JOGL: Proper handling of Read Drawable Support (if not supported), add query.

Read Drawable feature reflects the make context current API
having a seperate read drawable next to the write drawable (default).
  glXMakeContextCurrent(write, read, ..)

On X11 a ready drawable is only supported for GLX >= 1.3,
on Windows only if extension WGL_ARB_make_current_read is available,
on EGL it's always supported, on OSX not at all.

API cleanup GLContext:
  changes: setGLDrawableRead(GLDrawable) ->  setGLReadDrawable(GLDrawable)
  new:     isGLReadDrawableAvailable()
  new:     getGLExtensionsString();

Access qualifier cleanup.

GLContextImpl: GLVersionNumber moved out.

1 files changed, 1 insertions, 1 deletions

diff --git a/src/junit/com/jogamp/test/junit/jogl/offscreen/ReadBufferBase.java b/src/junit/com/jogamp/test/junit/jogl/offscreen/ReadBufferBase.java
index bd85dd879..63215223a 100644
--- a/src/junit/com/jogamp/test/junit/jogl/offscreen/ReadBufferBase.java
+++ b/src/junit/com/jogamp/test/junit/jogl/offscreen/ReadBufferBase.java
@@ -65,7 +65,7 @@ public class ReadBufferBase implements GLEventListener {
 
         System.out.println(_gl);
 
-        _gl.getContext().setGLDrawableRead(externalRead);
+        _gl.getContext().setGLReadDrawable(externalRead);
         if(_gl.isGL2GL3()) {
             _gl.getGL2GL3().glReadBuffer(GL2GL3.GL_FRONT);
         }