Alpha blending under Linux

OpenGL Development JOGL Development
#1

Hi,

The patch that allows the selection of 8 bits alpha GLCapabilities is here ! Now, alpha transparency works under Linux. As I said in a previous post, the problem was due to the fact that no matching GraphicsConfiguration was selected to create a GLCanvas with the GLCapabilities passed in parameters to the GLDrawableFactory.

The patch consists in :

  • a modified file : src/net/java/games/jogl/GLDrawableFactory.java
  • 3 new files :
    src/native/jogl/X11Utils.c
    src/net/java/games/jogl/impl/x11/X11GLDrawableFactory.java
    src/net/java/games/jogl/impl/x11/X11Utils.java

To apply the modif, start with a fresh jogl tree from CVS.
Download the file http://tkdhurepoix.chez.tiscali.fr/modifsAlpha.tar.bz2

bunzip it, you will get 3 files :

  • patchAlphaX11.txt : a patch file against the jogl CVS repository of today, generated as described in the “Contributing patches” page. Cd to your jogl directory, put the patch file in it and execute patch < patchAlphaX11.txt

  • put the file alphaX11.tar in the jogl dir, then untar it

compile jogl (ant linux)

You can then try the test program I joined with the patch :
PAlphaTest.java

If everything is OK, you will see two overlapping squares.

This modification isn’t perfect. I would be pleased to discuss about it with Jogl developpers, in the aim that the next Jogl release allows alpha blending under Linux.

#2

Great! As soon as I can lay my hands on a build with this in, I’ll update my V-Script/S-Type webstart files and linux users might actually get the thing to work. :slight_smile: