HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.
 * 
 * You acknowledge that this software is not designed or intended for use
 * in the design, construction, operation or maintenance of any nuclear
 * facility.
 * 
 * Sun gratefully acknowledges that this software was originally authored
 * and developed by Kenneth Bradley Russell and Christopher John Kline.
 */

package javax.media.opengl;

import java.awt.Canvas;
import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.GraphicsConfiguration;
import java.awt.GraphicsDevice;
import java.lang.reflect.*;
import java.security.*;
import com.sun.opengl.impl.*;

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

/** A heavyweight AWT component which provides OpenGL rendering
    support. This is the primary implementation of {@link GLDrawable};
    {@link GLJPanel} is provided for compatibility with Swing user
    interfaces when adding a heavyweight doesn't work either because
    of Z-ordering or LayoutManager problems. */

public class GLCanvas extends Canvas implements GLAutoDrawable {

  private static final boolean DEBUG = Debug.debug("GLCanvas");

  private GLDrawableHelper drawableHelper = new GLDrawableHelper();
  private GLDrawable drawable;
  private GLContextImpl context;
  private boolean autoSwapBufferMode = true;
  private boolean sendReshape = false;

  /** Creates a new GLCanvas component with a default set of OpenGL
      capabilities, using the default OpenGL capabilities selection
      mechanism, on the default screen device. */
  public GLCanvas() {
    this(null);
  }

  /** Creates a new GLCanvas component with the requested set of
      OpenGL capabilities, using the default OpenGL capabilities
      selection mechanism, on the default screen device. */
  public GLCanvas(GLCapabilities capabilities) {
    this(capabilities, null, null, null);
  }

  /** Creates a new GLCanvas component. The passed GLCapabilities
      specifies the OpenGL capabilities for the component; if null, a
      default set of capabilities is used. The GLCapabilitiesChooser
      specifies the algorithm for selecting one of the available
      GLCapabilities for the component; a DefaultGLCapabilitesChooser
      is used if null is passed for this argument. The passed
      GLContext specifies an OpenGL context with which to share
      textures, display lists and other OpenGL state, and may be null
      if sharing is not desired. See the note in the overview
      documentation on <a
      href="../../../overview-summary.html#SHARING">context
      sharing</a>. The passed GraphicsDevice indicates the screen on
      which to create the GLCanvas; the GLDrawableFactory uses the
      default screen device of the local GraphicsEnvironment if null
      is passed for this argument. */
  public GLCanvas(GLCapabilities capabilities,
                  GLCapabilitiesChooser chooser,
                  GLContext shareWith,
                  GraphicsDevice device) {
    // The platform-specific GLDrawableFactory will only provide a
    // non-null GraphicsConfiguration on platforms where this is
    // necessary (currently only X11, as Windows allows the pixel
    // format of the window to be set later and Mac OS X seems to
    // handle this very differently than all other platforms). On
    // other platforms this method returns null; it is the case (at
    // least in the Sun AWT implementation) that this will result in
    // equivalent behavior to calling the no-arg super() constructor
    // for Canvas.
    super(unwrap((AWTGraphicsConfiguration)
                 GLDrawableFactory.getFactory().chooseGraphicsConfiguration(capabilities,
                                                                            chooser,
                                                                            new AWTGraphicsDevice(device))));
    drawable = GLDrawableFactory.getFactory().getGLDrawable(this, capabilities, chooser);
    context = (GLContextImpl) drawable.createContext(shareWith);
    context.setSynchronized(true);
  }
  
  public GLContext createContext(GLContext shareWith) {
    return drawable.createContext(shareWith);
  }

  public void setRealized(boolean realized) {
  }

  public void display() {
    maybeDoSingleThreadedWorkaround(displayOnEventDispatchThreadAction,
                                    displayAction);
  }

  /** Overridden to cause OpenGL rendering to be performed during
      repaint cycles. Subclasses which override this method must call
      super.paint() in their paint() method in order to function
      properly. <P>

      <B>Overrides:</B>
      <DL><DD><CODE>paint</CODE> in class <CODE>java.awt.Component</CODE></DD></DL> */
  public void paint(Graphics g) {
    display();
  }

  /** Overridden to track when this component is added to a container.
      Subclasses which override this method must call
      super.addNotify() in their addNotify() method in order to
      function properly. <P>

      <B>Overrides:</B>
      <DL><DD><CODE>addNotify</CODE> in class <CODE>java.awt.Component</CODE></DD></DL> */
  public void addNotify() {
    super.addNotify();
    disableBackgroundErase();
    drawable.setRealized(true);
    if (DEBUG) {
      System.err.println("GLCanvas.addNotify()");
    }
  }

  /** Overridden to track when this component is removed from a
      container. Subclasses which override this method must call
      super.removeNotify() in their removeNotify() method in order to
      function properly. <P>

      <B>Overrides:</B>
      <DL><DD><CODE>removeNotify</CODE> in class <CODE>java.awt.Component</CODE></DD></DL> */
  public void removeNotify() {
    try {
      if (Threading.isSingleThreaded() &&
          !Threading.isOpenGLThread()) {
        // Workaround for termination issues with applets --
        // sun.applet.AppletPanel should probably be performing the
        // remove() call on the EDT rather than on its own thread
        if (Threading.isAWTMode() &&
            Thread.holdsLock(getTreeLock())) {
          // The user really should not be invoking remove() from this
          // thread -- but since he/she is, we can not go over to the
          // EDT at this point. Try to destroy the context from here.
          destroyAction.run();
        } else {
          Threading.invokeOnOpenGLThread(destroyAction);
        }
      } else {
        destroyAction.run();
      }
    } finally {
      drawable.setRealized(false);
      super.removeNotify();
      if (DEBUG) {
        System.err.println("GLCanvas.removeNotify()");
      }
    }
  }

