Hey all,
So I am finally trying to tackle enemy AI…one of the things I’ve been dreading the most. There are tons of AI stuff out there but not so much on Space Sim type game play. I found a tutorial out there for AI avoiding obstacles which was fairly useful but aside from that I haven’t successfully found anything online that could help with a proper behavior of an enemy spaceship when it encounters the player.
So far I have the enemy waiting until the player is within a set distance, it then heads towards the player while avoiding obstacle which is great. But I am having an issue trying to wrap my head around the behavior beyond that. So far the ship just heads to the player and currently just flies in an orbit around the player. Unfortunately I am not quite sure how to have it react and how to code it…I imagine the ship wants to fly past the player, turn around at some point and then fire again? Was hoping someone could point me to a better tutorial or give some helpful advise on how to tackle this monster…
Here is my code so far;
using UnityEngine;
using System.Collections;
using System.Collections.Generic;
using System.Linq;
public class Enemy_Movement : MonoBehaviour
{
private Transform target;
private Transform myTransform;
Vector3 storeTarget;
Vector3 newTargetPos;
bool savePos;
bool overrideTarget;
Transform obstacle;
public List<Vector3> EscapeDirections = new List<Vector3>();
//AI Checks
public bool chasing = false;
public bool evading = false;
//AI stuff
public float rotationSpeed;
public float maxDist;
public float minDist;
public float fireDist;
//AI Speeds
public float moveSpeed;
void Start()
{
target = GameObject.FindGameObjectWithTag("Player").transform;
myTransform = this.transform;
}
void FixedUpdate ()
{
//Find Distance to target
var distance = (target.position - myTransform.position).magnitude;
if(chasing)
{
//Rotate to look at player
myTransform.rotation = Quaternion.Slerp(myTransform.rotation, Quaternion.LookRotation(target.position - myTransform.position), rotationSpeed * Time.deltaTime);
//Move towards the player
myTransform.position += myTransform.forward * moveSpeed * Time.deltaTime;
//Moves too far away from player
if (distance > maxDist)
{
chasing = false;
}
//Attack if close enough
if (distance < fireDist)
{
//insert attack commands here when ready
}
if (distance < minDist)
{
myTransform.rotation = Quaternion.Slerp(myTransform.rotation, Quaternion.LookRotation(myTransform.position - target.position), rotationSpeed * Time.deltaTime);
myTransform.position += myTransform.forward * moveSpeed * Time.deltaTime;
}
}
else
{
if (distance < maxDist)
{
chasing = true;
}
}
ObstacleAvoidance(transform.forward, 0);
}
void ObstacleAvoidance(Vector3 direction, float offsetX)
{
RaycastHit[] hit = Rays(direction, offsetX);
for(int i = 0; i < hit.Length -1; i++)
{
//So we dont detect ourself as a hit collision
if (hit[i].transform.root.gameObject != this.gameObject)
{
if(!savePos)
{
storeTarget = target.position;
obstacle = hit[i].transform;
savePos = true;
}
FindEscapeDirections(hit[i].collider);
}
}
if (EscapeDirections.Count > 0)
{
if (!overrideTarget)
{
newTargetPos = getClosests();
overrideTarget = true;
}
}
float distance = Vector3.Distance(transform.position, target.position);
if(distance < 5)
{
if (savePos)
{
//if we reach the target
target.position = storeTarget;
savePos = false;
}
else
{
//if we had waypoints
//index++
}
overrideTarget = false;
EscapeDirections.Clear();
}
}
Vector3 getClosests()
{
Vector3 clos = EscapeDirections[0];
float distance = Vector3.Distance(transform.position, EscapeDirections[0]);
foreach(Vector3 dir in EscapeDirections)
{
float tempDistance = Vector3.Distance(transform.position, dir);
if(tempDistance < distance)
{
distance = tempDistance;
clos = dir;
}
}
return clos;
}
void FindEscapeDirections(Collider col)
{
//Check for obstacles above
RaycastHit hitUp;
if(Physics.Raycast(col.transform.position, col.transform.up, out hitUp, col.bounds.extents.y * 2 + 5))
{
}
else
{
//if there is something above
Vector3 dir = col.transform.position + new Vector3(0, col.bounds.extents.y * 2 + 5, 0 );
if (!EscapeDirections.Contains(dir))
{
EscapeDirections.Add(dir);
}
}
//Check for obstacles below
RaycastHit hitDown;
if(Physics.Raycast(col.transform.position, -col.transform.up, out hitDown, col.bounds.extents.y * 2 + 5))
{
}
else
{
//if there is something below
Vector3 dir = col.transform.position + new Vector3(0, -col.bounds.extents.y * 2 - 5, 0 );
if (!EscapeDirections.Contains(dir))
{
EscapeDirections.Add(dir);
}
}
//Check for obstacles to the Right
RaycastHit hitRight;
if(Physics.Raycast(col.transform.position, col.transform.right, out hitRight, col.bounds.extents.x * 2 + 5))
{
}
else
{
//if there is something to the right
Vector3 dir = col.transform.position + new Vector3(col.bounds.extents.x * 2 + 5, 0, 0 );
if (!EscapeDirections.Contains(dir))
{
EscapeDirections.Add(dir);
}
}
//Check for obstacles to the Left
RaycastHit hitLeft;
if(Physics.Raycast(col.transform.position, -col.transform.right, out hitLeft, col.bounds.extents.x * 2 + 5))
{
}
else
{
//if there is something to the right
Vector3 dir = col.transform.position + new Vector3(-col.bounds.extents.x * 2 - 5, 0, 0 );
if (!EscapeDirections.Contains(dir))
{
EscapeDirections.Add(dir);
}
}
}
RaycastHit[] Rays(Vector3 direction, float offsetX)
{
Ray ray = new Ray(transform.position + new Vector3(offsetX,0,0), direction);
Debug.DrawRay(transform.position + new Vector3(offsetX,0,0), direction * 10 * moveSpeed, Color.red);
float distanceToLookAhead = moveSpeed * 5;
//Adjust 5 to proper radius around object to pick up raycast hits
RaycastHit[] hits = Physics.SphereCastAll(ray, 5, distanceToLookAhead);
return hits;
}
}
