Bug A weird collision bug

I made an enemy in 2d with Box2d Collision. Additional I define with code areas to check if the enemy touch the ground, wall and if the area above is free for jumping. Now I have a weird collision bug, which comes rarely, that the soldier is hanging in the air endless in jumping phase at the edge if the ground/wall. I thought, that the collision of the enemy and the ground/wall is touching but the check with the touching to the ground fails. So paused the game and zoomed very near in and see that the collision of the enemy and the ground aren't even touching! I don't know how clear this bug.

My code:

Code (CSharp):

1.     protected override void CheckWallCollision()
2.     {
3.  
4.         m_onJumpLeftWall = false;
5.         m_onJumpRightWall = false;
6.  
7.         colliderWall = Physics2D.OverlapBox((Vector2)groundCheck.position, groundCollisionSize, 0.0f, whatIsGround);
8.         if (colliderWall != null)
9.         {
10.             isGrounded = true;
11.             timerFalling = 0f;
12.             //isJumping = false;
13.         }
14.         else
15.         {
16.             isGrounded = false;
17.             timerFalling += Time.deltaTime;
18.         }
19.            
20.  
21.         // check if on wall
22.         colliderWall = Physics2D.OverlapBox(objectPosition + wallRightOffset, wallCollisionSize, 0.0f, whatIsGround);
23.         if (colliderWall != null)
24.             m_onRightWall = true;
25.         else
26.             m_onRightWall = false;
27.  
28.         colliderWall = Physics2D.OverlapBox(objectPosition + wallLeftOffset, wallCollisionSize, 0.0f, whatIsGround);
29.         if (colliderWall != null)
30.             m_onLeftWall = true;
31.         else
32.             m_onLeftWall = false;
33.  
34.         if (m_facingRight)
35.         {
36.             if (m_onRightWall)
37.             {
38.                 colliderWall = Physics2D.OverlapBox(objectPosition + wallJumpRightOffset, wallCollisionSize, 0.0f, whatIsGround);
39.                 if (colliderWall == null || isJumping)
40.                 {
41.                     m_onJumpRightWall = true;
42.                     //Debug.Log("m_onJumpRightWall = true;   isJumping = " + isJumping);
43.                 }
44.                 else
45.                 {
46.                     m_onJumpRightWall = false;
47.                     if ((m_rb.velocity.y > 0f) == false && isGrounded)
48.                     {
49.                         //Debug.Log("RIGHT Flip  isJumping = " + isJumping + "  m_rb.velocity.y=" + m_rb.velocity.y + "m_facingRight =" + m_facingRight + "  isGround=" + isGrounded + "  isShooting=" + isShooting + "  leftWall=" + m_onLeftWall + "  leftJump=" + m_onJumpLeftWall + "  right=" + m_onRightWall + "  rightJump=" + m_onJumpRightWall);
50.                         FlipL();
51.                     }
52.                 }
53.             }
54.         }
55.         else
56.         {
57.             if (m_onLeftWall)
58.             {
59.                 colliderWall = Physics2D.OverlapBox(objectPosition + wallJumpLeftOffset, wallCollisionSize, 0.0f, whatIsGround);
60.                 if (colliderWall == null || isJumping)
61.                 {
62.                     m_onJumpLeftWall = true;
63.                     //Debug.Log("m_onJumpLeftWall = true;    isJumping = " + isJumping);
64.                 }
65.                 else
66.                 {
67.                     m_onJumpLeftWall = false;
68.                     if ((m_rb.velocity.y > 0f) == false && isGrounded)
69.                     {
70.                         //Debug.Log("LEFT Flip  isJumping = " + isJumping + "m_rb.velocity.y=" + m_rb.velocity.y + "m_facingRight=" + m_facingRight + "  isGround=" + isGrounded + "  isShooting=" + isShooting + "  leftWall=" + m_onLeftWall + "  leftJump=" + m_onJumpLeftWall + "  right=" + m_onRightWall + "  rightJump=" + m_onJumpRightWall);
71.                         FlipR();
72.                     }
73.                 }
74.             }
75.         }
76.     }
77.  

 

Had this exact issue before. What I had done was assign a new physics material on the tiles on the far left and right and add 0 friction to the physics material so the player would slide off.

You could also use a CircleCollider for the entire player (or a CircleCollider for the lower half and BoxCollider for the top half) to prevent this issue.

