Randomising the
behaviour of Sprites
Games Programming in
Scratch
Games Programming in Scratch
L4 Randomising the behaviour of Sprites
STARTER
Your game is developing nicely… but what could
you add to it to make it…
• Realistic
• Interesting
• Fun
• Different each time
?
Games Programming in Scratch
L4 Randomising the behaviour of Sprites
Learning Objectives:
o Use the Pick Random block to position objects randomly on the
screen
o Understand the use of the operators <, =, >, and, or, not and use
them in my game where needed
Excellence
I can make use of ‘randomising’ within another feature of my own
design in my game
Developing
I can use ‘randomising’ to change Sprite positions and experiment
with the script to change movement
Secure
I can use ‘randomizing’ in my game to change positions of Spites on
screen and describe basically how the script works
Foundation
I can with support add ‘randomising’ of sprites in my game
Games Programming in Scratch
L4 Randomising the behaviour of Sprites
Working with Operators
• You have already used some operators
with variables (e.g. Lives = 0)
• But lots more available that can be used to make
your game better / more interesting / fun!
Games Programming in Scratch
L4 Randomising the behaviour of Sprites
Where to use Randomisation
• You can combine the use of operators, sprites,
and coordinates to make objects appear at
various points on the screen randomly.
• For example, this might be useful if:
– You died and wanted to come back to a specific
location and use another life
– Enemies that have been killed return
– Collectable treasures appear on screen randomly
• Work out how to make objects appear randomly
on screen
Games Programming in Scratch
L4 Randomising the behaviour of Sprites
The Scratch window
• The Scratch window has coordinates
• Where is 0,0?
180
y
-240
240
x
-180
Games Programming in Scratch
L4 Randomising the behaviour of Sprites
Using randomisation
One possible use!...
• Make sprites appear at random locations
using the Show and Hide blocks
But you could use the ‘pick random’ number action with
many other different examples! (which we will explore)
Games Programming in Scratch
L4 Randomising the behaviour of Sprites
Getting stuck
Getting stuck is all part of programming. It is
learning how to find a solution that really matters.
Remember, if you are stuck:
1. Try to solve the problem yourself
2. Use the help files and tutorials
3. Look at the Scratch Community projects for tips
4. Use the Internet
5. Ask a friend
6. Ask the teacher
Games Programming in Scratch
L4 Randomising the behaviour of Sprites
Add another object to collect
• Think about your game, then Find, Save, and
Import (or get it from gallery) another object to
collect in your game
• Now add the following events
to your new object to collect
(similar to your other object so far!)
Games Programming in Scratch
L4 Randomising the behaviour of Sprites
Making the new object to collect ‘RaNdOm!’
• Now to make the new object behaviour more ‘randomly’
using our new blocks. Add this script to your new item…
It will make it go to a random
place on the screen!
But now, your challenge is to make it more random again!
Lots to choose from, experiment with some of these…
Games Programming in Scratch
L4 Randomising the behaviour of Sprites
Comment your Code
Add comments to explain the blocks, particularly any
‘random’ actions used in your new ‘item to collect’