Update 5 (v1.5) has gone live on the Unreal Engine Marketplace. This is a v4.13 exclusive update & listed below are the main changes introduced in this update:
- Implemented a new & improved component based Threat Detection system for the Creep AI. The two new components - Visual Perception & Threat Response together form a modular system that enables creation of new AI as well as extending features of existing AI with ease. Here is a brief overview of the components:
Visual Perception component: This component uses a combination of distance, angular, & line trace based checks to relay information about the highest priority target to the owning actor.
Threat Response component: This component comes into play once the owning actor has acquired an active target. It determines whether to move to/attack the active target based on the distance to it. The final decision is then relayed back to the parent actor for execution. For example, an attack order to melee parent actor would be executed in a different manner when compared to the execution by a ranged parent actor.
The components act independently & are not aware of the existence of other components. They are only aware of their own existence as well as that of the owning actor. Any information that is being relayed between these components happen through the parent class & interface functions. This facilitates creation of new creep types with different combination of components [along with their associated interfaces]. For example, all creep classes are now equipped with the Threat Response component by default, while the Ranged creep class will use the Visual Perception component as well, thus enabling it to attack towers along it’s path.
- Added a new Global Ability - ‘Tower Guardians’ than allows the player to summon Tower Guardians along the enemy path to block enemy units & engage them in combat. Each Tower Guardian can be used to lock down one enemy unit in combat, thus providing the nearby towers with an opportunity to take down the locked target. This is especially useful against fast moving or tanky creeps as the Tower Guardians can block them long enough for the Towers to inflict massive damage. The ability works on a cooldown & hence can be used multiple times similar to the Airstrike. However in order to prevent the player from spawning an endless supply of Tower Guardians between the waves, the Tower Guardians are set to have a definite lifespan, which causes them to die after a certain period of time has elapsed.
The Tower Guardians also use the aforementioned Visual Perception & Threat Response components to acquire & attack their targets. A Tower Guardian will always try to lock on to a creep that is not locked into combat with another Tower Guardian. But if there are no other non-locked creeps in the vicinity, it will lock on to another locked creep. However as soon as it detects a non locked creep, it will perceive this new target as the highest priority threat & move in to attack it.
Any creep that is locked in to combat by a Tower Guardian will stop all movement until the lock has been lifted, which happens only if the Tower Guardian is destroyed. The Tower Guardian, on the other hand will move towards it’s target until it’s within the attack range. The locked creep will keep evaluating it’s distance to the Tower Guardian & commence assault once the Tower Guardian is within it’s attack range.
**Preview Video (Tower Guardians): **
https://www.youtube.com/watch?v=epeyBRs8mTw
Gameplay demo of the v1.5 Tower Defense Starter Kit (Windows): https://www.dropbox.com/s/epyjcj9y1fvh0ca/Tower%20Defense%20Starter%20Kit%20Sample%20Game%20Demo.7z?dl=0
All changes within the blueprints are marked with the boolean variable ‘Version1.5’ in order to easily identify the workflow changes introduced with this update. Comments are also written to describe the major changes. The new variables as well as functions added to existing blueprints are also marked in the event graph as shown below:
Changes in the Content Browser:
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Added new actor components: BPC_ThreatResponse, BPC_VisualPerception, & BPC_TowerGuardiansAbility.
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Added new character blueprint: BP_FriendlyAI_TowerGuardian.
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New item added to enum ‘EGlobalAbilities’.
