Game Lab Documentation

group.displace()

Category:Groups

Makes each sprite in the group push the target as long as they are touching each other. The sprites keep moving normally.

Most games will involve sprites colliding with each other. There are four types of collisions available in Game Lab: bounce, bounceOff, collide and displace. These blocks will cause a certain type of interaction between each sprite and its target and must be used within the draw function.

Examples

Avoid the Rain

Use the left and right keys to avoid the raindrops or get pushed off the screen.

// Use the left and right keys to avoid the raindrops or get pushed off the screen.
var umbrella = createSprite(200, 300);
umbrella.setAnimation("umbrella");
umbrella.scale = 0.1;
var group = createGroup();
for (var i = 0; i < 100; i++) {
  var sprite = createSprite(randomNumber(0, 400), randomNumber(-200, 0), 10, 10);
  sprite.setAnimation("raindrop");
  sprite.scale=0.03;
  sprite.velocityY=randomNumber(1, 5);  
  group.add(sprite);
}

function draw() {
  background("white");
  group.displace(umbrella);
  drawSprites();
  if (keyDown("right")) {
    umbrella.x = umbrella.x+10;
  }
  if (keyDown("left")) {
    umbrella.x = umbrella.x-10;
  }    
}

Syntax

group.displace(target)

Parameters

Name	Type	Required?	Description
target	Sprite or Group		The name of the target sprite or target group you want to check for a collision.

Returns

Boolean true or false. Changes output in the display after the sprites touch and drawSprites() is called.

Tips

All four of the collisions are similar to including an "if (sprite.isTouching(target))" in the draw function, and then depending on the collision type, updating the sprite and target velocityX and velocityY properties.
Only one of the four types of collisions should be specified for each pair of sprites.
To fine tune your collision detection use setCollider to change the shape and size of the collider area and set debug to true for the sprites.
A sprite that is not visible can still collide with other sprites and user mouse interactions.

Found a bug in the documentation? Let us know at support@code.org.