esengine/demo/src/game/SpawnerSystem.ts

module system {
    export class SpawnerSystem extends es.EntityProcessingSystem {
        constructor(matcher: es.Matcher){
            super(matcher);
        }

        public processEntity(entity: es.Entity){
            let spawner = entity.getComponent<component.SpawnComponent>(component.SpawnComponent);
            if (!spawner)
                return;

            if (spawner.numAlive <= 0)
                spawner.enabled = true;

            if (!spawner.enabled)
                return;

            console.log("cooldown", spawner.cooldown);
            if (spawner.cooldown == -1){
                spawner.cooldown = Math.random() * 60;
                spawner.cooldown /= 4;
            }

            spawner.cooldown -= es.Time.deltaTime;
            if (spawner.cooldown <= 0){
                spawner.cooldown = Math.random() * 60;
                // CreateEnemy
                spawner.numSpawned ++;
                spawner.numAlive ++;

                if (spawner.numAlive > 0)
                    spawner.enabled = false;
            }
        }
    }
}