Question

How’d I go about this one? I want to tween a value from one to another in x time. While also taking into account that it’d be nice to have an ‘ease’ at the start and end.

I know, I shouldn’t ask really, but I’ve tried myself, and I’m stuck.
Please assume that to cause a delay, you need to call function wait(time).

Answer 1

One simple approach that might work for you is to interpolate along the unit circle:

To do this, you simply evaluate points along the circle, which ensures a fairly smooth movement, and ease-in as well as ease-out. You can control the speed of the interpolation by changing how quickly you alter the angle.

Assuming you’re doing 1-dimensional interpolation (i.e. a simple scalar interpolation, like from 3.5 to 6.9 or whatever), it might be handy to use Y-values from -π/2 to π/2. These are given by the sine function, all you need to do is apply suitable scaling:

angle = -math.pi / 2
start = 3.5
end = 6.9
radius = (end - start) / 2
value = start + radius + radius * math.sin(angle)

I’m not 100% sure if this is legal Lua, didn’t test it. If not, it’s probably trivial to convert.