fx (property)

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

Get

Get the horizontal friction on the sprite.

let mySprite: Sprite = null

let horzAccel = mySprite.fx

horzAccel = mySprite.fx

Returns

• a number that is the current horizontal friction of the sprite.

Set

Set the horizontal friction for the sprite.

let mySprite: Sprite = null

mySprite.fx = 0

mySprite.fx = 0

Parameter

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

Sprite horizontal friction

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

Examples

Measure stopping time

Move the sprite from left to right across the screen. Use the correct amount of friction (fx) 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.left = 0
mySprite.fx = 30
mySprite.vx = 90
game.onUpdateInterval(100, function () {
    if (counting) {
        stopTime += 0.1
        if (mySprite.vx == 0) {
            counting = false
            mySprite.sayText("" + stopTime + "sec", 5000, false)
        }
    }
})

Skipping sprite

Make a sprite move from the left to the right. 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.left = 0
mySprite.fx = 80
mySprite.vx = 80
for (let index = 0; index < 3; index++) {
    mySprite.vx = 80
    pause(1000)
}

See also

fy, ax