Jump Unpredictable

Questions & Answers
1

Hello, I have a script, that controls both the gravity and the jumping. I am not using anything like character controller or anything, and it is a simple

function Jump () {
    if(down){
				    rigidbody.AddForce(transform.up * 800 * 10 * 8 * Time.deltaTime);
    }else{
				rigidbody.AddForce(transform.up * -800 * 10 * 8 * Time.deltaTime);
    }
}

function Gravity () {
    if(down){
		rigidbody.AddRelativeForce(transform.up * -10 * 10 * 8 * Time.deltaTime);
    }else{
		rigidbody.AddRelativeForce(transform.up * 10 * 10 * 8 * Time.deltaTime);
    }
}

The problem is that the jump will sometimes be super short or really high. I normally would have simply used rigidbody for gravity but the game focuses on flipping gravity.

2

#pragma strict

@HideInInspector
var Gravity : float;
@HideInInspector
var JumpHeight : float;
@HideInInspector
var CanJump : int;
@HideInInspector
var falling : int;
@HideInInspector
var IsJumping : int;
@HideInInspector
var DoJump : int;


function Start () {
	
	CanJump = 1;
	Gravity = 3.0;
	JumpHeight = 1.0;
	falling = 0;
	IsJumping = 0;
	DoJump = 0;
	
}

function Update () {

}

function FixedUpdate () {
	ActivateJump();
}

function ActivateJump() {
	if ( Input.GetKey(KeyCode.Space) && CanJump == 1 ) {
		if ( IsJumping == 0 ){
			IsJumping = 1;
			CanJump = 0;
			DoJump = 1;
		}
	}
	
	if ( DoJump == 1 ) {
		Jump();
	}
}

function Jump() {
	transform.position.y += JumpHeight;
	JumpHeight = JumpHeight - Gravity * Time.deltaTime;
	
	if ( JumpHeight < 0 ) {
		falling = 1;
		//do Collision checks when falling;
		//when you hit floor or platform reset everything
		FloorCollisionCheck();		
	}
}


function FloorCollisionCheck() {
	//just s imple function to test if the y location is below 0.
	// If it is then we stop and reset jumping;
	
	if ( transform.position.y <= 0 && falling == 1) {
		falling = 0;
		CanJump = 1;
		JumpHeight = 1.0;
		IsJumping = 0;
		DoJump = 0;
	}
}

Don’t use too high a value for JumpHeight or too low a value for Gravity when multiplying by Time.DeltaTime.

Yes it doesn’t use built-in physics stuff in unity but it should put you on the correct track.