Scratch. Creative Computing

Transcription

1 Scratch Creative Computing

2 Section 1 INTRODUCTION TO SCRATCH

3 Scratch Browser based Created at MIT Creative Computing Using a tool to easily create a computer program. Typically a drag-and-drop tool. Emphasizes creativity instead of programming syntax The ease of use allows beginners to be creative while programming.

4 Section 1 Objectives By the end of this unit, students will: Understand the concept of computational creation, in the context of Scratch be able to imagine possibilities for their own Scratch-based computational creation become familiar with resources that support their computational creation Mr. Stoll s account: sestoll99

5 Scripts and Commands Command A statement that tells the computer what to do. In Scratch each command is called a Block Other scripting languages (block = set of commands) Script - list of commands that are executed by a certain program or scripting engine. Scratch uses scripts Python is a scripting language

6 Sprite Sprite - an image and its location on the stage (screen). Three sprites on the stage (screen) The Parrot sprite is selected Work with Parrot Scripts What are score and birdcounter? (top of screen)

7 The Scratch Interface Script Menus (Motion Menu Selected) Stage Sprites Motion Commands Script Window

8 Part of the Sound Menu Creating Scripts (Lego Block Concept) Create scripts by snapping blocks together Command blocks applied to the sprite Part of the Motion Menu

9 Dancing Cat Demonstration Control Repeat 10 Repeat the following four statements 10 times: Motion - Move 10 steps Sound - Play drum Sample Script (move and play drum repeatedly) Motion - Move 10 steps Sound - Play drum

10 Tips For Using Scratch Drag a set of blocks from the top While dragging a block, everything below moves as well Separate blocks from the bottom Recommended: The green flag event is useful for setting up your scene Programming commands are under the tab. Most script commands apply to a specific Sprite Sprite1 is selected

11 Time to Explore Scratch 1. Sign-up for Scratch: Use account information you can remember. Forgetting this may hurt your grade in the future. 2. Play with Scratch Try to make something surprising happen to a sprite. Work together if desired!!! Be ready to discuss what you have learned.

12 Section 2 TALKING SPRITES

13 Making Sprites Talk Make sure you select the desired sprite first. The when this sprite clicked event is very useful

14 Mr. Stoll s Example (About Me) Click Here to Review the Project in Scratch

15 Create Your Own Project Create your own (About Me) project Make it more elaborate than mine. It is due at the beginning of the next class period Advanced students: Make it way better than mine.

16 About Me Project Review Review student projects with class: Ask for volunteers Select some students randomly if necessary.

17 Section 3 ANIMATION DANCE PARTY

18 Dance Party Project Dance Party - a Scratch project in which sprites get down with cool costumes and funky beats. ie. claptrap from Borderlands For the next three slides we will create a Dance Party Scene. We will: Define Sprite Define Costume Different images for a given sprite. Assemble code blocks so sprite dances when clicked.

19 Sprite Sprite - an image and its location on the screen. Games have been using them for decades. Used to be hardware dependent. Sprite on Stage Sprite definition Press the in the upper left corner of the sprite definition to see details about the sprite.

20 What is a Costume A sprite may have many costumes. Costumes are typically used for animation.

21 Dancing Ballerina 1. Press choose sprite from library button 2. Select a sprite from the library and press the OK button. 3. Create the following script:

22 Adding Music to Ballerina Separate simultaneous notes into separate block sets. They run in parallel At the same time, when the ballerina is clicked..4 secs is the same as.4 beats Synchronize music and animation. Drum 4 is the symbol. It plays at the end of the animation

23 Sprites and Costumes Review What is the difference between a sprite and a sprite s costume? When might you want to use a sprite? When might you want to use a costume?

24 Resetting Your Scene Initialize To assign starting values. This is a set of code blocks for a sprite. This block: 1. Executes when the green flag is pressed. 2. Moves the sprite to its starting point 3. Displays its initial costume (Picture1) There are several things you can initialize in your scene. Most of them are in the and menus.

25 Incremental Incremental - increasing gradually by regular degrees or additions. Always add and test small amounts of code at a time.

26 Assignment: Dance Party Dance party Assignment Requirements 1. Sprites / Costumes Select from one of these two options: Find a sprite (in Scratch or outside of Scratch) that has multiple costumes. Take an existing sprite and modify it to have different costumes. 2. Animate the sprite when the user clicks on it Move the sprite and change its costume. 3. Play at least two notes each time the sprite changes costumes. Notes to be played at the same time must be in separate sets of blocks. Review P. 49 of your Scratch Guide Everyone must have a unique project

27 Section 4 GAMES

28 Blocks for Games (Variables) Examples: health; movespeed; ammo; defensepoints happiness (Sims); lives (old school games) Score Variable Initializing the Score Incrementing the Score Display/Hide Score See PP For More Information

29 Blocks for Games (Random) Very Useful: Enemy appears in random place on screen. Enemy starts with random # health points Dice rolls for video Monopoly Card drawn in a video card game Anybody Have an Example for us??: Sims Tetris Mario Kart

30 Blocks for Games (Visibility) The visibility of sprites Visible Invisible See PP For More Information

31 Blocks for Games (Timing) Timing Examples: Consistent game speed same on slow and fast computers Change the image on the screen to display the next frame of animation. See PP For More Information

32 Blocks for Games (Events) Event - an action or occurrence detected by the program that may be handled by the program. key press events Code executes when user clicks on the sprite. Initialization Event Code that executes when program is starting to run. Green Flag To Initialize Sprites and Variables

33 Blocks for Games (Comparisons) The player must not get a point unless the Orange touches the Parrot without touching the Cat sprite. Don t increase the birdspeed if it is already moving at 15 or above. See PP For More Information

34 Blocks for Games (Collision Detection) Collision Detection Detecting when one sprite overlaps another sprite. If this sprite is touching specified sprite, edge, or mouse-pointer. If this sprite is touching a specific color If a specified color on this sprite is touching another color.

35 Games Assignment (Make a game) Review P (blocks for games and collision detection)

36 Blocks for Games (Strings) I currently plan to wait to discuss strings until we start working with Python. See PP For More Information

37 Section 5 PROGRAMMING CONCEPTS

38 PROGRAMMING CONCEPTS (How they relate to blocks) Decisions - Allows the program to compare two or more values. Most programming languages use the "if" keyword. Loop Repeat one or more commands until a condition is met. Variable - Stores a value to be used later in the program. Random - Event - an action or occurrence detected by the program that may be handled by the program. Etc.

39 Decision Structure Scratch Python if mrstollsage > 49: print ( You are old ) if playerhealth < 10: movespeed = 3

40 Sequential Structure Scratch Python Print ( Hello ) movespeed = 3 xposition = xposition + 10 yposition = yposition + 10

41 Loops Scratch Python while guessestaken < 6: Command Command etc. while True: command command etc.

42 Variables Scratch Python Score = 17 birdcounter = 30 birdspeed = 5

43 Random Numbers Scratch Python random.randint(1, 10)