JAWT Support JDK >=1.3

2 files changed, 203 insertions, 136 deletions

diff --git a/gl4java/awt/GLAnimCanvas.java b/gl4java/awt/GLAnimCanvas.java
index 77fd21f..6133e60 100644
--- a/gl4java/awt/GLAnimCanvas.java
+++ b/gl4java/awt/GLAnimCanvas.java
@@ -83,6 +83,13 @@ import java.lang.Math;
  * because a GL-Context can be shared by many threads,
  * but one thread can have just one GL-Context !
  *
+ * <p>
+ *
+ * Since GL4Java 2.5.2 and using a JVM >= 1.3
+ * the multithreading support is stable !
+ *
+ * <p>
+ *
  * (comments welcome)
  * 
  * <p>
@@ -102,7 +109,7 @@ import java.lang.Math;
         <a href="GLAnimCanvas.html#ReInit()">ReInit - ReInitialisation after stop for setSuspended(false)</a>
  * </pre>
  *
- * @see GLCanvas
+ * @see gl4java.awt.GLCanvas
  * @version         2.0, 21. April 1999
  * @author      Sven Goethel
  * 
@@ -116,11 +123,18 @@ public class GLAnimCanvas extends GLCanvas
          *
          * A little GUI is supported !
          *
-         * @see GLAnimCanvas#run    
+         * @see gl4java.awt.GLAnimCanvas#run    
          */
         protected double FramesPerSec=20;
         protected long   mSecPerFrame=0;
 
+        protected static int    globalThreadNumber=0;
+
+        public static int getGlobalThreadNumber()
+	{
+		return globalThreadNumber;
+	}
+
 	/**
 	 * the delays ..
 	 */
@@ -129,16 +143,16 @@ public class GLAnimCanvas extends GLCanvas
         /**
          * The thread  for  referencing Thread (Animation)
          *
-         * @see GLAnimCanvas#stop
-         * @see GLAnimCanvas#start
-         * @see GLAnimCanvas#run
+         * @see gl4java.awt.GLAnimCanvas#stop
+         * @see gl4java.awt.GLAnimCanvas#start
+         * @see gl4java.awt.GLAnimCanvas#run
          */      
         protected Thread killme = null;
 
         /**
          * Instead of using suspend (JAVA2)
          *
-         * @see GLAnimCanvas#run
+         * @see gl4java.awt.GLAnimCanvas#run
          */      
         protected boolean threadSuspended = false;
 
@@ -151,7 +165,7 @@ public class GLAnimCanvas extends GLCanvas
          *
          * Constructor
          *
-         * @see GLCanvas#GLCanvas
+         * @see gl4java.awt.GLCanvas#GLCanvas
          *
          */
         public GLAnimCanvas( int width, int height,
@@ -169,7 +183,7 @@ public class GLAnimCanvas extends GLCanvas
          *
          * Uses the default GLFunc and GLUFunc implementation !
          *
-         * @see GLCanvas#GLCanvas
+         * @see gl4java.awt.GLCanvas#GLCanvas
          *
          */
         public GLAnimCanvas( int width, int height )
@@ -206,16 +220,24 @@ public class GLAnimCanvas extends GLCanvas
 	 *
          * <p>
          *
+	 * You MUST encapsulate your OpenGL call's within:
+	 * <pre>
+		- glj.gljMakeCurrent()
+			YOUR OpenGL commands here !
+		- glj.gljFree()
+	 * </pre>
+         * <p>
+         *
          * You should set shallWeRender here,
          * to signalize the animation-loop 'run' to supsend
          * <p>
          * To restart the thread, just call setSuspended(false)
          *
-         * @see GLAnimCanvas#shallWeRender
-         * @see GLAnimCanvas#run
-         * @see GLAnimCanvas#setSuspended
-         * @see GLCanvas#sDisplay
-         * @see GLCanvas#paint
+         * @see gl4java.awt.GLAnimCanvas#shallWeRender
+         * @see gl4java.awt.GLAnimCanvas#run
+         * @see gl4java.awt.GLAnimCanvas#setSuspended
+         * @see gl4java.awt.GLCanvas#sDisplay
+         * @see gl4java.awt.GLCanvas#paint
          */ 
          public void display()
          {
@@ -229,7 +251,7 @@ public class GLAnimCanvas extends GLCanvas
 			return;
 		  }
 
