From 933a2932d3f07b7a471675b34fb64ca11cae4cc7 Mon Sep 17 00:00:00 2001
From: xLinka <Oliver.dunnington@outlook.com>
Date: Wed, 13 Sep 2023 18:34:20 +0100
Subject: [PATCH] Physics Nodes

CentipetalForce
Drag
Kinectic Friction
Refraction
---
 .../Math/Physics/CentripetalForceNode.cs      | 12 +++++++
 NEOSPlus/Logix/Math/Physics/DragNode.cs       | 27 ++++++++++++++++
 .../Logix/Math/Physics/KineticFrictionNode.cs | 23 +++++++++++++
 NEOSPlus/Logix/Math/Physics/Refractions.cs    | 32 +++++++++++++++++++
 4 files changed, 94 insertions(+)
 create mode 100644 NEOSPlus/Logix/Math/Physics/CentripetalForceNode.cs
 create mode 100644 NEOSPlus/Logix/Math/Physics/DragNode.cs
 create mode 100644 NEOSPlus/Logix/Math/Physics/KineticFrictionNode.cs
 create mode 100644 NEOSPlus/Logix/Math/Physics/Refractions.cs

diff --git a/NEOSPlus/Logix/Math/Physics/CentripetalForceNode.cs b/NEOSPlus/Logix/Math/Physics/CentripetalForceNode.cs
new file mode 100644
index 0000000..9b82e75
--- /dev/null
+++ b/NEOSPlus/Logix/Math/Physics/CentripetalForceNode.cs
@@ -0,0 +1,12 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace NEOSPlus.Logix.Math.Physics
+{
+    internal class FileName
+    {
+    }
+}
diff --git a/NEOSPlus/Logix/Math/Physics/DragNode.cs b/NEOSPlus/Logix/Math/Physics/DragNode.cs
new file mode 100644
index 0000000..aeaec07
--- /dev/null
+++ b/NEOSPlus/Logix/Math/Physics/DragNode.cs
@@ -0,0 +1,27 @@
+using System;
+using BaseX;
+
+namespace FrooxEngine.LogiX.Math;
+
+[NodeName("Drag Calculation")]
+[Category(new string[] { "LogiX/Math/Physics" })]
+internal class DragNode : LogixNode
+{
+    public readonly Input<float> FluidDensity;        // rho
+    public readonly Input<float3> ObjectVelocity;     // v
+    public readonly Input<float> DragCoefficient;     // Cd
+    public readonly Input<float> CrossSectionalArea;  // A
+
+    public readonly Output<float3> DragForce;
+
+    protected override void OnEvaluate()
+    {
+        float rho = FluidDensity.EvaluateRaw();
+        float3 v = ObjectVelocity.EvaluateRaw();
+        float Cd = DragCoefficient.EvaluateRaw();
+        float A = CrossSectionalArea.EvaluateRaw();
+
+        float3 dragForce = 0.5f * rho * v * v * Cd * A; // Calculate the drag force
+        DragForce.Value = -dragForce;  // Drag acts in the opposite direction of motion
+    }
+}
diff --git a/NEOSPlus/Logix/Math/Physics/KineticFrictionNode.cs b/NEOSPlus/Logix/Math/Physics/KineticFrictionNode.cs
new file mode 100644
index 0000000..5c3b389
--- /dev/null
+++ b/NEOSPlus/Logix/Math/Physics/KineticFrictionNode.cs
@@ -0,0 +1,23 @@
+using System;
+using BaseX;
+
+namespace FrooxEngine.LogiX.Math;
+
+[NodeName("Kinetic Friction Calculation")]
+[Category(new string[] { "LogiX/Math/Physics" })]
+internal class KineticFrictionNode : LogixNode
+{
+    public readonly Input<float3> NormalForce; // Assuming it's a 3D force, change as needed
+    public readonly Input<float> KineticFrictionCoefficient;
+
+    public readonly Output<float3> KineticFrictionalForce;
+
+    protected override void OnEvaluate()
+    {
+        float3 normal = NormalForce.EvaluateRaw();
+        float coefficient = KineticFrictionCoefficient.EvaluateRaw(0f); // Default to 0 if not provided
+
+        // Kinetic friction formula: f_kinetic = mu_kinetic * N
+        KineticFrictionalForce.Value = coefficient * normal;
+    }
+}
diff --git a/NEOSPlus/Logix/Math/Physics/Refractions.cs b/NEOSPlus/Logix/Math/Physics/Refractions.cs
new file mode 100644
index 0000000..2e00d4f
--- /dev/null
+++ b/NEOSPlus/Logix/Math/Physics/Refractions.cs
@@ -0,0 +1,32 @@
+using System;
+using BaseX;
+
+namespace FrooxEngine.LogiX.Math;
+
+[NodeName("Refraction Calculation")]
+[Category(new string[] { "LogiX/Math/Physics" })]
+internal class RefractionNode : LogixNode
+{
+    public readonly Input<float> RefractiveIndex1;  // Refractive index of medium 1
+    public readonly Input<float> RefractiveIndex2;  // Refractive index of medium 2
+    public readonly Input<float> AngleOfIncidence;  // Angle of incidence in degrees
+
+    public readonly Output<float> AngleOfRefraction;  // Angle of refraction in degrees
+
+    protected override void OnEvaluate()
+    {
+        float n1 = RefractiveIndex1.EvaluateRaw();
+        float n2 = RefractiveIndex2.EvaluateRaw();
+        float theta1Rad = AngleOfIncidence.EvaluateRaw() * (float)MathX.PI / 180.0f;  // Convert angle to radians 
+        // for the love of god why does mathx not have a toradians function
+
+        // Calculate using Snell's Law
+        float sinTheta2 = n1 * (float)MathX.Sin(theta1Rad) / n2;
+
+        // Ensure value is within [-1, 1] due to numerical inaccuracies
+        sinTheta2 = MathX.Min(MathX.Max(sinTheta2, -1.0f), 1.0f);
+
+        float theta2Rad = (float)MathX.Asin(sinTheta2);
+        AngleOfRefraction.Value = theta2Rad * 180.0f / (float)MathX.PI;  // Convert angle back to degrees
+    }
+}