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Last updated on Oct-18-2019 Download

Use of the in vblank flag.

Use of the in vblank flag.
by on (#48449)
I've got a situation where it would be easier to not use the nmi interrupt. (I got my reasons)
The situation is as follows:
I wanna make a title screen with nothing moving or anything fancy....but I need to have two options. Now I want a cursor but that'll need to be updated when a button is pressed....would it hurt if I used the in vblank flag in this case? Since it wont matter that much if it misses a few frames?

by on (#48452)
You can use it if missing frames isn't an issue, but I don't understand why you'd ditch the NMI. It's perfectly possible and not hard at all to do everything with NMIs instead.

Maybe you have your NMI tailored for in-game logic? It shouldn't be hard to make it work with other "sections" (such as the title screen) of your program as well.

BTW, it's misleading to call it "the in vblank flag", because it's cleared as soon as you read it, it does not stay set during all of Vblank. Although it would be really helpful if it did!

by on (#48453)
Ok it's not the in vblank flag then. Anyway....the reason I ask is cause i'm lazy. And this just helps me being lay ;-)