feat: Add Systems

star-dash/star-dash.xcodeproj/project.xcworkspace/xcshareddata/swiftpm/Package.resolved

@@ -0,0 +1,14 @@
+{
+  "pins" : [
+    {
+      "identity" : "swift-collections",
+      "kind" : "remoteSourceControl",
+      "location" : "https://github.com/apple/swift-collections.git",
+      "state" : {
+        "revision" : "94cf62b3ba8d4bed62680a282d4c25f9c63c2efb",
+        "version" : "1.1.0"
+      }
+    }
+  ],
+  "version" : 2
+}

star-dash/star-dash/Events/Event.swift

@@ -0,0 +1,15 @@
+//
+//  Event.swift
+//  star-dash
+//
+//  Created by Jason Qiu on 13/3/24.
+//
+
+import Foundation
+
+protocol Event {
+    var timestamp: Date { get }
+    var entityId: EntityId { get }
+
+    func execute(on target: EventModifiable)
+}

star-dash/star-dash/Events/EventManager.swift

@@ -0,0 +1,29 @@
+//
+//  EventManager.swift
+//  star-dash
+//
+//  Created by Jason Qiu on 14/3/24.
+//
+
+import DequeModule
+import Foundation
+
+typealias EventQueue = Deque<Event>
+
+class EventManager {
+    private var events: EventQueue
+
+    init() {
+        events = EventQueue()
+    }
+
+    func add(event: Event) {
+        events.append(event)
+    }
+
+    func executeAll(on target: EventModifiable) {
+        while let event = events.popFirst() {
+            event.execute(on: target)
+        }
+    }
+}

star-dash/star-dash/Events/EventModifiable.swift

@@ -0,0 +1,11 @@
+//
+//  EventModifiable.swift
+//  star-dash
+//
+//  Created by Jason Qiu on 14/3/24.
+//
+
+import Foundation
+
+/// EventModifiable represents objects that can be modified by events.
+protocol EventModifiable { }

star-dash/star-dash/Events/MoveEvent.swift

@@ -0,0 +1,25 @@
+//
+//  MoveEvent.swift
+//  star-dash
+//
+//  Created by Jason Qiu on 14/3/24.
+//
+
+import Foundation
+
+class MoveEvent: Event {
+    var entityId: EntityId
+    var timestamp: Date
+
+    var displacement: CGVector
+
+    init(entityId: EntityId, displacement: CGVector, timestamp: Date = Date.now) {
+        self.entityId = entityId
+        self.timestamp = timestamp
+        self.displacement = displacement
+    }
+
+    func execute(on target: EventModifiable) {
+        // TODO: Use PositionSystem from target to modify entity of entityId
+    }
+}

star-dash/star-dash/Entities/EntityManager.swift → star-dash/star-dash/GameEngine/Entities/EntityManager.swift

@@ -41,4 +41,16 @@ class EntityManager {
         }
         self.entityMap[entity.id] = entity
     }
+
+    func component<T: Component>(ofType type: T.Type, of entityId: EntityId) -> T? {
+        guard let components = entityComponentMap[entityId] else {
+            return nil
+        }
+
+        guard let componentId = components.first(where: { componentMap[$0] is T }) else {
+            return nil
+        }
+
+        return componentMap[componentId] as? T
+    }
 }

star-dash/star-dash/GameEngine/GameEngine.swift

@@ -0,0 +1,37 @@
+//
+//  GameEngine.swift
+//  star-dash
+//
+//  Created by Ho Jun Hao on 14/3/24.
+//
+
+import Foundation
+
+class GameEngine {
+    private let systemManager: SystemManager
+    private let entityManager: EntityManager
+    private let eventManager: EventManager
+
+    init(scene: GameScene) {
+        self.systemManager = SystemManager()
+        self.entityManager = EntityManager()
+        self.eventManager = EventManager()
+        // TODO: link game engine to renderer
+
+        setUpSystems()
+    }
+
+    func update(by deltaTime: TimeInterval) {
+        systemManager.update(by: deltaTime)
+        eventManager.executeAll(on: self)
+    }
+
+    private func setUpSystems() {
+        systemManager.add(PositionSystem(entityManager, dispatcher: self))
+        systemManager.add(PhysicsSystem(entityManager, dispatcher: self))
+    }
+}
+
+extension GameEngine: EventModifiable {
+    // TODO: functions of event modifiable
+}

