ML-Agents

PlayerAcademy.cs

using UnityEngine;
using MLAgents;

public class PlayerAcademy : Academy
{
    public float CoinSpeed { get; private set; }

    public override void InitializeAcademy()
    {
        CoinSpeed = 0;

        FloatProperties.RegisterCallback("coin_speed", f => {
            CoinSpeed = f;
        });
    }
}

PlayerAgent.cs

using UnityEngine;
using MLAgents;

public class PlayerAgent : Agent
{
    public float moveSpeed = 5f;
    public float turnSpeed = 180f;

    private PlayerArea playerArea;
    private PlayerAcademy playerAcademy;
    new private Rigidbody rigidbody;

    public override void InitializeAgent()
    {
        base.InitializeAgent();
        playerArea = GetComponentInParent<PlayerArea>();
        playerAcademy = FindObjectOfType<PlayerAcademy>();
        rigidbody = GetComponent<Rigidbody>();
    }

    public override void AgentAction(float[] vectorAction)
    {
        Debug.Log(vectorAction[0] + "\t" + vectorAction[1]);
        float forwardAmount = vectorAction[0];
        float turnAmount = 0f;
        if (vectorAction[1] == 1f)
        {
            turnAmount = -1f;
        }
        else if (vectorAction[1] == 2f)
        {
            turnAmount = 1f;
        }
        rigidbody.MovePosition(transform.position + transform.forward * forwardAmount * moveSpeed * Time.fixedDeltaTime);
        transform.Rotate(transform.up * turnAmount * turnSpeed * Time.fixedDeltaTime);
        AddReward(-1f / agentParameters.maxStep);
    }

    public override float[] Heuristic()
    {
        float forwardAction = 0f;
        float turnAction = 0f;
        if (Input.GetKey(KeyCode.W))
        {
            forwardAction = 1f;
        }
        if (Input.GetKey(KeyCode.A))
        {
            turnAction = 1f;
        }
        else if (Input.GetKey(KeyCode.D))
        {
            turnAction = 2f;
        }
        return new float[] { forwardAction, turnAction };
    }

    public override void AgentReset()
    {
        playerArea.ResetArea();
    }

    public override void CollectObservations()
    {
        AddVectorObs(playerArea.coinList.Count);
        AddVectorObs(transform.forward);
    }

    private void FixedUpdate()
    {

    }

    private void OnCollisionEnter(Collision collision)
    {
        if(collision.transform.CompareTag("coin"))
        {
            CollectCoin(collision.gameObject);
        }
    }

    private void CollectCoin(GameObject obj)
    {
        playerArea.RemoveSpecificCoin(obj);
        AddReward(1f);
        
        if(playerArea.CoinsRemaining <= 0)
        {
            Done();
        }
    }

}

PlayerArea.cs

using System.Collections.Generic;
using UnityEngine;
using MLAgents;
using TMPro;

public class PlayerArea : Area
{
    public PlayerAgent playerAgent;
    public TextMeshPro rewardText;
    public Coin coinPrefab;
    private PlayerAcademy playerAcademy;
    public List<GameObject> coinList;

    public override void ResetArea()
    {
        RemoveAllCoins();
        PlacePlayer();
        SpawnCoins(5);
    }

    public void RemoveSpecificCoin(GameObject coinObj)
    {
        coinList.Remove(coinObj);
        Destroy(coinObj);
    }

    public int CoinsRemaining
    {
        get { return coinList.Count; }
    }

    public static Vector3 ChooseRandomPosition(int c, Vector3 center)
    {
        if (c == 0)
        {
            return center + new Vector3(UnityEngine.Random.Range(1f, 4f), 2f, UnityEngine.Random.Range(-1f, 1f));
        }
        else if (c == 1)
        {
            return center + new Vector3(UnityEngine.Random.Range(-4.5f, 4.5f), 1.85f, UnityEngine.Random.Range(-2.5f, 2.5f));
        }
        else
        {
            return center + new Vector3(0, 0, 0);
        }
    }

    private void RemoveAllCoins()
    {
        if (coinList != null)
        {
            for (int i = 0; i < coinList.Count; i++)
            {
                if (coinList[i] != null)
                {
                    Destroy(coinList[i]);
                }
            }
        }
        coinList = new List<GameObject>();
    }

    private void PlacePlayer()
    {
        Rigidbody rigidbody = playerAgent.GetComponent<Rigidbody>();
        rigidbody.velocity = Vector3.zero;
        rigidbody.angularVelocity = Vector3.zero;
        playerAgent.transform.position = ChooseRandomPosition(0, transform.position) + Vector3.up * .5f;
        // playerAgent.transform.rotation = Quaternion.Euler(0f, UnityEngine.Random.Range(0f, 360f), 0f);
    }

    private void SpawnCoins(int c)
    {
        for (int i = 0; i < c; i++)
        {
            GameObject coinObj = Instantiate<GameObject>(coinPrefab.gameObject);
            coinObj.transform.position = ChooseRandomPosition(1, transform.position) + Vector3.up * .5f;
            coinObj.transform.SetParent(transform);
            coinList.Add(coinObj);
        }
    }

    private void Start()
    {
        playerAcademy = FindObjectOfType<PlayerAcademy>();
        ResetArea();
    }

    private void Update()
    {
        rewardText.text = playerAgent.GetCumulativeReward().ToString("0.00");
    }
}