Week 4: Keeping score with variables

Today we’ll create collectable objects that increase our score when we collide with them. We’ll edit the player script and start using number variables for a score system.

Programming concepts we’ll learn:

• Variables
• Data types

1: Adding collectable objects

In this step we’ll add collectable objects to our playable level. Watch the video below for a refresher on tagging objects and reusing scripts.

• Place collectables
• Add script to collectable
• “When created” from events
• “add tag tag name to myself” from sensing
• Change tag to “collectable”

• Add collectable script to all collectables
• In the next step we’ll create a variable for the score.

2: Creating a variable

Next we’ll create a number variable for a scoring system. Watch the video below to learn how to create a new variable.

• Edit player script
• Create a new variable by grabbing “set true/false i” from variables
• Add this block to “when the level starts”
• Change true/false to number
• Click on i and choose new variable, name it “score”
• Grab 0 block from operators

• In the next step we’ll increase this number variable when the player collides with a collectable

3: Increasing the score

Now we’ll increase the score when the player touches a collectable object. Watch the video below to learn how to change the value of a variable.

• Add another “if do” block (from control flow) to “when touched get toucher”
• “Myself has tag” from sensing
• Replace myself with “instance toucher” from variables
• Destroy myself from control flow
• Change myself to toucher
• Change tag to “collectable”
• “Set number score to” from variables
• “+” from operators
• “Number score” from variables
• “0” from operators, change it to “1”

• In the next step we’ll get the score to display on screen

4: Displaying the score on screen

In this step we’ll get the score to display on screen. Watch the video below to learn how to display text in your game.

• “Create new textfield” from draw
• Put this block inside “when level starts
• Type “0” in the textfield

• “Set x position of myself to 0” from transform
• Put this block inside constantly
• Replace “myself” with “instance textfield” from variables
• Replace 0 with “camera x” from looks
• Duplicate these blocks for y position and camera y

• Close script and save
• Play game to see score in corner of camera
• But it doesn’t update! In the next step we’ll get the score to update.

5: Updating the score textfield

Now we’ll get the score textfield to update. Watch the video below to learn how to update the value displayed in a textfield.

• “Set text of instance textfield to” from draw
• Put this block in the collectable collision detection
• “Number score” from variables, put this block in “set text of instance textfield to”, but it won’t go in because number datatype can’t be used where a text datatype is required
• We need to convert it using this block: “create text with” from operators in the text section

• Next week we’ll program a patrolling obstacle.