About to break scene tree.

src/ecs/ecssystem.c

@@ -0,0 +1,59 @@
+/**
+ * Copyright (c) 2025 Dominic Masters
+ * 
+ * This software is released under the MIT License.
+ * https://opensource.org/licenses/MIT
+ */
+
+#include "ecssystem.h"
+#include "util/memory.h"
+#include "assert/assert.h"
+
+ecssystem_t ECS_SYSTEM;
+
+void ecsSystemInit() {
+  memoryZero(&ECS_SYSTEM, sizeof(ecssystem_t));
+
+  // Fill ECS ids
+  for(uint32_t i = 0; i < ECS_ENTITY_COUNT_MAX; i++) {
+    ECS_SYSTEM.entities[i].id = i;
+  }
+
+  // Fill the available array.
+  for(uint32_t i = 0; i < ECS_ENTITY_COUNT_MAX; i++) {
+    ECS_SYSTEM.available[i] = &ECS_SYSTEM.entities[i];
+  }
+  ECS_SYSTEM.availableCount = ECS_ENTITY_COUNT_MAX;
+
+  // Reserve root entity
+  ECS_SYSTEM.root = ecsEntityAdd();
+}
+
+ecsid_t ecsEntityAdd() {
+  assertTrue(ECS_SYSTEM.availableCount > 0, "No available entities to create");
+
+  // Pop off the last available entity.
+  ecsentity_t *entity = ECS_SYSTEM.available[--ECS_SYSTEM.availableCount];
+  assertTrue((entity->flags & ECS_ENTITY_FLAG_USED) == 0, "Entity is used.");
+  assertTrue(entity->id >= 0, "Entity is invalid.");
+  assertTrue(entity->id < ECS_ENTITY_COUNT_MAX, "Entity ID out of bounds");
+
+  entity->flags |= ECS_ENTITY_FLAG_USED;
+
+  return entity->id;
+}
+
+void ecsEntityRemove(const ecsid_t id) {
+  assertTrue(id < ECS_ENTITY_COUNT_MAX, "Invalid entity ID");
+
+  ecsentity_t *entity = &ECS_SYSTEM.entities[id];
+  assertTrue(entity->id >= 0, "Entity is invalid.");
+  assertTrue((entity->flags & ECS_ENTITY_FLAG_USED) != 0, "Entity is not used.");
+
+  // Mark the entity as available.
+  ECS_SYSTEM.available[ECS_SYSTEM.availableCount++] = entity;
+  assertTrue(
+    ECS_SYSTEM.availableCount <= ECS_ENTITY_COUNT_MAX,
+    "Available count exceeded maximum limit"
+  );
+}