Introduction to Computer Science with Scratch and App Inventor
Introduction to Computer Science with Scratch and App Inventor
Introduction to Computer Science with Scratch and App Inventor
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Interacting <strong>with</strong> Other Sprites<br />
So far we have used the if block <strong>to</strong> let the user control the actions of our sprite, but we can also use the<br />
if block <strong>to</strong> make different sprites interact <strong>with</strong> each other. First I need <strong>to</strong> add a second sprite <strong>to</strong> my<br />
program. Scripts are sprite-specific. Every new sprite will need its own script(s) <strong>to</strong> tell it how <strong>to</strong><br />
behave.<br />
Now I have two sprites – a dinosaur <strong>and</strong> a bowl of<br />
cheesy poofs.<br />
I can control my dinosaur using the arrow keys on<br />
the keyboard using the script I wrote before.<br />
Let’s try <strong>to</strong> make the dinosaur eat the cheesy poofs!<br />
First, we need <strong>to</strong> move the dinosaur <strong>to</strong> the cheesy<br />
poofs – that is easy <strong>to</strong> do using the arrow keys<br />
The second step is <strong>to</strong> write a script so that we know<br />
when the dinosaur arrives at the cheesy poofs.<br />
When the dinosaur gets <strong>to</strong> the cheesy poofs, we<br />
want <strong>to</strong> make them disappear so that it looks like<br />
they’ve been gobbled up.<br />
Let’s write a script for the cheesy poofs that makes it look like the dinosaur is eating them. First, <strong>to</strong><br />
detect when the dinosaur gets <strong>to</strong> the cheesy poofs we can use an if block. What should the condition<br />
be? Luckily, one of the sensing blocks will tell us when two sprites are <strong>to</strong>uching each other. Here, we<br />
want <strong>to</strong> pick the condition “if <strong>to</strong>uching sprite1” since the dinosaur is sprite1.<br />
Check down here <strong>to</strong> see what each sprite is named.<br />
You can change the name of your sprites if you like.<br />
mbrace Game Development Workbook Page 18