star-dash/star-dash/GameEngine/Systems/PhysicsSystem.swift

@@ -0,0 +1,69 @@
+//
+//  PhysicsSystem.swift
+//  star-dash
+//
+//  Created by Ho Jun Hao on 13/3/24.
+//
+
+import Foundation
+
+class PhysicsSystem: System {
+    var isActive: Bool
+    var dispatcher: EventModifiable?
+    var entityManager: EntityManager
+
+    init(_ entityManager: EntityManager, dispatcher: EventModifiable? = nil) {
+        self.isActive = true
+        self.dispatcher = dispatcher
+        self.entityManager = entityManager
+    }
+
+    func update(by deltaTime: TimeInterval) {
+        let physicsComponents = entityManager.componentMap.values.compactMap({ $0 as? PhysicsComponent })
+
+        for physicsComponent in physicsComponents {
+            physicsComponent.force = .zero
+        }
+    }
+
+    func isMoving(_ entityId: EntityId) -> Bool {
+        guard let physicsComponent = getPhysicsComponent(of: entityId) else {
+            return false
+        }
+
+        return physicsComponent.velocity != .zero
+    }
+
+    func isJumping(_ entityId: EntityId) -> Bool {
+        guard let physicsComponent = getPhysicsComponent(of: entityId) else {
+            return false
+        }
+
+        return physicsComponent.velocity.dy != .zero
+    }
+
+    func applyForce(to entityId: EntityId, newForce: CGVector) {
+        guard let physicsComponent = getPhysicsComponent(of: entityId) else {
+            return
+        }
+
+        let newForce = CGVector(dx: physicsComponent.force.dx + newForce.dx,
+                                dy: physicsComponent.force.dy + newForce.dy)
+
+        physicsComponent.force = newForce
+    }
+
+    func sync(entityVelocityMap: [EntityId: CGVector]) {
+        for (entityId, newVelocity) in entityVelocityMap {
+            guard let physicsComponent = getPhysicsComponent(of: entityId) else {
+                continue
+            }
+
+            physicsComponent.velocity = newVelocity
+        }
+    }
+
+    private func getPhysicsComponent(of entityId: EntityId) -> PhysicsComponent? {
+        entityManager.component(ofType: PhysicsComponent.self, of: entityId)
+    }
+ }

star-dash/star-dash/GameEngine/Systems/PositionSystem.swift

@@ -0,0 +1,50 @@
+//
+//  PositionSystem.swift
+//  star-dash
+//
+//  Created by Ho Jun Hao on 13/3/24.
+//
+
+import Foundation
+
+class PositionSystem: System {
+    var isActive: Bool
+    var dispatcher: EventModifiable?
+    var entityManager: EntityManager
+
+    init(_ entityManager: EntityManager, dispatcher: EventModifiable? = nil) {
+        self.isActive = true
+        self.entityManager = entityManager
+        self.dispatcher = dispatcher
+    }
+
+    func move(entityId: EntityId, to newPosition: CGPoint) {
+        guard let positionComponent = getPositionComponent(of: entityId) else {
+            return
+        }
+
+        positionComponent.setPosition(position: newPosition)
+    }
+
+    func rotate(entityId: EntityId, to newRotation: Float) {
+        guard let positionComponent = getPositionComponent(of: entityId) else {
+            return
+        }
+
+        positionComponent.setRotation(rotation: newRotation)
+    }
+
+    func sync(entityPositionMap: [EntityId: CGPoint], entityRotationMap: [EntityId: Float]) {
+        for (entityId, newPosition) in entityPositionMap {
+            move(entityId: entityId, to: newPosition)
+        }
+
+        for (entityId, newRotation) in entityRotationMap {
+            rotate(entityId: entityId, to: newRotation)
+        }
+    }
+
+    private func getPositionComponent(of entityId: EntityId) -> PositionComponent? {
+        entityManager.component(ofType: PositionComponent.self, of: entityId)
+    }
+}

star-dash/star-dash/GameEngine/Systems/System.swift

@@ -0,0 +1,20 @@
+//
+//  System.swift
+//  star-dash
+//
+//  Created by Ho Jun Hao on 13/3/24.
+//
+
+import Foundation
+
+protocol System {
+    var isActive: Bool { get set }
+    var dispatcher: EventModifiable? { get set }
+    var entityManager: EntityManager { get set }
+
+    func update(by deltaTime: TimeInterval)
+}
+
+extension System {
+    func update(by deltaTime: TimeInterval) {}
+}

star-dash/star-dash/GameEngine/Systems/SystemManager.swift

@@ -0,0 +1,22 @@
+//
+//  SystemManager.swift
+//  star-dash
+//
+//  Created by Ho Jun Hao on 13/3/24.
+//
+
+import Foundation
+
+class SystemManager {
+    private var systems: [System] = []
+
+    func add(_ system: System) {
+        systems.append(system)
+    }
+
+    func update(by deltaTime: TimeInterval) {
+        for system in systems where system.isActive {
+            system.update(by: deltaTime)
+        }
+    }
+}