Re: [gtkextra] OpenGL

[<li...@li...>]

On Wed, Mar 13, 2002 at 02:00:31PM -0500, Adrian Feiguin was heard to remark:
> All right, I'll tell you a little secret then ;-) I've tried implementing
> and opengl driver, and I actually have it, although it's not included in
> the distro. 

We can't debug it if its not in the distro. :)

> The problem is that my knowledge of opengl is very primitive,
> and I found that surprisingly for reasons that I don't completely
> understand, it makes drawing slow. 

I'm not sure, but ... its possible that if you are drawing to the front
buffer, that maybe its stuck in this mode where it draws into a pixmap,
and then copies the pixmap to the screen after every line is drawn ... 
to fix this, draw into the backbuffer, and swapbuffers only after you
are done.

> Another thing is that opengl
> apparently doesn not support patterns of more of 8 bits for drawing dotted
> lines. 

Hmm. I forget if its supposed to be 8 or 16 or 32.  I thought it was 16
... but if its only 8, there's still a multiplier so that you can 'zoom' 
the pattern. (typcally, you'd zoom by 2 or 3 or 5 so that the linestyle
would be some 30-80 pixels long).

> What I can do is to post the driver, so you can tweek it and
> improve it.

No promises, my gtkplot project is sidelined this week/month.

> Regarding antialiasing, SciGraphica includes a driver for libart with
> antialiasing, you just have to compile it with your program and use
> gtk_plot_canvas_set_pc.

any reason its not with gtkextra by default?

--linas

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