2013/7/19 Thien-Thi Nguyen <ttn@gnu.org>

> () Panicz Maciej Godek <godek.maciek@gmail.com>
> () Fri, 19 Jul 2013 12:39:55 +0200
>
>    and the whole thing can be used as follows
>
>    (let ((resources '()))
>      (supply (((release-resource r)
>                   (set! r (cons r resources))))
>        (let ((r (allocate-resource)))
>          (demand 'release-resource r)
>          (do-something-constructive-with r)))
>      (for-each release-resource resources))
>
>    (of course, this makes little sense if the
>    resource is released within the same
>    procedure it is allocated, but if the release
>    cannot be performed locally, it seems the
>    right thing)
>
>    I wonder whether this design pattern has ever
>    been used before, or if there are any potential
>    flaws with its application.
>
> Maybe i'm missing something about this particular situation, but i
> think generally, the open-use-close pattern in the presence of gc is
> best handled by SMOBS and guardians.  The resource is "opened" on SMOB
> construction, used for some time and then either explicitly "closed"
> (and forgotten) or forgotten.  The guardian notes the state (still
> open, already closed) of its objects and closes the ones that need it.
>
> In this case, are OpenGL "lights" not amenable to wrapping as a SMOB?
>
>
I've been considering making new type for lights -- perhaps that would
be a little more introspective -- but it turned out more efficient to
represent them in straightforward manner as integers.
However, the thing with the lights is that they need to be disabled
explicitly -- otherwise the lights that are no longer needed would
still lit the scene until the garbage collector decides to disable them.

Of course, I could call gc explicitly, but that would result in too big
overhead (I have tried before to run gc after rendering each frame,
but the CPU usage grew considerably; now I call it after every 64
frames or so). I could also disable all the lights after the scene
is rendered, requiring to initialize them again and again before
rendering a new frame. I think that it would do.

Also, I recently read an article about garbage collector in mobile
apps, and perhaps having some means to do without it would
be a nice option. Here's the link:
http://sealedabstract.com/rants/why-mobile-web-apps-are-slow/