Merge branch 'release/0.16.0' into master

README.md

@@ -1,12 +1,11 @@
 # Fireblade ECS (Entity-Component System)
-[![github CI](https://github.com/fireblade-engine/ecs/workflows/CI/badge.svg)](https://github.com/fireblade-engine/ecs/actions?query=workflow%3ACI)
 [![license](https://img.shields.io/badge/license-MIT-brightgreen.svg)](LICENSE)
-[![swift version](https://img.shields.io/badge/swift-5.1+-brightgreen.svg)](https://swift.org)
-[![platforms](https://img.shields.io/badge/platforms-%20macOS%20|%20iOS%20|%20tvOS%20|%20watchOS-brightgreen.svg)](#)
-[![platforms](https://img.shields.io/badge/platforms-linux-brightgreen.svg)](#)
-[![platforms](https://img.shields.io/badge/platforms-WebAssembly-brightgreen.svg)](https://github.com/swiftwasm/swift#swiftwasm)
+[![github CI](https://github.com/fireblade-engine/ecs/workflows/CI/badge.svg)](https://github.com/fireblade-engine/ecs/actions?query=workflow%3ACI)
 [![codecov](https://codecov.io/gh/fireblade-engine/ecs/branch/master/graph/badge.svg)](https://codecov.io/gh/fireblade-engine/ecs)
-[![documentation](https://github.com/fireblade-engine/ecs/workflows/Documentation/badge.svg)](https://github.com/fireblade-engine/ecs/wiki)
+[![documentation](https://github.com/fireblade-engine/ecs/workflows/Documentation/badge.svg)](https://github.com/fireblade-engine/ecs/wiki)  
+[![spi-swift-versions](https://img.shields.io/endpoint?url=https%3A%2F%2Fswiftpackageindex.com%2Fapi%2Fpackages%2Ffireblade-engine%2Fecs%2Fbadge%3Ftype%3Dswift-versions)](https://swiftpackageindex.com/fireblade-engine/ecs)
+[![spi-swift-platforms](https://img.shields.io/endpoint?url=https%3A%2F%2Fswiftpackageindex.com%2Fapi%2Fpackages%2Ffireblade-engine%2Fecs%2Fbadge%3Ftype%3Dplatforms)](https://swiftpackageindex.com/fireblade-engine/ecs)
+[![platform-webassembly](https://img.shields.io/badge/Platform-WebAssembly-blue.svg)](https://github.com/swiftwasm/swift#swiftwasm)
 
 This is a **dependency free**, **lightweight**, **fast** and **easy to use** [Entity-Component System](https://en.wikipedia.org/wiki/Entity_component_system) implementation in Swift. It is developed and maintained as part of the [Fireblade Game Engine project](https://github.com/fireblade-engine).
 
@@ -36,7 +35,7 @@ import PackageDescription
 let package = Package(
     name: "YourPackageName",
     dependencies: [
-        .package(url: "https://github.com/fireblade-engine/ecs.git", from: "0.15.4")
+        .package(url: "https://github.com/fireblade-engine/ecs.git", from: "0.16.0")
     ],
     targets: [
         .target(

Sources/FirebladeECS/ComponentIdentifier.swift

@@ -7,22 +7,18 @@
 
 /// Identifies a component by it's meta type
 public struct ComponentIdentifier {
-    @usableFromInline
-    typealias Hash = Int
-    @usableFromInline
-    typealias StableId = UInt64
-
-    @usableFromInline let hash: Hash
+    public typealias Identifier = Int
+    public let id: Identifier
 }
 
 extension ComponentIdentifier {
     @usableFromInline
     init<C>(_ componentType: C.Type) where C: Component {
-        self.hash = Self.makeRuntimeHash(componentType)
+        self.id = Self.makeRuntimeHash(componentType)
     }
 
