Well I put my own sine wave function together using some info from here (This was what I used).

After peeking through Shook and Grif's code I was surprised I nearly got it right.
So, my questions are, why do they divide their phase by twenty? What do wavenumber and AngularFrequency do? And when I use my code, I have to update my wave's X position every frame, and when using Shook or Grif's code, the object moves on its own, Why?

My code + function. (Moves up, not right)
Shook's code + function.

The only significance about the number 20 I can think of is that it is equivalent to one in-game meter.

Then wouldn't FrameMan.MPP work better?

1. Arbitrary numbers are easier to type than static variable names?
2. wavenumber I think just allows for changing the position of the particle (on the y axis) when it first starts out. Not sure on angularfrequency, I suppose it might be another modifier for frequency.
3. You do not use the velocity of the particle for the x axis (or y axis in your case), Shook/Grif do. If you notice in their code, they reference self.Vel.X, storing the initial value to a variable to check against later. They only modify self.Pos.Y of the particle in question. They use the self.Pos.X as, well, x in a y=sin(x) sort of way. You increment Alpha in a sort of parametric way. x = sin(alpha), y = y-1

Thank you Duh. The reason I did the Alpha thingy is because Wikipedia had Phase marked as a theta, so I figured is some kind of angle. Thanks for clearing that up. I can finally understand they mean here!

Edit: Wow, this phase stuff makes everything a lot clearer. Wavenumber = Frequency^(-1) Am I right?

It is an angle measurement. The sine function is usually used in a circle, so the value you put in there is usually an angle. Sine gives the ratio of the opposite leg to the angle over the hypotenuse. Sorry if I sound pedantic, but I don't know where you're coming from as far as trigonometry.


Not sure if we're talking the same thing, but yes, Wavelength = 1 / Frequency.

I just finished 8th grade, (Never taken any trig classes) but don't worry, I understand what you mean.

I meant wavenumber, but never mind I did some testing and seems to be what I think it is.

The division by twenty is just an arbitrary constant that I cooked up to "slow" the entire wave down.

Dividing by FrameMan.PPM works as well. Does anyone have any idea about what angular frequency does?

Wiki says:


So, i'm guessing the higher the value, the faster waves curve.