GD205 Spring 2017 Week 5

PhysicsMove.cs

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class PhysicsMove : MonoBehaviour {

	public Rigidbody myRb;
	public GameObject target;
	Vector3 targetPos;
	public float thrust;

	// Use this for initialization
	void Start () {
		//assign myRb to the rigidbody of the current GameObject
		myRb = GetComponent<Rigidbody>();
	}
	
	//for physics scripts, we use fixedupdate to be less dependent on the framerate
	void FixedUpdate () {
		//update the targets position each fixedupdate
		targetPos = target.transform.position;
		//by subtracting our objects position from the targets, we get the distance
		//normalizing this means making largest number in the vector3 1 and keeping the ratio with the other axes
		//so if the distance is (4,2,1), meaning 4 units to the right, 2 units above and 1 unit forward
		//it will become (1, 0.5, 0.25), which is a direction instead of a distance
		Vector3 direction = Vector3.Normalize(targetPos - transform.position);
		//we use the addforce function of Rigidbody to push our object
		//we push it in the direction we calculated (direction of the target from our objects position
		//and multiply it by a force amount
		myRb.AddForce(direction * thrust);

/*
		if (Input.GetKeyDown ("up")) {
			myRb.AddForce(transform.forward * thrust);
		}
		if (Input.GetKeyDown ("down")) {
			myRb.AddForce(-transform.forward * thrust);
		}
		if (Input.GetKeyDown ("left")) {
			myRb.AddForce(-transform.right * thrust);
		}
		if (Input.GetKeyDown ("right")) {
			myRb.AddForce(transform.right * thrust);
		}
*/
	}
}