Moving Sprites a certain amount

CS Discoveries Coding and Debugging Help
1

This may be too complicated for where we are. But in lesson 13 a student wants a sprite to move a certain amount- but the loop has it always move. Is it possible to have a sprite only move a certain amount?

2

Salutations @slpruit,
As per your current request within your situation i would assume your student has probably done 1 of the 2 things that i can think on the top of my head

1: Sprite.x / Sprite.y is being increased because it’s in the draw loop

2: Student is using velocityX / velocityY / setSpeedAndDirection which is applied regaurdless of weather it’s invoked in a loop or outside of one

for the sake of simplicity of using movement we will just be modifying x & y properties of a given sprite in our program… here’s my little demo

var duck = createSprite(200, 200);
var duckSpeed = 5;
function draw() {
background(255);
// moves the duck left
if(keyDown("left")) {
duck.x = duck.x - duckSpeed; // can also be written as duck.x -= duckSpeed;
}
// moves the duck right
if(keyDown("right")) {
duck.x = duck.x + duckSpeed; // can also be written as duck.x += duckSpeed;
}
// moves the duck up
if(keyDown("up")) {
duck.y = duck.y - duckSpeed; // can also be written as duck.y -= duckSpeed;
}
// moves the duck down
if(keyDown("down")) {
duck.y = duck.y + duckSpeed; // can also be written as duck.y += duckSpeed;
}
drawSprites();
}

I’m not sure how far unit 13 is into Gamelab… but i feel like it shouldn’t be to hard to learn what this does in fact maybe just hand your student this and see what they can figure out. I remember starting out with unrecognizable code demos in fact i still learn from examples! the worst thing is being told it’s not possible when it is or being told your too far ahead.

Anyways, hope this little demo helps you out

2 Likes
3

Hi @slpruit,

@varrience has a great solution, I know in Lesson 13, you haven’t yet learned keyboard movement(but @varrience gave you a great preview). Another good method is to think about why the sprite should move or for how long? For example, if sprite.x <300 then sprite.x = sprite.x + 5. This will tell the sprite to move right as long as it is before 300 on the grid and then stop. And yes, you’ll eventually learn many other ways to stop the sprite (if it is colliding with another sprite, if the key is down, etc.)
Hope this helps!
~Michelle