Re: [AD] bitmaps and displays

[Milan Mimica <milan.mimica@xxxxxxxxxx>]

Peter Hull wrote:
> When you create a new context in OS X, you can specify an existing
> context that you want it to share with. Then, internally, it
> reference-counts the resources and deletes them when the last context
> is deleted.

Great. The same is in GLX.

> It's not clear to me (it's not in the docs AFAICS) what the rules are
> for when you can and can't share (for example, can 2 contexts with
> different colour depths share?) We'd have to allow for there being
> groups of mutually incompatible sets of displays.

That's not a problem really. If contexts cannot be shared for whatever reason 
glxCreateContext() will fail (we call it again without sharing and it succeeds). 
If it fails then the BITMAP will be listed only in the vector of that DISPLAY. 
Other DISPLAYs will return false when such BITMAP is passed to 
is_compatible_bitmap() and bitmap locking will be used do draw it to 
incompatible DISPLAYs.

So the implementation of is_compatible_bitmap() in pseudcode is:
if (vector_contains(&display->bitmaps, bitmap) {
   return true;
}
else {
   return false;
}


The problem happens when such display is destroyed. I think it would be the best 
to convert its bitmaps to memory bitmaps so that they can still be drawn to 
other DISPLAYs. Anyone sees any problem with this?


--
Milan Mimica
http://sparklet.sf.net