From 4b5a0f6557d7152ec770bc13ad3c494449de0529 Mon Sep 17 00:00:00 2001
From: Sven Gothel <sgothel@jausoft.com>
Date: Sun, 22 Jul 2012 04:16:55 +0200
Subject: Fix Bug 606 - New AWT threading implementation breaks .. ; Fix
 GLAutoDrawable multi-threading w/ proper pattern (hope so)

Considering code changes and remarks:
  3ed491213f8f7f05d7b9866b50d764370d8ff5f6
  1a91ec5c8b6fd9d9db7bc115569c369fe7b38e9b
  3334a924309a9361a448d69bc707d4cce416b430
  4f27bcecf7484dc041551f52a5c49e2884cb3867

It seems necessary to have

- recursive locking employed for all semantic actions which changes drawable & context (and the Window resource)

- to avoid deadlock, we have to ensure the locked code segment will not spawn
  off to another thread, or a thread holds the lock, spawns of an action requiring the lock. .. sure

- other read-only methods (flags, ..) shall at least utilize a safe local copy of a volatile field
  if further use to produce the result is necessary.

- flags like sendReshape require to be volatile to guarantee it's being processed

Patch impacts: AWT/SWT GLCanvas, GLAutoDrawableBase [and it's specializations]
and hopefully closes any loopholes of missing a cache hit, etc.

If you review this and find optimizations, i.e. removing a lock due to semantics etc,
don't hold back and discuss it, please.
---
 src/jogl/classes/jogamp/opengl/GLPbufferImpl.java | 29 +++++++++++++++++++----
 1 file changed, 24 insertions(+), 5 deletions(-)

(limited to 'src/jogl/classes/jogamp/opengl/GLPbufferImpl.java')

diff --git a/src/jogl/classes/jogamp/opengl/GLPbufferImpl.java b/src/jogl/classes/jogamp/opengl/GLPbufferImpl.java
index bbc28e283..6b64120fe 100644
--- a/src/jogl/classes/jogamp/opengl/GLPbufferImpl.java
+++ b/src/jogl/classes/jogamp/opengl/GLPbufferImpl.java
@@ -42,10 +42,14 @@ package jogamp.opengl;
 
 import javax.media.opengl.GLCapabilitiesImmutable;
 import javax.media.opengl.GLContext;
+import javax.media.opengl.GLDrawable;
 import javax.media.opengl.GLDrawableFactory;
 import javax.media.opengl.GLException;
 import javax.media.opengl.GLPbuffer;
 
+import com.jogamp.common.util.locks.LockFactory;
+import com.jogamp.common.util.locks.RecursiveLock;
+
 /** Platform-independent class exposing pbuffer functionality to
     applications. This class is not exposed in the public API as it
     would probably add no value; however it implements the GLDrawable
@@ -101,7 +105,7 @@ public class GLPbufferImpl extends GLAutoDrawableBase implements GLPbuffer {
   //
   // GLDrawable delegation
   // 
-  
+    
   @Override
   public final void setRealized(boolean realized) {
   }
@@ -109,6 +113,10 @@ public class GLPbufferImpl extends GLAutoDrawableBase implements GLPbuffer {
   //
   // GLAutoDrawable completion
   //
+  private final RecursiveLock lock = LockFactory.createRecursiveLock();  // instance wide lock
+  
+  @Override
+  protected final RecursiveLock getLock() { return lock; }
   
   @Override
   public final Object getUpstreamWidget() {
@@ -117,7 +125,7 @@ public class GLPbufferImpl extends GLAutoDrawableBase implements GLPbuffer {
   
   @Override
   public void destroy() {
-    defaultDestroyOp();
+    defaultDestroy();
   }
 
   @Override
@@ -126,12 +134,23 @@ public class GLPbufferImpl extends GLAutoDrawableBase implements GLPbuffer {
   }
 
   @Override
-  public void display() {
-    if( null != drawable && drawable.isRealized() && null != context ) {
-      helper.invokeGL(drawable, context, defaultDisplayAction, initAction);
+  public final void display() {
+    final RecursiveLock _lock = lock;        
+    _lock.lock(); // sync: context/drawable could been recreated/destroyed while animating
+    try {
+        if( null != context ) {
+          helper.invokeGL(drawable, context, defaultDisplayAction, initAction);
+        }
+    } finally {
+        _lock.unlock();
     }
   }
 
+  @Override
+  public final void swapBuffers() throws GLException {
+      defaultSwapBuffers();
+  }
+  
   //----------------------------------------------------------------------
   // Internals only below this point
   //
-- 
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