Rotation snaps every 90 degrees

Development Programming & Scripting
1

enter code here enter code here`there’s probably a better way to do this, but I’m simply rotating a mesh on the yaw rotation and it snaps in place every 90 degrees. I’m currently using

float param = GetInputAxisValue(LookRightBinding);
float param2 = GetInputAxisValue(LookUpBinding); 
     
GunRSideMeshComponent->RelativeRotation.Yaw = atan2(param, param2)* 57.2957795;

I just rotated like I did in my own engine when I only used radians so I didn’t have to convert to degrees and it didn’t do this snapping every 90 degrees. Am I not doing the calculation correctly?

EDIT:

this is a video showing my problem. I’m rotating it smoothly around on the analog , but it snaps every 90 degrees 0/90/180/270/360 :

This is in my old engine I made myself, rotating smoothly without any snapping:

2

There a define value for it, so try with atan2(param, param2) * RadiusToDegree

3

HI,

you should check param and param2 values, GetInputAxisValue may always return -1.f, 0.f or 1.f instead of analogic value in range [-1.f 1.f].

Hope it helps.

4

I tried RadiansToDegrees but it needed a variable so I did:

float param = FMath::RadiansToDegrees(GetInputAxisValue(LookRightBinding));
float param2 = FMath::RadiansToDegrees(GetInputAxisValue(LookUpBinding));

but it the rotation barely moved like it was still radians :frowning:

What function would use analogic value ?

5

Hi,

i think you misunderstood, GetInputAxisValue returns a number between -1.f and 1.f that represent the gamepad stick position (left/right and up/down), as it is not an angle it makes no sens converting it to Radian.

I asked you to double check the values in param and param2 (by printing it or breaking in code and watching them) to be sure these values are valid.

6

Oh sorry. yeah, it returns -1 , 1 and 0 when doing nothing. What retrieves degrees/radians then?

The snap isn’t drastic as it still rotates 360 degrees , but it’s noticeable .

I tried

   const float FireForwardValue = GetInputAxisValue(FireForwardBinding);
	const float FireRightValue = GetInputAxisValue(FireRightBinding);

 const FVector LookDirection = FVector(FireForwardValue, FireRightValue, 0.0f);
    const FRotator LookRotation = LookDirection.Rotation();
    float rot = LookRotation.Yaw;
    
    WheelArmBackComponent->RelativeRotation.Yaw = rot;

and this is the exact way the samples rotate and it feels exactly the same as doing it the first way(they also use the get function).

I don’t know how else to do it…

Well, thanks for your help anyways ^ ^

7

I tried atan2(param, param2) * RadiusToDegree

as Fmath::RadiusToDegree(param); ect but it didn’t do anything :frowning:

8

Usually we’re accumulating deltas from the gamepad inputs with something like:

const float FireForwardValue = GetInputAxisValue(FireForwardBinding);
const float FireRightValue = GetInputAxisValue(FireRightBinding);

const FVector LookDirection = FVector(FireForwardValue, FireRightValue, 0.0f);
const FRotator LookRotation = LookDirection.Rotation();
float DeltaYaw = LookRotation.Yaw * GetWorld()->GetDeltaSeconds() * RotateSpeed;

WheelArmBackComponent->RelativeRotation.Yaw += DeltaYaw;
9

I tried that and it’s smooth, but not the effect I was looking for. With that, the object keeps rotating simply by pressing one way.

I’m needing to have it move where ever the stick is pointing for a gun

this is a prototype I made (temp art) for the game I’m making and this is how the character moves.

I dunno, the prototype one rotated butter smooth(just used C++/DirectX), but UE 4 rotation feels off

seriously though, thanks for helping :slight_smile:

10

Looking at the vid there are 2 posibilities you want:

Option 1. Rotate the yaw based on 1 input axis. Notice that obtaining 2 input axis’ values to adjust 1 angle (Yaw) makes no sense. If you use 2 input values to adjust 1 angle, you’ll get shaking effects.

The solution for this is as follows, make sure you make an axis binding to a function that gets called.

For example: InputComponent->BindAxis(“Mouse X”, this, &YourClassName::OnMouseXChange);

Then in the function OnMouseXChange(float val)

const float speed = 10; WheelArmBackComponent->RelativeRotation.Yaw
+= val * speed;

Option 2: Make the gun point in the direction of the mouse position on screen.

The direction vector depends on the mouse position to the axis of rotation of the gun: FVector shootDir = mousePos - gunRotationOrigin. (Make sure they are both in screenSpace or in worldSpace)

From then, you can just obtain the rotation with: WheelArmBackComponent->RelativeRotation
= shootDir.Rotation();

11

Thanks for the input! But I’m using an analog stick, not the mouse(but I will be as a second control option)
The video show my old one . The shakiness in the vid is done on purpose as it’s a machine gun

this is a video showing my problem. I’m rotating it smoothly around on the analog , but it snaps every 90 degrees 0/90/180/270/360 :

This is the way that it should be:

12

The mouse was just an example. Both mouse and gamepad provide a value in range of [-1 +1]. So it makes no difference.
The only thing you have to do is read the Axis value out and add it to the RelativeRotation.Yaw with some speed multiplier.
eg.
WheelArmBackComponent->RelativeRotation.Yaw += AxisValue * Speed;
Btw, in the ‘correct’ example its also wrong. If the character is aiming down it flips 180 degrees.

13

changing the Deadzone fixed it