How to define offset to get sine wave effect?

[Hrvoje]

At 6:14 timestamp, Rick said that he makes them offset… I can’t figure out how to make them move in that “wavy” motion, all of my objects are moving as one.
Thanks

[Nina]

Hi Hrvoje,

Have you already compared your code to the Lecture Project Changes which can be found in the Resources of this lecture?

Did you implement a delay? If so, check the value via a Debug.Log method call.

[Hrvoje]

Yea, I suppose there needs to be some kind of delay for every moving obstacle, but I can’t find any changes in this lecture in Oscilator.cs script. What I managed to do is to make them move as wave by changing different Time.time value on every object just by creating
[SerializeField] float timeDelay = 0f;
variable and adding the value to Time.time in
float cycles = Time.time + timeDelay / period;
The thing is, now they move at high speed and I can’t change the speed but I’m not sure why…

EDIT: here’s a video, if it helps…

[Nina]

Your video shows that the obstacles are undulating. Maybe I misunderstood your initial problem or you have a new one. Could you please elaborate on what you expected to see in the video?

[Hrvoje]

Haha, sry if I’m being a little hard to understand.

My initial problem was to make objects undulating, but I managed to do it. Now, as you say, I have a different, new problem and that is that I’m unable to slow them down. Can you see how fast are they moving? When I change the period, it seems the speed is unaffected.

[Nina]

Could you please post the entire algorithm for the movement?

[Hrvoje]

using System;
using System.Collections;
using System.Collections.Generic;
using UnityEngine;

[DisallowMultipleComponent] // allows only one script per game object
public class Oscillator : MonoBehaviour
{

    [SerializeField] Vector3 movementVector = new Vector3(10f, 10f, 10f);
    Vector3 offsetVector = new Vector3(0f, 0f, 0f);
    [SerializeField] float period = 2f;
    [SerializeField] float timeDelay = 0f; // delay too make wave effect

    [Range(1,20)][SerializeField] float movementFactor; //0 not moved, 1 fully moved

    Vector3 startingPos;
    // Start is called before the first frame update
    void Start()
    {
        startingPos = transform.position;
    }

    // Update is called once per frame
    void Update()
    {
        //Invoke("UpdateMovement", timeDelay);
        UpdateMovement();
    }

    private void UpdateMovement()
    {
        if (period <= Mathf.Epsilon) { period = 1; } // protect from devide by zero
        float cycles = Time.time - timeDelay / period; // grows constantly from 0

        const float tau = (float)Math.PI * 2;
        float rawSinWave = Mathf.Sin(cycles * tau); // goes from -1 to +1

        //print("rawSinWave: " + rawSinWave + " cycles: " + cycles);

        movementFactor = rawSinWave / 2f + 0.5f;
        offsetVector = movementFactor * movementVector;
        transform.position = offsetVector + startingPos;
    }
}

[Nina]

Please go to this website and paste the following into the field on the left side:

y=\sin\left(\frac{t}{p}\cdot\ 2\pi\ +\ \left(\frac{\pi}{2}-\pi\right)\right)\ \ \cdot\frac{1}{2}+0.5

t is time, p the period variable. Remove (2pi - pi) to see what it does.

---

Take a close look at your code. Does it really do what the function on desmos does?

Your original line

float cycles = Time.time - timeDelay / period;

translates to:

float cycles = Time.time - (timeDelay / period);

[Hrvoje]

Ok, I think I got it now. I changed the cycles part to
float cycles = (Time.time / period) - timeDelay;
and now, upon changing period value, I’m changing speed of the wave effect.

Thanks Nina!