Unity 2019.3 - Player getting stuck on wall

Question

Problem

I have a wall made with a Tilemap and a Tilemap Collider 2D. Sometimes, when the player jumps against the walls, it seems to get stuck. You do not need to be pressing the directional button, when pressing jump, for this to happen. Just being pressed against the wall, and then pressing the jump button alone, reproduces the error.

Demo

What I have tried

I applied a Physics collider to the Walls with friction set to 0. It didnt solve the issue.

Info that might be relevant to solve this

This is the player controller for the movement. Notice the FixedUpdate method, to see how I control the velocity of the Rigidbody2D.

using UnityEngine;
using UnityEngine.InputSystem;

namespace Notan
{
    public enum Direction3 { Left, Right, Still }

    [RequireComponent(typeof(Rigidbody2D))]
    public class PlayerMovement : MonoBehaviour
    {
        [SerializeField, Range(0f, 100f)] float speed = 10f;
        [SerializeField, Range(1f, 20f)] float jumpForce = 3f;

        Rigidbody2D body;
        Direction3 direction;
        bool jumpScheduled;

        void Awake()
        {
            body = GetComponent<Rigidbody2D>();
        }

        void Update()
        {
            UpdateDirection();
            UpdateJump();
        }

        void FixedUpdate()
        {
            UpdateVelocity();
        }

        bool LeftPressed() => Keyboard.current.leftArrowKey.isPressed;

        bool RightPressed() => Keyboard.current.rightArrowKey.isPressed;

        bool SpacePressed() => Keyboard.current.spaceKey.wasPressedThisFrame;

        void UpdateDirection()
        {
            direction = LeftPressed() ? Direction3.Left : RightPressed() ? Direction3.Right : Direction3.Still;
        }

        void UpdateJump()
        {
            if (SpacePressed()) jumpScheduled = true;
        }

        // Left is -1
        // Right is 1
        // Still is 0
        int GetHorizontalDirection() => direction == Direction3.Left ? -1 : direction == Direction3.Right ? 1 : 0;

        void UpdateVelocity()
        {
            var velocity = body.velocity;
            velocity.x = GetHorizontalDirection() * speed;
            if (jumpScheduled)
            {
                velocity.y = jumpForce;
                jumpScheduled = false;
            }

            body.velocity = velocity;
        }
    }
}

This is the configuration of the players Rigidbody2D

Unity version

I am using Unity 2019.3.9f1.

Answer 1

This is a common physics engine artifact caused by considering each tile's collider separately. Bennett Foddy illustrates why it happens in this GDC talk. It means your falling object can catch on the lip of the next tile down and be stopped from falling, before the tile to the side pushes it back out sideways, just due to bad luck in the order the collisions were evaluated.

We can fix it by adding a CompositeCollider2D component to the tilemap, and ticking the "used by composite" box on the TileMapCollider2D.

What this does is combine all the physics shapes of all the connected tiles into one big polygon, without internal edges to get snagged on. Since collision with the whole shape is considered at once, you don't run into the same ordering artifacts.

There's a cost to this, which is why Unity doesn't apply it by default. Not every tilemap needs it, but if you want to smoothly slide along continuous walls/floors then it's worthwhile to add.