-		  if( glj.gljMakeCurrent(true) == false ) 
+		  if( glj.gljMakeCurrent() == false ) 
 		  {
 		      if(glj.gljClassDebug)
 			 System.out.println("GLAnimCanvas problem in gljMakeCurrent() method");
@@ -248,7 +270,7 @@ public class GLAnimCanvas extends GLCanvas
          * ReInit should be overwritten by you,
          * to enter your re-initialisation within setSuspended(false) 
          * 
-         * @see GLAnimCanvas#setSuspended
+         * @see gl4java.awt.GLAnimCanvas#setSuspended
          */
         public void ReInit()
         {
@@ -271,8 +293,8 @@ public class GLAnimCanvas extends GLCanvas
          * <p>
          * 
          * @param b if true, uses repaint (default), otherwise directly sDisplay
-         * @see GLCanvas#sDisplay
-         * @see GLAnimCanvas#setUseFpsSleep
+         * @see gl4java.awt.GLCanvas#sDisplay
+         * @see gl4java.awt.GLAnimCanvas#setUseFpsSleep
          */
         public void setUseRepaint(boolean b)
         {
@@ -288,8 +310,8 @@ public class GLAnimCanvas extends GLCanvas
          * <p>
          * 
          * @param b if true, uses Fps sleeping, else not !
-         * @see GLCanvas#sDisplay
-         * @see GLAnimCanvas#setUseRepaint
+         * @see gl4java.awt.GLCanvas#sDisplay
+         * @see gl4java.awt.GLAnimCanvas#setUseRepaint
          */
         public void setUseFpsSleep(boolean b)
         {
@@ -324,21 +346,42 @@ public class GLAnimCanvas extends GLCanvas
         public synchronized void stop() 
         {
             killme = null;
-            threadSuspended=false;
-            notify();
+	    threadSuspended=false;
+
+            notifyAll();
         }
 
         /**
+          * You should call this before releasing/dispose this Window ! 
+          * Also you can overwrite this class,
+          * to dispose your own elements, e.g. a Frame etc. - 
+          * but be shure that you call
+          * cvsDispose implementation call this one !
+          * 
+          * This function calls gljDestroy of GLContext !
+          *
+          * @see gl4java.GLContext#gljDestroy
+          * @see gl4java.awt.GLCanvas#cvsDispose
+          * @see gl4java.awt.GLCanvas#doCleanup
+          */
+    	public void cvsDispose()
+    	{
+		stop();
+		super.cvsDispose();
+	}
+
+        /**
          * Should be set in display,
          * whether to render or not while the animation loop
          * <p>
          * If shallWeRender is false,
          * this thread will suspend !
          *
-         * @see GLAnimCanvas#display
-         * @see GLAnimCanvas#run
+         * @see gl4java.awt.GLAnimCanvas#display
+         * @see gl4java.awt.GLAnimCanvas#run
          */
         protected boolean shallWeRender = true;
+        protected boolean isRunning     = false;
 
 	private long _fDelay = 0;
 	private long _fDelay_Frames = 10;
@@ -349,14 +392,18 @@ public class GLAnimCanvas extends GLCanvas
           *  The running loop for animations
           *  which initiates the call of display
           *
-          * @see GLAnimCanvas#shallWeRender
-          * @see GLAnimCanvas#display
-          * @see GLAnimCanvas#diplay
+          * @see gl4java.awt.GLAnimCanvas#shallWeRender
+          * @see gl4java.awt.GLAnimCanvas#display
           */
         public void run() 
         {
             Thread thisThread = Thread.currentThread();
 
+	    isRunning = true;
+
+	    synchronized (this) {
+	    	globalThreadNumber++;
+	    }
 
             while (killme==thisThread)
             {
@@ -370,8 +417,7 @@ public class GLAnimCanvas extends GLCanvas
 			      else 
 				      sDisplay();
 			  } else {
-			      // lets sleep ...
-			      synchronized (this) {
+                              synchronized (this) {
 				      threadSuspended=true;
 			      }
 			  }
@@ -399,7 +445,9 @@ public class GLAnimCanvas extends GLCanvas
 			   } 
 
