can i 2d wall collision without major changes?

Question

im in the very early stages of making a 2d RPG and i want my 2d player(only a sprite but has been given a 2d box collider and 2d rigidbody) to stop moving once he touches anything on he touches, i havent used unity in this scope in 4 years and dont retain the knowledge on it that i had, i want the following code to incorperate collision with as little change to current formula as possible:

 using System.Collections;
 using System.Collections.Generic;
 using UnityEngine;
 
 public class PlayerAI : MonoBehaviour
 {
     private int Playerlevel;
     private float speed = 0.1f;
     private Vector2 playerpos;
     private Rigidbody2D player_rb;
 
     // Start is called before the first frame update
     void Start()
     {
         //player_rb = GetComponent<Rigidbody2D>();
         playerpos = transform.position;
     }
 
     // Update is called once per frame
     void Update()
     {
         if (Input.GetKey(KeyCode.W)) playerpos.y += speed; // y++
         if (Input.GetKey(KeyCode.A)) playerpos.x -= speed; // x--
         if (Input.GetKey(KeyCode.S)) playerpos.y -= speed; // y--
         if (Input.GetKey(KeyCode.D)) playerpos.x += speed; // x++
         transform.position = playerpos;
     }
 
     void OnCollisionEnter2D(Collision2D collision)
     {
     }
 
     void OnGUI()
     {
         GUI.Label(new Rect(0, 45, 200, 50), playerpos.x.ToString() + ", " + playerpos.y.ToString());
     }
 }

Answer 1

Best Answer

Answer by RodrigoAbreu · Feb 07, 2021 at 06:34 AM

Hey @Advigames, here is how you should do it.

 using UnityEngine;
 
 public class PlayerAI : MonoBehaviour
 {
     private int Playerlevel;
     private float speed = 100f;
     private Vector2 playerpos;
     private Rigidbody2D player_rb;
 
     void Start()
     {
         player_rb = GetComponent<Rigidbody2D>();
     }
     
     public void FixedUpdate()
     {
         player_rb.velocity = new Vector3(Input.GetAxisRaw("Horizontal") * speed * Time.fixedDeltaTime, 
                                          Input.GetAxisRaw("Vertical") * speed * Time.fixedDeltaTime);
     }
 
     void OnCollisionEnter2D(Collision2D collision)
     {
         player_rb.velocity = Vector2.zero;
     }
 
     void OnGUI()
     {
         GUI.Label(new Rect(0, 45, 200, 50), playerpos.x.ToString() + ", " + playerpos.y.ToString());
     }
 }

This is the Player Setup:

alt text

For the wall you just need to add a BoxCollider2D

Remember to lock your rotation constraints Z on your Player's rigidBody2D

playersetup.png (31.5 kB)

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Answer 2

Answer by logicandchaos · Feb 06, 2021 at 01:47 PM

if you have a collision box and rb on your character already, you just need to put collision on your walls, no coding needed.

You can also do this:

 void OnCollisionEnter2D(Collision2D collision)
 {
       rb.velocity=Vector2.zero;
 }

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Advigames · Feb 06, 2021 at 07:53 PM 0

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i tried adding that code and nothing happened, also my objects that i want the player to collide into already have a 3d box collider and 2d rigidbody. do i have to completely rework how the inputs move the player?

Advigames · Feb 07, 2021 at 04:32 AM 0

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i meant a 2d box collider

RodrigoAbreu Advigames · Feb 07, 2021 at 04:50 AM 0

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@Advigames It will not work, because you're not moving your character with velocity. You need to actually make sure your walls have a collider on them, they won't need a rigidbody. Also make sure all your colliders are not marked as "trigger".

Advigames RodrigoAbreu · Feb 07, 2021 at 05:29 AM 0

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okay, so how do i edit my code so i can move my character with velocity?

can i 2d wall collision without major changes?

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