Initial commit

ecs/system_manager.odin

@@ -0,0 +1,65 @@
+package ecs 
+
+import "base:intrinsics"
+import "core:log"
+
+SystemBase :: struct {
+    entities: map[EntityID]struct{}, // Treat as set
+}
+
+SystemManager :: struct {
+    signatures: map[typeid]Signature,
+    systems: map[typeid]^SystemBase
+}
+
+system_manager_create :: proc() -> SystemManager {
+    system_manager := SystemManager{
+        signatures = make(map[typeid]Signature, context.allocator),
+        systems = make(map[typeid]^SystemBase, context.allocator),
+    }
+
+    return system_manager
+}
+
+system_manager_register_system :: proc($T: typeid, system_manager: ^SystemManager) -> ^T {
+    log.assertf(T not_in system_manager.systems, "Registering system more than once")
+    log.assertf(intrinsics.type_has_field(T, "entities"), "Registering non system type")
+
+    system := new(T, context.allocator)
+    system.entities = make(map[EntityID]struct{})
+    system_manager.systems[T] = system
+
+    return system
+}
+
+system_manager_set_signature :: proc($T: typeid, system_manager: ^SystemManager, signature: Signature) {
+    log.assertf(T in system_manager.systems, "System used before registered")
+    system_manager.signatures[T] = signature
+}
+
+system_manager_destroy_entity :: proc(system_manager: ^SystemManager, entity_id: EntityID) {
+    for _, system in system_manager.systems {
+        delete_key(&system.entities, entity_id)
+    }
+}
+
+system_manager_change_entity_signature :: proc(system_manager: ^SystemManager, entity_id: EntityID, entity_signature: Signature) {
+    for type, system in system_manager.systems {
+        system_signature := system_manager.signatures[type]
+        if (entity_signature & system_signature) == system_signature {
+            system.entities[entity_id] = {}
+        } else {
+            delete_key(&system.entities, entity_id)
+        }
+    }
+}
+
+system_manager_destroy :: proc(system_manager: ^SystemManager) {
+    for _, system in system_manager.systems {
+        delete(system.entities)
+        free(system)
+    }
+
+    delete(system_manager.systems)
+    delete(system_manager.signatures)
+}