crong/ball.lua

import "pixie"

class("Ball").extends(Pixie)

function Ball:init(width, height, color, x, y)
   Ball.super.init(self, width, height, color, x, y)
   -- trying to use a table / array for the direction vector doesn't work for bizarre reasons...
   -- it fails on the init() call at runtime.
   self.dirX = -1
   self.dirY = 1
   self.speed = 3
   return self
end

function Ball:levelUp()
   self.speed += 1
end

function Ball:move()
   self:moveBy(self.dirX * self.speed,
               self.dirY * self.speed)
end

function Ball:setDirection(x, y)
   x = x or self.dirX
   y = y or self.dirY
   self.dirX = x
   self.dirY = y
end

function Ball:_normalizePosition()
   local changeVector = Ball.super._normalizePosition(self)
   if changeVector[1] ~= 0 then
      self.dirX = changeVector[1]
   end
   if changeVector[2] ~= 0 then
      self.dirY = changeVector[2]
   end
end