Hi! I'm Final Rockstar I want to thank you for buying this plugin for Unreal Engine 4 I had so much fun while making this plugin I sincerely hope you get the desired result you want to. This is my first unreal Engine project so I apologize in advance if you find something is not working fine or the quality of the plugin is not up to the mark I will try my best to help you. You may try to connect on my Discord channel for any issues, feedback, or suggestions or you can even mail me on gmail . For video preview and setup related thing you can visit my Youtube Channel. It's a learning experience for me. I want to thanks Ben Tristem, Tom Looman for there unreal engine 4 courses which helped me a lot, Epic, and its awesome community.

Version 3 Released

Version 3 has been released on marketplace with more bug fixes,more features and also have a resource manager to save performance.Plugin Contains Demo Folder with an overview Map MortarOverview_P.

Details

The plugin is about creating a Mortar Gun with basic functionalities as quickly as possible. This plugin is developed using C++ and the usage of the blueprint has been very limited. Certain Components are made generic so that they can be used with other Actors. The plugin contains 12 classes and few blueprints which are documented as much as possible so users will easily know what all things are going on. Each source file and blueprint have been prefixed with Mortar keyword to avoid name collision. Following are the files included

C++ Source Files.

Header File	Description
Mortar	This is Main Class of the Mortar Plugin which will be spawned at a game level. Derives from the Actor Class which will contain all the other components.
MortarAIController	This is the mind of AI which will be responsible for detecting other actors and setting up keys for the blackboard. This Derives from AIController
MortarBarrel	This is a StaticMeshComponent which is the topmost part of the Mortar From where the Projectile will fire. This will allow only Vertical movement
MortarTurret	This is also a StaticMeshComponent This is the Middle Part of the Mortar on which the Barrel will be attached. This allows movement in the horizontal direction only
MortarTeamComponent	This is an ActorComponent which is responsible for assigning a team to any actor.
MortarAimingComponent	This is an ActorComponent which is responsible for aiming the barrel to the desired location and other fire-related things
MortarProjectile	This is an Actor Class that is spawned by Mortar's Aiming Component for firing. Includes functionality for projectile launching damaging etc.
MortarMineProjectile	This Class inherits from Mortar Projectile Class which allows using Mine Projectile with delay explosion
MortarHealthComponent	This is a generic ActorComponent Class for health-related functionalities
MortarAIBaseTaskNode	This is the base class for Behavior Tree Task Node Which inherits from UBTTaskNode. All Behavior Tree tasks should inherit from this class. This class checks some conditions and selects the best enemy among the detected actors. This best enemy then can be used by other tasks as the main Target.
MortarShootingTask	This is the Behavior Tree Task node for Shooting an enemy which inherits from MortarAIBaseTaskNode
ActorsObject	It is simply a UObject which stores TArray of Actors
MortarResourceManager	It is a new class which is responisble for restricting the total number of projectiles that can be spawned

Blueprints.

Blueprint Name	Description
BP_Mortar_01,BP_Mortar_02	Blueprint deriving from Mortar C++ Class This is the blueprint that will be placed in the world. User have to setup StaticMeshs before using finally in level
BP_MortarProjectile,BP_MortarMineProjectile	Blueprint deriving from MortarProjectile C++ Class This will be the class spawned by BP_Mortar on firing
W_MortarHealthBar	Health Bar widget is shown on Mortar
BB_MortarAIBlackboard	Blackboard Key Values used in behavior tree
BP_MortarAIController	Blueprint deriving from MortarAIController C++ Class.Things like AIperception, blackboard asset, behavior tree asset has to be set up in it
BT_MortarAIBehaviorTree	Simple Behavior Tree Containing Behavior of each mortar
BP_MortarResourceManager	Blueprint deriving from MortarResourceManager .In this blueprint the number of resources that can be spawned are specified

Meshes and Materials.

Although the plugin is mainly about C++ but for demonstration purposes it also includes few simple static Meshes and materials and effects.

