Introduction to Computer Science with Scratch and App Inventor

Recommendations

Info

The sensing menu contains many blocks that test different conditions. The one that we are going to use to help control our sprite checks to see if a certain key is pressed. The default key is the space bar, but we can change it to select any key we want by clicking on the arrow to bring up a drop down menu Here the arrow keys are the ones that we want to use in our condition since they will tell our sprite which direction to move on the stage. Now that we know where to find the condition blocks, let’s use if, conditions, and movement blocks to build a user controlled sprite. What do you think our script will look like? Here is one example of a script that will work for creating a user-controlled dinosaur. You can write a script that does the exact same thing that looks very different – in programming there are often lots of different ways to do the same thing – that is OK. The different ways to approach the same problem are called algorithms. Coming up with good algorithms to solve a problem is a big part of what programmers do. mbrace Game Development Workbook Page 14
Costumes and Animation Now that you have your sprite moving around the screen, let’s make our program a little fancier. Let’s have the sprite change the direction he is pointing so that when the user pushes the right arrow or the left arrow, the sprite will face the same direction he moves. We will use costumes to do this. Costumes give you a way to change the way a given sprite looks. You can see the costumes available to your sprite by clicking on the costumes tab in the current sprite info pane in the middle of the screen. Right now you can see that our dinosaur (named Sprite1) had only one costume available. This costume is named dinosaur1. To add more costumes for a sprite, you can copy existing costumes, import new costumes from the library (if available), make your own costume using drawing tools or a photo, or edit existing costumes. Here, we want to provide a new costume for our sprite that is exactly the same as dinosaur1, only we want it to be facing the opposite direction. To do this we will first copy and then edit the existing costume. On the costumes tab: 1. Click the copy button to make a copy of the dinosaur1 costume 2. On the new copy of the costume (dinosaur2), click the edit button to bring up the paint editor 3. In the paint editor, click the flip button to flip the costume to face the other direction Now you should have two costumes for your sprite – one that faces to the left and one that faces to the right. Look at the names of the costumes to figure out which is which, in my example: dinosaur1 faces to the right and dinosaur2 faces to the left You can always rename your costumes (or your sprites) to something that makes more sense. Here I am going to rename the dinosaur1 costume to be rightDino and the dinosaur2 costume to be leftDino mbrace Game Development Workbook Page 15
Page 1 and 2: Introduction to Computer Science wi
Page 3 and 4: LESSON 1: Getting Started with Scra
Page 5 and 6: I decided to pick a dinosaur. You c
Page 7 and 8: The direction that your sprite move
Page 9 and 10: Let’s add some yellow wait blocks
Page 11 and 12: Changing the Background on the Stag
Page 13: To use an if block to control the m
Page 17 and 18: Other useful blocks are the say and
Page 19 and 20: ? Now we know how to tell when the
Page 21 and 22: Here is one script that works. To m
Page 23 and 24: After you create a variable, you wi
Page 25 and 26: Winning, Losing, and Game Play Our
Page 27 and 28: You might have noticed that when th
Page 29 and 30: Click the checkbox next to timer to
Page 31 and 32: Scratch Review Now you have built y
Page 33 and 34: App Inventor Interface The App Inve
Page 35 and 36: The first thing that we will do is
Page 37 and 38: To add the mole to our program, we
Page 39 and 40: Your Blocks Editor Screen should lo
Page 41 and 42: We know that our X and Y locations
Page 43 and 44: Our mole shows up in the emulator,
Page 45 and 46: The last thing we need is the value
Page 47 and 48: Team Project Worksheet We have lear

Introduction to Computer Science with Scratch and App Inventor

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?