TryPickup
virtual protected bool TryPickup(in out Actor toucher)
Usage
A virtual function called by Inventory items when they're received (either by being picked up from the world, or by being given directly). This is the main function related to picking up that performs a whole host of checks, such as:
- Calling HandlePickup to let other items in the inventory process this pickup (not all items do that, however)
- Checking whether the toucher already has this item in their inventory, and whether its MaxAmount allows a new item to be picked up.
- Calls Use if the item has the INVENTORY.AUTOACTIVATE flag.
and others.
Note, this function should never be called directly. If you want to call it manually, it should be done through a special wrapper, CallTryPickup, which performs a series of extra checks before calling this function.
| Note: If you need to make an item do something once it's being picked up, consider overriding Use or AttachToOwner instead. TryPickup comes with a large list of checks and assumptions, and overriding it directly is very rarely necessary or useful. |
Parameters
- Actor toucher
- The actor who is attempting to receive this item.
Return values
Returns true if the item was successfully received. Note, this doesn't guarantee that the item itself keep existing. Many classes, such as Health, perform their function (such as healing the toucher) and then disappear. TryPickup still returns true in this case, because technically the item was sucecssfully received.
ZScript definition
| Note: The ZScript definition below is for reference and may be different in the current version of GZDoom.The most up-to-date version of this code can be found on GZDoom GitHub. |
Various items may override this function, but the base Inventory class defines it as follows:
virtual protected bool TryPickup (in out Actor toucher)
{
Actor newtoucher = toucher; // in case changed by the powerup
// If HandlePickup() returns true, it will set the IF_PICKUPGOOD flag
// to indicate that self item has been picked up. If the item cannot be
// picked up, then it leaves the flag cleared.
bPickupGood = false;
if (toucher.Inv != NULL && toucher.Inv.CallHandlePickup (self))
{
// Let something else the player is holding intercept the pickup.
if (!bPickupGood)
{
return false;
}
bPickupGood = false;
GoAwayAndDie ();
}
else if (MaxAmount > 0)
{
// Add the item to the inventory. It is not already there, or HandlePickup
// would have already taken care of it.
let copy = CreateCopy (toucher);
if (copy == NULL)
{
return false;
}
// Some powerups cannot activate absolutely, for
// example, PowerMorph; fail the pickup if so.
if (copy.bInitEffectFailed)
{
if (copy != self) copy.Destroy();
else bInitEffectFailed = false;
return false;
}
// Handle owner-changing powerups
if (copy.bCreateCopyMoved)
{
newtoucher = copy.Owner;
copy.Owner = NULL;
bCreateCopyMoved = false;
}
// Continue onwards with the rest
copy.AttachToOwner (newtoucher);
if (bAutoActivate)
{
if (copy.Use (true))
{
if (--copy.Amount <= 0)
{
copy.bSpecial = false;
copy.SetStateLabel ("HoldAndDestroy");
}
}
}
}
else if (bAutoActivate)
{
// Special case: If an item's MaxAmount is 0, you can still pick it
// up if it is autoactivate-able.
// The item is placed in the inventory just long enough to be used.
toucher.AddInventory(self);
bool usegood = Use(true);
// Handle potential change of toucher/owner because of morph
if (usegood && self.owner)
{
toucher = self.owner;
}
toucher.RemoveInventory(self);
if (usegood)
{
GoAwayAndDie();
}
else
{
return false;
}
}
return true;
}
Examples
|
Note: This article lists no examples. If you make use of this feature in your own project(s) or know of any basic examples that could be shared, please add them. This will make it easier to understand for future authors seeking assistance. Your contributions are greatly appreciated. |
