Forums

Overview › Felgo 3 Support (Qt 5) › Collision between two objects

Viewing 5 posts - 1 through 5 (of 5 total)

Author

Posts
May 4, 2017 at 10:41 #16186
Patricia
Hi everyone,

Im doing a simply game and I have a problem with the collision. I want that when I throw the bird and this one collision with a box, the box move like a real life when something crash with other thing.

I let you the part of my code that I modify.

MyBox.qml FILE:

import QtQuick 2.0
```
import QtQuick.Window 2.2
```
```
import QtQuick.Controls 2.1
```
```
import Felgo 3.0
```
```
EntityBase {
```
```
  id: boxElement
```
```
  entityType: "mybox"
```
```
  width: 100
```
```
  height: 100
```
```
  MultiResolutionImage {
```
```
    id: box
```
```
    width: boxElement.width
```
```
    height: boxElement.height
```
```
    source: "img/box.png"
```
```
  }
```
```
  BoxCollider {
```
```
    id: collider
```
```
    width: box.width
```
```
    height: box.height
```
```
    bodyType: Body.Static
```
```
    collisionTestingOnlyMode: true
```
```
  }
```
```
}

Bird.qml FILE--->

import QtQuick 2.0
```
```
import Felgo 3.0
```
```
EntityBase {
```
```
  id: birdElement
```
```
  entityType: "bird"
```
```
  property int salud: 3
```
```
     MultiResolutionImage{
```
```
      id: bird
```
```
      height: 75
```
```
      width: 75
```
```
      source: "img/pollito.png"
```
```
    }
```
```
    BoxCollider {
```
```
    id: birdCollider
```
```
    collisionTestingOnlyMode: true
```
```
    bodyType: Body.Dynamic
```
```
    height: bird.height
```
```
    width: bird.width
```
```
  }
```
```
}
```
```
Main.qml FILE:


 PhysicsWorld {
```
```
        id: world
```
```
        opacity: 0
```
```
        updatesPerSecondForPhysics: 60
```
```
    }
```
```
Thank you!
```
May 4, 2017 at 10:59 #16187

Alex
Felgo Team

Hi Patricia,

if you want the Box to be influenced by collisions, both collisionTestingOnlyMode and Body.Static won’t quite work for you, as you might can guess from their names. E.g. from the documentation “A static body is a body which isn’t affected by world forces it does not react to collisions.”

So in general, if you want 2 bodies to be displaced by a collision, you need both bodies to by dynamic. Static bodies are used for walls or ground, collisionTestingOnlyMode bodies are e.g. used for sensors to check if a ball passed through a gate.

If you have gravity in your game, but want the dynamic Box to float in the air as if it was static, you can set the gravityScale property to 0.

Hope you get the idea and this answer was helpful!

Cheers,
Alex

May 4, 2017 at 11:13 #16188

Patricia

Ok, now the bird recognize that there is a box and crash with it, but the box doesnt move, how I can fix it? and that the box move like it would be in a real life?

thank you!

May 4, 2017 at 11:22 #16189
Patricia
I added in MyBox.qml File—->

import QtQuick 2.0
```
import QtQuick.Window 2.2
```
```
import QtQuick.Controls 2.1
```
```
import Felgo 3.0
```
```
EntityBase {
```
```
  id: boxElement
```
```
  entityType: "mybox"
```
```
  width: 100
```
```
  height: 100
```
```
  MultiResolutionImage {
```
```
    id: box
```
```
    width: boxElement.width
```
```
    height: boxElement.height
```
```
    source: "img/box.png"
```
```
  }
```
```
  BoxCollider {
```
```
    id: collider
```
```
    width: box.width
```
```
    height: box.height
```
```
    bodyType: Body.Dynamic
```
```
    gravityScale: 1
```
```
    restitution:1
```
```
    friction: 1
```
```
  }
```
```
}
```
```
Now the box move but, not fall because of the gravity. it keeps flying.
```
May 4, 2017 at 11:23 #16190

Alex
Felgo Team

Are both colliders set to bodyType: Body.Dynamic ?

Also there are several properties you can use to change the way bodies interact like restitiution, density, friction, damping…

You can find more info about this in the documentation of the physics components like https://felgo.com/doc/vplay-boxcollider/ (the link “List of all members, including inherited members” is usually pretty helpful)

EDIT: I see you just posted code while I wrote this answer. Did you specify any gravity in your PhysicsWorld component? Also you can use the fixture.onBeginContact signal of colliders to change the properties, e.g. enable/disable the gravityScale.

Cheers,
Alex