     /// object identifier hash (only stable during runtime) - arbitrary hash is ok.
-    internal static func makeRuntimeHash<C>(_ componentType: C.Type) -> Hash where C: Component {
+    internal static func makeRuntimeHash<C>(_ componentType: C.Type) -> Identifier where C: Component {
         ObjectIdentifier(componentType).hashValue
     }
 }

Sources/FirebladeECS/EntityIdentifierGenerator.swift

@@ -5,18 +5,23 @@
 //  Created by Christian Treffs on 26.06.20.
 //
 
-/// An entity identifier generator provides new entity
-/// identifiers on entity creation.
-/// It also allows entity ids to be marked for re-use.
-/// Entity identifiers must be unique.
+/// **Entity Identifier Generator**
+///
+/// An entity identifier generator provides new entity identifiers on entity creation.
+/// It also allows entity ids to be marked as unused (to be re-usable).
+///
+/// You should strive to keep entity ids tightly packed around `EntityIdentifier.Identifier.min` since it has an influence on the underlying memory layout.
 public protocol EntityIdentifierGenerator {
-    /// Initialize the generator with entity ids already in use.
-    /// - Parameter entityIds: The entity ids already in use. Default should be an empty array.
-    init(inUse entityIds: [EntityIdentifier])
+    /// Initialize the generator providing entity ids to begin with when creating new entities.
+    ///
+    /// Entity ids provided should be passed to `nextId()` in last out order up until the collection is empty.
+    /// The default is an empty collection.
+    /// - Parameter initialEntityIds: The entity ids to start providing up until the collection is empty (in last out order).
+    init<EntityIds>(startProviding initialEntityIds: EntityIds) where EntityIds: BidirectionalCollection, EntityIds.Element == EntityIdentifier
 
     /// Provides the next unused entity identifier.
     ///
-    /// The provided entity identifier is at least unique during runtime.
+    /// The provided entity identifier must be unique during runtime.
     func nextId() -> EntityIdentifier
 
     /// Marks the given entity identifier as free and ready for re-use.
@@ -27,55 +32,71 @@ public protocol EntityIdentifierGenerator {
 }
 
 /// A default entity identifier generator implementation.
+public typealias DefaultEntityIdGenerator = LinearIncrementingEntityIdGenerator
+
+/// **Linear incrementing entity id generator**
 ///
-/// Provides entity ids starting at `0` incrementing until `UInt32.max`.
-public struct DefaultEntityIdGenerator: EntityIdentifierGenerator {
+/// This entity id generator creates linearly incrementing entity ids
+/// unless an entity is marked as unused then the marked id is returned next in a FIFO order.
+///
+/// Furthermore it respects order of entity ids on initialization, meaning the provided ids on initialization will be provided in order
+/// until all are in use. After that the free entities start at the lowest available id increasing linearly skipping already in-use entity ids.
+public struct LinearIncrementingEntityIdGenerator: EntityIdentifierGenerator {
     @usableFromInline
     final class Storage {
-        @usableFromInline var stack: [UInt32]
+        @usableFromInline var stack: [EntityIdentifier.Identifier]
         @usableFromInline var count: Int { stack.count }
 
         @usableFromInline
-        init(inUse entityIds: [EntityIdentifier]) {
-            stack = entityIds.reversed().map { UInt32($0.id) }
+        init<EntityIds>(startProviding initialEntityIds: EntityIds) where EntityIds: BidirectionalCollection, EntityIds.Element == EntityIdentifier {
+            let initialInUse: [EntityIdentifier.Identifier] = initialEntityIds.map { $0.id }
+            let maxInUseValue = initialInUse.max() ?? 0
+            let inUseSet = Set(initialInUse) // a set of all eIds in use
+            let allSet = Set(0...maxInUseValue) // all eIds from 0 to including maxInUseValue
+            let freeSet = allSet.subtracting(inUseSet) // all "holes" / unused / free eIds
+            let initialFree = Array(freeSet).sorted().reversed() // order them to provide them linear increasing after all initially used are provided.
+            stack = initialFree + initialInUse
+        }
+
+        @usableFromInline
+        init() {
+            stack = [0]
         }
 
