Introduction to Scratch!

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Introduction to Scratch! Powered By Docstoc
					   Scratch for
   Storytelling
        Dr. Ben Schafer
Department of Computer Science
  University of Northern Iowa
       Concept Summary
•   The layout of the Scratch stage
•   Basic sequencing of commands
•   The Motion and Pen menus
•   The repeat command from the
    Control menu
      Recall from this
         morning…
• “Scratch is a free programmable
  toolkit that enables kids to create
  their own games, animated stories,
  and interactive art”
  This afternoon’s focus
• “Scratch is a free programmable
  toolkit that enables kids to create
  their own games, animated stories,
  and interactive art”
Choose a different Sprite!
 • While the cat is a good first step, he
   isn’t always the character we want to
   work with
 • You can choose a different sprite to
   program from a library in Scratch, or
   you can draw your own!
    Choose Your Sprite!
• To choose a sprite
  from the Scratch
  library, click on the
  Folder with a Star
  icon. When you
  hover your mouse
  over it, it will say
  “Choose new sprite
  from file”.
     Choose Your Sprite!
Open the folders of the
  different categories of
  sprites. (you may use
  those loaded with
  Scratch or any standard
  image file).
Choose one that you’d like
  to experiment with by
  double clicking on it.
    Choose Your Sprite!
You can have more
  than one sprite in
  your animation!
For this demo I am
  going to load “Dan5”
  and “Marissa”
      Choose Your Sprite!
• Once you have the sprites
  that you’d like to program,
  you can delete the orange
  cat sprite by clicking the
  scissor icon and clicking on
  the cat!
• Make sure that you click on
  the arrow icon before you
  do anything else –
  otherwise, you’ll delete
  something that you really
  wanted!
    Choose Your Sprite!
• You can also right
  click on the icon to
  delete that sprite
    Resize Your Sprite!
• You can make your sprite larger or
  smaller by using the “grow sprite” or
  “shrink sprite” icons.
• You click on one of these icons, then
  click on your sprite until it is the size
  you’d like.
   Naming your sprites!
• Scratch uses the name sprite# by
  default
• To make things more helpful we
  normally want to assign our sprites
  meaningful names.
• You do that with the text box above
  the sprite’s script area.
Choose Your Background!
• Right now, you have a plain, white
  background – boring!
• You can also change your background
  by choosing one from the Scratch
  library or creating your own!
Choose Your Background!
• Click on the Stage:



• Now, select the
  “Backgrounds” tab!
Change Your Background!
• You can experiment with creating or
  importing your own background later,
  but, for right now – choose one from
  the library by selecting Import.
Change The Background!
From this screen, you can choose one of
the category folders, and select a
background that you like by double clicking
on it!
Change The Background!
I chose the “hall” background from the
“indoor” category.




                 CS4HS Summer 2010
Sidenote : While I didn’t
  use it this morning…
Depending on how you want to introduce
 Scratch you may want to consider using
 the graph paper background.




                  CS4HS Summer 2010
Now, We’re Ready to
     Program!
Changing a Sprite’s Looks
• Click on the Looks menu.
  – Take a few minutes to look at your
    options.
Changing a Sprite’s Looks
• Click on the Looks menu.
  – Take a few minutes to look at your
    options.


• The one we are interested in right
  now is the “say .. for” block (notices,
  “square-edged” blocks expect text).
       Let’s consider the
        following script
•   Marissa : Knock, Knock.
•   Dan : Who’s there?
•   Marissa : Dwayne.
•   Dan : Dwayne who?
•   Marissa : Dwayne the bathtub. I’m
    dwowning.
  How could we program
          this?
• Divide the lines between each sprite
• Sequence them together
  What is the problem?
• The “actors” talk over the top of
  each other
  – We didn’t think this through carefully.
       Let’s consider the
        following script
•   Marissa : Knock, Knock. (but Dan waits)
•   Dan : Who’s there? (but Marissa waits)
•   Marissa : Dwayne. (…)
•   Dan : Dwayne who? (…)
•   Marissa : Dwayne the bathtub. I’m
    dwowning. (…)
  What is the solution?
• Use the “wait” block from the control
  menu!
What is the solution?
Changing a Sprite’s Looks
• Recall the Looks menu.
  – One of the options under here was
    changing a costume
  – Let’s improve the animation with some
    costumes.
Changing a Sprite’s Looks
•   Select the Dan Sprite
•   Select the “Costumes” tab
•   Select the import button
•   Navigate and select “Dan4” under the
    “people” folder.
    – Notice that Scratch gives the costumes a
      different name from the “image” name
    – Rename this costume “thinking”
Changing a Sprite’s Looks
• Let’s have Dan “think” for two seconds
  before saying Dwayne who?
• This means:
  –   Changing the costume at the right time
  –   Waiting two seconds
  –   Changing back to his original costume
  –   (It also means having Marissa wait longer since
      Dan’s turn takes longer).
Changing a Sprite’s Looks
    Another option for
       coordination
• The last technique we used involved
  counting (very carefully) how long we
  expected things to take and then
  having sprites wait for a set amount
  of time.
   Another option for
      coordination
• But what happens when
 – there are large sets of
   collaborating sprites (the count is
   complicated)?
 – the waiting depends on something
   specific happening (the count is
   impossible to determine)?
 broadcast-ing messages
    between sprites
• Scratch allows sprites to listen for
  messages from other sprites.
• When one sprite wants to signal the
  others it uses broadcast to send a
  message.
  Under Marissa’s script
• Select the control
  menu from script
• Drag out the
  broadcast block
• Select the arrow in
  the text box
• Select “new”
• Give the message
  name as
  “playsounds”
               Sound!
• Now, let’s add some sound to our
  animation!
• There are many different ways to get
  sound in your animation.
• The first way we’re going to experiment
  with is by importing a sound from the
  Scratch sound library.
Importing Sound From The
  Scratch Sound Library
• Click on the sprite you want to have
  sound
• In this example, let’s actually add it
  to the stage
• Click on the Sounds tab and select
  Import.


                  CS4HS Summer 2010
   Scratch Sound Library
• You will see different categories of
  sounds that you can use in your
  animation that are available for you
  in the Scratch library.
      Inserting Sound
• Once you find a sound that you like,
  select it and click on OK.
  – (I selected “laugh-female” under
    “human” AND “gong” under “percussion”
• You will see the sound you just
  selected show up under the Sound
  tab.



                  CS4HS Summer 2010
      Play Your Sound
• If you click on the “Play” button, you
  can preview your sound.
  Adding The Sound To
    Your Animation
• Now, you’re ready to add the sound
  to your animation!
• Click on the Script tab.
• Select the sprite you want to have
  sound.
• Now select the Sound button.
         Adding Sound
• Now, select one of the blocks that says,
  “play sound…”




• Select your sound from the drop-down
  menu by clicking on the triangle next to
  “pop”.
Under the Stage’s script
• Select the control
  menu from script
• Drag out the When
  I receive block
• Select the arrow in
  the text box
• Select the message
  named “playsounds”
• Add in the two
  sounds
     Concept Summary
• Creating new sprites
• Changing backgrounds and costumes
• Sequencing and coordinating actions
  between multiple sprites.
• The Looks and Sounds menus
• The broadcast command from the
  Control menu

				
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posted:10/4/2012
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