Mouse pointer erratic behaviour

[ciro-unity]

Short description
Sometimes, the camera spins very fast when using the mouse to control the camera, even if the mouse is moved by a tiny fraction.

Expected behaviour
The camera should follow the speed of movement of the mouse.

To Reproduce
Steps to reproduce the behavior:

1. Open the scene "TestingGround"
2. Press Play
3. Once the game is in Play Mode, hold down the RMB and move the mouse left or right by a very tiny amount.
4. Notice the camera spins around a full circle, before resuming at the right speed.

Notes

• See this video for an example of the issue occurring

[kgc00]

hi @ciro-unity , i just saw this- we could just have mouse movement without RMB to sidestep this. sound good? I'm also down to debug if you'd like.

[adoart]

It looks like it depends where the click starts, the further from the center bigger the rotation, @ciro-unity clicked once close to the center and rotation was little. That's what I got from the video...

[khush2o2o]

I known this bus to how to solve...

[drbier1729]

Just tried to check this out but I'm unable to replicate the issue.

I'm guessing that maybe the InputReader or InputSystem isn't updating the cursor's position when it jumps to the center when the cursor is locked (in CameraManager.cs). This causes the mouse delta on the first frame when the mouse is moved after enabling camera controls to be crazy high since it is calculating the difference between the position where the RMB was clicked and the center of the frame.

I'm pretty new to Unity so this might be incorrect, but hopefully this noticing is helpful! I'll keep working on it but without being able to recreate it, I'm not optimistic about producing a fix.

[khush2o2o]

I have an idea to slove this bug...

[ErikBehar]

I have an idea to slove this bug...

Please provide the idea in writing or a link to the PR, stating that you know how to solve a bug with no further info is not useful to anybody.

[ErikBehar]

ok so I think @drbier1729 has it correct ... you can more easily replicate the issue, by popping out the game window, then click outside so the window looses focus and then click back into the window to get focus, then rm on the edge of the window. You will get the crazy spin and yeah I think its due to the initial difference.

with the above steps you can replicate the issue many times within 1 play session.

So this is caused by the cursor lock placing the mouse at 0,0 ... you get the initial diff ...

This can be fixed by adding a small wait time, before allowing camera movement when you enable the cursor lock:

      private bool cameraMovementLock = false;
      ...

       private void OnEnableMouseControlCamera()
	{
		_isRMBPressed = true;

		Cursor.lockState = CursorLockMode.Locked;
		Cursor.visible = false;

		StartCoroutine(DisableMouseControlForFrame());
	}

	IEnumerator DisableMouseControlForFrame()
	{
		cameraMovementLock = true;
		yield return new WaitForSeconds(.1f);
		cameraMovementLock = false;
	}

      ... 

	private void OnCameraMove(Vector2 cameraMovement, bool isDeviceMouse)
	{
		if (cameraMovementLock)
			return;
         ...

[davejrodriguez]

Could someone who was able to reproduce the bug test #249?

[drbier1729]

@ErikBehar Cool! Thanks for finding a better way to replicate it. And I was thinking the same thing for a potential workaround, but there was no way for me to test it earlier today haha.

@davejrodriguez I'll check out your work tomorrow morning if I can recreate the bug using the steps ErikBehar suggested.

[ErikBehar]

I think some of what @davejrodriguez did is probably good, but needs a bit more work ... I've added the simple fix mentioned above meanwhile.