Notes:
In the script for the barrier, I have used a “when [ ] key pressed” block from Control, with its value set to “t”. Think back – the script for the lights also starts when you press the “t” key. In this way, lights and barrier are synchronised: that means they both start at the same time. To lower the barrier, we will rotate the pole in stages by using a “repeat” block. Experiment with the number of repeats and the angle of turn to move the barrier just the right amount.
After a set time, 13 seconds, we raise the barrier using another repeat block. The train has passed, all the cars are safe. Well done!
For an example of this project in its finished state, open RPiScratch/Projects/level_crossing.
Over to you
Task: As an extra feature for this program, create a train sprite that moves across the screen when the barrier drops.
Lesson 1.7: Scratch games
Learning objective: In this exercise, you will learn some of the techniques used for game programming by playing some Scratch games.
Some of the most fun that you can have with Scratch is through programming games. You can make games about anything you like. We have included two sample games for you to investigate, and there are plenty more games and other examples of programs in the Scratch Projects folder. The starting point for each new game is the theme or idea, and the aim of the game. When you have an idea for a game, think about the “story” you want to tell and the game’s characters, players, pieces etc. that you will need. These will be the sprites. You can find great images for sprites and backgrounds by importing them from the Scratch Media folders or by searching on Google Images, saving and importing into Scratch. If you want to get some idea of how to get started and what you can do, have a look at some other people’s games. The best way to learn how to program is to examine other people’s scripts to see how they made cool things happen.
Tip...
Finally, you will need backgrounds for your stage to create the rooms, levels and scenes in your game, so that your characters have somewhere to move around in.
Don’t forget to add sounds and music, as this greatly enhances a game.
A beginner’s guide to Scratch
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