         @usableFromInline
         func nextId() -> EntityIdentifier {
-            if stack.count == 1 {
-                defer { stack[0] += 1 }
-                return EntityIdentifier(stack[0])
-            } else {
+            guard stack.count == 1 else {
                 return EntityIdentifier(stack.removeLast())
             }
+            defer { stack[0] += 1 }
+            return EntityIdentifier(stack[0])
         }
 
         @usableFromInline
         func markUnused(entityId: EntityIdentifier) {
-            stack.append(UInt32(entityId.id))
+            stack.append(entityId.id)
         }
     }
 
     @usableFromInline let storage: Storage
-
     @usableFromInline var count: Int { storage.count }
 
     @inlinable
-    public init() {
-        self.init(inUse: [EntityIdentifier(0)])
+    public init<EntityIds>(startProviding initialEntityIds: EntityIds) where EntityIds: BidirectionalCollection, EntityIds.Element == EntityIdentifier {
+        self.storage = Storage(startProviding: initialEntityIds)
     }
 
     @inlinable
-    public init(inUse entityIds: [EntityIdentifier]) {
-        self.storage = Storage(inUse: entityIds)
+    public init() {
+        self.storage = Storage()
     }
 
-    @inlinable
+    @inline(__always)
     public func nextId() -> EntityIdentifier {
         storage.nextId()
     }
 
-    @inlinable
+    @inline(__always)
     public func markUnused(entityId: EntityIdentifier) {
         storage.markUnused(entityId: entityId)
     }

Sources/FirebladeECS/Family.swift

@@ -114,7 +114,7 @@ extension Family {
             guard let entityId = memberIdsIterator.next() else {
                 return nil
             }
-            return nexus.get(unsafeEntity: entityId)
+            return Entity(nexus: nexus, id: entityId)
         }
     }
 }

Sources/FirebladeECS/Generated/Family.generated.swift

@@ -28,7 +28,7 @@ public struct Requires1<Comp1>: FamilyRequirementsManaging where Comp1: Componen
     }
 
     public static func entityAndComponents(nexus: Nexus, entityId: EntityIdentifier) -> (Entity, Comp1) {
-        let entity: Entity = nexus.get(unsafeEntity: entityId)
+        let entity = Entity(nexus: nexus, id: entityId)
         let comp1: Comp1 = nexus.get(unsafeComponentFor: entityId)
         return (entity, comp1)
     }
@@ -122,7 +122,7 @@ public struct Requires2<Comp1, Comp2>: FamilyRequirementsManaging where Comp1: C
     }
 
     public static func entityAndComponents(nexus: Nexus, entityId: EntityIdentifier) -> (Entity, Comp1, Comp2) {
-        let entity: Entity = nexus.get(unsafeEntity: entityId)
+        let entity = Entity(nexus: nexus, id: entityId)
         let comp1: Comp1 = nexus.get(unsafeComponentFor: entityId)
         let comp2: Comp2 = nexus.get(unsafeComponentFor: entityId)
         return (entity, comp1, comp2)
@@ -222,7 +222,7 @@ public struct Requires3<Comp1, Comp2, Comp3>: FamilyRequirementsManaging where C
     }
 
     public static func entityAndComponents(nexus: Nexus, entityId: EntityIdentifier) -> (Entity, Comp1, Comp2, Comp3) {
-        let entity: Entity = nexus.get(unsafeEntity: entityId)
+        let entity = Entity(nexus: nexus, id: entityId)
         let comp1: Comp1 = nexus.get(unsafeComponentFor: entityId)
         let comp2: Comp2 = nexus.get(unsafeComponentFor: entityId)
         let comp3: Comp3 = nexus.get(unsafeComponentFor: entityId)
@@ -328,7 +328,7 @@ public struct Requires4<Comp1, Comp2, Comp3, Comp4>: FamilyRequirementsManaging
     }
 