                           Thread.currentThread().sleep(dFpsMilli, 0 );
-                       }
+                       } else {
+		          Thread.yield();
+		       }
 
                        if (threadSuspended) {
                            stopFpsCounter();
@@ -411,6 +459,15 @@ public class GLAnimCanvas extends GLCanvas
 		  } catch (InterruptedException e)
 	          {}
             }
+
+	    if(glj!=null)
+		    glj.gljFree(); // just to be sure ..
+
+	    synchronized (this) {
+	    	globalThreadNumber--;
+	    }
+
+	    isRunning = false;
         }
 
          /** 
@@ -422,8 +479,8 @@ public class GLAnimCanvas extends GLCanvas
 	  * @param suspend  if true the thread will be suspended,
 	  *                 if false, the thread will be (re)started
 	  *
-          * @see GLAnimCanvas#isAlive
-          * @see GLAnimCanvas#start
+          * @see gl4java.awt.GLAnimCanvas#isAlive
+          * @see gl4java.awt.GLAnimCanvas#start
           */
         public void setSuspended(boolean suspend)
         {
@@ -442,8 +499,8 @@ public class GLAnimCanvas extends GLCanvas
 	  * @param reInit   if true the ReInit will be called additionally,
 	  *                 where the user can set additional initialisations
 	  *
-          * @see GLAnimCanvas#isAlive
-          * @see GLAnimCanvas#start
+          * @see gl4java.awt.GLAnimCanvas#isAlive
+          * @see gl4java.awt.GLAnimCanvas#start
           */
         public synchronized void setSuspended(boolean suspend, boolean reInit)
         {
@@ -461,17 +518,17 @@ public class GLAnimCanvas extends GLCanvas
 			    ReInit();
 
