Time for action – building the gems

There are basically two types of match-three games, those in which the selection of matches takes place automatically and those in which the matches are selected by the player. Candy Crush is a good example of the former, and Diamond Dash of the latter. When building the first type of game, you must add extra logic to ensure you start the game with a grid that contains no matches. This is what we'll do now:

1. We start with the buildGrid method:

   function GameScene:buildGrid ()
      math.randomseed(os.clock())
      self.enabled = false
       local g
       for c = 1, constants.GRID_SIZE_X do
           self.grid[c] = {}
           self.gridGemsColumnMap[c] = {}
           for r = 1, constants.GRID_SIZE_Y do
               if (c < 3) then
                   self.grid[c][r] =  constants.TYPES[ self:getVerticalUnique(c,r) ]
               else
                   self.grid[c][r] =  constants.TYPES[ self:getVerticalHorizontalUnique(c,r) ]
               end
              g = Gem:create...