transform.Rotate not working as it should

Hello, so I have this problem - I want my "fish" to move right/left and up/down. It should change direction when its position.x is more/less than... so it doesnt "jump off" aquarium. The movement right/left was all okey, but when I implemented up and down rotation (in my case z axis) it sometimes wont work as it should. I really dont know why, sometimes the fish rotates perfectly and another time it rotates weird. I also saw that the fish rotation on x axis changed from 0 to 180 but in my code I dont rotate x...
My code:

Code (CSharp):

1. //to know if we go right (1,1) or left (-1,1),     up (1,1) or down (1,-1)
2.     private Vector2 rightMove = new Vector2(1,1), upMove = new Vector2(1,1);
3.     private Vector2 diagonalVector = new Vector2(0.5f, 0.5f); //diagonal move
4.     private bool leftMoving = false, upMoving = true;
5.  
6.     protected override void Move()
7.     {
8.          if (transform.position.y < -4 && !upMoving) // goes down, we want up
9.         {
10.             transform.Rotate(0, 0, 90);
11.             upMoving = true;
12.             upMove = new Vector2(1, 1);
13.         }
14.         else if (transform.position.y > -1 && upMoving) // goes up, we want down
15.         {
16.             transform.Rotate(0, 0, -90);
17.             upMoving = false;
18.             upMove = new Vector2(1, -1);
19.         }
20.         if (transform.position.x < -8 && leftMoving) //goes left, we want right
21.         {
22.             rightMove = new Vector2(1,1);
23.             leftMoving = false;
24.             transform.Rotate(0,180,0);
25.         }
26.         else if (transform.position.x > 8 && !leftMoving) // goes right, we want left
27.         {
28.             rightMove = new Vector2(-1,1);
29.             leftMoving = true;
30.             transform.Rotate(0,180,0);
31.         }
32.  
33.      
34.         // movement
35.         rb.velocity = diagonalVector * speed * upMove * rightMove;

Thanks for help

 

There is a maths reason that your X rotation is changing as a result of the Rotate operation since you're altering both Z and Y rotations.

There are a ton of ways to do this kind of motion & rotation, but I'll give you some simple things to try based on how you're currently doing it.

1. Only rotate on Z, never do Y rotation. Instead, invert your Y scale to flip the sprite upside down. (or experiment with SpriteRenderer.flipY). That should make sure your X and Y rotations never change.
   
2. Instead of doing relative rotations, set the rotation directly like this:

   transform.rotation = Quaternion.Euler(x,y,z);

   or

   transform.eulerAngles = new Vector3(x,y,z);

I would suggest you make sure your fish faces along the X axis by default (when no rotation is applied). Then you don't have to account for the default diagonal offset.

Here's an example for your consideration:

Code (CSharp):

1. private bool leftMoving = false, upMoving = true;
2. private Vector2 movementDirection = Vector2.one;
3. private SpriteRenderer fishSpriteRenderer;
4.  
5. protected override void Move()
6. {
7.     if (transform.position.y < -4 && !upMoving) // goes down, we want up
8.     {
9.         movementDirection.y = 1;
10.         upMoving = true;
11.     }
12.     else if (transform.position.y > -1 && upMoving) // goes up, we want down
13.     {
14.         movementDirection.y = -1;
15.         upMoving = false;
16.     }
17.     if (transform.position.x < -8 && leftMoving) //goes left, we want right
18.     {
19.         movementDirection.x = 1;
20.         leftMoving = false;
21.     }
22.     else if (transform.position.x > 8 && !leftMoving) // goes right, we want left
23.     {
24.         movementDirection.x = -1;
25.         leftMoving = true;
26.     }
27.  
28.     // flip the sprite when moving left
29.     fishSpriteRenderer.flipY = leftMoving;
30.     // movement
31.     rb.velocity = movementDirection.normalized * speed;
32.     // point the X axis in the velocity direction
33.     transform.right = rb.velocity.normalized;
34. }

Hope that helps give you some ideas for how to fix your issues.

 

Thanks very much for detailed reply. I've learned much from this It worked.