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bresenham.lua
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bresenham.lua
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-- bresenham.lua - v1.0 (2012-05)
-- Copyright (c) 2011 Enrique García Cota
-- Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
-- The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
-- THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
local Bresenham = {}
function Bresenham.los(x0,y0,x1,y1, callback)
local sx,sy,dx,dy
if x0 < x1 then
sx = 1
dx = x1 - x0
else
sx = -1
dx = x0 - x1
end
if y0 < y1 then
sy = 1
dy = y1 - y0
else
sy = -1
dy = y0 - y1
end
local err, e2 = dx-dy, nil
if not callback(x0, y0) then return false end
while not(x0 == x1 and y0 == y1) do
e2 = err + err
if e2 > -dy then
err = err - dy
x0 = x0 + sx
end
if e2 < dx then
err = err + dx
y0 = y0 + sy
end
if not callback(x0, y0) then return false end
end
return true
end
function Bresenham.line(x0,y0,x1,y1,callback)
local points = {}
local count = 0
local result = Bresenham.los(x0,y0,x1,y1, function(x,y)
if callback and not callback(x,y) then return false end
count = count + 1
points[count] = {x,y}
return true
end)
return points, result
end
return Bresenham