Random.Range always generates the exact same numbers in Start()

Question

          float n1 = Random.value;
          float n2 = Random.Range(0f, 100f);
          int n3 = Random.Range(0, 100);
  
          Debug.Log(n1 + " " + n2 + " " + n3);

If I put this into the Start() function of an object, the exact same series of values will be generated every single time I run the game. I have no clue how to fix this absurd problem, so does anyone have any ideas?

Answer 1

Answer by Arycama · Sep 28, 2015 at 06:24 AM

Before calling your Random functions, set the Random.Seed to a number that isn't likely to be the same twice in a row. An easy way to do this would be:

 Random.seed = System.DateTime.Now.Millisecond;

Add this line above your existing code (Before you call Random.value etc), and it will make the values seem much more random, as they would only be the same if you could go back in time and run the program again at the exact same millisecond as before. ;)

Think of a random number generator on a computer as a list of seemingly unrelated numbers, derived from a starting number (Called the "seed"). Changing the seed changes the random numbers you'll get. Some random number generators can be more complicated, but in many cases, having a repeatable output from a random number generator is useful, for example in Minecraft, the world seems random, but if you make a new world with the same seed as a previous world, everything will be generated exactly the same.

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TommyZakh · Sep 28, 2015 at 06:36 AM 0

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I am working on a voxel project, and for testing I had set the seed as a constant number, but didn't realize until shortly after posting the question.

Answer 2

Answer by Graham-Dunnett · Sep 27, 2015 at 05:16 PM

Come on @TommyZakh... Spending a few seconds doing some reading will help you out:

http://docs.unity3d.com/ScriptReference/Random-seed.html

:-)

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TommyZakh · Sep 28, 2015 at 06:35 AM 1

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Don't worry, I already spent more than a few seconds reading.

:-)

Random.Range always generates the exact same numbers in Start()

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