游戏编程精粹学习 - 可预测随机数

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

public class InfinityPlanet : MonoBehaviour
{
    public int x;
    public int y;
    public int probability = 70;
    List<GameObject> mCreatedCubeList = new List<GameObject>();


    void Update()
    {
        GetArea(x - 10, y - 10, x + 10, y + 10);
    }

    void GetArea(int beginX, int beginY, int endX, int endY)
    {
        for (int i = 0; i < mCreatedCubeList.Count; i++)
            Destroy(mCreatedCubeList[i]);

        var cacheState = Random.state;

        mCreatedCubeList.Clear();

        for (int x = beginX; x < endX; x++)
        {
            for (int y = beginY; y < endY; y++)
            {
                Random.InitState(x + y * x);

                var r = (int)(Random.value * 100);
                if (r % 100 < probability)
                {
                    var cube = GameObject.CreatePrimitive(PrimitiveType.Cube);
                    cube.transform.position = new Vector3(x, 0, y);

                    GalaxyBuild(r, cube);

                    mCreatedCubeList.Add(cube);
                }
            }
        }

        Random.state = cacheState;

    }

    void GalaxyBuild(int seed, GameObject go)
    {
        var cacheState = Random.state;
        Random.InitState(seed);
        var meshRenderer = go.GetComponent<MeshRenderer>();
        switch ((int)(Random.value * 100 % 3))
        {
            case 0://行星类型1
                meshRenderer.material.color = Color.red;
                break;

            case 1://行星类型2
                meshRenderer.material.color = Color.blue;
                break;

            case 2://行星类型3
                meshRenderer.material.color = Color.green;
                break;
        }

        Random.state = cacheState;
    }
}