     public static func entityAndComponents(nexus: Nexus, entityId: EntityIdentifier) -> (Entity, Comp1, Comp2, Comp3, Comp4) {
-        let entity: Entity = nexus.get(unsafeEntity: entityId)
+        let entity = Entity(nexus: nexus, id: entityId)
         let comp1: Comp1 = nexus.get(unsafeComponentFor: entityId)
         let comp2: Comp2 = nexus.get(unsafeComponentFor: entityId)
         let comp3: Comp3 = nexus.get(unsafeComponentFor: entityId)
@@ -440,7 +440,7 @@ public struct Requires5<Comp1, Comp2, Comp3, Comp4, Comp5>: FamilyRequirementsMa
     }
 
     public static func entityAndComponents(nexus: Nexus, entityId: EntityIdentifier) -> (Entity, Comp1, Comp2, Comp3, Comp4, Comp5) {
-        let entity: Entity = nexus.get(unsafeEntity: entityId)
+        let entity = Entity(nexus: nexus, id: entityId)
         let comp1: Comp1 = nexus.get(unsafeComponentFor: entityId)
         let comp2: Comp2 = nexus.get(unsafeComponentFor: entityId)
         let comp3: Comp3 = nexus.get(unsafeComponentFor: entityId)
@@ -558,7 +558,7 @@ public struct Requires6<Comp1, Comp2, Comp3, Comp4, Comp5, Comp6>: FamilyRequire
     }
 
     public static func entityAndComponents(nexus: Nexus, entityId: EntityIdentifier) -> (Entity, Comp1, Comp2, Comp3, Comp4, Comp5, Comp6) {
-        let entity: Entity = nexus.get(unsafeEntity: entityId)
+        let entity = Entity(nexus: nexus, id: entityId)
         let comp1: Comp1 = nexus.get(unsafeComponentFor: entityId)
         let comp2: Comp2 = nexus.get(unsafeComponentFor: entityId)
         let comp3: Comp3 = nexus.get(unsafeComponentFor: entityId)
@@ -682,7 +682,7 @@ public struct Requires7<Comp1, Comp2, Comp3, Comp4, Comp5, Comp6, Comp7>: Family
     }
 
     public static func entityAndComponents(nexus: Nexus, entityId: EntityIdentifier) -> (Entity, Comp1, Comp2, Comp3, Comp4, Comp5, Comp6, Comp7) {
-        let entity: Entity = nexus.get(unsafeEntity: entityId)
+        let entity = Entity(nexus: nexus, id: entityId)
         let comp1: Comp1 = nexus.get(unsafeComponentFor: entityId)
         let comp2: Comp2 = nexus.get(unsafeComponentFor: entityId)
         let comp3: Comp3 = nexus.get(unsafeComponentFor: entityId)
@@ -812,7 +812,7 @@ public struct Requires8<Comp1, Comp2, Comp3, Comp4, Comp5, Comp6, Comp7, Comp8>:
     }
 
     public static func entityAndComponents(nexus: Nexus, entityId: EntityIdentifier) -> (Entity, Comp1, Comp2, Comp3, Comp4, Comp5, Comp6, Comp7, Comp8) {
-        let entity: Entity = nexus.get(unsafeEntity: entityId)
+        let entity = Entity(nexus: nexus, id: entityId)
         let comp1: Comp1 = nexus.get(unsafeComponentFor: entityId)
         let comp2: Comp2 = nexus.get(unsafeComponentFor: entityId)
         let comp3: Comp3 = nexus.get(unsafeComponentFor: entityId)

Sources/FirebladeECS/Hashing.swift

@@ -45,15 +45,6 @@ public func hash(combine seed: Int, _ value: Int) -> Int {
     return Int(bitPattern: uSeed)
 }
 
-/// Calculates the combined hash value of the elements. This implementation is based on boost::hash_range.
-/// Is sensitive to the order of the elements.
-/// - Parameter hashValues: sequence of hash values to combine.
-/// - Returns: combined hash value.
-public func hash<S: Sequence>(combine hashValues: S) -> Int where S.Element == Int {
-    /// http://www.boost.org/doc/libs/1_65_1/doc/html/hash/reference.html#boost.hash_range_idp517643120
-    hashValues.reduce(0) { hash(combine: $0, $1) }
-}
-
 /// Calculates the combined hash value of the elements. This implementation is based on boost::hash_range.
 /// Is sensitive to the order of the elements.
 /// - Parameter hashValues: sequence of hash values to combine.

