Add Screen Shake feature

[salianifo]

Adds a new screen shake feature, allowing you to set the amplitude/frequency for both horizontal and vertical screen shakes, independently.

Note: This feature requires adding the Screen Shake Layer to your styles, and it has NOT been added to the default styles at this time.

Amplitude/frequency can both be faded over time, and they have a separate duration that does not include the fade time. This allows for a smooth transition into and out of shaking the screen, while still allowing the full strength of the shake to last for a particular duration.

There is an additional option to wait for completion if the duration is greater than 0, or if the amplitude is 0 and there is a fade time greater than 0.

If the duration is 0 and the amplitude is not 0, the screen will continue shaking until the next screen shake event. To end a screen shake, you can either set the amplitude to 0 in another screen shake event, or use the clear event (this will clear both directions simultaneously).

The edges of the screen are drawn with the color specified at rendering/environment/defaults/default_clear_color in the Project Settings.

Amplitude is in the range of 0 to 1, with a step value of 0.01. An amplitude of 1 will move the entire size of the screen at its peak.

Frequency has a minimum of 0.1 (a frequency of 0 would cause it to no longer update), and has no upper bound. It is measured in hertz or cycles per second, so higher numbers means faster shaking. This means a value of 1 will move the screen from one side to the other and back to the center in 1 second.

Here is an example of shaking the screen in both directions at different rates, then using the clear event.

2024-10-31.11-46-48.mp4

[UsernameIsInUse]

So there's a chance I've done something wrong, but pulling this request as is and making no changes results in this error:
event_screen_shake.gd line 31 dialogic.ScreenShake.update_shake_x(amplitude, frequency, fade, duration)
Invalid access to property or key 'ScreenShake' on a base object of type 'Node (DialogicGameHandler)'.
I added the layer to the style, just dropping the default screenshake onto the timeline results in this issue.

Okay, adding

var ScreenShake := preload("res://addons/dialogic/Modules/ScreenShake/subsystem_screen_shake.gd").new():
	get: return get_subsystem("ScreenShake")

to DialogicGameHandler.gd seems to have fixed the issue -- the module wasn't being loaded.

[salianifo]

Yup, that is indeed a mistake on my part. I will update this when I get some time.