February 23, 2019
Tower Defense Tutorial
Episode 19 – Upgrade
Youtube – How to make a Tower Defense Game (E19 UPGRADE) – Unity Tutorial
By: Brackeys
Ep. 19
This tutorial goes over upgrading our turrets after selecting them.
We started by moving the BuildTurretOn method from the BuildManager script to the Node script, and renamed it BuildTurret (since it will be obvious it is “on” that node now anyway). This was done because BuildTurretOn was making a lot of references to the Node script anyway, so it made more sense to just handle everything locally to reduce the number of references needed.
Next we created the UpgradeTurret method. This was mostly a copy/paste of our BuildTurret method, with a few tweaks (having a separate cost, possibly a separate effect). The biggest difference was that we couldn’t just instantiate the upgraded turret since we already have one there; we need to remove the initial turret first.
We created a new prefab for the upgraded version of our standard turret. We duplicated the original, scaled that up some, and changed one of the material colors just to make it clear it was a different version. I liked the way they organized this in the Asset hierarchy. Our folder structure was already: Imports -> Models -> [Model Name]. We further branched this into two separate folders to hold the materials for the standard turret and a folder for the materials of the upgraded turret.
We edited the NodeUI so that the upgrade cost is tied to the currently selected turret’s TurretBluePrint now. This makes sure the upgrade cost updates according to which type of turret is selected.
Finally, we created the case for when the turret has no more upgrades available. In the NodeUI script, we check the upgrade state (currently just isUpgraded) on the turret. If it is not in the final state, perform normal upgrade functions, if it is, set the text to something like “Done” or “Maxed Out”, and set the upgrade button itself it be non-interactible (upgradeButton.interactable = false).
SUMMARY
- If a method makes a lot of references to another script/class, it might make more sense to just move that method into the script/class
- They use an underscore ( _ ) before a variable to indicate it is just a local variable field version of a variable (i.e. _turret instead of turret since _turret is created and used specifically within a single, smaller method)
- If you have upgraded versions of models that are mostly varying the materials, create separate Material folders for each variation to keep organized
- Use buttonName.interactible = false to stop button from having hovering animations or performing actions when pressed