18 - Generating Gold

Practice: Create a GoldGenerator Prefab

Create a new GameObject to represent your GoldGenerator building
Add a model (or multiple models) as children objects to the GoldGenerator

Feel free to use any model you would like! In this document, I will combine two of the Kenney models together.

If necessary, adjust the models positions within the parent object to fit nicely on a tile
Convert your object into a Prefab

When you are finished, you should have a GoldGenerator Prefab that you can place on any tile in your game scene:

Practice: GoldGenerator MonoBehaviour

Create a new MonoBehaviour called GoldGenerator
Add a float Delay property which represents how often it will generate gold
Add an int Gold property which represents how much gold is generated
Add a GoldGenertor component to your GoldGenerator prefab
In the Inspector set Delay to 2 and Gold to 1

When you've finished your prefab should look similar to the image below:

Referencing the PlayerController

To be able to update the player's gold, the GoldGenerator requires a reference to the PlayerController. You will not be able to set this in the Prefab because the PlayerController does not exist here. One way you can acquire a reference to it without the need to set it in the Inspector is to assume that the PlayerController will be a parent of the GoldGenerator. Then, use GetComponentInParent to set the reference.

Add a PlayerController Controller property to your GoldGenerator
Add an Awake() method
In Awake() use GetComponentInParent<PlayerController>() to assign Controller

Testing the PlayerController Reference

Add a GoldGenerator to your game scene as a child of the PlayerController
Enter Play Mode
Observe that the PlayerController property is set when the game starts

Challenge: GenerateGold Method

Review how you used InvokeRepeating and CancelInvoke to spawn enemies into your game
Add a GenerateGold() method to your GoldGenerator MonoBehaviour
Use InvokeRepeating to cause GenerateGold() to execute every Delay seconds
Don't forget to use CancelInvoke when the GoldGenerator is disabled
Enter Play Mode to test that your Gold is now increasing

When you're finished, your game should look similar to the video below:

Spawning GoldGenerators

The TurretSpawner you created previously does almost everything you need to be able to spawn GoldGenerators into your game.

Select your TurretSpawner in the Hierarchy
In the Inspector change the Turret Prefab property to your GoldGenerator prefab
Enter Play Mode and place a GoldGenerator
Observe the error that occurs

Setting the Parent Transform

If you investigate the error, you will find that the newly spawned GoldGenerator does not have a PlayerController. This is because the object is being instantiated without a parent.

The Instatiate method has several overloaded versions that allow you to specify additional information about how to create the specified GameObject. One version allows you to specify the parent object: Instantiate(GameObject, Transform)

Update TurretSpawner.SpawnTurret to set the parent of the object of the turret to be the PlayerController's transform when it is spawned. (Controller.transform)
Enter Play Mode to test that you are able to spawn your Gold Generators
When you are finished, your game should look and act similar to the video below:

Changing the Prefab

Currently, you only have a single Build button that enables the TurretSpawner game which knows references your GoldGenerator prefab. Next, you will update the Build button to set the prefab.

Update your TurretSpawner.TurretPrefab field to have a public setter
Select the Button in the Hierarchy
In the Inspector add a listener to the On Click event
Set the TurretSpawner as the listening object
Select the TurretSpanwer.TurretPrefab property
Set the GameObject to be your Turret prefab

Enter Play Mode and test that your TurretSpawner field is changed when the button is clicked. This results in the player being able to spawn Turrets (rather than GoldGenerators)

Challenge: Create a Generator Button

Currently, your player is only capable of building Turrets when they click the Build button. Can you add another button that allows them to create generators?

Add a button to your Canvas
The button should be labeled "Generator"
Use Pivots and Anchors to set the buttons position relative to the screen
When the button is clicked, the player should be able to place generators
Enter Play Mode to test that both of your buttons works

When you have finished, your game should look and act similar to the video below: