Creating AI Ghost
This page documents the workflow to follow when creating a new Ghost AI
Setup
Make sure the head bone forward is the blue Z-Axis, up is green Y-Axis; if not, create a child component such that its forward is the blue Z-Axis and up is green Y-Axis and assign it as the head bone.
The finished setup head bone should look like the image below.
Eye Man Implementation:
// Copyright Š 2024 by MADKEV Studio, all rights reserved
using System;
using System.Collections;
using Animancer;
using UnityEngine;
/// <summary>
/// Implementation for Eye Man ghost character.
/// </summary>
public class EyeMan : BaseGhostAI<EyeMan.AIStates>
{
private const float WALK_SPEED = 3f;
private const float RUN_SPEED = 6.8f;
private const int CHOKE_ATTACK_AMOUNT = 100;
private const int LONG_ATTACK_AMOUNT = 68;
private const float ATTACK_RANGE = 2.86f;
private const float CHOKE_ATTACK_RANGE = 1.26f;
[Header("Setup")]
public Transform mHandTransform;
public AnimationClip mWalkClip;
public AnimationClip mRunClip;
public AnimationClip mStandingClip;
public AnimationClip mChokeAttackClip;
public AnimationClip mLongAttackClip;
private float mDoorWaitTime;
private Door mObstacleDoor;
protected override AISettings OnInitializeAISettings()
{
AISettings setting = new AISettings();
setting.StartingState = AIStates.Wondering;
setting.AlertDistance = 5;
setting.VisionAngle = 145;
setting.VisionDistance = 10;
return setting;
}
protected override void OnLosePlayerTargetRequested()
{
// Get difficulty multiplier to see if we should lose player
// More difficult has higher percentage, so here we need to 1 - percent to calculate percentage chance of losing player
if (AIMath.Decide2(LIMENDefine.GetAIProbabilityPercent(1 - GameManager.Instance.GetDifficulty())))
{
// Lose player: set state to wondering. We don't clear the current player target,
// but if player target is no longer visible, AI won't keep chasing
ChangeAIStateServer(AIStates.Wondering);
}
}
public enum AIStates
{
Wondering, // This will be the default state since it's the first enum
Chase,
Attack,
HandleDoor,
}
protected override void OnAIDoorObstacleTick(Door obstacleDoor)
{
mObstacleDoor = obstacleDoor;
ChangeAIStateServer(AIStates.HandleDoor);
}
// TICKING //
protected override void OnAIPreTickServer()
{
base.OnAIPreTickServer();
// Validate if player target becomes null (Player disconnected) before invoking base
// So we don't have to null check or validate if player is already killed in every ticking state later
// Pre tick validate
if (!ValidatePlayerTarget() && (GetCurrentState() == AIStates.Chase || GetCurrentState() == AIStates.Attack))
ChangeAIStateServer(AIStates.Wondering);
}
// State - HandleDoor
protected void OnStateEnterHandleDoor()
{
SetMovementState(BaseGhostAI<AIStates>.MovementState.NoMovement);
mDoorWaitTime = UnityEngine.Random.Range(1.0f, 3.0f);
}
protected void OnStateTickHandleDoor()
{
PlayAnimation(mStandingClip);
if (mObstacleDoor)
FaceTarget(mObstacleDoor.transform);
// Wait a random amount before proceeding to open the door or if door is no longer closed
if (!IsObstacleDoor(mObstacleDoor) || GetCurrentStateTimer() >= mDoorWaitTime)
{
// This function will also leave a hand-print on the door after opening it
TryOpenDoor(mObstacleDoor);
// Change to attack, AI pre-tick would fallback to wondering if does not have valid player target.
