cocos2d for iPhone

A fast, easy to use, free, and community supported 2D game engine

1. 

   fms
   Member

   Hello,

   I want to have a random number generator.

   Currently I'm using

   fdur = (rand()%2)+0.7;

   But I've been having some inconsistencies so perhaps I'm doing something wrong.

   The "fdur" variable is a float.

   Posted 9 months ago #
2. 

   clarus
   Member

   rand()%2 will be either 0 or 1, so fdur will always be either 0.7 or 1.7. Is that what you're after?

   Posted 9 months ago #
3. 

   fms
   Member

   No. I was thinking of a range

   From 0.7 to 2 seconds. Of course going through 0.8, 0.9 , 1, 1.1 etc etc

   How can I get that?

   Posted 9 months ago #
4. 

   Mark Sawicki
   Member

   @fms,

   Unless you have some some sort of extraordinary entropy requirement, you could just do it the easy way:
   

   float theMinimum = 0.7f;
   float theMaximum = 2.0f;
   float theRandomRange = theMaximum - theMinimum;
   float theResult = (CC_RANDOM_0_1() * theRandomRange) + theMinimum;

   That will give you a number between theMinimum and theMaximum .

   See CC_RANDOM_0_1() in the source.

   Mark

   Posted 9 months ago #
5. 

   fms
   Member

   Thank you.

   I have a question what is CC_RANDOM_0_1() ??

   Is that some kind of random generator?

   Posted 9 months ago #
6. 

   clarus
   Member

   Put it in your code and then command-click on it to see the definition.

   Posted 9 months ago #
7. 

   fms
   Member

   Oh thanks I just did that. It really works for me. It actually removed the strange change of time the third and fourth time I returned from menu to game scene.

   Posted 9 months ago #
8. 

   timTheMystic
   Member

   Make sure you seed the random function somewhere when the app delegate is initialized - like using the current time for the seed usually works well : srandom(time(0)

   Posted 9 months ago #

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