GetAxis being missed in FixedUpdate work around?

Questions & Answers
1

I feel like I’m having a colossal brain fart right now, but I can’t figure this out.

void FixedUpdate()
    {
        moveHorizontal = Input.GetAxis("Horizontal");
        moveVertical = Input.GetAxis("Vertical");
        jump = Input.GetAxis("Jump");

        movement = new Vector3(moveHorizontal, 0.0f, moveVertical);

        rb.AddForce(movement * speed);

        if (canJump)
        {
            rb.AddForce(0, jump * jumpHeight, 0);
        }
    }

Player movement works fine but jumping is buggy. If I apply the force to jump in FixedUpdate, it gets missed sometimes if the player is jumping a lot, and also, for some reason, if the player is moving diagonally(Like maybe GetAxis is being overloaded with three buttons being pressed?!).

But if I move it to Update, a. I’ll have frame rate related issues in the build, right? And b. the jumping works perfect except every once in a while the player jumps much higher, which I believe is the result of the force being added twice. Maybe I’m interpreting it all wrong? I don’t like using GetAxis or Unity’s physics engine, there’s too much going on under the hood.

2

Two golden rules:

  • Always listen for input in Update.
  • Always apply physics functions in FixedUpdate.

To achieve this, all you need to do is separate your code:

float jump;
Vector3 movement;

void Update() {
     float moveHorizontal = Input.GetAxis("Horizontal");
     float moveVertical = Input.GetAxis("Vertical");
     movement = new Vector3(moveHorizontal, 0.0f, moveVertical);
     jump = Input.GetAxis("Jump");
}

void FixedUpdate() {
     rb.AddForce(movement * speed);
     if (canJump) {
         rb.AddForce(0, jump * jumpHeight, 0);
     }
 }