Procedural Generation in Ruby

A lightning talk I did at VanRuby in December 2016. I talked about video games and pseudo-random number generators!

Transcript

1. Procedural Generation
   in Ruby
   

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2. Alex Taylor @mctaylorpants
   

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3. Alex Taylor @mctaylorpants
   

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4. Alex Taylor @mctaylorpants
   566034820233894 =
   Images from noelberry.ca
   

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5. Alex Taylor @mctaylorpants
   rand
   

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6. Alex Taylor @mctaylorpants
   def generate_world(seed = 123)
   end
   

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7. Alex Taylor @mctaylorpants
   

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8. Alex Taylor @mctaylorpants
   

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9. Alex Taylor @mctaylorpants
   rand != ‘truly random’
   

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10. Alex Taylor @mctaylorpants
    PRNG
    ● Pseudo-random number generator
    ● Appears random...
    ● ...but actually deterministic
    rspec --seed 123
    

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11. Alex Taylor @mctaylorpants
    srand
    ● Initializes Ruby’s PRNG
    ● Per-process
    

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12. Alex Taylor @mctaylorpants
    a = [1, 2, 3, 4, 5]
    srand(123)
    a.sample
    => 3
    a.sample
    => 5
    a.sample
    => 3
    a.shuffle
    => [1, 5, 3, 4, 2]
    rand
    => 0.7800277619120791
    

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13. Alex Taylor @mctaylorpants
    

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14. Alex Taylor @mctaylorpants
    a = [1, 2, 3, 4, 5]
    srand(123)
    a.sample
    => 3
    a.sample
    => 5
    a.sample
    => 3
    a.shuffle
    => [1, 5, 3, 4, 2]
    rand
    => 0.7800277619120791
    

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15. Alex Taylor @mctaylorpants
    123
    

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16. Alex Taylor @mctaylorpants
    LOVE ME
    

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17. Alex Taylor @mctaylorpants
    srand(123)
    a = ['n', 't', 'k', 'h', 'a', 's']
    a.shuffle.join
    => “thanks”
    

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