RandomStream

Seed-based random stream of numbers. Useful for deterministic RNG problems, for instance, inside a Client Context so all players get the same outcome without the need to replicate lots of data from the server. Bad quality in the lower bits (avoid combining with modulus operations).

Constructors

Constructor Name	Return Type	Description	Tags
`RandomStream.New([integer seed])`	`RandomStream`	Constructor with specified seed, defaults to a random value.	None

Properties

Property Name	Return Type	Description	Tags
`seed`	`integer`	The current seed used for RNG.	Read-Write

Functions

Function Name	Return Type	Description	Tags
`GetInitialSeed()`	`integer`	The seed that was used to initialize this stream.	None
`Reset()`	`None`	Function that sets the seed back to the initial seed.	None
`Mutate()`	`None`	Moves the seed forward to the next seed.	None
`GetNumber([number min, number max])`	`number`	Returns a floating point number between `min` and `max` (inclusive), defaults to `0` and `1` (exclusive).	None
`GetInteger(integer min, integer max)`	`number`	Returns an integer number between `min` and `max` (inclusive).	None
`GetVector3()`	`Vector3`	Returns a random unit vector.	None
`GetVector3FromCone(Vector3 direction, number halfAngle)`	`Vector3`	Returns a random unit vector, uniformly distributed, from inside a cone defined by `direction` and `halfAngle` (in degrees).	None
`GetVector3FromCone(Vector3 direction, number horizontalHalfAngle, number verticalHalfAngle)`	`Vector3`	Returns a random unit vector, uniformly distributed, from inside a cone defined by `direction`, `horizontalHalfAngle` and `verticalHalfAngle` (in degrees).	None

Examples

Example using:

`New`

`seed`

`GetNumber`

With Random Stream we can generate a sequence of random values and guarantee they will always be the same values. This is useful in various situations, but in this example we initialize a Random Stream on the server and send the seed to all clients, so they can reproduce the sequence. This way, we only need to send the seed across the network, instead of sending the entire sequence of RNG. The "NetworkedObject" is a Core Object in the hierarchy that has networking enabled, plus it has a custom property called "seed" that is set as dynamic. The seed could also have been sent via a networked event, but a custom property allows players who join later to read the value at any time.

-- Server script
print("Server")
local NET_OBJ = script:GetCustomProperty("NetworkedObject"):WaitForObject()

local rng = RandomStream.New()
NET_OBJ:SetCustomProperty("seed", rng.seed)

for i = 1, 5 do
    print(rng:GetNumber(1, 10))
end

-- Client script
print("Client")
local NET_OBJ = script:GetCustomProperty("NetworkedObject"):WaitForObject()

local seed = NET_OBJ:GetCustomProperty("seed")
local rng = RandomStream.New(seed)

for i = 1, 5 do
    print(rng:GetNumber(1, 10))
end