bind objects cannonjs

What is Bind Objects in Cannon.js?#

Bind Objects in Cannon.js refers to the process of connecting two or more physical objects in a 3D space so that they move together as a single unit. This can be achieved using constraints such as hinges or sliders, which restrict the movement of the objects relative to each other.

How to Bind Objects in Cannon.js#

To bind two objects together in Cannon.js, we first need to create the objects themselves. This can be done using the CANNON.Body() method, which creates a new rigid body with a mass, position, and orientation. We can then add shapes to the body using the CANNON.Shape() method, which defines the geometry of the body.

Once we have created the bodies, we can use constraints to bind them together. The CANNON.HingeConstraint() method creates a new hinge constraint between two bodies, which allows them to rotate around a common axis. The CANNON.SliderConstraint() method creates a new slider constraint between two bodies, which allows them to move along a common axis.

Example Code#

// Create two boxes
var box1 = new CANNON.Body({ mass: 1 });
var shape1 = new CANNON.Box(new CANNON.Vec3(1, 1, 1));
box1.addShape(shape1);
world.addBody(box1);

var box2 = new CANNON.Body({ mass: 1 });
var shape2 = new CANNON.Box(new CANNON.Vec3(1, 1, 1));
box2.addShape(shape2);
world.addBody(box2);

// Create a hinge constraint between the two boxes
var hinge = new CANNON.HingeConstraint(box1, box2, {
  pivotA: new CANNON.Vec3(1, 0, 0),
  pivotB: new CANNON.Vec3(-1, 0, 0),
  axisA: new CANNON.Vec3(0, 1, 0),
  axisB: new CANNON.Vec3(0, 1, 0),
});
world.addConstraint(hinge);

In the above example, we create two boxes using the CANNON.Body() method and add shapes to them using the CANNON.Box() method. We then create a hinge constraint between the two boxes using the CANNON.HingeConstraint() method and add it to the world.

We can also create a slider constraint between the two boxes using the CANNON.SliderConstraint() method:

// Create a slider constraint between the two boxes
var slider = new CANNON.SliderConstraint(box1, box2, {
  pivotA: new CANNON.Vec3(1, 0, 0),
  pivotB: new CANNON.Vec3(-1, 0, 0),
  axis: new CANNON.Vec3(1, 0, 0),
  min: -1,
  max: 1,
});
world.addConstraint(slider);

The above code creates a slider constraint between the two boxes using the CANNON.SliderConstraint() method and adds it to the world. The slider constraint allows the two boxes to move along a common axis within a specified range.