Write a script named EnemyDropItemProc that would be grabbed into an enemy or other item-droppable objects. There are some adjustable parameters in this class:
-
Enemy LevelThe enemies can be divided into several levels, there are 5 levels in the Shooter Example. It more likes that the enemy will drop the same level items when they killed by the player. Particular level means special. -
Level ManagerThe pointer to the level manager in the scene. It will handle all item drop functions. -
Drop Item PerThe probability of the enemy to drop items when is killed.
The codes in script named EnemyDropItemProc are listed below.
public ItemLevel enemyLevel = ItemLevel.Level1;
public LevelManager levelManager = null;
public float dropItemPer = 0.1f;
// Use this for initialization
void Start () {
if (!levelManager)
{
levelManager = GameObject.FindGameObjectWithTag(Tags.gameController).GetComponent<LevelManager>();
}
}
public Item DropItem()
{
if (Random.Range(0f, 1f) < dropItemPer)
{
Debug.Log("Drop an item");
return levelManager.GenerateRandomItem(transform);
}
return null;
}Function DropItem will be called when the enemy is killed by the player. It would be called in Die function of Enemy script like this:
protected override void Die()
{
SendMessage("DropItem");
lm.killEnemyNum++;
GameObject.Destroy(gameObject);
}In script LevelManager, the function GenerateRandomItem , that will handle all random generate items process, can be write like this:
public Item GenerateRandomItem(Transform dropper)
{
float r = Random.value;
int itemLevel = (int)currentLevel;
int enemyLevel = (int)dropper.gameObject.GetComponent<EnemyDropItemProc>().enemyLevel;
if (r < 0.8) // There is 80% to generate the same level item
{
itemLevel = enemyLevel;
}
else if (r < 0.9) // 10% to generate 1 higher level item
{
itemLevel += 1;
}
else if (r < 0.95) // 5% to generate 2 higher level item
{
itemLevel += 2;
}
else if (r < 0.96) // 1% to generate particular, menas special, level item
{
itemLevel = (int)ItemLevel.Particular;
}
else
return null;
// if the enemy itself is special level, it has more opportunity to drop special item
if (enemyLevel == (int)ItemLevel.Particular)
{
if (Random.value < 0.33)
{
itemLevel = (int)ItemLevel.Particular;
}
}
itemLevel = (itemLevel < allLevelItems.Length) ? itemLevel : (allLevelItems.Length - 1);
// call `GenerateRandomLevelItem` to finally drop a random item in this level
Item droppedItem = allLevelItems[itemLevel].GenerateRandomLevelItem();
Debug.Assert(droppedItem!=null);
droppedItem = (Item)GameObject.Instantiate(droppedItem, dropper.position, Quaternion.identity);
droppedItem.SetupRandomPickableItem();
return droppedItem;
}All droppable items would be managed in a script named ItemsCollection, it can return random , use function GenerateRandomLevelItem, or particular item from a particular item level list.
More details, please check the sample project here.