Sources/FirebladeECS/Nexus+Entity.swift

@@ -9,7 +9,7 @@ extension Nexus {
     @discardableResult
     public func createEntity() -> Entity {
         let entityId: EntityIdentifier = entityIdGenerator.nextId()
-        entityStorage.insert(entityId, at: entityId.id)
+        componentIdsByEntity[entityId] = []
         delegate?.nexusEvent(EntityCreated(entityId: entityId))
         return Entity(nexus: self, id: entityId)
     }
@@ -30,22 +30,15 @@ extension Nexus {
 
     /// Number of entities in nexus.
     public var numEntities: Int {
-        entityStorage.count
+        componentIdsByEntity.keys.count
     }
 
     public func exists(entity entityId: EntityIdentifier) -> Bool {
-        entityStorage.contains(entityId.id)
+        componentIdsByEntity.keys.contains(entityId)
     }
 
-    public func get(entity entityId: EntityIdentifier) -> Entity? {
-        guard let id = entityStorage.get(at: entityId.id) else {
-            return nil
-        }
-        return Entity(nexus: self, id: id)
-    }
-
-    public func get(unsafeEntity entityId: EntityIdentifier) -> Entity {
-        Entity(nexus: self, id: entityStorage.get(unsafeAt: entityId.id))
+    public func entity(from entityId: EntityIdentifier) -> Entity {
+        Entity(nexus: self, id: entityId)
     }
 
     @discardableResult
@@ -55,7 +48,7 @@ extension Nexus {
 
     @discardableResult
     public func destroy(entityId: EntityIdentifier) -> Bool {
-        guard entityStorage.remove(at: entityId.id) != nil else {
+        guard componentIdsByEntity.keys.contains(entityId) else {
             delegate?.nexusNonFatalError("EntityRemove failure: no entity \(entityId) to remove")
             return false
         }
@@ -64,6 +57,10 @@ extension Nexus {
             update(familyMembership: entityId)
         }
 
+        if let index = componentIdsByEntity.index(forKey: entityId) {
+            componentIdsByEntity.remove(at: index)
+        }
+
         entityIdGenerator.markUnused(entityId: entityId)
 
         delegate?.nexusEvent(EntityDestroyed(entityId: entityId))

Sources/FirebladeECS/Nexus+Internal.swift

@@ -56,19 +56,7 @@ extension Nexus {
     }
 
     func assign(_ componentId: ComponentIdentifier, _ entityId: EntityIdentifier) {
-        if componentIdsByEntity[entityId] == nil {
-            componentIdsByEntity[entityId] = Set<ComponentIdentifier>(arrayLiteral: componentId)
-        } else {
-            componentIdsByEntity[entityId]?.insert(componentId)
-        }
-    }
-
-    func assign(_ componentIds: Set<ComponentIdentifier>, _ entityId: EntityIdentifier) {
-        if componentIdsByEntity[entityId] == nil {
-            componentIdsByEntity[entityId] = componentIds
-        } else {
-            componentIdsByEntity[entityId]?.formUnion(componentIds)
-        }
+        componentIdsByEntity[entityId]!.insert(componentId)
     }
 
     func update(familyMembership entityId: EntityIdentifier) {
@@ -92,7 +80,7 @@ extension Nexus {
 
     func update(familyMembership traits: FamilyTraitSet) {
         // FIXME: iterating all entities is costly for many entities
-        var iter = entityStorage.makeIterator()
+        var iter = componentIdsByEntity.keys.makeIterator()
         while let entityId = iter.next() {
             update(membership: traits, for: entityId)
         }