Class: ConwayDeathmatch::BoardState

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

Overview

data structure for the board - 2d array implements standard and deathmatch evaluation static boundaries are treated as dead

Defined Under Namespace

Classes: BoundsError

Constant Summary collapse

DEAD = 
'.'
ALIVE = 
'0'

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(x_len, y_len, deathmatch = nil) ⇒ BoardState

Returns a new instance of BoardState.



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# File 'lib/conway_deathmatch/board_state.rb', line 22

def initialize(x_len, y_len, deathmatch = nil)
  @x_len = x_len
  @y_len = y_len
  @state = self.class.new_state(x_len, y_len)
  @deathmatch = deathmatch
end

Instance Attribute Details

#deathmatch ⇒ Object

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



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# File 'lib/conway_deathmatch/board_state.rb', line 20

def deathmatch
  @deathmatch
end

Class Method Details

.new_state(x_len, y_len) ⇒ Object 



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# File 'lib/conway_deathmatch/board_state.rb', line 13

def self.new_state(x_len, y_len)
  state = []
  x_len.times { state << Array.new(y_len, DEAD) }
  state
end

Instance Method Details

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

set several points (2d array), ignore OOB



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

def add_points(points, x_off = 0, y_off = 0, val = ALIVE)
  points.each { |point|
    x = point[0] + x_off
    y = point[1] + y_off
    @state[x][y] = val if self.in_bounds?(x, y)
  }
  self
end

#alive?(x, y) ⇒ Boolean

out of bounds considered dead

Returns:

  • (Boolean) 


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# File 'lib/conway_deathmatch/board_state.rb', line 100

def alive?(x, y)
  @state[x][y] != DEAD rescue false
end

#in_bounds!(x, y) ⇒ Object

Raises:



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# File 'lib/conway_deathmatch/board_state.rb', line 95

def in_bounds!(x, y)
  raise(BoundsError, "(#{x}, #{y})") unless in_bounds?(x, y)
end

#in_bounds?(x, y) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/conway_deathmatch/board_state.rb', line 91

def in_bounds?(x, y)
  x.between?(0, @x_len - 1) and y.between?(0, @y_len - 1)
end

#neighbor_population(x, y) ⇒ Object

population of every neighboring entity, including DEAD



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

def neighbor_population(x, y)
  neighbors = Hash.new(0)
  (x-1 > 0 ? x-1 : 0).upto(x+1 < @x_len ? x+1 : @x_len - 1) { |xn|
    (y-1 > 0 ? y-1 : 0).upto(y+1 < @y_len ? y+1 : @y_len - 1) { |yn|
      neighbors[@state[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/board_state.rb', line 40

def neighbor_stats(x, y)
  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 = (@state[x][y] == DEAD or @deathmatch == :aggressive)
    total = 0
    largest = 0
    birthrights = []
    npop.each { |sym, cnt|
      total += cnt
      return [0, DEAD] if total >= 4  # [optimization]
      if determine_majority
        if cnt > largest
          largest = cnt
          birthrights = [sym]
        elsif cnt == largest
          birthrights << sym
        end
      end
    }
    [total, determine_majority ? (birthrights.sample || DEAD) : @state[x][y]]

  when :friendly
    # [optimized] 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 @state[x][y] == DEAD
                 npop.reduce([]) { |memo, (sym,cnt)|
                   cnt == 3 ? memo + [sym] : memo
                 }.sample || DEAD
               else
                 @state[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/board_state.rb', line 30

def next_value(x, y)
  n, birthright = neighbor_stats(x, y)
  if alive?(x, y)
    (n == 2 or n == 3) ? birthright : DEAD
  else
    (n == 3) ? birthright : DEAD
  end
end

#populate(x, y, val = ALIVE) ⇒ Object

set a single point, raise on OOB



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

def populate(x, y, val = ALIVE)
  in_bounds!(x, y)
  @state[x][y] = val
end

#population ⇒ Object

full board scan



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# File 'lib/conway_deathmatch/board_state.rb', line 148

def population
  population = Hash.new(0)
  @state.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/board_state.rb', line 142

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

#tick ⇒ Object

generate the next state table



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# File 'lib/conway_deathmatch/board_state.rb', line 116

def tick
  new_state = self.class.new_state(@x_len, @y_len)
  @x_len.times { |x|
    @y_len.times { |y| new_state[x][y] = next_value(x, y) }
  }
  @state = new_state
  self
end

#value(x, y) ⇒ Object 



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# File 'lib/conway_deathmatch/board_state.rb', line 86

def value(x, y)
  in_bounds!(x,y)
  @state[x][y].dup
end