fy (property)

Get or set the friction opposing a sprite’s motion in the vertical direction.

Get

Get the vertical friction on the sprite.

let mySprite: Sprite = null

let horzAccel = mySprite.fy

horzAccel = mySprite.fy

Returns

a number that is the current vertical friction of the sprite.

Set

Set the vertical friction for the sprite.

let mySprite: Sprite = null

mySprite.fy = 0

mySprite.fy = 0

Parameter

value: the new vertical friction opposing the sprite’s motion in pixels per second, per second.

Sprite vertical friction

Friction is an opposing force against the motion of a sprite. If a sprite has a vertical velocity (vy), it’s friction will slow the sprite down until it’s vertical velocity becomes 0. This is similar to setting an opposite vertical acceleration but the opposite acceleration goes away once the sprite stops.

Examples

Measure stopping time

Move the sprite from top to bottom across the screen. Use the correct amount of friction (fy) to make the sprite stop at 3 seconds.

let stopTime = 0
let counting = true
let mySprite = sprites.create(img`
    . . . . . . . . . . . . . . . . 
    . . . . . . . . . . . . . . . . 
    . . . . . 5 5 5 5 5 5 . . . . . 
    . . . 5 5 5 5 5 5 5 5 5 5 . . . 
    . . . 5 5 5 5 5 5 5 5 5 5 . . . 
    . . 5 5 5 5 5 5 5 5 5 5 5 5 . . 
    . . 5 5 5 5 5 5 5 5 5 5 5 5 . . 
    . . 5 5 5 5 5 5 5 5 5 5 5 5 . . 
    . . 5 5 5 5 5 5 5 5 5 5 5 5 . . 
    . . 5 5 5 5 5 5 5 5 5 5 5 5 . . 
    . . 5 5 5 5 5 5 5 5 5 5 5 5 . . 
    . . . 5 5 5 5 5 5 5 5 5 5 . . . 
    . . . 5 5 5 5 5 5 5 5 5 5 . . . 
    . . . . . 5 5 5 5 5 5 . . . . . 
    . . . . . . . . . . . . . . . . 
    . . . . . . . . . . . . . . . . 
    `, SpriteKind.Player)
mySprite.setStayInScreen(true)
mySprite.top = 0
mySprite.fy = 20
mySprite.vy = 60
game.onUpdateInterval(100, function () {
    if (counting) {
        stopTime += 0.1
        if (mySprite.vy == 0) {
            counting = false
            mySprite.sayText("" + stopTime + "sec", 5000, false)
        }
    }
})

Skipping sprite

Make a sprite move from the top to the bottom. Make it skip to the right once every second.

let mySprite = sprites.create(img`
    . . . . . . . . . . . . . . . . 
    . . . . . . . . . . . . . . . . 
    . . . . . 5 5 5 5 5 5 . . . . . 
    . . . 5 5 5 5 5 5 5 5 5 5 . . . 
    . . . 5 5 5 5 5 5 5 5 5 5 . . . 
    . . 5 5 5 5 5 5 5 5 5 5 5 5 . . 
    . . 5 5 5 5 5 5 5 5 5 5 5 5 . . 
    . . 5 5 5 5 5 5 5 5 5 5 5 5 . . 
    . . 5 5 5 5 5 5 5 5 5 5 5 5 . . 
    . . 5 5 5 5 5 5 5 5 5 5 5 5 . . 
    . . 5 5 5 5 5 5 5 5 5 5 5 5 . . 
    . . . 5 5 5 5 5 5 5 5 5 5 . . . 
    . . . 5 5 5 5 5 5 5 5 5 5 . . . 
    . . . . . 5 5 5 5 5 5 . . . . . 
    . . . . . . . . . . . . . . . . 
    . . . . . . . . . . . . . . . . 
    `, SpriteKind.Player)
mySprite.setStayInScreen(true)
mySprite.top = 0
mySprite.fy = 60
mySprite.vy = 60
for (let index = 0; index < 3; index++) {
    mySprite.vy = 60
    pause(1000)
}