Re: graphics and OpenGL rendering

[Shai Ayal]

On Dec 24, 2007 5:55 PM, Michael Goffioul <address@hidden> wrote:
> Hi,
>
> The last few days, I've been exploring how JHandles could make use of the
> native property system of octave instead of implementing its own. Up to now,
> I tried to find a way to keep both synchronized, but this just adds
> implementation
> problems with no gain. These last days, I tried something else: make the
> rendering code use directly the native octave properties without C++/java
> conversion. This is possible by writing the rendering code in C++ and use
> JNI to integrate it into Java. This looks promising, but has a big drawback 
> for
> me, because it means dropping the current properties in Java (including
> listeners, dynamic properties...). However, I think it may pay in the long 
> run.
>
> So I converted a small part of my rendering code into C++ and it seems
> to work OK. Now the interesting part is that the rendering code is almost
> full OpenGL, so it might be used by any other OpenGL-based backend,
> including the one Shai is working on. I don't know what's the current status
> of the graphics backend, but JHandles code support full 3D rendering with
> high Matlab compatibility (camera-based, lighting, transparency...). If
> there is interest in sharing code, I'm willing to convert my code to C++
> and make it usable by core octave (I think I'll convert my code anyway,
> for speed reasons). What do you think?

Michael, I think this is an excellent idea and fits in with my plans
perfectly. I have started writing the backend and decided that it
would be best to split the toolkit part (which in my case is based on
fltk) which deals with all the OS specific parts, and the generic
OS-independent OpenGL part which should be just that -- pure OpenGL.
It would be great to have help (and it sounds like it would be a lot
of help) in this part -- especially the 3D part which I do not have
any experience with (octplot is 2D). I think we could probably end up
sharing everything but the font rendering for which you do using java
libraries and I plan to do using FTGL.

Some questions remain to be answered:

1. How will we avoid code duplication -- i.e. we would need a single
cvs/svn repository. I planned on using octave's cvs. Will that work
for you?
2. After this is done, what will be the differences between the 2
backends? What will remain in Java in Jhandles? Will they just be two
similar OpenGL backends using different toolkits?

Shai

> Merry christmas.
>
> Michael.
>