  /** Overridden to cause {@link GLDrawableHelper#reshape} to be
      called on all registered {@link GLEventListener}s. Subclasses
      which override this method must call super.reshape() in
      their reshape() method in order to function properly. <P>

      <B>Overrides:</B>
      <DL><DD><CODE>reshape</CODE> in class <CODE>java.awt.Component</CODE></DD></DL> */
  public void reshape(int x, int y, int width, int height) {
    super.reshape(x, y, width, height);
    sendReshape = true;
  }

  /** <B>Overrides:</B>
      <DL><DD><CODE>update</CODE> in class <CODE>java.awt.Component</CODE></DD></DL> */
  // Overridden from Canvas to prevent the AWT's clearing of the
  // canvas from interfering with the OpenGL rendering.
  public void update(Graphics g) {
    paint(g);
  }
  
  public void addGLEventListener(GLEventListener listener) {
    drawableHelper.addGLEventListener(listener);
  }

  public void removeGLEventListener(GLEventListener listener) {
    drawableHelper.removeGLEventListener(listener);
  }

  public GLContext getContext() {
    return context;
  }

  public GL getGL() {
    return getContext().getGL();
  }

  public void setGL(GL gl) {
    getContext().setGL(gl);
  }

  public void setAutoSwapBufferMode(boolean onOrOff) {
    drawableHelper.setAutoSwapBufferMode(onOrOff);
  }

  public boolean getAutoSwapBufferMode() {
    return drawableHelper.getAutoSwapBufferMode();
  }

  public void swapBuffers() {
    maybeDoSingleThreadedWorkaround(swapBuffersOnEventDispatchThreadAction, swapBuffersAction);
  }

  public GLCapabilities getChosenGLCapabilities() {
    if (drawable == null)
      return null;

    return drawable.getChosenGLCapabilities();
  }

  //----------------------------------------------------------------------
  // Internals only below this point
  //

  private void maybeDoSingleThreadedWorkaround(Runnable eventDispatchThreadAction,
                                               Runnable invokeGLAction) {
    if (Threading.isSingleThreaded() &&
        !Threading.isOpenGLThread()) {
      Threading.invokeOnOpenGLThread(eventDispatchThreadAction);
    } else {
      drawableHelper.invokeGL(drawable, context, invokeGLAction, initAction);
    }
  }

  class InitAction implements Runnable {
    public void run() {
      drawableHelper.init(GLCanvas.this);
    }
  }
  private InitAction initAction = new InitAction();
  
  class DisplayAction implements Runnable {
    public void run() {
      if (sendReshape) {
        // Note: we ignore the given x and y within the parent component
        // since we are drawing directly into this heavyweight component.
        int width = getWidth();
        int height = getHeight();
        getGL().glViewport(0, 0, width, height);
        drawableHelper.reshape(GLCanvas.this, 0, 0, width, height);
        sendReshape = false;
      }

      drawableHelper.display(GLCanvas.this);
    }
  }
  private DisplayAction displayAction = new DisplayAction();

  class SwapBuffersAction implements Runnable {
    public void run() {
      drawable.swapBuffers();
    }
  }
  private SwapBuffersAction swapBuffersAction = new SwapBuffersAction();

  // Workaround for ATI driver bugs related to multithreading issues
  // like simultaneous rendering via Animators to canvases that are
  // being resized on the AWT event dispatch thread
  class DisplayOnEventDispatchThreadAction implements Runnable {
    public void run() {
      drawableHelper.invokeGL(drawable, context, displayAction, initAction);
    }
  }
  private DisplayOnEventDispatchThreadAction displayOnEventDispatchThreadAction =
    new DisplayOnEventDispatchThreadAction();
  class SwapBuffersOnEventDispatchThreadAction implements Runnable {
    public void run() {
      drawableHelper.invokeGL(drawable, context, swapBuffersAction, initAction);
    }
  }
  private SwapBuffersOnEventDispatchThreadAction swapBuffersOnEventDispatchThreadAction =
    new SwapBuffersOnEventDispatchThreadAction();

  class DestroyAction implements Runnable {
    public void run() {
      GLContext current = GLContext.getCurrent();
      if (current == context) {
        context.release();
      }
      context.destroy();
    }
  }
  private DestroyAction destroyAction = new DestroyAction();

  // Disables the AWT's erasing of this Canvas's background on Windows
  // in Java SE 6. This internal API is not available in previous
  // releases, but the system property
  // -Dsun.awt.noerasebackground=true can be specified to get similar
  // results globally in previous releases.
  private static boolean disableBackgroundEraseInitialized;
  private static Method  disableBackgroundEraseMethod;
  private void disableBackgroundErase() {
    if (!disableBackgroundEraseInitialized) {
      try {
        AccessController.doPrivileged(new PrivilegedAction() {
            public Object run() {
              try {
                disableBackgroundEraseMethod =
                  getToolkit().getClass().getDeclaredMethod("disableBackgroundErase",
                                                            new Class[] { Canvas.class });
                disableBackgroundEraseMethod.setAccessible(true);
              } catch (Exception e) {
              }
              return null;
            }
          });
      } catch (Exception e) {
      }
      disableBackgroundEraseInitialized = true;
    }
    if (disableBackgroundEraseMethod != null) {
      try {
        disableBackgroundEraseMethod.invoke(getToolkit(), new Object[] { this });
      } catch (Exception e) {
        throw new GLException(e);
      }
    }
  }

  private static GraphicsConfiguration unwrap(AWTGraphicsConfiguration config) {
    if (config == null) {
      return null;
    }
    return config.getGraphicsConfiguration();
  }
}