RosettaCodeData/Task/Galton-box-animation/Lua/galton-box-animation.lua
2023-07-01 13:44:08 -04:00

74 lines
1.7 KiB
Lua

Bitmap.render = function(self)
for y = 1, self.height do
print(table.concat(self.pixels[y], " "))
end
end
-- globals (tweak here as desired)
math.randomseed(os.time())
local W, H, MIDX = 15, 40, 7
local bitmap = Bitmap(W, H)
local AIR, PIN, BALL, FLOOR = ".", "", "", ""
local nballs, balls = 60, {}
local frame, showEveryFrame = 1, false
-- the game board:
bitmap:clear(AIR)
for row = 1, 7 do
for col = 0, row-1 do
bitmap:set(MIDX-row+col*2+1, 1+row*2, PIN)
end
end
for col = 0, W-1 do
bitmap:set(col, H-1, FLOOR)
end
-- ball class
Ball = {
new = function(self, x, y, bitmap)
local instance = setmetatable({ x=x, y=y, bitmap=bitmap, alive=true }, self)
return instance
end,
update = function(self)
if not self.alive then return end
self.bitmap:set(self.x, self.y, AIR)
local newx, newy = self.x, self.y+1
local below = self.bitmap:get(newx, newy)
if below==PIN then
newx = newx + (math.random(2)-1)*2-1
end
local there = self.bitmap:get(newx, newy)
if there==AIR then
self.x, self.y = newx, newy
else
self.alive = false
end
self.bitmap:set(self.x, self.y, BALL)
end,
}
Ball.__index = Ball
setmetatable(Ball, { __call = function (t, ...) return t:new(...) end })
-- simulation:
local function spawn()
if nballs > 0 then
balls[#balls+1] = Ball(MIDX, 0, bitmap)
nballs = nballs - 1
end
end
spawn()
while #balls > 0 do
if frame%2==0 then spawn() end
alive = {}
for _,ball in ipairs(balls) do
ball:update()
if ball.alive then alive[#alive+1]=ball end
end
balls = alive
if frame%50==0 or #alive==0 or showEveryFrame then
print("FRAME "..frame..":")
bitmap:render()
end
frame = frame + 1
end