Re: [gl4java-usergroup] Re: Drawing on top of GLCanvas with AWT...

[Kenneth B. R. <kbr...@al...>]

> On Tuesday 20 February 2001 05:42, Joe & Bobbey Huwaldt wrote:
> >
> > Is there a method by which I can draw on top of a GLCanvas using the
> > regular AWT methods?  For example, I would like to render a 3D scene using
> > GL4Java, then draw some items on top of part of that scene using a regular
> > AWT graphics context.  My first thought was that I would override paint(),
> > but I see that you have prevented that.  Did you provide any other way to
> > do the same thing?  Is it even possible (I haven't looked at the source
> > code, so I don't know how the implementation works)?
> 
> In the upcoming 2.5.0-test3 this should work, if you use the new factory api,
> because the java window itself will have all the capabilities needed 
> while using the JDK 1.3 class GraphicsConfiguration internaly
> (-> no more new native window will be created) !

Actually this is not guaranteed to work. The AWT may not be able
to draw to the same window being drawn to by OpenGL. I believe
the root of the problem is a driver issue on Windows; I think it
is illegal to mix Windows GDI and OpenGL calls to the same device
context.

> > I want to do this because it is often easier to draw simple geometry and
> > images using the AWT methods than it is to try and do the same thing
> > through OpenGL.  It would be really nice if I could draw AWT graphics
> > elements over top of an OpenGL scene.

There are several C/C++ libraries which use OpenGL to draw non-3D
images which you might be able to borrow from or port pieces of
to make this easier. See GLUI, for example:
http://www.cs.unc.edu/~rademach/glui/

-Ken