Sensors

A Sensor is a class that reads the current state of the world and provides this information to the WorldState when it's needed. The Resolver uses this information to determine the best action to perform based on the current state of the world.

Sensors can provide the values for two types of data/keys:

• WorldKey: A WorldKey references a value in the world. For example AppleCount. All values must be represented by ints.

• TargetKey: A TargetKey references a position in the world. For example AppleTree. All positions must be represented by Vector3.

Sensors can work in two scopes: Global or Local.

• Global: These sensors give information for all agents of an AgentType. For instance, IsDaytimeSensor checks if it's day or night for everyone.

• Local: They give information for just one agent. For example, ClosestAppleSensor finds the nearest apple for a specific agent.

	Local	Global
WorldKey	LocalWorldSensorBase	GlobalWorldSensorBase
TargetKey	LocalTargetSensorBase	GlobalTargetSensorBase

Sensor data flow

WorldSensor

WorldSensor checks the game's situation for an agent. It uses WorldKey to show each situation. The Planner uses this to pick the best action.

Examples:

• IsHungrySensor checks if the agent is hungry.

• HasAppleSensor checks if the agent has an apple.

Example

To create a new WorldSensor, create a new class that inherits from LocalWorldSensorBase or GlobalWorldSensorBase and implement its Sense method.

IsHungrySensor.cs

using CrashKonijn.Agent.Core;
using CrashKonijn.Goap.Core;
using CrashKonijn.Goap.Demos.Simple.Behaviours;
using CrashKonijn.Goap.Runtime;

namespace CrashKonijn.Goap.Demos.Simple.Goap.Sensors.World
{
    [GoapId("Simple-IsHungrySensor")]
    public class IsHungrySensor : LocalWorldSensorBase
    {
        public override void Created()
        {
        }

        public override void Update()
        {
        }

        public override SenseValue Sense(IActionReceiver agent, IComponentReference references)
        {
            var hungerBehaviour = references.GetCachedComponent<SimpleHungerBehaviour>();

            if (hungerBehaviour == null)
                return false;

            return hungerBehaviour.hunger > 20;
        }
    }
}

TargetSensor

TargetSensor finds a position for a TargetKey. The Planner uses this to know how far actions are.

There are two kinds of Target: TransformTarget and PositionTarget.

• TransformTarget: Use this when the target can move. For example, ClosestEnemySensor finds a moving enemy.

• PositionTarget: Use this for a fixed spot. Like, WanderTargetSensor finds a random spot that doesn't move.

Example

To create a new TargetSensor, create a new class that inherits from LocalTargetSensorBase or GlobalTargetSensorBase and implement its Sense method.

ClosestTreeSensor.cs

using CrashKonijn.Agent.Core;
using CrashKonijn.Goap.Demos.Simple.Behaviours;
using CrashKonijn.Goap.Runtime;
using Demos;

namespace CrashKonijn.Goap.Demos.Simple.Goap.Sensors.Target
{
    [GoapId("Simple-ClosestTreeSensor")]
    public class ClosestTreeSensor : LocalTargetSensorBase
    {
        private TreeBehaviour[] trees;

        public override void Created()
        {            
            this.trees = Compatibility.FindObjectsOfType<TreeBehaviour>();
        }

        public override void Update()
        {
        }

        public override ITarget Sense(IActionReceiver agent, IComponentReference references, ITarget target)
        {
            return new TransformTarget(this.trees.Closest(agent.Transform.position).transform);
        }
    }
}

WanderTargetSensor.cs

using CrashKonijn.Agent.Core;
using CrashKonijn.Goap.Runtime;
using UnityEngine;

namespace CrashKonijn.Goap.Demos.Simple.Goap.Sensors.Target
{
    [GoapId("Simple-WanderTargetSensor")]
    public class WanderTargetSensor : LocalTargetSensorBase
    {
        private static readonly Vector2 Bounds = new Vector2(15, 8);

        public override void Created()
        {
        }

        public override void Update()
        {
        }

        public override ITarget Sense(IActionReceiver agent, IComponentReference references, ITarget target)
        {
            var random = this.GetRandomPosition(agent);
            
            return new PositionTarget(random);
        }

        private Vector3 GetRandomPosition(IActionReceiver agent)
        {
            var random =  Random.insideUnitCircle * 5f;
            var position = agent.Transform.position + new Vector3(random.x, 0f, random.y);
            
            if (position.x > -Bounds.x && position.x < Bounds.x && position.z > -Bounds.y && position.z < Bounds.y)
                return position;

            return this.GetRandomPosition(agent);
        }
    }
}