Class: LineOfSite

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

Overview

LineOfSite is a class for finding neighbors in a map that are visible

Instance Method Summary collapse

Constructor Details

#initialize(map) ⇒ LineOfSite

Returns a new instance of LineOfSite.



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# File 'lib/line_of_sight.rb', line 3

def initialize(map)
  @map = map
end

Instance Method Details

#brensenham_line(x, y, x2, y2) ⇒ Object

Brensenham line algorithm



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# File 'lib/line_of_sight.rb', line 20

def brensenham_line(x,y,x2,y2)
  steep = false
  coords = []
  dx = (x2 - x).abs
  if (x2 - x) > 0
    sx = 1
  else 
    sx = -1
  end
  dy = (y2 - y).abs
  if (y2 - y) > 0
    sy = 1
  else
    sy = -1
  end
  if dy > dx
    steep = true
    x,y = y,x
    dx,dy = dy,dx
    sx,sy = sy,sx
  end
  d = (2 * dy) - dx

  dx.times do
    if steep 
      coords << [y,x]
    else
      coords << [x,y]
    end
    while d >= 0
      y = y + sy
      d = d - (2 * dx)
    end
    x = x + sx
    d = d + (2 * dy)
  end
  coords << [x2,y2]
  
  coords             
end

#losline(x, y, x2, y2) ⇒ Object 



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# File 'lib/line_of_sight.rb', line 7

def losline(x, y, x2, y2)
  brensenham_line(x, y, x2, y2).each do |i|
    iterx, itery = *i
    occ = @map.occupant(loc2(iterx,itery))
    return unless occ
    occ.lit = true
    occ.seen = true
    
    return if occ.solid?      
  end
end