AgentRandom

Remarks

Stateless, and keyed on identity rather than on a slot. A weighted-random selector reading Random.Shared is a desync per NPC per second: two machines running the same build would draw in whatever order their threads happened to reach the agents, and the choices would diverge within a frame. A value here is a pure function of who is asking, on which stream, for what, so any thread can compute any agent's number at any time without having computed anybody else's first.

⚠ The salt is not optional. Two uses of randomness on one agent must not agree with each other, or a RandomSelector and a service's random deviation would draw the same number and every agent that took the first branch would also tick early — a correlation that looks like behaviour and is not. The salt is what the number is for: a node's execution index, an action's index, a named constant.

The mixing function is VfxRandom's — Chris Wellons' lowbias32, three multiplies and three xor-shifts, no avalanche anomalies — and it is copied rather than shared because the two live in sibling assemblies and neither may reference the other. When a third caller wants it, the hash is what moves to Vixen.Core, not this type: a particle's stream is keyed on an identifier and a graph operation, an agent's on an entity and a node, and the two contracts are not the same one.

Methods (6)

• public static uint SeedOf(Entity entity)

  A stream seed for an entity, stable across runs and machines.

• public static uint Hash(uint value)

  Mixes one integer.

• public static uint Hash(Entity entity, uint seed, uint salt)

  Mixes an agent, a stream and a use.

• public static float Value(Entity entity, uint seed, uint salt)

  A number in [0,1).

• public static float Range(Entity entity, uint seed, uint salt, float minimum, float maximum)

  A number in a range.

• public static int Index(Entity entity, uint seed, uint salt, int count)

  An index into a set.

Used by (12)

• AgentContextVixen.Ai
• AgentRandomTestsVixen.Ai.Tests
• AiSystemVixen.Ai
• AiSystemTestsVixen.Ai.Tests
• BehaviorTreeCostTestsVixen.Ai.Tests
• BehaviorTreeInstanceVixen.Ai
• BehaviorTreeServiceTestsVixen.Ai.Tests
• GoapHarnessVixen.Ai.Tests
• HarnessVixen.Ai.Tests
• PerceptionSystemVixen.Ai.Perception
• TreeHarnessVixen.Ai.Tests
• UtilitySelectorTestsVixen.Ai.Tests