Basic syntax of unity script (2) -record time in unity

stay Unity It takes to record time in Time class .
Time The more important variables in the class are deltaTime( read-only )
deltaTime： The time taken to complete the last frame ( The interval from the last frame to the current frame （ In seconds ）), That is, incremental time
Use ： If you want to rotate an object evenly , Regardless of the frame rate , It can be multiplied by Time.deltaTime.

// rotate 
void Update () {
    
		this.transform.Rotate(10 * Time.deltaTime, 0, 0);
	}
// Move 
void Update () {
    
		this.transform.Translate(0, 0, 10 * Time.deltaTime);// Move... Every second 10 rice 
	}

If you want to increase or decrease one value per second , need multiply Time.deltaTime, At the same time, it should also be clear that in the game, it takes every second 1 Units per frame 1 Effect of units . If it is multiplied by Time.deltaTime, Then the game object will follow a fixed rhythm instead of depending on the frame rate of the game , therefore , The motion of the game object becomes easier to control .

Why use Time.deltaTime？
Update() The number of frames updated per second is different , Incremental time changes in real time , And every frame changes . The incremental time guarantees that no matter what the frame rate , Can make the object move to a fixed value .
1 second 30 frame , So the frame size time is 1/30 second
1 second 180 frame , So the frame size time is 1/180 second

in general , Use Time.deltaTime The object can be moved or rotated to a specified value . such as , Move... Every second N rice
for example

	public GameObject gameObject;
	void Update () {
    

		Vector3 te = gameObject.transform.position;// Get the position coordinates of the game object 
		te.y += 5 * Time.deltaTime;// Along the y The axis rises every second 5 A unit of 
		gameObject.transform.position = te;// Set the position coordinates of the game object 

// This method is actually the same as MovePOSiton Method phase view 
	}

If rigid bodies are involved , It can be written in FixedUpdate In the method . stay FixedUpdate In the method , If you want to increase or decrease one value per second , It needs to be multiplied by Time.fixedDeltaTime.
for example

public GameObject gameObject;

    void FixedUpdate()
    {
    
        Vector3 te = gameObject.GetComponent<Rigidbody>().transform.position;
        te.y += 5 * Time.fixedDeltaTime;
        gameObject.GetComponent<Rigidbody>().transform.position = te;
   
    }