Engineer Combat Task

Introduction

The EngineerCombatTask implements the entire shooting functionality of Engineers and enables them to detect and attack enemy mobs. It scans for mobs every second and takes a high priority if a mob is detected.

It is ran by the HumanWanderTask and works in coordination with HumanWaitTask and HumanMovementTask to give the Engineers a fighting chance as a last straw against enemies.

Responsibilities of this task include switching through multiple Engineer states, playing the required animations and sounds, and spawning Projectiles in the enemy's direction.

Usage

This task is instantiated by HumanWanderTask through the EngineerCombatTask(float maxRange) constructor, which takes the maximum shooting range of the Engineer entity as a parameter.

Task Actions

The following task actions are called based on the game area's current state inside the overridden update() method, which is handled by the task runner implemented in AITaskComponent.

Detecting Enemy Mobs: isTargetVisible()

This method is used to detect any mobs within 5 lanes of the Engineer on either end of the map.

To detect a mob in a certain lane, the inbuilt physics.raycast() method is used between two vector positions on the map to detect any entities within a certain layer.

If detected, the position of the enemy mob is stored in a list. After the detection sequence finishes running, the method returns true or false depending on whether one or more targets have been found.

Code:

public boolean isTargetVisible() {
    Vector2 position = owner.getEntity().getCenterPosition();

    for (int i = 5; i > -5; i--) {
        if (physics.raycast(position, new Vector2(position.x + maxRange, position.y + i), TARGET, hit)) {
            hits.add(hit);
            targets.add(new Vector2(position.x + maxRange, position.y + i));
        }
    }
    return !hits.isEmpty();
}

Changing Engineer State: updateEngineerState()

This method runs a state machine for the Engineer entity to enable switching between idle and firing states.

If the Engineer is idle, i.e in the IDLE_RIGHT (Right facing) state, the state machine detects for any targets using the isTargetVisible() method. If a target is found, the state is updated to FIRING and the firing animation is played for the Engineer entity.

If the Engineer is in the FIRING state, the state machine first detects whether all targets have been downed. If there is no remaining target, the state is switched back to IDLE_RIGHT with the corresponding animation.

The STATE enum is used to store all possible

Helper Methods

The following methods are used to optimize the primary methods and remove code redundancy.

Retrieving the closest target: fetchTarget()

This method is responsible for returning the nearest target's position from the list of detected targets. To implement this logic, it uses a placeholder integer to store the distance between the Engineer and Mob lanes, and iterates through the stored positions to find the one closest to the Engineer.

Getting the task priority: getPriority()

This method returns the task's priority, thus deciding if it should be run before any other game tasks or not. It returns the default priority (3) if any enemies are visible, otherwise 0.

Entering the combat state: combatState()

This method triggers a FIRING event, of a string value "firingSingleStart". This trigger runs the required firing animation in the Engineer entity that owns this task. The method also changes the Engineer's state to enable the firing routine.