Random.state

Description

Gets/Sets the full internal state of the random number generator.

This property is usually used to save and restore a previously saved state of the random number generator (RNG). The RNG state can also be initialized with a seed using the Random.InitState function, but the effect is quite different, as shown in the following example.

#pragma strict
function Start() {
	Random.InitState(255);
	PrintRandom("Step 1");
	PrintRandom("Step 2");
	var oldState: Random.State = Random.state;
	PrintRandom("Step 3");
	PrintRandom("Step 4");
	Random.state = oldState;
	PrintRandom("Step 5");
	PrintRandom("Step 6");
	Random.InitState(255);
	PrintRandom("Step 7");
	PrintRandom("Step 8");
}
function PrintRandom(label: String) {
	Debug.Log(String.Format("{0} - RandomValue {1}", label, Random.Range(1, 100)));
}

using UnityEngine;
using System.Collections;

public class ExampleClass : MonoBehaviour {
    void Start () {
        Random.InitState (255);

        PrintRandom ("Step 1");
        PrintRandom ("Step 2");

        Random.State oldState = Random.state;

        PrintRandom ("Step 3");
        PrintRandom ("Step 4");

        Random.state = oldState;

        PrintRandom ("Step 5");
        PrintRandom ("Step 6");

        Random.InitState (255);

        PrintRandom ("Step 7");
        PrintRandom ("Step 8");
    }

    void PrintRandom (string label)
    {
        Debug.Log (string.Format("{0} - RandomValue {1}", label, Random.Range (1, 100)));
    }
}

After running this script we will observe that the random values from step 5 and 6 will be equal to those from step 3 and 4 because the internal state of the RNG was restored by using Random.state property. Also, the random values from step 7 and 8 will be equal to the ones from step 1 and 2 because Random.InitState reinitializes the state of the RNG with the initial seed.