ml-agents/unity-environment/Assets/ML-Agents/Examples/Basic/Scripts/BasicAgent.cs

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class BasicAgent : Agent
{

	public int position;
	public int smallGoalPosition;
	public int largeGoalPosition;
	public GameObject largeGoal;
	public GameObject smallGoal;
	public int minPosition;
	public int maxPosition;

	public override List<float> CollectState()
	{
		List<float> state = new List<float>();
		state.Add(position);
		return state;
	}

	public override void AgentStep(float[] act)
	{
		float movement = act[0];
		int direction = 0;
		if (movement == 0) { direction = -1; }
		if (movement == 1) { direction = 1; }

		position += direction;
		if (position < minPosition) { position = minPosition; }
		if (position > maxPosition) { position = maxPosition; }

		gameObject.transform.position = new Vector3(position, 0f, 0f);

        reward -= 0.01f;

		if (position == smallGoalPosition)
		{
			done = true;
			reward = 0.1f;
		}

		if (position == largeGoalPosition)
		{
			done = true;
			reward = 1f;
		}
	}

	public override void AgentReset()
	{
		position = 0;
		minPosition = -10;
		maxPosition = 10;
		smallGoalPosition = -3;
		largeGoalPosition = 7;
		smallGoal.transform.position = new Vector3(smallGoalPosition, 0f, 0f);
		largeGoal.transform.position = new Vector3(largeGoalPosition, 0f, 0f);
	}

	public override void AgentOnDone()
	{

	}
}