View Rotation is currently frame-rate dependent

Development Programming & Scripting
1

Hey guys,

Just came across a bug with the update of the view controller.

We noticed our camera rotation was different on our main and test maps, and I came across the following:

void APlayerController::UpdateRotation( float DeltaTime )
{
	// Calculate Delta to be applied on ViewRotation
	FRotator DeltaRot(RotationInput);

 	// ^ Should be: FRotator DeltaRot(RotationInput * DeltaTime);

...

Seems someone just missed a delta-time multiplication.

Cheers.

2

Hi FacePalm,

I tried to reproduce the issue that you described, and was unable to do so. Would you be able to provide some additional information?

  • What version of the Engine are you using?
  • Do you only see this happening in your own project, or can you reproduce it in a new project as well?
3

Currently we are running 4.5.1, but this code hasn’t changed in 4.6.
This is in the engine player controller. It is not project dependent.

It’s simply a matter of DeltaRot being incorrect.
It’s very noticeable between a low frame-rate and high frame-rate map.

Cheers.

4

Hey -

Thanks for bringing this to our attention. The fix you suggested (multiplying by deltaTime) would be an excellent pull request. Would you like to enter a pull request to have your suggested fix entered into the engine or would you like for us to handle this fix internally?

Cheers

5

It’s probably better if you guys handle it internally as your QA process is better that ours.
I should also note that you will need to take the slomo command into account when doing a fix.

I’m currently doing the following:

float InputScale = DeltaTime;

// Remove any TimeDialation
if (GetWorld())
	InputScale /= GetWorld()->GetWorldSettings()->GetEffectiveTimeDilation();

So the camera ignores any world TimeDilation.
Otherwise the camera becomes unusable when using slomo.

Cheers guys.

6

Hey -

I have submitted a feature request to update the UpdateRotation() function. Let us know if you have any other questions and best of luck in your project.