Setup

This Plugin is developed in Unreal Engine 4.26. After you have downloaded the plugin from Epic Store you will get a Plugins Folder.

Update - Plugin Now supports Niagara Effects and also ships with some effects.

 

1. To Import this plugin into any project copy the Plugins folder into the Main Directory of the project. There are two main folders in this plugin. Content - Containing All the blueprints,Meshes and Materials related to the plugin. Source - Source Code for the Plugins. AI-related code is added in an AI subdirectory.
2. After Importing compile the source code and open unreal engine 4. You will find two folders added in the Main folder.

 

Note - If you are not able to view source code for plugin then all the temporary folders of your project like Binaries,DerivedDataCache,Intermediate,Saved and Project.sln and then generate visual studio files by right clicking Project.uproject

Step 1 - Importing Static Meshes For Mortar

We have 3 levels of the hierarchy of Static Meshes in BP_Mortar

• Mortar Base - It is the immovable Static Mesh which acts as a base and will be the root component.
  • Mortar Turret - It will allow the middle portion of the Mortar Gun which can move horizontally only.
    • Mortar Barrel - It will be the topmost static Mesh which will fire projectiles and can move vertically only

Mesh Setup

 

• Setting Up Socket for Mortar Barrel Static Mesh Whatever mesh you are using for Mortar Barrel we require a Socket named Projectile to be added from where the projectile actors would be spawned.

Update - Plugin Now allows spawning More than one Projectile from a mesh.

Step 2 - Setting Up BP_Mortar

We need to set up a few things before we can use BP_Mortar. As you open the blueprint you can see all the required components have been already added through C++. We need to set up static meshes for Mortar and some other parameters like health bar widget, destroy delay, unlimited spawning There are Few BlueprintImplementableEvent Events exposed to Blueprints from C++.

• ActorDeathEvent - This is a BlueprintImplementableEvent which have to be handheld in this Blueprint. This Event is called as soon as Mortar is Killed. User can spawn a projectile or a sound at that location.
• ActorRespawnEvent - This is called before Mortar is going to respawn. User may spawn projectils or sound or print text in BP_Mortar through this event.
• ActorTeamChangeEvent - This is called after Team of a Mortar has been changed from a Neutral state to a desired state.

 

In addition to this there are three Events.

1. FMortarDeathEvent - Event Called On Death. Here we generally like to disconnect Controller which then can be deleted.
2. FMortarPauseEvent - Event Called When Mortar Dies and in future would want to resume Both Player and AI controller would want to pause their's controllers.
3. FMortarResumeEvent - Event Called When Mortar Respawns.

Setting Up Components in BP_Mortar.

• Setting Up AI Controller To Enable working of AI we need to set the mind of our mortar to BP_MortarAIController in BP_Mortar
• Setting Up Health Component - There are three Parameters Default Health - The starting Health,Current Health - Current health of the actor,Max Health - Maximum Health that can be reached. By default, all values are 100 units.

Update in Version 3 Three New Events Have been added for Health Component.

1. Mortar Critical Health Event - Event Generated Whenever Life of mortar Drops beyond a critical limit
2. Mortar Critical Health Recover Event - Event Generated Whenever Life of mortar Goes beyond critical limit
3. DeadEvent - Event Generated Whenever Actor Dies i.e when health becomes less than or equal to 0.

 

• Setting Up Aiming Component - There are few parameters in this component as shown in the image.*Projectile* - Class to spawn when firing,Firing Speed - Speed of each projectile,Reload Time In Seconds - Time Delay in between two shots,Firing Left - No of ammunition left only useful if unlimited ammo is off, Unlimited Ammo - No limit on ammunition,Projectile Spawn Socket Name - Name of the socket in Mortar Barrel Static Mesh from where the projectile will spawn. Vector Threshold Comparision - Threshold limit for comparing two vectors direction

 

• Setting Up Team Component - This Component allows one to assign a team to each actor. There are two main categories and three parameters for each category. Starting with parameters Team ID - Unique ID for each team,Team Name - Name of each team,Team Color - Color for each team.
• Team Info - It is the current Team Information.
• Default Team Info - It is the team Information that will be used after respawning or after reset.