 		    threadSuspended=false;
-		    notify();
+		    notifyAll();
 	    }
         }
 
         /**
          * is the thread alive, means is started and not died ?
          *
-         * @see GLAnimCanvas#run
-         * @see GLAnimCanvas#setSuspended
-         * @see GLAnimCanvas#start
-         * @see GLAnimCanvas#stop
+         * @see gl4java.awt.GLAnimCanvas#run
+         * @see gl4java.awt.GLAnimCanvas#setSuspended
+         * @see gl4java.awt.GLAnimCanvas#start
+         * @see gl4java.awt.GLAnimCanvas#stop
          */      
         public boolean isAlive()
 	{ 
@@ -483,10 +540,10 @@ public class GLAnimCanvas extends GLCanvas
          * is the thread suspended, means is started but waiting, 
 	 * or not alive (ok :-| - but it is practical)
          *
-         * @see GLAnimCanvas#run
-         * @see GLAnimCanvas#setSuspended
-         * @see GLAnimCanvas#start
-         * @see GLAnimCanvas#stop
+         * @see gl4java.awt.GLAnimCanvas#run
+         * @see gl4java.awt.GLAnimCanvas#setSuspended
+         * @see gl4java.awt.GLAnimCanvas#start
+         * @see gl4java.awt.GLAnimCanvas#stop
          */      
         public boolean isSuspended()
 	{ 
@@ -507,14 +564,14 @@ public class GLAnimCanvas extends GLCanvas
          * this function is called automatically by
          * start and setSuspended
          *
-         * @see GLAnimCanvas#start
-         * @see GLAnimCanvas#setSuspended
-         * @see GLAnimCanvas#resetFpsCounter
-         * @see GLAnimCanvas#stopFpsCounter
-         * @see GLAnimCanvas#getFps
-         * @see GLAnimCanvas#getFpsDuration
-         * @see GLAnimCanvas#getFpsFrames
-         * @see GLAnimCanvas#setVerboseFps
+         * @see gl4java.awt.GLAnimCanvas#start
+         * @see gl4java.awt.GLAnimCanvas#setSuspended
+         * @see gl4java.awt.GLAnimCanvas#resetFpsCounter
+         * @see gl4java.awt.GLAnimCanvas#stopFpsCounter
+         * @see gl4java.awt.GLAnimCanvas#getFps
+         * @see gl4java.awt.GLAnimCanvas#getFpsDuration
+         * @see gl4java.awt.GLAnimCanvas#getFpsFrames
+         * @see gl4java.awt.GLAnimCanvas#setVerboseFps
          */
         public void resetFpsCounter()
         {
@@ -535,14 +592,14 @@ public class GLAnimCanvas extends GLCanvas
          * All data's are print out on System.out 
          * if verboseFps is set !
          *
-         * @see GLAnimCanvas#run
-         * @see GLAnimCanvas#shallWeRender
-         * @see GLAnimCanvas#resetFpsCounter
-         * @see GLAnimCanvas#stopFpsCounter
-         * @see GLAnimCanvas#getFps
-         * @see GLAnimCanvas#getFpsDuration
-         * @see GLAnimCanvas#getFpsFrames
-         * @see GLAnimCanvas#setVerboseFps
+         * @see gl4java.awt.GLAnimCanvas#run
+         * @see gl4java.awt.GLAnimCanvas#shallWeRender
+         * @see gl4java.awt.GLAnimCanvas#resetFpsCounter
+         * @see gl4java.awt.GLAnimCanvas#stopFpsCounter
+         * @see gl4java.awt.GLAnimCanvas#getFps
+         * @see gl4java.awt.GLAnimCanvas#getFpsDuration
+         * @see gl4java.awt.GLAnimCanvas#getFpsFrames
+         * @see gl4java.awt.GLAnimCanvas#setVerboseFps
          */
         public void stopFpsCounter()
         {
@@ -571,14 +628,14 @@ public class GLAnimCanvas extends GLCanvas
          * <p>
          * verboseFps is set to true by default !
          *
-         * @see GLAnimCanvas#run
-         * @see GLAnimCanvas#shallWeRender
-         * @see GLAnimCanvas#resetFpsCounter
-         * @see GLAnimCanvas#stopFpsCounter
-         * @see GLAnimCanvas#getFps
-         * @see GLAnimCanvas#getFpsDuration
-         * @see GLAnimCanvas#getFpsFrames
-         * @see GLAnimCanvas#setVerboseFps
+         * @see gl4java.awt.GLAnimCanvas#run
+         * @see gl4java.awt.GLAnimCanvas#shallWeRender
+         * @see gl4java.awt.GLAnimCanvas#resetFpsCounter
+         * @see gl4java.awt.GLAnimCanvas#stopFpsCounter
+         * @see gl4java.awt.GLAnimCanvas#getFps
+         * @see gl4java.awt.GLAnimCanvas#getFpsDuration
