Class: MagicCloud::BitMatrix

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

Overview

Dead simple 2-dimensional “bit matrix”, storing 1s and 0s. Not memory effectife at all, but the fastest pure-Ruby solution I’ve tried.

Direct Known Subclasses

CollisionBoard, Spriter::Sprite

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(width, height) ⇒ BitMatrix

Returns a new instance of BitMatrix.



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# File 'lib/magic_cloud/bit_matrix.rb', line 7

def initialize(width, height)
  @width, @height = width, height
  @bits = [0] * height*width
end

Instance Attribute Details

#bits ⇒ Object (readonly)

Returns the value of attribute bits.



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# File 'lib/magic_cloud/bit_matrix.rb', line 12

def bits
  @bits
end

#height ⇒ Object (readonly)

Returns the value of attribute height.



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# File 'lib/magic_cloud/bit_matrix.rb', line 12

def height
  @height
end

#width ⇒ Object (readonly)

Returns the value of attribute width.



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# File 'lib/magic_cloud/bit_matrix.rb', line 12

def width
  @width
end

Instance Method Details

#at(x, y) ⇒ Object

returns true/false FIXME: maybe #put should also accept true/false



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# File 'lib/magic_cloud/bit_matrix.rb', line 23

def at(x, y)
  bits[y*@width + x] != 0 # faster than .zero?
end

#dump ⇒ Object 



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# File 'lib/magic_cloud/bit_matrix.rb', line 27

def dump
  (0...height).map{|y|
    (0...width).map{|x| at(x, y) ? ' ' : 'x'}.join
  }.join("\n")
end

#put(x, y, px = 1) ⇒ Object 



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# File 'lib/magic_cloud/bit_matrix.rb', line 14

def put(x, y, px = 1)
  x < width or fail("#{x} outside matrix: #{width}")
  y < height or fail("#{y} outside matrix: #{height}")

  bits[y*@width + x] = 1 unless px == 0 # It's faster with unless
end