[vcf-midatlantic] What's wrong with my program experiment?

Dave McGuire mcguire at neurotica.com
Thu Apr 6 17:48:17 EDT 2017

On 04/06/2017 05:38 PM, Evan Koblentz via vcf-midatlantic wrote:
>> ​some other guy mentioned cross-talk, that's why I posted that link to
>> the
>> 1982 issue which explains how that operates. ​It also mentions a work
>> around in Assembly code, since adding more delay defeats the purpose of
>> using assembly code. But I'm not sure yet if there's a work around for
>> Basic code, maybe there is, perhaps using the same Kernal Rom Calls. But
>> then your game isn't really time critical as in an assembly program.
>> So you
>> most likely won't suffer any lag.
> Yeah I'm happy with how it works now.
> Primitive collision detection 101: I added a line that if X=10 and Y=10
> (where I'd made a plot) then switch to text mode and print something. It
> didn't work and I wasn't sure why. Then I remembered the joystick is
> never * exactly * at 10,10, but rather at 10.(lots of decimals). So I
> put in another line saying X=INT(X):Y=INT(Y) to force the whole number.
> Now when I move the joystick to the plot of 10,10 it works.

   Much goodness.

   This is a classic input qualification/range bounding problem.  It's 
generally considered to be much safer to just check to see if X>10, 
rather than look for equality.  This handles the fractional data as well 
of course.


Dave McGuire, AK4HZ
New Kensington, PA

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