The document discusses Entity system architecture with Unity using the Entitas framework. It describes common Unity pain points like testability, code sharing, and co-dependent logic that Entitas aims to address. Entitas uses components as data, entities as containers for components, and systems to define behavior. Components, entities, and systems allow for improved testability, code sharing, querying, and optimizations compared to traditional Unity scripts. The document provides examples of creating entities and systems with Entitas and demonstrates its capabilities.
21. Create Blocker Entity
public static Entity CreateBlocker(this Pool pool, int x, int y)
{
return pool.CreateEntity()
.IsGameBoardElement(true)
.AddPosition(x, y)
.AddResource(Res.Blocker);
}
22. Pool contains all entities
+------------------+
| Pool |
|------------------|
| e e |
| e e |
| e e |
| e e e |
| e e |
| e e |
| e e e |
| e e e |
+------------------+
24. Groups are subsets of entities
4 Performance optimization for querying
4 Matcher is a filter description
+-------------+ Groups:
| e | Subsets of entities in the pool
| e e | for blazing fast querying
| +------------+
| e | | |
| e | e | e |
+--------|----+ e |
| e |
| e e |
+------------+
25. Get Group from pool
_pool.GetGroup(
Matcher.AllOf(
Matcher.GameBoardElement,
Matcher.Position
)
);
26. +------------------+
| Pool | Entitas in a nutshell
|------------------|
| e e | +-----------+
| e e---|----> | Entity |
| e e | |-----------|
| e e e | | Component |
| e e | | | +-----------+
| e e | | Component-|----> | Component |
| e e e | | | |-----------|
| e e e | | Component | | Data |
+------------------+ +-----------+ +-----------+
|
|
| +-------------+ Groups:
| | e | Subsets of entities in the pool
| | e e | for blazing fast querying
+---> | +------------+
| e | | |
| e | e | e |
+--------|----+ e |
| e |
| e e |
+------------+
29. +------------------+ +-----------------------------+
| Pool | | System |
|------------------| |-----------------------------|
| e e | | - Execute |
| e e | | |
| e e | | +-------------+ |
| e e e | | | e | Groups |
| e e |+----|->| e e | |
| e e | | | +------------+ |
| e e e | | | e | | | |
| e e e | | | e | e | e | |
+------------------+ | +--------|----+ e | |
| | e | |
| | e e | |
| +------------+ |
+-----------------------------+
30. MoveSystem
public void Execute() {
var movables = _pool.GetGroup(
Matcher.AllOf(
Matcher.Move,
Matcher.Position
));
foreach (var e in movables.GetEntities()) {
var move = e.move;
var pos = e.position;
e.ReplacePosition(pos.x, pos.y + move.speed, pos.z);
}
}
31. Chain of Responsibility
| |
|-------------------------------- Game Loop --------------------------------|
| |
+------------+ +------------+ +------------+ +------------+
| | | | | | | |
| System | +---> | System | +---> | System | +---> | System |
| | | | | | | |
+------------+ +------------+ +------------+ +------------+
36. Render Position System
public class RenderPositionSystem : IReactiveSystem {
public IMatcher trigger { get { return Matcher.AllOf(Matcher.Position, Matcher.View); } }
public GroupEventType eventType { get { return GroupEventType.OnEntityAdded; } }
public void Execute(Entity[] entities) {
foreach (var e in entities) {
var pos = e.position;
e.view.gameObject.transform.position = new Vector3(pos.x, pos.y);
}
}
}
49. var pool = Pools.pool;
var e = pool.CreateEntity();
e.AddPosition(1, 2, 3);
e.ReplacePosition(4, 5, 6);
e.RemovePosition();
var posX = e.position.x;
var hasPos = e.hasPosition;
e.isMovable = true;
e.isMovable = false;
var isMovable = e.isMovable;
55. Advantages
4 Straightforward to achieve Determinism and
therefore Replay
4 Simulation Speed (2x, 4x)
4 Headless Simulation, just remove systems which rely
on GameObjects (render systems)
4 Save Game (Serialization / Deserialization) send
data to backend on change