2013/7/19 Thien-Thi Nguyen <[email protected]> > () Panicz Maciej Godek <[email protected]> > () 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/
