How to make a world-to-player inventory system?

Question

I am running into an issue of trying to implement an inventory system within XNA (doesn't really matter, could be any platform) but so far. Here is the issue I am trying to wrap my head around:

How can I get an item from the world (think when you kill a monster it drops armor) and get it into my player's inventory?

If an inventory is just a list of items, technically, how could I get Steel Sword from the world into my player's inventory without having a class do more than one thing?

I currently have an item struct, which contains a unique hex value, a count of how many items there are (for stackables, like arrows) and a Texture for rendering within the inventory, and some other unimportant properties (name, description, etc).

It would be bad design if I had to modify my existing item class to house a world position, along with collision detection (don't want the item falling through the earth).

Thanks for any considerations!

Answer 1

The approach I would go for is to have 2 different structs (or classes). WorldItem and InventoryItem.

You could then add an InventoryItem as a property/field of your WorldItem which is what gets placed in the player's inventory when the world item is picked up.

You'd want a method somewhere (on the player class, or either item class) that handles adding an inventory item to the player's inventory, to deal with stacking like items.

Answer 2

As mentioned before splitting up into multiple classes or arrays would be your best bet. I'd create 3 classes, World, Player and Item The world class would have a List WorldItems in it, so would the Player class, but named List Inventory When a player picks up an item, you move it from the list in the World class to the list in the Player class.

In the draw loop of your game you could make a loop which draws all the Items in the WorldItems list to the screen, but off course ignores the Inventory list on the player object.