Fix problem with external context on CentOS 5.5 inside VMWare

This fixes a problem that's analogous to one we've had on Windows;
apparently querying OS-specific info like hardware device contexts
or framebuffer configuration IDs from external GL contexts doesn't
always work properly, especially on 32-bit OSes and from within
virtual machines.

1 files changed, 15 insertions, 1 deletions

diff --git a/src/jogl/classes/jogamp/opengl/x11/glx/X11ExternalGLXContext.java b/src/jogl/classes/jogamp/opengl/x11/glx/X11ExternalGLXContext.java
index c488fe5cf..39032117c 100644
--- a/src/jogl/classes/jogamp/opengl/x11/glx/X11ExternalGLXContext.java
+++ b/src/jogl/classes/jogamp/opengl/x11/glx/X11ExternalGLXContext.java
@@ -75,7 +75,21 @@ public class X11ExternalGLXContext extends X11GLXContext {
     X11GraphicsScreen x11Screen = (X11GraphicsScreen) X11GraphicsScreen.createScreenDevice(display, val[0]);
 
     GLX.glXQueryContext(display, ctx, GLX.GLX_FBCONFIG_ID, val, 0);
-    X11GLXGraphicsConfiguration cfg = X11GLXGraphicsConfiguration.create(glp, x11Screen, val[0]);
+    X11GLXGraphicsConfiguration cfg = null;
+    // sometimes glXQueryContext on an external context gives us a framebuffer config ID
+    // of 0, which doesn't work in a subsequent call to glXChooseFBConfig; if this happens,
+    // create and use a default config (this has been observed when running on CentOS 5.5 inside
+    // of VMWare Server 2.0 with the Mesa 6.5.1 drivers)
+    if( 0 == X11GLXGraphicsConfiguration.glXFBConfigID2FBConfig(display, x11Screen.getIndex(), val[0]) ) {
+        GLCapabilities glcapsDefault = new GLCapabilities(GLProfile.getDefault());
+        cfg = X11GLXGraphicsConfigurationFactory.chooseGraphicsConfigurationStatic(glcapsDefault, glcapsDefault, null, x11Screen);
+        if(DEBUG) {
+            System.err.println("X11ExternalGLXContext invalid FBCONFIG_ID "+val[0]+", using default cfg: " + cfg);
+        }
+    }
+    else {
+        cfg = X11GLXGraphicsConfiguration.create(glp, x11Screen, val[0]);
+    }
 
     WrappedSurface ns = new WrappedSurface(cfg);
     ns.setSurfaceHandle(drawable);