Unity beginner 1 - character movement control (2D)

This article comes from learning chutianbo Teacher's notes , link b standing
stay unity The role of China Mobile generally adopts the control role transtion Attribute position The coordinate axis on which it is based , Generally, it's a quadratic equation xy Axis

The simplest move

public class RubyController : MonoBehaviour
{
    //  Once per frame  Update
    //  Move the game object to the right every frame  0.1
    void Update()
    {
        //  Create a  Vector2  object  position, Used to get the location of the current object 
        Vector2 position = transform.position;
        //  change  position  Of  x  Coordinate value , Let it   add  0.05
        position.x = position.x + 0.05f;
        //  Update the location of the current object to the new location 
        transform.position = position;
    }
}

So every frame our character will show x The positive axis of moves 0.05 distance （ The higher the number of frames , The faster you move ）.

Move with control

public class RubyController : MonoBehaviour
{
   //  Once per frame  Update
    //  Move the game object to the right every frame  0.1
    void Update()
    {
        //  Get horizontal input , Press left , Will get  -1.0 f ;  Press right , Will get  1.0 f
        float horizontal = Input.GetAxis("Horizontal");
        //  Get vertical input , Press down , Will get  -1.0 f ;  Press up , Will get  1.0 f
        float vertical = Input.GetAxis("Vertical");

        //  Get the current location of the object 
        Vector2 position = transform.position;
        //  modify location 
        position.x = position.x + 0.1f * horizontal;
        position.y = position.y + 0.1f * vertical;
        //  New location for game object 
        transform.position = position;
    }
}

This seems to be used unity Move the built-in components , By getting the default vertical keys and horizontal cases , That is, it directly corresponds to wasd And direction keys .

The second way to control movement

public class RubyController : MonoBehaviour
{
    // Start is called before the first frame update
    void Start()
    {
        
    }

    // Update is called once per frame
    void Update()
    {
    
        Vector2 position = transform.position;

        if (Input.GetKey("w"))
        {
            position.y = position.y + 0.05f;
        }else if (Input.GetKey("a"))
        {
            position.x = position.x - 0.05f;
        }else if (Input.GetKey("s"))
        {
            position.y = position.y - 0.05f;
        }
        else if(Input.GetKey("d")){
            position.x = position.x +0.05f;
        }

        
       
        transform.position = position;
    }
}

Use getkey Customize the control method

But the one used in the first and second GetKey and GetAxis The difference between the two methods is this .GetKey Only 0 and 1 The difference between , No existence 0.5 perhaps 0.05. however getAxis It's a smooth curve （ Mobile control recommendation ）.

Use it directly update Disadvantages of mobile

because update Is directly linked to the number of game frames , That is, one call per frame update, So the higher your frame number , The faster the character moves
Suppose the game 30 frame , that 0.1f Moving in one second is 0.1*30 by 3 A unit of . If it is 60 frame , One second is 6 A unit of .

The first method to solve the problem that the number of frames affects the moving rate ： Lock frame

  void Start()
    {
    // Turn on vertical synchronization //
        QualitySettings.vSyncCount = 0;
        // Frame rate set to 50//
        Application.targetFrameRate = 50;
    }

But locking frames will reduce the quality of the game picture , So we use unit seconds to control Ruby Action of

The temporary final solution

public class RubyController : MonoBehaviour
{
 public float speed = 0.1f;
 // Start is called before the first frame update
 void Start()
 {

 }

 // Update is called once per frame
 void Update()
 {
     float horizontal = Input.GetAxis("Horizontal");
     float vertical = Input.GetAxis("Vertical");
     Vector2 position = transform.position;
     position.x = position.x + speed * horizontal * Time.deltaTime;
     position.y = position.y + speed * vertical * Time.deltaTime;
     transform.position = position;
 }
}

In this case , We will find that speed=5 Only when you use frame control 0.1 The speed of ;

Solve the problem of collision bug

If you control the movement according to the last code above , Then we will find that when two rigid bodies collide , There will be ghosts in our characters , That is, our position first enters the position occupied by the collision body , Then it bounced out , So here we need to introduce the rigid body components of the object to solve

void Start()
 {
     // Get the rigid body component of the current game object 
     rigidbody2d = GetComponent<Rigidbody2D>();


 }
   void Update()
 {
    horizontal = Input.GetAxis("Horizontal");
    vertical = Input.GetAxis("Vertical");

 }
 // Fixed interval refresh method 
 private void FixedUpdate()
 {
    
     Vector2 position = transform.position;
     position.x = position.x + speed * horizontal * Time.deltaTime;
     position.y = position.y + speed * vertical * Time.deltaTime;
     rigidbody2d.position = position;
 }

Here we need to put the acquisition mobile in update in , Because it's called every frame , It will be smoother , Put it in FixedUpdate Is about 20ms One call .

good , The conventional bug Time
After the above set of movements using physical systems , We will join the enemy's movement later , After colliding with other powerful objects , Our protagonist will also get the force in the moving direction of another object （ It's about the robot walking down , The protagonist is collided under the robot , The protagonist will go down until he meets another collider ）
According to the solution, rigid body movement cannot directly use position assignment
therefore rigidbody2d.position = position; We should change this sentence into rigidbody2d.MovePosition(position);

This article is only a personal preliminary study unity used
link : Ruby’s Adventure：2D beginner
link : What is vertical synchronization
link :Time.deltaTime Official documents of