Maybe some of you have something similar alreay but since I’ve been flashing for more than 5 years and have never before realised I was missing this until I made it, I’m figuring quite a few would benefit from it.
As you know the Math.random function in flash generates:
0 <= n < 1.
When you want a random integer from 0 to n you might do like this:
Math.round(Math.random() * n);
This indeed generates a number between and including 0 and n, but 0 and n will appear less often since they only have half the rounding span compared to the values in between.
So we use floor instead like this:
Math.floor(Math.random() * (n+1));
This will give us a value between and including 0 and n with equal chance.
To get a value from n1 to n2 you write:
Math.floor(Math.random() * (n2-n1+1)) + n1;
Now. What if we want a float between and including 0 and n, or n1 and n2?
This was the idea that got me to write this function:
function randomRange(min:Number, max:Number, nrOfDecimals:int=2):Number {
var randomVal:Number = Math.random() * (max-min + Math.pow(10, -nrOfDecimals)) + min;
var returnVal:Number = int(randomVal * Math.pow(10, nrOfDecimals)) / Math.pow(10, nrOfDecimals);
return returnVal;
}
If you want integers you simply pass 0 as the argument for “nrOfDecimals”.
This has come in handy for me working with objects that has a lot of properties set with min and max random values. And for positioning graphics you really don’t need more than 2 decimals for floating values.
cheers :: nook
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