Bounce for Norns

bounce.lua

--- bounce by declutter; can't remember who first created this app in Max for the monome
--- to-do:
--- sound on collision
--- multiple balls

g = grid.connect()

function init()
  --- set up variables and grid
  
  position = {1,1}
  v = {1,1}
  map = {}
  for i = 1,16 do
    map[i] = {}
    for j = 1,8 do
      map[i][j] = 0
    end
  end
  
  --- initial state to make it more interesting
  
  map[4][1] = 1
  map[4][2] = 1
  map[4][3] = 1
  map[9][6] = 1
  map[9][7] = 1
  map[9][8] = 1
  
  ---timing
  
  counter = metro.alloc()
  counter.time = 0.1
  counter.count = -1
  counter.callback = count
  counter:start()
end

function count()
  --- move ball
  position[1] = position[1] + v[1]
  position[2] = position[2] + v[2]
  
  --- detect edges
  --- this is ugly; there must be a prettier way
  if (position[1] == 16) or (position[1] == 1) or (map[position[1]+1][position[2]] == 1) or (map[position[1]-1][position[2]] == 1) then v[1] = (-1)*v[1] end
  if (position[2] == 8) or (position[2] == 1) or (map[position[1]][position[2]+1] == 1) or (map[position[1]][position[2]-1] == 1) then v[2] = (-1)*v[2] end
  
  --- redraw grid
  g.all(0)
  for i = 1,16 do
    for j = 1,8 do
      g.led(i,j,(map[i][j] == 1) and 5 or 0)
    end
  end
  g.led(position[1],position[2],15)
  g.refresh()

end

g.event = function(x,y,z)
  --- key presses build walls
  if z == 1 then
    map[x][y] = 1 - map[x][y]
    end
  g.refresh()
end

@trentgill somehow I missed this comment. This is excellent - will do some looking at it. Thank you.