How can I call a function from a nearby gameobject's script?

[Kurt-Dekker]

Your question embodies at least three different fundamental Unity beginner concepts, all completely unrelated to each other. I’m not sure which of these you’re having issues with, but basically:

1. How to find a particular NPC you’re close to or looking at. See what @Nad_B posted or any one of ten billion other similar videos. This is well-solved well-described territory.

2. How to spawn stuff and keep a reference to it: Instantiate() returns a reference to what you spawn. Use that reference. That’s why Unity gives it to you. Do not spawn things blindly into the scene, then go looking for it with Find / Get. That approach does not make logical sense.

3. How to access things (call methods, access fields) on other instances. This is just basic Unity inter-object signaling / messaging. The basics are posted below:

Referencing variables, fields, methods (anything non-static) in other script instances:

Help creating function for changing vars in another script

Like all inter-script interaction, all you need is: Script A needs a reference to script B, which you will populate in the editor: // inside of ScriptA: public ScriptB myBScript; Script B needs to have something public that script A can change: // variable / field inside of ScriptB: public int myFooInteger; // function inside of ScriptB: public void DoStuff( string reason) { } Script A can then change it directly using the reference to B: // here is ScriptA accessing something in Scrip…

accessing a gameobject in different scene

within a class there are reference to gameobjects in the scene A, the same gameobjects are available in the scene B. i have dragged the gameobjects in scene A into inspector fields. now how to reference these gameobjects in the scene B via script into relevant fields in the inspector? please give me some idea. thanls.

It isn’t always the best idea for everything to access everything else all over the place. For instance, it is BAD for the player to reach into an enemy and reduce his health.

Instead there should be a function you call on the enemy to reduce his health. All the same rules apply for the above steps: the function must be public AND you need a reference to the class instance.

That way the enemy (and only the enemy) has code to reduce his health and simultaneously do anything else, such as kill him or make him reel from the impact, and all that code is centralized in one place.

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I’ll also tack this on as it appears this is part of some kind of inventory / NPC shop system:

These things (inventory, shop systems, character customization, dialog tree systems, crafting, etc) are fairly tricky hairy beasts, definitely deep in advanced coding territory.

Inventory code never lives “all by itself.” All inventory code is EXTREMELY tightly bound to prefabs and/or assets used to display and present and control the inventory. Problems and solutions must consider both code and assets as well as scene / prefab setup and connectivity.

Inventories / shop systems / character selectors all contain elements of:

• a database of items that you may possibly possess / equip
• a database of the items that you actually possess / equip currently
• perhaps another database of your “storage” area at home base?
• persistence of this information to storage between game runs
• presentation of the inventory to the user (may have to scale and grow, overlay parts, clothing, etc)
• interaction with items in the inventory or on the character or in the home base storage area
• interaction with the world to get items in and out
• dependence on asset definition (images, etc.) for presentation

Just the design choices of such a system can have a lot of complicating confounding issues, such as:

• can you have multiple items? Is there a limit?
• if there is an item limit, what is it? Total count? Weight? Size? Something else?
• are those items shown individually or do they stack?
• are coins / gems stacked but other stuff isn’t stacked?
• do items have detailed data shown (durability, rarity, damage, etc.)?
• can users combine items to make new items? How? Limits? Results? Messages of success/failure?
• can users substantially modify items with other things like spells, gems, sockets, etc.?
• does a worn-out item (shovel) become something else (like a stick) when the item wears out fully?
• etc.

Your best bet is probably to write down exactly what you want feature-wise. It may be useful to get very familiar with an existing game so you have an actual example of each feature in action.

Once you have decided a baseline design, fully work through two or three different inventory tutorials on Youtube, perhaps even for the game example you have chosen above.

Breaking down a large problem such as inventory:

Weapon Inventory and how to script weapons.

You’re welcome of course. One thing you could try to really get a “feel” for what happens in this case is make a simple script that is just one cell of your inventory. Put this into a script that you can access through an “inventory API” that does certain things to a cell. These functions might be: “Set the type of item” “Query the type and quantity of item in this cell” “Add 1 item to this cell.” “Add N number of items to this cell.” “Remove N item from this cell.” Then you can have pr…

If you want to see most of the steps involved, make a “micro inventory” in your game, something whereby the player can have (or not have) a single item, and display that item in the UI, and let the user select that item and do things with it (take, drop, use, wear, eat, sell, buy, etc.).

Everything you learn doing that “micro inventory” of one item will apply when you have any larger more complex inventory, and it will give you a feel for what you are dealing with.

Breaking down large problems in general:

Options for implementing mining/digging in an asteroid belt game?

Whenever engineering seems too much to tackle, it's always best to see if you can break the problem down. What you describe above is by no means simple, as just the different ways all of it could be implemented are complex: does the camera rotate with the player on the asteroid? Do the player's controls rotate as they walk around the asteroid? Does the camera lock to the rotating asteroid? What does the camera do if the player digs down a ways? If the player digs a tunnel into the asteroid,…

The moment you put an inventory system into place is also a fantastic time to consider your data lifetime and persistence. Create a load/save game and put the inventory data store into that load/save data area and begin loading/saving the game state every time you run / stop the game. Doing this early in the development cycle will make things much easier later on.