+         * @see gl4java.awt.GLAnimCanvas#getFpsFrames
+         * @see gl4java.awt.GLAnimCanvas#setVerboseFps
          */
         public void setVerboseFps(boolean v)
         {
@@ -590,12 +647,12 @@ public class GLAnimCanvas extends GLCanvas
          * <p>
          * this data is avaiable after calling stopFpsCounter
          *
-         * @see GLAnimCanvas#resetFpsCounter
-         * @see GLAnimCanvas#stopFpsCounter
-         * @see GLAnimCanvas#getFps
-         * @see GLAnimCanvas#getFpsDuration
-         * @see GLAnimCanvas#getFpsFrames
-         * @see GLAnimCanvas#setVerboseFps
+         * @see gl4java.awt.GLAnimCanvas#resetFpsCounter
+         * @see gl4java.awt.GLAnimCanvas#stopFpsCounter
+         * @see gl4java.awt.GLAnimCanvas#getFps
+         * @see gl4java.awt.GLAnimCanvas#getFpsDuration
+         * @see gl4java.awt.GLAnimCanvas#getFpsFrames
+         * @see gl4java.awt.GLAnimCanvas#setVerboseFps
          */
         public double getFps()
         {
@@ -607,12 +664,12 @@ public class GLAnimCanvas extends GLCanvas
          * <p>
          * this data is avaiable after calling stopFpsCounter
          *
-         * @see GLAnimCanvas#resetFpsCounter
-         * @see GLAnimCanvas#stopFpsCounter
-         * @see GLAnimCanvas#getFps
-         * @see GLAnimCanvas#getFpsDuration
-         * @see GLAnimCanvas#getFpsFrames
-         * @see GLAnimCanvas#setVerboseFps
+         * @see gl4java.awt.GLAnimCanvas#resetFpsCounter
+         * @see gl4java.awt.GLAnimCanvas#stopFpsCounter
+         * @see gl4java.awt.GLAnimCanvas#getFps
+         * @see gl4java.awt.GLAnimCanvas#getFpsDuration
+         * @see gl4java.awt.GLAnimCanvas#getFpsFrames
+         * @see gl4java.awt.GLAnimCanvas#setVerboseFps
          */
         public long getFpsDuration()
         {
@@ -624,12 +681,12 @@ public class GLAnimCanvas extends GLCanvas
          * <p>
          * this data is avaiable after calling stopFpsCounter
          *
-         * @see GLAnimCanvas#resetFpsCounter
-         * @see GLAnimCanvas#stopFpsCounter
-         * @see GLAnimCanvas#getFps
-         * @see GLAnimCanvas#getFpsDuration
-         * @see GLAnimCanvas#getFpsFrames
-         * @see GLAnimCanvas#setVerboseFps
+         * @see gl4java.awt.GLAnimCanvas#resetFpsCounter
+         * @see gl4java.awt.GLAnimCanvas#stopFpsCounter
+         * @see gl4java.awt.GLAnimCanvas#getFps
+         * @see gl4java.awt.GLAnimCanvas#getFpsDuration
+         * @see gl4java.awt.GLAnimCanvas#getFpsFrames
+         * @see gl4java.awt.GLAnimCanvas#setVerboseFps
          */
         public long getFpsFrames()
         {
@@ -651,7 +708,7 @@ public class GLAnimCanvas extends GLCanvas
          /** 
           * Just set the FramePerSecounds for Animation
 	  *
-          * @see GLAnimCanvas#getMaxFps    
+          * @see gl4java.awt.GLAnimCanvas#getMaxFps    
           */
         public void setAnimateFps(double fps)
         {
@@ -675,7 +732,7 @@ public class GLAnimCanvas extends GLCanvas
 	  * this value is avaiable after the thread is started
 	  * and the first frames are rendered !
 	  *
-          * @see GLAnimCanvas#setAnimateFps    
+          * @see gl4java.awt.GLAnimCanvas#setAnimateFps    
           */
         public double getMaxFps()
         {
diff --git a/gl4java/awt/GLCanvas.java b/gl4java/awt/GLCanvas.java
index 4a537f9..78775b6 100644
--- a/gl4java/awt/GLCanvas.java
+++ b/gl4java/awt/GLCanvas.java
@@ -62,7 +62,7 @@ import java.awt.event.*;
  * </pre>
  * <p>        
  *
- * @see GLAnimCanvas
+ * @see gl4java.awt.GLAnimCanvas
  * @version 	2.0, 21. April 1999
  * @author      Sven Goethel
  * 
@@ -87,8 +87,8 @@ public class GLCanvas extends Canvas
      * This value is updated after a GLContext is created with the
      * original updated value of GLContext !
      *
-     * @see GLCanvas#preInit
-     * @see GLCanvas#paint
+     * @see gl4java.awt.GLCanvas#preInit
+     * @see gl4java.awt.GLCanvas#paint
      */
     protected boolean doubleBuffer = true;
 
