Write Your First Computer Game!

Coding: Programming Languages• Just like you can speak Chinese to someone

who understands Chinese to tell them what to do…• A programming language tells a computer what

to do!• During this project, we will learn how to tell a

computer how to make a fun game about a Tadpole and Frog!

Big Ideas

What is Coding?

How Can you Write

Code?What is Scratch?

This is Scratch!

To sign up: Go to http://scratch.mit.edu

and click on Join Scratch

Enter a username and password

Use your Type2Learn username and

password on the label

Enter birth month and year, gender, country and e-mail

Use this e-mail address

Click on Let’s Go!

Click on OK Let’s Go!

Create a New Project

Click on Create

Title your project

Title your project first name + last initial + 1

Scratch: Stage

Stage

Like in real life, the stage is where the performance, or game happens!

Scratch: Sprite

Sprite

Not the soda! An actor or a character that is on the stage, doing what you tell it to do!

Scratch: Script

Scripts

This is where you tell your actor/sprite what to do!

Create Tadpole and Evil Fish

Change the Stage:Choose a background

Code to make Evil Fish move randomly

Code to make Tadpole escape Evil Fish

Make it a gameEnd game when Tadpole gets caught or besomes a frog after 20 seconds of avoiding the evil fish!

Delete the cat sprite

First click on the cut tool

Then click on the cat sprite

Create a SpriteLet’s Get our Hero on Stage!

Click here to find our tadpole!

Create a SpriteHere is our tadpole. On stage, ready to respond to our commands!

The Evil FishNow lets’ get the evil fish on stage!

Choose a sprite from the

library!

The Evil FishNow lets’ get the evil fish on stage!

Choose fish 2. He looks ready

to eat!

Ready for Instructions!Both our actors are on stage. Now we need to tell them what to do!

But first, let’s put them in the water!We need the stage to look like a pond. So let’s do that…

Choose a new backdrop!

But first, let’s put them in the water!Choose “underwater” scene 1, 2, or 3!

Nature Scenes

Our Tadpole and Fish are in Water

Let’s Start by Giving Evil Fish instructions

Click on Evil Fish, so he knows we are telling him what to do.

Click to make him active

Scripts: Instructions to your sprites

There are all sorts of script blocks. These blocks are instructions to tell your sprite what to do. We’ll start with “motion” blocks.

Make sure “motion” is selected

Make Evil Fish Move Forward!

Point at “move” block and DRAG to the script area.

Choose move 10 steps

Nothing Happened!You have to TELL him when to start moving!Click on Events.Drag When [green flag] clicked onto your scripts area.

Choose when green flag is clicked

Move Blocks together to give instructions to your character

Now, the fish will move 10 steps when you click the green flag!

Give it a try!

Slide the blocks together!

Evil Fish Doesn’t Move Very FarEach click of the green flag moves him only 10 steps. Let’s make him keep moving!

Keep pressing the green flag to see Evil Fish move 10

steps

Make Evil Fish Swim ForeverGo to the CONTROL area. These are blocks that let you CONTROL your sprites even more

CONTROL options control what your sprites do

Make Evil Fish Move ForeverA Forever loop tells Evil Fish to do what is inside the loop FOREVER. Till the end of time. And then keep going!

Choose Forever

Make Evil Fish Move ForeverA forever loop tells Evil Fish to move 10 steps FOREVER. Till the end of time.

Give it a try!

Forever loops tell your charater to do what you say

forever and ever

Uh-oh! He disappeared!Evil Fish disappeared. We have to tell him to stay on stage!

If on edge, bounce

Now he’s going only back and forth… lets’ have him turn

Use the turn motion block to tell him to turn

Turn right 15 degrees

Now he’s spinning. Let’s randomize it!

Random: let the computer pick a number!

Let the computer choose a number to turn Evil Fish

Lets do that with the steps too!

This makes it harder to guess where Evil Fish will move next!

Evil Fish is Ready for The Game!

Let’s remember to tell Evil Fish to get on stage to start

the game!

Let’s Save our Progress!

Enter a name for your game

Then click SAVE NOW

Time to Move The Tadpole

First, we need to select the sprite we want to give instructions to.

Click on the tadpole!

Follow The Mouse!For Tadpole to escape the evil fish, we need to make her move by following the mouse pointer around.

Follow The Mouse!For Tadpole to escape the evil fish, we need to make her move by following the mouse pointer around.

Uh-oh. She stopped when he moved once. How do we make her always follow the mouse pointer around?

Follow The Mouse!Now tadpole will follow the mouse pointer forever.

Let’s Make it a Game!

In order for a tadpole to grow into a frog, she needs to be able to avoid evil fish long enough to grow up!

Let’s make it so that Tadpole has to stay away from Evil Fish for 20 seconds to become a frog!

Adding Time to The Game

First, click on your stage.

We are going to now set controls for the whole game, not just our actors/sprites

Adding Time to The GameWhen the flag is clicked, we want to wait 20 seconds then alert the game that the tadpole has won!

From Control

From Sensing

Adding Time to The GameAfter 20 seconds goes by, we need to send off a broadcast, which tells all the actors to pay attention and do something special!

From Events. Choose New Message

Broadcast frog

Adding Time to The GameWhen the actors hear the broadcast frog we need them all to do something!

Tadpole should change into his frog costume.

Evil fish should stop swimming because the game is over!

When 20 seconds has gone by, all the actors will

hear the message frog.

Tell Tadpole She Won!

Click back on Tadpole. Let’s have her respond to the frog broadcast.

Click on Event and choose When I receive . . .

Change this to be frog

Make Tadpole Turn into a Frog!

Tadpole needs to change into her Frog costume

Click on New Costume and choose the Frog costume

Make Tadpole Turn into a Frog!

Choose Frog, click OK

Make Tadpole Turn into a Frog!

Go back to Scripts and Have Tadpole Change costumes when she receives the Frog message!

Check your work! Click the flag. Do you see the timer? Does Tadpole turn into a frog?

Make Evil Fish Stop and Hide!Click back on the Evil Fish so that you can see the script for him.

Click on this last one in the list to tell the other script (the one above that is moving evil fish)

to stop running.

Check your work! Click the flag. Do you see the timer? Does Tadpole turn into a frog?

Wait! Tadpole is still a Frog!We have to go back to the start and have Tadpole get her tadpole costume on!

Tells tadpole actor to start in the tadpole costume

Now . . . if Tadpole swims away for 20 seconds, she turns into a frog!

But wait . . .

What if Evil Fish catches Tadpole???

If Tadpole touches Evil Fish . . .then she loses

An If . . .then looptells a computer: IF something happens, THEN do something

Find this in CONTROL

Let’s put that in code!

Touches the evil fish

Choose evil Fish

Find this in SENSING

If touching evil fish Drag touching

onto the IF until it turns white

Let’s put that in code!

Send a message it’s game over Broadcast!

If Tadpole touches Evil Fish . . .then she loses

Final instructions for tadpole

Tell tadpole what to do if she hears game over!

Tadpole hides!

If Tadpole touches Evil Fish . . .then she loses

But Evil Fish wins!

Tells everyone he won

So if Evil Fish hears GAME OVER…

Tells Evil Fish to stop moving

Final project:

http://scratch.mit.edu/projects/19135697/