Re: A89: putsprite routine
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Re: A89: putsprite routine
In a message dated 9/5/99 4:49:47 PM Eastern Daylight Time, S43R80@aol.com
writes:
> lets say for example i originally place a sprite at (33,3) using
> PUT_SPRITE...and then everytime from this moment on that 'left' is
pressed,
> the x coordinate is decreased by 12...so for instance after 'left' is
> pressed
> the first time, the new coordinate becomes (21,3) then the second: (9,3)
and
>
> 3rd (-3,3) and so on...now i know putsprite deals w/ the address error
> situation w/ clipping...but why then does after around the 8th or 9th time
> left is pressed when the sprite is in the 'high negatives' does it then
> re-appear on the other side of the screen...??? and why does it only do
> this
> ONCE...if i try it again the sprite will_not appear at the other
side...only
>
> drift further and further into happily ever after negative land...
hmm....well whenever l try even a low negative value l'm always greeted with
an Address Error...but anyways l think it has something to do with the video
memory like on the 92 (yes l know this is an 89 here) but it's just
displaying it "off the screen" because the 89 screen isn't as wide as the 92,
until it finally comes back on to the screen from the other side. This is
all that l know about that.
instead of letting it slip into negatives, why not just take the max of the x
coordinate and zero to keep it on the screen?