X11: Fix unavailable GLX (Server): Use fallback GraphicsConfigurationFactory (X11GLX -> X11)

- GraphicsConfigurationFactory.registerFactory(..) returns previous mapped GraphicsConfigurationFactory.
  This allows daisy chaining of GraphicsConfigurationFactory, in case one is not suitable.

- X11GLXGraphicsConfigurationFactory:
  - Store the previously mapped factory as fallback
  - choose*Impl(): If GLX is not available, use fallback

4 files changed, 35 insertions, 21 deletions

diff --git a/src/jogl/classes/jogamp/opengl/x11/glx/GLXUtil.java b/src/jogl/classes/jogamp/opengl/x11/glx/GLXUtil.java
index 8b90d6887..7d03bbb88 100644
--- a/src/jogl/classes/jogamp/opengl/x11/glx/GLXUtil.java
+++ b/src/jogl/classes/jogamp/opengl/x11/glx/GLXUtil.java
@@ -43,6 +43,20 @@ import com.jogamp.common.util.VersionNumber;
 public class GLXUtil {
     public static final boolean DEBUG = Debug.debug("GLXUtil");
     
+    public static synchronized boolean isGLXAvailableOnServer(X11GraphicsDevice x11Device) {
+        if(null == x11Device) {
+            throw new IllegalArgumentException("null X11GraphicsDevice");
+        }
+        if(0 == x11Device.getHandle()) {
+            throw new IllegalArgumentException("null X11GraphicsDevice display handle");
+        }        
+        boolean glXAvailable = false;
+        try {
+            glXAvailable = GLX.glXQueryExtension(x11Device.getHandle(), null, 0, null, 0);
+        } catch (Throwable t) { /* n/a */ }
+        return glXAvailable;        
+    }
+    
     public static VersionNumber getGLXServerVersionNumber(long display) {
         int[] major = new int[1];
         int[] minor = new int[1];
@@ -92,17 +106,6 @@ public class GLXUtil {
         return clientVersionNumber;
     }
     
-    public static synchronized boolean isGLXAvailable(long handle) {
-        if(0 == handle) {
-            throw new IllegalArgumentException("null X11 display handle");
-        }        
-        boolean glXAvailable = false;
-        try {
-            glXAvailable = GLX.glXQueryExtension(handle, null, 0, null, 0);
-        } catch (Throwable t) { /* n/a */ }
-        return glXAvailable;        
-    }
-    
     public static synchronized void initGLXClientDataSingleton(X11GraphicsDevice x11Device) { 
         if(null != clientVendorName) {
             return; // already initialized
diff --git a/src/jogl/classes/jogamp/opengl/x11/glx/X11GLXDrawableFactory.java b/src/jogl/classes/jogamp/opengl/x11/glx/X11GLXDrawableFactory.java
index 2ba067b02..55d0e9400 100644
--- a/src/jogl/classes/jogamp/opengl/x11/glx/X11GLXDrawableFactory.java
+++ b/src/jogl/classes/jogamp/opengl/x11/glx/X11GLXDrawableFactory.java
@@ -220,8 +220,8 @@ public class X11GLXDrawableFactory extends GLDrawableFactoryImpl {
                     //                       NativeWindowFactory.getNullToolkitLock(), true); // own non-shared display connection, no locking
             sharedDevice.lock();
             try {
-                if(!GLXUtil.isGLXAvailable(sharedDevice.getHandle())) {
-                    throw new GLException("GLX not available on device: "+sharedDevice);
+                if(!GLXUtil.isGLXAvailableOnServer(sharedDevice)) {
+                    throw new GLException("GLX not available on device/server: "+sharedDevice);
                 }
                 GLXUtil.initGLXClientDataSingleton(sharedDevice);                
                 final String glXServerVendorName = GLX.glXQueryServerString(sharedDevice.getHandle(), 0, GLX.GLX_VENDOR);
diff --git a/src/jogl/classes/jogamp/opengl/x11/glx/X11GLXGraphicsConfigurationFactory.java b/src/jogl/classes/jogamp/opengl/x11/glx/X11GLXGraphicsConfigurationFactory.java
index 344c56f64..e77cba9d0 100644
--- a/src/jogl/classes/jogamp/opengl/x11/glx/X11GLXGraphicsConfigurationFactory.java
+++ b/src/jogl/classes/jogamp/opengl/x11/glx/X11GLXGraphicsConfigurationFactory.java
@@ -52,7 +52,6 @@ import javax.media.opengl.GLProfile;
 import com.jogamp.common.nio.PointerBuffer;
 import jogamp.nativewindow.x11.X11Lib;
 import jogamp.nativewindow.x11.XVisualInfo;
-import jogamp.opengl.Debug;
 import jogamp.opengl.GLGraphicsConfigurationFactory;
 import jogamp.opengl.GLGraphicsConfigurationUtil;
 
