From 40470e765a22a0b2657e447a3ca3e98b87121ebc Mon Sep 17 00:00:00 2001
From: Wulferis <acer1171090@gmail.com>
Date: Sun, 17 Mar 2024 01:19:57 +1100
Subject: [PATCH] Simple Rigidbody based Character Controller

---
 .../Components/Physics/CharacterController.cs | 115 ++++++++++++++++++
 1 file changed, 115 insertions(+)
 create mode 100644 Prowl.Runtime/Components/Physics/CharacterController.cs

diff --git a/Prowl.Runtime/Components/Physics/CharacterController.cs b/Prowl.Runtime/Components/Physics/CharacterController.cs
new file mode 100644
index 00000000..cd5eec4b
--- /dev/null
+++ b/Prowl.Runtime/Components/Physics/CharacterController.cs
@@ -0,0 +1,115 @@
+using Jitter2;
+using Jitter2.Collision.Shapes;
+using Jitter2.Dynamics;
+using Jitter2.Dynamics.Constraints;
+using Jitter2.LinearMath;
+using Prowl.Icons;
+using Silk.NET.Input;
+using Silk.NET.Vulkan;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace Prowl.Runtime
+{
+    [AddComponentMenu($"{FontAwesome6.HillRockslide}  Physics/{FontAwesome6.Gamepad}  Character Controller")]
+    public class CharacterController : MonoBehaviour
+    {
+        private PhysicalSpace space;
+        public PhysicalSpace Space {
+            get => space ??= Physics.DefaultSpace;
+            set {
+                space = value;
+                if (Body != null)
+                {
+                    space.world.Remove(Body);
+                    Body = null;
+                }
+            }
+        }
+
+        public float height = 2.0f;
+        public float radius = 0.5f;
+
+        public bool isGrounded { get; private set; } = false;
+        public Shape floor { get; private set; } = null;
+        public Vector3 hitPoint { get; private set; } = Vector3.zero;
+
+        public RigidBody Body { get; private set; }
+
+        private float capsuleHalfHeight;
+        private Vector3 accumulatedMovement;
+
+        public override void Awake()
+        {
+            Body = Space.world.CreateRigidBody();
+            var cs = new CapsuleShape(radius, height * 0.5f);
+            Body.AddShape(cs);
+            Body.Position = this.GameObject.transform.position;
+            Body.AffectedByGravity = false;
+
+            // disable velocity damping
+            Body.Damping = (0, 0);
+
+            this.capsuleHalfHeight = cs.Radius + cs.Length * 0.5f;
+
+            // Disable deactivation
+            Body.DeactivationTime = TimeSpan.MaxValue;
+
+            // Make the capsule stand upright, but able to rotate 360 degrees.
+            var ur = Space.world.CreateConstraint<HingeAngle>(Body, Space.world.NullBody);
+            ur.Initialize(JVector.UnitY, AngularLimit.Full);
+        }
+
+        public override void Update()
+        {
+            this.GameObject.transform.position = Body.Position;
+        }
+
+        public override void FixedUpdate()
+        {
+            if (Body == null) return;
+            this.Body.SetActivationState(true);
+
+            isGrounded = IsOnFloor(out var floor, out var hitPoint);
+            this.floor = floor;
+            this.hitPoint = hitPoint;
+
+            //this.Body.Position += accumulatedMovement;
+            this.Body.AddForce(accumulatedMovement * 30);
+            accumulatedMovement = Vector3.zero;
+
+            if (isGrounded)
+                this.Body.Velocity *= 0.98f;
+        }
+
+        public void Move(Vector3 deltaMove) => accumulatedMovement += deltaMove;
+
+        private World.RayCastFilterPre? preFilter = null;
+        private bool FilterShape(Shape shape)
+        {
+            if (shape.RigidBody != null)
+            {
+                if (shape.RigidBody == Body) return false;
+            }
+            return true;
+        }
+
+        private bool IsOnFloor(out Shape? floor, out JVector hitPoint)
+        {
+            preFilter ??= FilterShape;
+
+            bool hit = space.world.RayCast(Body.Position, -JVector.UnitY, preFilter, null,
+                out floor, out JVector normal, out float fraction);
+
+            float delta = fraction - capsuleHalfHeight;
+
+            hitPoint = Body.Position - JVector.UnitY * fraction;
+            return (hit && delta < 0.04f && floor != null);
+        }
+
+
+    }
+}