Fix Bug 761 (part 1/2): Move GLDrawableFactory.shutdownHook -> NativeWindowFactory.shutdownHook, the latter handles customShutdownHooks for NativeWindow, JOGL and NEWT.

Unifying our shutdown mechanism is required to provide a controlled shutdown sequence.
NativeWindowFactory is chosen to be the new central entry point, since it is the lowest denominator (common module).

- Move GLDrawableFactory.shutdownHook -> NativeWindowFactory.shutdownHook
  Reverse the shutdown dependency for clarity and availability to all modules,
  i.e. NEWT may not know about JOGL.

  Remove the 'gamma' shutdown hook,
  instead simply call GLDrawableFactoryImpl.resetDisplayGamma() before destroy.

NativeWindowFactory.shutdownHook handles customShutdownHooks for NativeWindow, JOGL and NEWT
  - Modules can register their shutdown runnable at head or tail of list.
  - Allows controlled shutdown across all modules.

1 files changed, 7 insertions, 36 deletions

diff --git a/src/jogl/classes/jogamp/opengl/GLDrawableFactoryImpl.java b/src/jogl/classes/jogamp/opengl/GLDrawableFactoryImpl.java
index 06e856d41..4ac413545 100644
--- a/src/jogl/classes/jogamp/opengl/GLDrawableFactoryImpl.java
+++ b/src/jogl/classes/jogamp/opengl/GLDrawableFactoryImpl.java
@@ -575,16 +575,16 @@ public abstract class GLDrawableFactoryImpl extends GLDrawableFactory {
         rampEntry = 0.0f;
       gammaRamp[i] = rampEntry;
     }
-    registerGammaShutdownHook();
+    needsGammaRampReset = true;
     return setGammaRamp(gammaRamp);
   }
 
+  @Override
   public synchronized void resetDisplayGamma() {
-    if (gammaShutdownHook == null) {
-      throw new IllegalArgumentException("Should not call this unless setDisplayGamma called first");
+    if( needsGammaRampReset ) {
+        resetGammaRamp(originalGammaRamp);
+        needsGammaRampReset = false;
     }
-    resetGammaRamp(originalGammaRamp);
-    unregisterGammaShutdownHook();
   }
 
   //------------------------------------------------------
@@ -616,35 +616,6 @@ public abstract class GLDrawableFactoryImpl extends GLDrawableFactory {
   }
 
   // Shutdown hook mechanism for resetting gamma
-  private boolean gammaShutdownHookRegistered;
-  private Thread  gammaShutdownHook;
-  private Buffer  originalGammaRamp;
-  private synchronized void registerGammaShutdownHook() {
-    if (gammaShutdownHookRegistered)
-      return;
-    if (gammaShutdownHook == null) {
-      gammaShutdownHook = new Thread(new Runnable() {
-          @Override
-        public void run() {
-            synchronized (GLDrawableFactoryImpl.this) {
-              resetGammaRamp(originalGammaRamp);
-            }
-          }
-        });
-      originalGammaRamp = getGammaRamp();
-    }
-    Runtime.getRuntime().addShutdownHook(gammaShutdownHook);
-    gammaShutdownHookRegistered = true;
-  }
-
-  private synchronized void unregisterGammaShutdownHook() {
-    if (!gammaShutdownHookRegistered)
-      return;
-    if (gammaShutdownHook == null) {
-      throw new InternalError("Error in gamma shutdown hook logic");
-    }
-    Runtime.getRuntime().removeShutdownHook(gammaShutdownHook);
-    gammaShutdownHookRegistered = false;
-    // Leave the original gamma ramp data alone
-  }
+  private volatile Buffer originalGammaRamp;
+  private volatile boolean needsGammaRampReset = false;
 }