SetShaderValues.cs

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

public class SetShadervalues : MonoBehaviour
{

    MaterialPropertyBlock props;
    [SerializeField]
    Transform target;
    [SerializeField]
    string shaderID = "_PositionMoving";
    [SerializeField]
    float appearSpeed = 10f;
    [SerializeField]
    float disappearSpeed = 5f;
    [SerializeField]
    float radius = 12f;
    [SerializeField]
    float radiusRandomRange;
    [SerializeField]
    bool keep = false;

    [SerializeField]
    float minRangeRandomOffset = -3f;
    [SerializeField]
    float maxRangeRandomOffset = 3f;

    [SerializeField]
    MeshRenderer[] objects;
    float[] values;
    float[] offsets;
    float[] radiusRandomRanges;

    // Start is called before the first frame update
    void Start()
    {
        props = new MaterialPropertyBlock();
        values = new float[objects.Length];
        offsets = new float[objects.Length];
        radiusRandomRanges = new float[objects.Length];
        SetRandomOffset();
        MeshBounds(); // hack to stop culling because the object is so far from its origin
    }

    // Update is called once per frame
    void Update()
    {
        Shader.SetGlobalVector(shaderID, target.transform.position); // set position to follow
        for (int i = 0; i < objects.Length; i++)
        {
            Vector3 offset = objects[i].transform.position - target.position;
            float sqrLen = offset.sqrMagnitude;
            if (sqrLen < radius * radius + radiusRandomRanges[i])
            {
                values[i] = Mathf.Lerp(values[i], 1, Time.deltaTime * appearSpeed);// set property float to 1 over time
            }
            else if (!keep)
            {
                values[i] = Mathf.Lerp(values[i], 0, Time.deltaTime * disappearSpeed);// set property float to 0 over time if keep is not true
            }
            props.SetFloat("_Moved", values[i]);
            props.SetFloat("_RandomOffset", offsets[i]);
            objects[i].SetPropertyBlock(props);
        }
    }

    void SetRandomOffset()
    {
        for (int i = 0; i < objects.Length; i++)
        {
            offsets[i] = Random.Range(minRangeRandomOffset, maxRangeRandomOffset);
            radiusRandomRanges[i] = Random.Range(-radiusRandomRange, radiusRandomRange);


        }
    }

    void MeshBounds()
    {

        for (int i = 0; i < objects.Length; i++)
        {
            Mesh mesh = objects[i].GetComponent<MeshFilter>().mesh;
            mesh.bounds = new Bounds(Vector3.zero, 100f * Vector3.one);
        }

    }
}