CEnemy* spawnEnemy(CEnemyClass* _class)
{
    int i;

    for (i = 0; i < sizeof(world.enemyPool) / sizeof(CEnemy*); i++)
    {
        CEnemy* enemy;

        if (world.enemyPool[i])
            continue;

        enemy = (CEnemy*)sysAlloc(sizeof(CEnemy));
        memset(enemy, 0, sizeof(CEnemy));
        enemy->_class = _class;
        enemy->health = _class->maxHealth;
        enemy->x = randRange(0, gGetScreenWidth() - _class->sprite->width);
        enemy->y = randRange(-_class->sprite->height * 4, -_class->sprite->height);


        return world.enemyPool[i] = enemy;
    }

    return 0;
}