getkey loops

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Forum Attachments

Summary:

just a question

getkey loops

basickevin 31 May 2008 14:34

does anyone here know why most of the time getkey is put inside it's own loop on the turorials, etc. on this site? it seems completely useless to me to do that, a waste of a few bytes.

Re: getkey loops

Jonathan King 31 May 2008 15:13

it's so that the whole lot of code doesn't have to loop through, doing calculations it really doesn't have to do if Getkey=0. Instead, we just cycle through 3 lines of code. That way, when someone hits a key, it is registered immediately.

Last edited on 31 May 2008 15:19 by Jonathan King Show more

Re: getkey loops

DarkerLine 31 May 2008 16:39

Often, it will also reduce flicker. If you just had a loop in which a sprite was constantly erased, possibly moved by the arrow keys, and then redrawn, it would keep flickering when no key is pressed. Put getKey in its own loop and you make sure that the sprite is only erased when a key is pressed (which usually means it's going to be moved).

It really wouldn't save space if you took out the getKey loop, because a lot of the time, you'd end up making the getKey=0 case a special case anyway and those few bytes you didn't "waste" will be back five times over.

Re: getkey loops

basickevin 31 May 2008 17:11

true, but I do something a little different when I want a moving object, I only use line commands, like this.
getKey→K
not(K
Line(A,B,C,D,Ans
………
………

and so on. It's much easier, because it erases and draws lines within the same loop.

Re: getkey loops

Jonathan King 31 May 2008 20:36

what if the moving object is ">" for a custom menu? You'd have a heck of a time trying to use lines here. :)

Re: getkey loops

basickevin 31 May 2008 22:09

here is what I use for the arrow.
getKey→K
not(K
line(A,B,A-5,B,Ans
line(A,B,A-2,B+2,Ans
line(A,B,A-2,B-2,Ans

It works great.

Re: getkey loops

Jonathan King 31 May 2008 23:13

the original method is cheaper

Re: getkey loops

builderboy 09 Jun 2008 21:47

if you were programing a game where you were the only thing active on the screen, you would use the

0:repeat ans
getkey->K
end

Method, but this would not allow you to have another thing active while you were not moving. So then you would have to use the

while 1

getkey->k
"move"
"Opponent"

end

It all depends on the circumstance.