With the help of Team Id attitude of two agents can be decided.

• Enemies - Actors with Different Team ID.
• Friends - Actors with Same Team ID
• Neutrals - Actors with Team ID = 0

In addition to this we have one event in Team Component

• FTeamChangeEvent - Event Called On Team Change.

 

Step 3 - Setting Up BP_MortarAIController

Most of the Setting is already done through C++ code but few things have to be set up in blueprint.

Setting Up References for Blackboard and Behavior Tree

We need to set up the reference for Blackboard and Behavior Tree that we will use.

 

Setting Up AI Perception

Second We need to add perception through Blueprint and configure the senses. As of now for Unreal Engine 4.25 Adding AI Perception through C++ has an annoying bug where you are not able to add additional senses through the blueprint. Change the setting as you desire, by default following are the values used. Select AI Perception From The Components to see the following properties.

 

Step 4 - Setting Up BT_MortarAIBehaviorTree

This is the behavior tree for the Mortar which contains task like shooting more tasks can be added here but all tasks should inherit from MortarAIBaseTaskNode to get the best enemy to focus on. There are some settings which can be done for more custom behavior of Mortar AI like

• Select Enemy - If this is checked then Behavior Tree will consider the enemy for shooting. Two actors are enemies if they have different TeamID.
• Select Friends - If this is checked then Behavior Tree will consider friends also for shooting. Two actors are friends if they have the same TeamID.
• Select Neutrals - If this is checked then Behavior Tree will consider neutral actors also for shooting. Neutral actors are the actors who have a 0 team id.

 

Step 5 - Setting Up BB_MortarAIBlackboard

This contains all the keys that will be used by behavior Tree. We require only one Key which is DetectedEnemies. The Type of this key should be ActorsObject which will store the detected actors by AIPerception in memory.

 

Step 6 - Setting Up BP_MortarProjectile

BP_MortarProjectile is an Actor Class that is spawned by AimingComponent Required Components are already set up in C++ with CollisionMesh being the Root Component. You have to assign Static Mesh for Projectile in Collision Mesh properties. By Default it is visible and it generates ComponentHit .Event when it hits a surface.There are five major components excluding Projectile Movement Component and Niagara effects.

1. Collision Mesh - This is the mesh which will hit the target. This is where we will add projectile Mesh.
2. Launch Blast - This is a Particle System Component which will be activated as soon as projectile is spawned in the world. As soon as a projectile hits a surface this particle system will get deactivated.
3. Impact Blast - This is also a Particle System Component which will be activated as soon as projectile hits a surface.
4. Impact Blast - Particle to use for trailing effect.
5. Explosion Force - This is a Radial Force Component.This will include the damage radius ,ignore self actor option and many other options.You may want to change the default parameters if you observe your actor's health is not reducing on hit.

 

1. Along with that there is a BlueprintImplementableEvent which is exposed to blueprint. ExplosionEvent - This event is called as the projectile hits a surface and generates ComponentHit Event.This function can be used to spawn a projectile or a sound in blueprint.

 

Step 7 - Setting Up W_MortarHealthBar

This is a UI widget that will be shown for each mortar which will be showing the current health Percentage. There is a basic progress bar already set up in W_MortarHealthBar as shown in the picture with the corresponding function GetPercentage for filling up the health from Mortar.

 

We will setup the GetPercentage Function as shown below. We will make a public variable OwningMortar of Type Mortar which we will use in BP_Mortar to set the reference.

 

We will create a function InitHealthWidget in BP_Mortar as shown below which will be called on begin play which will set up a reference for the W_MortarHealthBar.

 

Step 8 - Compile All Blueprints

That's it after you have completed all the steps above you would be able to use this in your game.

Step 9 - Set Resource Max Count

A new blueprint has been added which is responisble for setting up the maximum projectiles there can be in a level.

For documentation related to code,follow this link