After I finished the new versions of Blindfold Pong and Blindfold Hopper, I asked my game testers what game they wanted next. Many of them asked for a bowling game. There are many visually impaired bowlers, and the American Blind Bowling Association helps set up leagues in each town across the country and elsewhere in the world, and holds annual competitions.
Bowling is a fairly easy game, but creating an version for an iPhone requires something none of my games had yet – the ability to simulate real world events, such as a ball hitting a bowling pin, and then that pin hitting another pin, as each pin falls over.
Most games use a physics engine to solve this problem. A physics engine is a computer program that emulates real world events, such as one object hitting another, or the effects of gravity and friction on a bouncing ball.
I didn’t want to dive into incorporating a physics engine into the games, so I thought I would tackle skee ball first. That’s a much simpler game, and from a quick study of the game, it could be done without a physics engine. You would flick the screen, and that would throw the ball into one of 5 holes, where the hardest hole to hit would earn 50 points, the easiest hole 10 points, and a bad throw wouldn’t earn any points.
When I announced the game, the testers had mixed feelings. Some liked the game from their visits to amusements parks, and liked being able to trade in the paper tickets for cheap, fun rewards. There are even some iPhone games that let you trade virtual paper tickets for virtual toys and gifts. But most of the testers said they preferred a bowling game.
It took a few weeks, but I found a two dimensional physics engine called BOX 2D, that is easy to integrate into iPhone apps. Most arcade games, like Space Invaders, Asteroids or Breakout, and many sports games, like Bowling or Pool, can be done with a two dimensional physics engine.
My next blog will discuss how a player can aim and throw the ball.