ChangeAIStateServer(AIStates.Chase);
}
}
// State - Wondering //
protected void OnStateEnterWondering()
{
SetMovementState(BaseGhostAI<AIStates>.MovementState.MoveTowardsWaypointTarget);
}
protected void OnStateTickWondering()
{
PlayAnimation(mWalkClip);
SetSpeed(WALK_SPEED);
// Patrol waypoint
if (GetWaypointTarget() == null || IsWithinDistance(GetWaypointTarget().transform.position, 2f))
SetWaypointTarget(GlobalWaypoint.Instance.GetNextWaypoint(GetWaypointTarget()));
// Search for player
Player foundPlayer = FindClosestVisiblePlayer(true);
if (foundPlayer)
{
SetPlayerTarget(foundPlayer);
ChangeAIStateServer(AIStates.Chase);
}
}
// State - Chase //
protected void OnStateEnterChase()
{
SetMovementState(BaseGhostAI<AIStates>.MovementState.MoveTowardsPlayerTarget);
}
protected void OnStateTickChase()
{
GetPlayerTarget().NotifyChase(this);
PlayAnimation(mRunClip);
SetSpeed(RUN_SPEED);
// Thanks to our player target check in OnAITickServer, we don't have to null check here for player target
if (IsWithinDistance(GetPlayerTarget().transform.position, ATTACK_RANGE))
ChangeAIStateServer(AIStates.Attack);
}
protected void OnStateEnterAttack()
{
// Decide which attack to use, choke attack or ranged attack
// If player is still very close and visible to AI, use choke attack. Else, use long range attack that deals regional damage to other players in radius as well.
bool useChokeAttack = CanSeePlayer(GetPlayerTarget()) && IsWithinDistance(GetPlayerTarget().transform.position, CHOKE_ATTACK_RANGE);
if (useChokeAttack)
{
GetPlayerTarget().ServerPinPlayerToTransform(HumanBodyBones.Head, mHandTransform, mChokeAttackClip.length);
PlayAnimation(mChokeAttackClip, OnAttackEnded, () => { DoAttack(true); }, 0.52f);
}
else
PlayAnimation(mLongAttackClip, OnAttackEnded, () => { DoAttack(false); }, 0.426f);
}
protected void OnStateTickAttack()
{
GetPlayerTarget().NotifyChase(this);
SetMovementState(BaseGhostAI<AIStates>.MovementState.NoMovement);
FaceTarget(GetPlayerTarget().transform);
}
// Invoked after attack animation has finished playing.
private void OnAttackEnded()
{
// Reset state to chase, pre-tick will handle fallback to wonder if no valid player target is set
ChangeAIStateServer(AIStates.Chase);
}
// Perform the actual attack and deal damage to players
private void DoAttack(bool isChokeAttack)
{
if (isChokeAttack)
GetPlayerTarget().OnSanityHit(this, CHOKE_ATTACK_AMOUNT);
else
TryAttackAllPlayersInRadius(ATTACK_RANGE, LONG_ATTACK_AMOUNT);
}
}
Implementation Requiements:
Configure AI settings by creating and returning an AISettings instance in override OnInitializeAISettings()
public TState StartingState;
[Tooltip("The angle in degrees of AI's field of view")]
public float VisionAngle = 120;
[Tooltip("The vision distance of AI.")]
public float VisionDistance = 10;
[Tooltip("The distance AI would be alerted if target is within, even if not visible or seen.")]
public float AlertDistance = 3;
[Tooltip("The distance AI is considered to have reached a target.")]
public float TargetReachedDistance = 3;
[Tooltip("If this Ghost will leave hand print when opening a door")]
public bool LeaveHandPrint = true;
[Tooltip("If this Ghost will leave foot print when opening a door")]
public bool LeaveFootPrint = true;
[Tooltip("Minimum number of foot steps to print on ground when leaving a foot print evidence trail")]
public int MinFootPrintsInTrail = 3;
[Tooltip("Maximum number of foot steps to print on ground when leaving a foot print evidence trail")]
public int MaxFootPrintsInTrail = 6;
[Tooltip("Time interval between sequential footprints")]
public float FootstepInterval = 0.86f;Your AI implementation must handle the following:
Mirage Visibility Change -
HandleAIVisibilityChangeClientcovers basics, override for additional logicDoor Handling - Override
OnAIDoorObstacleTick(Door obstacleDoor), recommended to cache the parameter Door and switch to door handling stateHandle Request to Lose Player - Override
OnLosePlayerTargetRequested()for logic, does not have to accept the request to lose player
Below are optional but recommended:
React to HostMachine
Override
OnHostMachineAttackedServerto handle response logic whenever a machine is attackedOverride
OnHostMachineDestroyedServerto handle response logic whenever a machine is destroyed
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