@@ -97,8 +97,8 @@ public class GLCanvas extends Canvas
      * This value is updated after a GLContext is created with the
      * original updated value of GLContext !
      *
-     * @see GLCanvas#preInit
-     * @see GLCanvas#paint
+     * @see gl4java.awt.GLCanvas#preInit
+     * @see gl4java.awt.GLCanvas#paint
      */
     protected int stencilBits = 0;
 
@@ -114,8 +114,8 @@ public class GLCanvas extends Canvas
      * The output value, after the constructor returns,
      * it is the summary of all accumulation bits of all components !
      *
-     * @see GLCanvas#preInit
-     * @see GLCanvas#paint
+     * @see gl4java.awt.GLCanvas#preInit
+     * @see gl4java.awt.GLCanvas#paint
      */
     protected int accumSize = 0;
 
@@ -124,8 +124,8 @@ public class GLCanvas extends Canvas
      * This value is updated after a GLContext is created with the
      * original updated value of GLContext !
      *
-     * @see GLCanvas#preInit
-     * @see GLCanvas#paint
+     * @see gl4java.awt.GLCanvas#preInit
+     * @see gl4java.awt.GLCanvas#paint
      */
     protected boolean stereoView = false;
 
@@ -134,8 +134,8 @@ public class GLCanvas extends Canvas
     * This value is updated after a GLContext is created with the
     * original updated value of GLContext !
     *
-    * @see GLCanvas#preInit
-    * @see GLCanvas#paint
+    * @see gl4java.awt.GLCanvas#preInit
+    * @see gl4java.awt.GLCanvas#paint
     */
     protected boolean rgba = true;    
 
@@ -144,16 +144,16 @@ public class GLCanvas extends Canvas
     * This value is updated after a GLContext is created with the
     * original updated value of GLContext !
     *
-    * @see GLCanvas#preInit
-    * @see GLCanvas#paint
+    * @see gl4java.awt.GLCanvas#preInit
+    * @see gl4java.awt.GLCanvas#paint
     */
     protected boolean createOwnWindow = false;
 
    /**
-    * The context with witch display lists and textures will be shared.
+    * The context with wich display lists and textures will be shared.
     *
-    * @see GLCanvas#preInit
-    * @see GLCanvas#paint
+    * @see gl4java.awt.GLCanvas#preInit
+    * @see gl4java.awt.GLCanvas#paint
     */
     protected GLContext sharedGLContext;	
 
@@ -240,7 +240,7 @@ public class GLCanvas extends Canvas
      * @param g		the Graphics Context
      * @return 		void
      *
-     * @see	GLCanvas#paint
+     * @see	gl4java.awt.GLCanvas#paint
      */ 
     public void update(Graphics g)
     {
@@ -260,7 +260,7 @@ public class GLCanvas extends Canvas
      *
      * @return 		void
      *
-     * @see	GLCanvas#paint
+     * @see	gl4java.awt.GLCanvas#paint
      */ 
     public final Window getTopLevelWindow()
     { return topLevelWindow; }
@@ -283,11 +283,11 @@ public class GLCanvas extends Canvas
      * in your derivation.
      *
      * @see gl4java.GLContext#GLContext
-     * @see GLCanvas#cvsIsInit
-     * @see GLCanvas#sDisplay
-     * @see GLCanvas#display
-     * @see GLCanvas#preInit
-     * @see GLCanvas#init
+     * @see gl4java.awt.GLCanvas#cvsIsInit
+     * @see gl4java.awt.GLCanvas#sDisplay
+     * @see gl4java.awt.GLCanvas#display
+     * @see gl4java.awt.GLCanvas#preInit
+     * @see gl4java.awt.GLCanvas#init
      */
     public synchronized final void paint( Graphics g )
     {
@@ -342,10 +342,6 @@ public class GLCanvas extends Canvas
 		if(glj!=null && glj.gljIsInit())
 			cvsInitialized=true;
 	} 
-	/*
-	if( mustResize ) size = getSize();
-	g.setClip(0, 0, size.width, size.height ) ;
-	*/
 	sDisplay();
     }
 
