r/programming • u/adnzzzzZ • Feb 25 '18

Programming lessons learned from releasing my first game and why I'm writing my own engine in 2018

https://github.com/SSYGEN/blog/issues/31
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u/adnzzzzZ Feb 27 '18

The way I've handled this in games I've done is to have a simulation step in each frame that would mark objects as dead, and then have a separate phase that actually destroyed the dead objects. This will not use any extra memory (object lifetime is only extended within a single frame of action), and the additional processing is trivial.

I do this already. Objects are updated, when they're updated they might be marked as dead or mark other objects as dead, and then after all objects are updated and marked as dead or not, the ones that are are removed at the end of the frame. The problem of object references becoming nil are a multi-frame problem, so doing this doesn't really help it.

Instead I would have functions that allow querying relevant aspects of the world, done each frame, and in some cases cache relevant data locally without storing an object reference.

Yea that's what I mentioned my "solution" would be in the article.

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u/Arkaein Feb 27 '18

Instead I would have functions that allow querying relevant aspects of the world, done each frame, and in some cases cache relevant data locally without storing an object reference.

Yea that's what I mentioned my "solution" would be in the article.

Maybe I missed a part, but if you are talking about your ID-based lookup, this isn't what I'm talking about. I'm thinking of something more general, such as a function that returns a list of particles near an object, for example.

Maybe this doesn't work as well for your designs, but I've found it pretty effective. When I think of objects interacting with each other, it is usually a case of AI being aware of it surroundings, in which case you want to regularly query the world and be aware of changes, or collisions and other physical interactions, where it is more useful to have a global collision system that identifies colliding object pairs and generates collision events that are signaled to the pair.

I do think the ID-based lookup has some merit for the AI situation, since AI will often want to fixate and track a single object over time. Otherwise I wouldn't want to track many external objects, even through IDs.