Why don't any of the examples use applyForce / applyImpulse?

[AndrewRayCode]

I'm trying to debug my jumping code (as mentioned on Twitter) and when looking at the FPS example code, http://schteppe.github.io/cannon.js/examples/js/PointerLockControls.js, to make the player jump, the velocity property of the body is mutated directly:

var velocity = cannonBody.velocity;

...

        case 32: // space
            if ( canJump === true ){
                velocity.y = jumpVelocity;

Why do you do this instead of using applyForce or applyImpulse? Are those innappropriate to use for applying movement forces to a player?

[schteppe]

If you run applyForce or applyImpulse, it will add to body.force or body.velocity. That makes the jump height unpredictable, which isn't acceptable when making a game. Instead, if you set the absolute value of the velocity, you always know what height you get.

[AndrewRayCode]

ah ok, thanks!

[AndrewRayCode]

On these lines of the FPS demo, PointerLockControls.js

    // Add to the object
    velocity.x += inputVelocity.x;
    velocity.z += inputVelocity.z;

Isn't that the same as applyImpulse?

[schteppe]

Yeah, it is! But applyImpulse can add angular velocity too, depending on where you apply the impulse.