 

After some test it seems that if I set FixedUpdate-timestep to 200fps the bug occurs more often, if I set the timestep to 50 fps the bug doesn't occur.

 

This is wrong, error occurs with 50 fps too.

 

I have set a physic material with Friction = 0 and Bounciness = 0 at the box collider 2D of the enemy and it seems to work! After one hour testing the bug don't occur! Thanks!

 

After using the physic material it seems to work great. I learnt this technic with this kit and used the controller-script as a base for the enemies:
https://assetstore.unity.com/packag...mer-controller-with-animated-character-245475

I'm new to Unity-devolping and this kit was a good start for me.

What I don't know exactly:
By a collision there comes an array of ContactPoint2D, how to know with ContactPoint of the array is the important one? I don't understand why I get more ContactPoint2D as only one single because I only check the tilemap for the overlaping check.

I use this code:

Code (CSharp):

1.         colliderWall = Physics2D.OverlapBox((Vector2)groundCheck.position, groundCollisionSize, 0.0f, whatIsGround);
2.         if (colliderWall != null)
3.         {
4.             int contactsCounts = colliderWall.GetContacts(collidersArray);
5.             for (int i = 0; i < contactsCounts; i++)
6.             {
7.                 if (collidersArray[i].normal.y <= -0.98)
8.                 {
9.                     if (!isGrounded)
10.                     {
11.                         if (Random.value > 0.5f && !isFliped && timerFalling > 0.59f)
12.                         {
13.                             Debug.Log("timerFalling Flip  isJumping = " + isJumping + "  m_rb.velocity.y=" + m_rb.velocity.y + "m_facingRight =" + m_facingRight + "  isGround=" + isGrounded + "  isShooting=" + isShooting + "  leftWall=" + m_onLeftWall + "  leftJump=" + m_onJumpLeftWall + "  right=" + m_onRightWall + "  rightJump=" + m_onJumpRightWall);
14.                             Debug.Log(timerFalling);
15.                             Flip();
16.                         }
17.                     }
18.                     //Debug.Log("y==-1" + collidersArray[0].normal);
19.                     isGrounded = true;
20.                     timerFalling = 0f;
21.                     break;
22.                 }
23.             }
24.         }
25.         else
26.         {
27.             isGrounded = false;
28.             if((m_rb.velocity.y > 0.001f) == false)
29.             {
30.                 timerFalling += Time.deltaTime;
31.             }
32.         }
33.  

 

Thanks, I will look at this and try it out.

 

I tried it and it works well!

 

I made a public ContactFilter2D and in the editor there is a Min Normal Angle and a Max Normal Angle. But is this x normal angle or y normal angle? How can I differentiate between x and y by the Normal Angle in the ContactFilter?

 

Thank you very much, now I understand it with the angle.

 

I have a problem with the ContactFilter. I use the ContactFilter2D with normal angles to check which angle have the ground so that the monster rotate in same angle, see this video:

This works well but when I made my monster falling from the top my problem is that I get false positive on landing the ground by 45° and 315° ContactFilter. The monster have a capsule collider 2d and if the monster touch the ground at some edge like in the picture the contactfilter with normal angle from 134° to 136° (for 45° diagonal ground) it gives me false positive and the monster rotates in wrong angle.

How can I correct the false positive?

My code:

Code (CSharp):

1. m_onBottomWall = m_rb.IsTouching(ContactFilterBottom);
2.  
3. m_onBottomRightWallFall = m_rb.IsTouching(ContactFilterBottomRightFall);
4. m_onBottomLeftWallFall = m_rb.IsTouching(ContactFilterBottomLeftFall);
5.  
6. if (isFalling && RotatingFirstStep && (m_onBottomWall || m_onBottomLeftWallFall || m_onBottomRightWallFall))
7. {
8.     MakeNotFalling();
9.     Debug.Log("MakeNotFalling  " + "   m_onBottomWall " + m_onBottomWall + "   m_onBottomLeftWallFall " + m_onBottomLeftWallFall + "  m_onBottomRightWallFall " + m_onBottomRightWallFall + "  rotationAngle " + rotationAngle);
10.     if (m_onBottomWall)
11.         Rotate(0, false);
12.     else if (m_onBottomLeftWallFall)
13.     {
14.         Rotate(315, false);
15.         Debug.Log("Rotate(315, false)");
16.     }
17.     else if (m_onBottomRightWallFall)
18.     {
19.         Rotate(45, false);
20.         Debug.Log("Rotate(45, false)");
21.     }
22.