Clean Code

Author: WeakKnight

.gitignore

@@ -10,6 +10,12 @@
 /[Ll]ogs/
 /[Uu]ser[Ss]ettings/
 
+Packages/Microsoft.CodeAnalysis.FxCopAnalyzers.3.0.0/
+Packages/Microsoft.CodeAnalysis.VersionCheckAnalyzer.3.0.0/
+Packages/Microsoft.CodeQuality.Analyzers.3.0.0/
+Packages/Microsoft.NetCore.Analyzers.3.0.0/
+Packages/Microsoft.NetFramework.Analyzers.3.0.0/
+
 # MemoryCaptures can get excessive in size.
 # They also could contain extremely sensitive data
 /[Mm]emoryCaptures/
@@ -67,4 +73,6 @@ crashlytics-build.properties
 
 # Temporary auto-generated Android Assets
 /[Aa]ssets/[Ss]treamingAssets/aa.meta
-/[Aa]ssets/[Ss]treamingAssets/aa/*
+/[Aa]ssets/[Ss]treamingAssets/aa/*
+.editorconfig
+packages.config

Assets/Scripts/Common.meta

@@ -0,0 +1,4 @@
+public interface IIntegrator 
+{
+    void StepOneFrame(PhysicalScene scene);
+}

Assets/Scripts/Common/IIntegrator.cs

@@ -12,6 +12,8 @@ public class PhysicalScene : MonoBehaviour
     public GameObject particlePrefab;
     public GameObject linePrefab;
 
+    [System.NonSerialized]
+    public string integratorType = "";
     [System.NonSerialized]
     public int objectCount = 0;
 
@@ -157,6 +159,19 @@ public void Load(TextAsset scene)
             edgeList.Add(lineRenderer);
             edgeIndexList.Add(new Vector2Int(i, j));
         }
+
+        // Frame Rate
+        XmlNodeList integrators = xmlDoc.GetElementsByTagName("integrator");
+        if(integrators.Count > 0)
+        {
+            XmlNode integrator = integrators[0];
+            float dt = float.Parse(integrator.Attributes["dt"]?.InnerText);
+            integratorType = integrator.Attributes["type"]?.InnerText;
+
+            Debug.Log("Target Delta Time Is " + dt.ToString());
+            Debug.Log("Integrator Type Is " + integratorType);
+            Application.targetFrameRate = (int)(1.0f / dt);
+        }
     }
 
     public void Dispose()

Assets/Scripts/Common/IIntegrator.cs.meta

@@ -10,12 +10,25 @@
 public class Runner : MonoBehaviour
 {
     PhysicalScene scene;
-    ExplicitEulerIntegrator explicitEuler = new ExplicitEulerIntegrator();
+    IIntegrator integrator;
 
     void Awake()
     {
         scene = GetComponent<PhysicalScene>();
         scene.Load();
+
+        if (scene.integratorType == "explicit-euler")
+        {
+            integrator = new ExplicitEulerIntegrator();
+        }
+        else if (scene.integratorType == "symplectic-euler")
+        {
+            integrator = new SymplecticEulerIntegrator();
+        }
+        else
+        {
+            Debug.Assert(false, "Can Not Find Any Suitable Integrator.");
+        }
     }
 
     void OnDestroy()
@@ -26,7 +39,7 @@ void OnDestroy()
     // Update is called once per frame
     void Update()
     {
-        explicitEuler.StepOneFrame(scene);
+        integrator.StepOneFrame(scene);
         scene.Frame();
     }
 

Assets/Scripts/PhysicalScene.cs renamed to Assets/Scripts/Common/PhysicalScene.cs

@@ -1,12 +1,9 @@
-using System.Collections;
-using System.Collections.Generic;
-using UnityEngine;
+using UnityEngine;
 using Unity.Jobs;
 using UnityEngine.Jobs;
 using Unity.Collections;
-using System.Xml;
 
-public class ExplicitEulerIntegrator
+public class ExplicitEulerIntegrator: IIntegrator
 {
     // By Order
     SimpleGravityJob m_GravityGradiantJob;

Assets/Scripts/PhysicalScene.cs.meta renamed to Assets/Scripts/Common/PhysicalScene.cs.meta

@@ -0,0 +1,51 @@
+using UnityEngine;
+using Unity.Jobs;
+using UnityEngine.Jobs;
+using Unity.Collections;
+
+public class SymplecticEulerIntegrator : IIntegrator
+{
+    // By Order
+    SimpleGravityJob m_GravityGradiantJob;
+    SymplecticEulerJob m_SymplecticEulerJob;
+    UpdateJob m_UpdateJob;
+
+    JobHandle m_GravityGradiantJobHandle;
+    JobHandle m_SymplecticEulerJobHandle;
+    JobHandle m_UpdateJobHandle;
+
+    public void StepOneFrame(PhysicalScene scene)
+    {
+        m_GravityGradiantJob = new SimpleGravityJob
+        {
+            gravity = scene.m_Gravity,
+            gradiant = scene.m_gradiants,
+            mass = scene.m_masses,
+            fixes = scene.m_fixes,
+        };
+
+        m_SymplecticEulerJob = new SymplecticEulerJob
+        {
+            deltaTime = Time.deltaTime,
+            velocity = scene.m_Velocities,
+            fixes = scene.m_fixes,
+            position = scene.m_Positions,
+            gradiant = scene.m_gradiants,
+            mass = scene.m_masses,
+        };
+
+        m_UpdateJob = new UpdateJob
+        {
+            position = scene.m_Positions,
+            gradiant = scene.m_gradiants,
+        };
+
+        m_GravityGradiantJobHandle = m_GravityGradiantJob.Schedule(scene.objectCount, 64);
+
+        m_SymplecticEulerJobHandle = m_SymplecticEulerJob.Schedule(scene.objectCount, 64, m_GravityGradiantJobHandle);
+
+        m_UpdateJobHandle = m_UpdateJob.Schedule(scene.m_TransformsAccessArray, m_SymplecticEulerJobHandle);
+
+        m_UpdateJobHandle.Complete();
+    }
+}

Assets/Scripts/Runner.cs renamed to Assets/Scripts/Common/Runner.cs

@@ -0,0 +1,31 @@
+using UnityEngine;
+using Unity.Jobs;
+using Unity.Collections;
+
+public struct SymplecticEulerJob : IJobParallelFor
+{
+    [ReadOnly]
+    public NativeArray<bool> fixes;
+    [ReadOnly]
+    public NativeArray<float> mass;
+    [ReadOnly]
+    public NativeArray<Vector3> gradiant;
+
+    public NativeArray<Vector3> position;
+    public NativeArray<Vector3> velocity;
+
+    public float deltaTime;
+
+    public void Execute(int index)
+    {
+        if (fixes[index])
+        {
+            return;
+        }
+
+        position[index] = position[index] + velocity[index] * deltaTime;
+
+        Vector3 force = -gradiant[index];
+        velocity[index] = velocity[index] + deltaTime * force / mass[index];
+    }
+}