Firewall
Firewall is the first group project I participated in. It is a tower defense, hack and slash style game where you defend your CPU against hordes of viruses.
Last updated
Firewall is the first group project I participated in. It is a tower defense, hack and slash style game where you defend your CPU against hordes of viruses.
Last updated
Here is a link to the published game on Itch.io
https://mountaingoats.itch.io/firewall
On this page I will break down the first time I worked with creating AI specifically for a game and the thought process behind it. The premise behind the game is to defend your CPU against hordes of viruses and to do this, you have many tools to your disposal. I worked on the turrets, traps and enemy AI.
The regular tower is a simple single target tower that shoots a single target in its range that is the closest to the CPU. It features a simple attack function that overrides from a base tower class.
In this snippet of code, I check the enemies that have entered the range of the turret and take the first enemy. It will then play a sound effect and rotate the tower to the enemy being targeted. I then deal damage and shoot a projectile to visualise the damage being done. Checks are used to ensure the target being attacked is not null and will remove them from the list when necessary.
The AOE tower targets multiple viruses and is useful for clearing many hordes. Benefits of having a good code base is that multiple variations of an object can be created.
The AOE tower works by checking if there are any enemies in range. It will select a random target from the list and set it as the target. It will then remove it from the list to ensure it is not picked again as an attack target.
I then use random positions to create a lightning visual effect to visualise this. It takes 4 points in total. The first and last points are the turret and virus respectively. Points 2 and 3 are randomly chosen and the lightning visual effect is then created. Once the effect is spawned the damage will be dealt to the enemy. After dealing damage, the virus is added back to the list to be chosen again for the next time the tower attacks.
The laser tower is a single target tower designed to deal with high health mobs. It does high and frequent damage to the selected target.
For the laser tower, some helper functions were created to assist in the functionality. A custom sort function was created to sort a list by HP which simply returns a 1 or -1 for usage in the inbuilt sort Unity provides. This is used in conjuction with the function SelectTarget to choose the highest HP virus in range.
After selecting a target, the overriden Attack function takes this target and uses Unity's line renderer to draw a laser beam from the tower to the virus. It then deals its damage to that virus until it is dead.
The first trap that was introduced to the game is the Firewall. This is used as a wall to block the viruses path and hinder their progress towards the CPU. All this trap does is sit there and take damage. Once its HP reaches 0, it will be destroyed. However, once it is destroyed the firewall will then repair itself slowly and regenerate.
The last trap in the game is the Coin Miner. This trap makes all viruses killed in the range of the trap drop more gold.
This trap uses Unity's trigger system and checks whether the character entering is an enemy. If they are, their gold value will increase or decrease.
When it comes to enemy AI, three types of enemies are present in the game. They are the melee mob, ranged mob and tank mob. All 3 mobs use a state machine and swap between targeting the player, or attackable buildings. melee and ranged mobs can attack buildings and players but tank mobs can only attack buildings. This dynamic was used to create a simple yet difficult experience for the player.
The melee and ranged mob share the same behaviour. They will follow the path until they detect a player or an attackable building. They will then attack that target until it is destroyed or out of range. The tank mob will follow the path until an attackable building is detected. They will then destroy it and continue to the next.
The decisions the mobs can make include CanChasePlayer, CoreInRange, PlayerInRange, PlayerInRangeRanged and WallInPath. These decisions function similarly and use distance math and raycasts to determine what is in the range of the player.
The base state allows for any functionality to be created depending on what is required. For Firewall, a state is required for running to the core, chasing the player and attacking buildings.
This is the scripts for attacking the player. It uses quaternions to aim at the player and rotate towards them. It then checks if the player is in attack range. From then on, all the attack functionality is played through. This includes notifying the animator, resetting the attack timer and dealing damage.
