Re: [Caml-list] How to synchtonize swap buffers with vertical retrace in lablgk/lablgtk, or labgl/labltk,

[Peter Ronnquist <pronnquist@yahoo.com>]

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--- Sven LUTHER <luther@dpt-info.u-strasbg.fr> wrote:
> On Thu, May 03, 2001 at 11:11:50AM -0700, Chris
> Hecker wrote:
> > 
> > >I am looking for a way to synchronize swapbuffers
> with
> > >the vertical retrace using lablg and lablgtk or
> labltk
> > >for creating the window to draw the opengl
> graphics
> > >in.
> > >Does anyone know if this is possible?
> > 
> > You usually have to do this through an extension. 
> It's a windowing system issue (or at least, that's
> how OpenGL thinks of it).  So, on windows there's a
> SwapInterval extension, and I'm not sure about X,
> but it's probably the same.
> > 
> > You'll need to write a thunk to the extension in C
> to use it, because lablgl does not support
> extensions yet.  I hope to fix this at some point
> soon. 
> 
> Does X not do this by himself, at least if you use
> hardware accelerated mesa
> drivers (the dri version of them). Not sure though.


I have looked into the examples that are provided with
lablgl and lablgtk and comparared it with the C
version of gears.c. You can notice a small disruption
in the animation gears.ml and planet.ml (when the
planet is closer and is displayed big on the screen).
This is due to that the swap buffer is done when the
monitors ray gun is in the middle of the graphics.

There are also some small and good tutorial examples
that uses C and glx that does not have this problem.
Here there is no disruption of the animation at all.
I can provide you with the link to this webpage when I
get access to the link.

It seems that it is up to the library that you use for
handling the window for opengl. Appearantly gtk and tk
does not do this syncronization.
glut, glx do this and I am almost sure that sdl do
that as well. 

Best Regards
Peter Rönnquist




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