group.bounceOff()

Category:Groups

Makes each sprite in the group bounce off the target when they touch each other. The target keeps moving as before.

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

Stay Cool

Keep all the bad vibes from getting you down! Use the mouse to move around your emoji and stop the mean emojis from reaching the bottom

                            // Stay cool! Keep all the bad vibes from getting you down.
// Uses createGroup to make a bunch of bouncing baddies, 
// createEdgeSprites to make sure the baddies don't just fly off.

var cool = createSprite(200, 325);
cool.setAnimation("cool");
createEdgeSprites();
var group = createGroup();

for (var i = 0; i < 20; i++) {
  var sprite = createSprite(randomNumber(0, 400), randomNumber(0, 100), 10, 10);
  sprite.velocityY=randomNumber(5, 10);
  sprite.velocityX=randomNumber(-5, 5);
  sprite.bounciness = 1
  group.add(sprite);
}

group.setAnimationEach("mean");

function draw() {
  background("white");
  drawSprites();
  cool.x = World.mouseX;
  group.bounceOff(cool);
  group.bounceOff(topEdge);
  group.bounceOff(leftEdge);
  group.bounceOff(rightEdge);  
}

                        

Syntax

group.bounceOff(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.

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