Class: ConwayDeathmatch

Inherits:
Object
  • Object
show all
Defined in:
lib/conway_deathmatch.rb

Overview

Provides a 2d array for the grid Implements standard and deathmatch evaluation rules Boundaries are toroidal: they wrap in each direction

Defined Under Namespace

Modules: Shapes

Constant Summary collapse

DEAD = 
'.'
ALIVE = 
'0'

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(width, height, deathmatch = nil) ⇒ ConwayDeathmatch

Returns a new instance of ConwayDeathmatch.



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# File 'lib/conway_deathmatch.rb', line 18

def initialize(width, height, deathmatch = nil)
  @width = width
  @height = height
  @grid = self.class.new_grid(width, height)
  @deathmatch = deathmatch
end

Instance Attribute Details

#deathmatch ⇒ Object

nil for traditional, otherwise :aggressive, :defensive, or :friendly



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# File 'lib/conway_deathmatch.rb', line 16

def deathmatch
  @deathmatch
end

Class Method Details

.new_grid(width, height) ⇒ Object 



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# File 'lib/conway_deathmatch.rb', line 9

def self.new_grid(width, height)
  grid = []
  width.times { grid << Array.new(height, DEAD) }
  grid
end

Instance Method Details

#add_points(points, x_off = 0, y_off = 0, val = ALIVE) ⇒ Object

set several points (2d array)



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# File 'lib/conway_deathmatch.rb', line 120

def add_points(points, x_off = 0, y_off = 0, val = ALIVE)
  points.each { |point| populate(point[0] + x_off, point[1] + y_off, val) }
  self
end

#neighbor_population(x, y) ⇒ Object

population of every neighboring entity, including DEAD



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# File 'lib/conway_deathmatch.rb', line 90

def neighbor_population(x, y)
  x = x % @width
  y = y % @height
  neighbors = Hash.new(0)
  (x-1).upto(x+1) { |xn|
    (y-1).upto(y+1) { |yn|
      xn = xn % @width
      yn = yn % @height
      neighbors[@grid[xn][yn]] += 1 unless (xn == x and yn == y)
    }
  }
  neighbors
end

#neighbor_stats(x, y) ⇒ Object

total (alive) neighbor count and birthright



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# File 'lib/conway_deathmatch.rb', line 41

def neighbor_stats(x, y)
  x = x % @width
  y = y % @height
  npop = neighbor_population(x, y).tap { |h| h.delete(DEAD) }

  case @deathmatch
  when nil
    [npop.values.reduce(0, :+), ALIVE]

  when :aggressive, :defensive
    # dead: determine majority (always 3, no need to sample for tie)
    # alive: agg: determine majority (may tie at 2); def: cell_val
    determine_majority = (@grid[x][y] == DEAD or @deathmatch == :aggressive)
    total = 0
    largest = 0
    birthrights = []
    npop.each { |sym, cnt|
      total += cnt
      return [0, DEAD] if total > 3   # [optimization]
      if determine_majority
        if cnt > largest
          largest = cnt
          birthrights = [sym]
        elsif cnt == largest
          birthrights << sym
        end
      end
    }
    [total, determine_majority ? (birthrights.sample || DEAD) : @grid[x][y]]

  when :friendly
    # [optimization] with knowledge of conway rules
    # if DEAD, need 3 friendlies to qualify for birth sampling
    # if ALIVE, npop simply has the friendly count
    cell_val = if @grid[x][y] == DEAD
                 npop.reduce([]) { |memo, (sym,cnt)|
                   cnt == 3 ? memo + [sym] : memo
                 }.sample || DEAD
               else
                 @grid[x][y]
               end
    # return [0, DEAD] if no one qualifies
    [npop[cell_val] || 0, cell_val]
  else
    raise "unknown: #{@deathmatch.inspect}"
  end
end

#next_value(x, y) ⇒ Object

Conway’s Game of Life transition rules



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# File 'lib/conway_deathmatch.rb', line 26

def next_value(x, y)
  # don't bother toroidaling, only called by #tick
  n, birthright = neighbor_stats(x, y)
  if @grid[x][y] != DEAD
    (n == 2 or n == 3) ? birthright : DEAD
  else
    (n == 3) ? birthright : DEAD
  end
end

#populate(x, y, val = ALIVE) ⇒ Object

set a single point



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# File 'lib/conway_deathmatch.rb', line 115

def populate(x, y, val = ALIVE)
  @grid[x % @width][y % @height] = val
end

#population ⇒ Object

full grid scan



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# File 'lib/conway_deathmatch.rb', line 132

def population
  population = Hash.new(0)
  @grid.each { |col| col.each { |val|  population[val] += 1  } }
  population
end

#render_text ⇒ Object Also known as: render

for line-based text output, iterate over y-values first (i.e. per row)



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# File 'lib/conway_deathmatch.rb', line 126

def render_text
  @grid.transpose.map { |row| row.join }.join("\n")
end

#tick ⇒ Object

generate the next grid table



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# File 'lib/conway_deathmatch.rb', line 105

def tick
  new_grid = self.class.new_grid(@width, @height)
  @width.times { |x|
    @height.times { |y| new_grid[x][y] = next_value(x, y) }
  }
  @grid = new_grid
  self
end

#value(x, y) ⇒ Object 



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# File 'lib/conway_deathmatch.rb', line 36

def value(x, y)
  @grid[x % @width][y % @height]
end