Random seed
- Game Development course
- Advanced
- Lesson 44/71
- 4 min
Learn repeatable randomness with the same seed.
Random Seed and Determinism
Randomness in computing is pseudo-random. Pseudo-random number generators initialize from a starting value called a Seed.
// The same seed always produces the identical sequence
Random.InitState(42);
int num1 = Random.Range(1, 100);Using the identical seed causes the generator to yield the exact same sequence of pseudo-random numbers every time, a property known as determinism.
Seed Sharing and World Synchronization
In multiplayer titles, sending entire world datasets across the network is unnecessary; transmitting a single seed integer (e.g. 94821) suffices.
public void SetWorldSeed(int seed) {
Random.InitState(seed);
}Both clients run the procedural generator locally with that shared seed, producing identical map topology.
Practice Deterministic generation with seed
Define a Start method. Inside, declare int seed = 42; and print "Kullanilan tohum: " + seed to the console using Debug.Log.
Starter code
using UnityEngine;
public class SeedTester : MonoBehaviour
{
// Start icinde seed tanimla ve yazdir
}Sample solution
using UnityEngine;
public class SeedTester : MonoBehaviour
{
void Start()
{
int seed = 42;
Debug.Log("Kullanilan tohum: " + seed);
}
}Expected output
Kullanilan tohum: 42
Questions and answers
Review the lesson questions together with their answers. To test yourself, solve the lesson interactively.
1 What occurs in Unity when Random.InitState(seed) is called with the identical seed value?
- The game immediately crashes and closes
- Character speed doubles every frame
- All game save files are deleted
- The random number generator produces the exact same sequence of numbers each time Correct answer
Explanation: The same seed resets the pseudo-random generator state, ensuring subsequent outputs occur in the exact same sequence.
2 Initialize random state
Random.____(seedValue);Random.InitState(seedValue);Explanation: The 'Random.InitState' method is used in Unity to initialize the random generator with a specific seed.
3 Randomness and seed concepts
| Term | Meaning |
|---|---|
Seed |
Seed value starting the generator |
Random.InitState |
Unity method configuring the seed value |
Deterministik |
Same input always gives same output |
Pseudo-random |
Fake randomness made by algorithms |