@@ -358,12 +354,12 @@ public class GLCanvas extends Canvas
      *
      * @return 		void
      *
-     * @see	GLCanvas#paint
-     * @see	GLCanvas#doubleBuffer
-     * @see	GLCanvas#stereoView
-     * @see	GLCanvas#rgba
-     * @see	GLCanvas#stencilBits
-     * @see	GLCanvas#accumSize
+     * @see	gl4java.awt.GLCanvas#paint
+     * @see	gl4java.awt.GLCanvas#doubleBuffer
+     * @see	gl4java.awt.GLCanvas#stereoView
+     * @see	gl4java.awt.GLCanvas#rgba
+     * @see	gl4java.awt.GLCanvas#stencilBits
+     * @see	gl4java.awt.GLCanvas#accumSize
      */ 
     public void preInit()
     {
@@ -378,7 +374,7 @@ public class GLCanvas extends Canvas
      *
      * @return 		void
      *
-     * @see	GLCanvas#paint
+     * @see	gl4java.awt.GLCanvas#paint
      */ 
     public void init()
     {
@@ -393,7 +389,7 @@ public class GLCanvas extends Canvas
      *
      * @return 		void
      *
-     * @see	GLCanvas#cvsDispose
+     * @see	gl4java.awt.GLCanvas#cvsDispose
      */
     public void doCleanup()
     {
@@ -406,8 +402,8 @@ public class GLCanvas extends Canvas
      *
      * @return 	boolean
      *
-     * @see	GLCanvas#paint
-     * @see	GLCanvas#init
+     * @see	gl4java.awt.GLCanvas#paint
+     * @see	gl4java.awt.GLCanvas#init
      */ 
     public boolean cvsIsInit()
     {
@@ -433,8 +429,8 @@ public class GLCanvas extends Canvas
      *
      * @return 		void
      *
-     * @see GLCanvas#paint
-     * @see GLCanvas#display
+     * @see gl4java.awt.GLCanvas#paint
+     * @see gl4java.awt.GLCanvas#display
      */ 
     public synchronized final void sDisplay()
     {
@@ -447,7 +443,7 @@ public class GLCanvas extends Canvas
 
 	if( mustResize )
 	{
-	    if( (ok = glj.gljMakeCurrent()) == true )
+	    if( glj.gljMakeCurrent() == true )
 	    {
 		size = getSize();
 		glj.gljResize( size.width, size.height ) ;
@@ -455,6 +451,7 @@ public class GLCanvas extends Canvas
 		mustResize = false;
 		invalidate();
 		repaint(100);
+		glj.gljFree();
 	    }
 	}
 	if(ok) 
@@ -471,6 +468,15 @@ public class GLCanvas extends Canvas
      * (and sDisplay is called by paint !).
      * The derived-class (Your Subclass) will redefine this, to draw it's own...
      *
+     * <p>
+     *
+     * You MUST encapsulate your OpenGL call's within:
+     * <pre>
+    	- glj.gljMakeCurrent()
+		YOUR OpenGL commands here !
+    	- glj.gljFree()
+     * </pre>
+     *
      * BE SURE, if you want to call 'display' by yourself
      * (e.g. in the run method for animation)
      * YOU HAVE TO CALL sDisplay !
@@ -480,8 +486,10 @@ public class GLCanvas extends Canvas
      *
      * @return 		void
      *
-     * @see GLCanvas#sDisplay
-     * @see GLCanvas#paint
+     * @see gl4java.awt.GLCanvas#sDisplay
+     * @see gl4java.awt.GLCanvas#paint
+     * @see gl4java.GLContext#gljMakeCurrent
+     * @see gl4java.GLContext#gljSwap
      */ 
     public void display()
     {
@@ -508,8 +516,8 @@ public class GLCanvas extends Canvas
      * @param height	the new height
      * @return 		void
      *
-     * @see GLCanvas#paint
-     * @see GLCanvas#sDisplay
+     * @see gl4java.awt.GLCanvas#paint
+     * @see gl4java.awt.GLCanvas#sDisplay
      */ 
     public void reshape( int width, int height )
     {
@@ -533,8 +541,8 @@ public class GLCanvas extends Canvas
      * @param e		the element, which is resized
      * @return 		void
      *
-     * @see GLCanvas#paint
-     * @see GLCanvas#reshape
+     * @see gl4java.awt.GLCanvas#paint
+     * @see gl4java.awt.GLCanvas#reshape
      */ 
     public void componentResized(ComponentEvent e)
     {
@@ -644,7 +652,7 @@ public class GLCanvas extends Canvas
       * This function calls gljDestroy of GLContext !
       *
       * @see gl4java.GLContext#gljDestroy
-      * @see GLCanvas#doCleanup
+      * @see gl4java.awt.GLCanvas#doCleanup
       */
     public void cvsDispose()
     {
@@ -664,11 +672,13 @@ public class GLCanvas extends Canvas
 			   context, so it all works out fine. */
 			try
 			{
-				glj.gljFree();
-				doCleanup();
-				//locks and free's GLContext	
 				glj.setEnabled(false); 
+
+				setVisible(false);
+				doCleanup();
+
 				glj.gljDestroy();
+				glj = null;
         			needCvsDispose = false;
 			}
 			catch (Exception ex)