@@ -67,11 +66,10 @@ import java.util.List;
     GraphicsDevice and GraphicsConfiguration abstractions. */
 
 public class X11GLXGraphicsConfigurationFactory extends GLGraphicsConfigurationFactory {
-    protected static final boolean DEBUG = Debug.debug("GraphicsConfiguration");
     static X11GLCapabilities.XVisualIDComparator XVisualIDComparator = new X11GLCapabilities.XVisualIDComparator();
-
+    static GraphicsConfigurationFactory fallbackX11GraphicsConfigurationFactory = null;
     static void registerFactory() {
-        GraphicsConfigurationFactory.registerFactory(javax.media.nativewindow.x11.X11GraphicsDevice.class, new X11GLXGraphicsConfigurationFactory());
+        fallbackX11GraphicsConfigurationFactory = GraphicsConfigurationFactory.registerFactory(javax.media.nativewindow.x11.X11GraphicsDevice.class, new X11GLXGraphicsConfigurationFactory());
     }
     private X11GLXGraphicsConfigurationFactory() {
     }
@@ -93,6 +91,16 @@ public class X11GLXGraphicsConfigurationFactory extends GLGraphicsConfigurationF
         if (chooser != null && !(chooser instanceof GLCapabilitiesChooser)) {
             throw new IllegalArgumentException("This NativeWindowFactory accepts only GLCapabilitiesChooser objects");
         }
+        
+        if(!GLXUtil.isGLXAvailableOnServer((X11GraphicsDevice)absScreen.getDevice())) {
+            if(null != fallbackX11GraphicsConfigurationFactory) {
+                if(DEBUG) {
+                    System.err.println("No GLX available, fallback to "+fallbackX11GraphicsConfigurationFactory.getClass().getSimpleName()+" for: "+absScreen);
+                }
+                return fallbackX11GraphicsConfigurationFactory.chooseGraphicsConfiguration(capsChosen, capsRequested, chooser, absScreen);
+            }
+            throw new InternalError("No GLX and no fallback GraphicsConfigurationFactory available for: "+absScreen);
+        }        
         return chooseGraphicsConfigurationStatic((GLCapabilitiesImmutable)capsChosen, (GLCapabilitiesImmutable)capsRequested,
                                                  (GLCapabilitiesChooser)chooser, (X11GraphicsScreen)absScreen);
     }
@@ -187,7 +195,7 @@ public class X11GLXGraphicsConfigurationFactory extends GLGraphicsConfigurationF
         if (capsChosen == null) {
             capsChosen = new GLCapabilities(null);
         }
-        X11GraphicsDevice x11Device = (X11GraphicsDevice) x11Screen.getDevice();
+        X11GraphicsDevice x11Device = (X11GraphicsDevice) x11Screen.getDevice();        
         X11GLXDrawableFactory factory = (X11GLXDrawableFactory) GLDrawableFactory.getDesktopFactory();
 
         capsChosen = GLGraphicsConfigurationUtil.fixGLCapabilities( capsChosen, factory.canCreateGLPbuffer(x11Device) );
diff --git a/src/nativewindow/classes/javax/media/nativewindow/GraphicsConfigurationFactory.java b/src/nativewindow/classes/javax/media/nativewindow/GraphicsConfigurationFactory.java
index 259644467..8570794d8 100644
--- a/src/nativewindow/classes/javax/media/nativewindow/GraphicsConfigurationFactory.java
+++ b/src/nativewindow/classes/javax/media/nativewindow/GraphicsConfigurationFactory.java
@@ -154,18 +154,21 @@ public abstract class GraphicsConfigurationFactory {
      * called by end users, only implementors of new
      * GraphicsConfigurationFactory subclasses.
      *
+     * @return the previous registered factory, or null if none
      * @throws IllegalArgumentException if the given class does not implement AbstractGraphicsDevice
      */
-    protected static void registerFactory(Class<?> abstractGraphicsDeviceImplementor, GraphicsConfigurationFactory factory)
+    protected static GraphicsConfigurationFactory registerFactory(Class<?> abstractGraphicsDeviceImplementor, GraphicsConfigurationFactory factory)
         throws IllegalArgumentException
     {
         if (!(abstractGraphicsDeviceClass.isAssignableFrom(abstractGraphicsDeviceImplementor))) {
             throw new IllegalArgumentException("Given class must implement AbstractGraphicsDevice");
         }
+        GraphicsConfigurationFactory prevFactory = registeredFactories.put(abstractGraphicsDeviceImplementor, factory);
         if(DEBUG) {
-            System.err.println("GraphicsConfigurationFactory.registerFactory() "+abstractGraphicsDeviceImplementor+" -> "+factory);
+            System.err.println("GraphicsConfigurationFactory.registerFactory() "+abstractGraphicsDeviceImplementor+" -> "+factory+
+                               ", overridding: "+prevFactory);
         }
-        registeredFactories.put(abstractGraphicsDeviceImplementor, factory);
+        return prevFactory;
     }
 
     /**