Dev (#32)

* Make Bodies in SoftBodyTetrahedron.cs public.

* Make internal variables in CollisionIsland.cs uppercase.

* Remove Filter2 in DynamicTreeCollisionFilter.cs

* Attaching the rigid body to the original shape not necessary in TransformedShape.cs

* Added soft bodies to feature list in README.md

* Use correct pattern for GC-free IEnumerable implementation

* Update changelog.md

README.md

@@ -38,6 +38,7 @@ JitterDemo uses [GLFW](https://www.glfw.org/) for accessing OpenGL and managing
 - [x] "One-shot" contact manifolds using auxiliary contacts for flat surface collisions.
 - [x] Efficient compound shapes.
 - [x] Easy integration of custom shapes. Integrated: Box, Capsule, Cone, Convex Hull, Point Cloud, Sphere, Triangle, Transformed.
+- [x] Soft-body dynamics!
 
 ## Documentation
 

docs/docs/changelog.md

@@ -4,10 +4,10 @@ sidebar_position: 4
 
 # Changelog
 
-<!-- ### Jitter 2.0.0-beta
+### Jitter 2.0.0-beta (10-17-2023)
 
-- Added softbodies. -->
+- Added softbodies
 
 ### Jitter 2.0.0-alpha (09-18-2023)
 
-Initial Release.
+Initial Release.

src/Jitter2/Collision/CollisionIsland.cs

@@ -33,8 +33,8 @@ namespace Jitter2.Collision;
 public sealed class Island : IListIndex
 {
     internal readonly HashSet<RigidBody> bodies = new();
-    internal bool markedAsActive;
-    internal bool needsUpdate;
+    internal bool MarkedAsActive;
+    internal bool NeedsUpdate;
 
     /// <summary>
     /// Gets a collection of all the bodies present in this island.

src/Jitter2/Collision/Shapes/TransformedShape.cs

@@ -132,7 +132,6 @@ public override void CalculateBoundingBox(in JMatrix orientation, in JVector pos
 
     public override void CalculateMassInertia(out JMatrix inertia, out JVector com, out float mass)
     {
-        OriginalShape.AttachRigidBody(RigidBody);
         OriginalShape.CalculateMassInertia(out inertia, out com, out mass);
 
         com = JVector.Transform(com, transformation) + translation;

src/Jitter2/DataStructures/ActiveList.cs

@@ -52,11 +52,16 @@ public bool IsActive(T element)
         return list.IsActive(element);
     }
 
-    public IEnumerator<T> GetEnumerator()
+    public ActiveList<T>.Enumerator GetEnumerator()
     {
         return new ActiveList<T>.Enumerator(list);
     }
 
+    IEnumerator<T> IEnumerable<T>.GetEnumerator()
+    {
+        return GetEnumerator();
+    }
+
     IEnumerator IEnumerable.GetEnumerator()
     {
         return GetEnumerator();
@@ -187,11 +192,16 @@ public void Remove(T element)
         element.ListIndex = -1;
     }
 
-    public IEnumerator<T> GetEnumerator()
+    public Enumerator GetEnumerator()
     {
         return new Enumerator(this);
     }
 
+    IEnumerator<T> IEnumerable<T>.GetEnumerator()
+    {
+        return GetEnumerator();
+    }
+
     IEnumerator IEnumerable.GetEnumerator()
     {
         return GetEnumerator();

src/Jitter2/SoftBodies/DynamicTreeCollisionFilter.cs

@@ -41,17 +41,4 @@ public static bool Filter(Shape shapeA, Shape shapeB)
 
         return false;
     }
-
-    public static bool Filter2(Shape shapeA, Shape shapeB)
-    {
-        if (shapeA.RigidBody != shapeB.RigidBody) return true;
-
-        if (shapeA is ISoftBodyShape softBodyShapeA &&
-            shapeB is ISoftBodyShape softBodyShapeB)
-        {
-            return true;
-        }
-
-        return false;
-    }
 }

src/Jitter2/SoftBodies/SoftBodyTetrahedron.cs

@@ -29,20 +29,20 @@ namespace Jitter2.SoftBodies;
 
 public class SoftBodyTetrahedron : Shape, ISoftBodyShape
 {
-    private readonly RigidBody[] bodies = new RigidBody[4];
-
     public SoftBodyTetrahedron(SoftBody body, RigidBody p1, RigidBody p2, RigidBody p3, RigidBody p4)
     {
-        bodies[0] = p1;
-        bodies[1] = p2;
-        bodies[2] = p3;
-        bodies[3] = p4;
+        Bodies[0] = p1;
+        Bodies[1] = p2;
+        Bodies[2] = p3;
+        Bodies[3] = p4;
 
         SoftBody = body;
 
         UpdateShape();
     }
 
+    public RigidBody[] Bodies { get; } = new RigidBody[4];
+
     public override JVector Velocity
     {
         get
@@ -51,7 +51,7 @@ public override JVector Velocity
 
             for (int i = 0; i < 4; i++)
             {
-                vel += bodies[i].Velocity;
+                vel += Bodies[i].Velocity;
             }
 
             vel *= 0.25f;
@@ -68,7 +68,7 @@ public override void CalculateMassInertia(out JMatrix inertia, out JVector com,
 
         for (int i = 0; i < 4; i++)
         {
-            com += bodies[i].Position;
+            com += Bodies[i].Position;
         }
 
         com *= 0.25f;
@@ -81,15 +81,15 @@ public RigidBody GetClosest(in JVector pos)
 
         for (int i = 0; i < 4; i++)
         {
-            float len = (pos - bodies[i].Position).LengthSquared();
+            float len = (pos - Bodies[i].Position).LengthSquared();
             if (len < dist)
             {
                 dist = len;
                 closest = i;
             }
         }
 
-        return bodies[closest];
+        return Bodies[closest];
     }
 
     public SoftBody SoftBody { get; }
@@ -103,8 +103,8 @@ public override void UpdateWorldBoundingBox()
 
         for (int i = 0; i < 4; i++)
         {
-            box.AddPoint(bodies[i].Position);
-            GeometricCenter += bodies[i].Position;
+            box.AddPoint(Bodies[i].Position);
+            GeometricCenter += Bodies[i].Position;
         }
 
         GeometricCenter *= 0.25f;
@@ -122,14 +122,14 @@ public override void SupportMap(in JVector direction, out JVector result)
 
         for (int i = 0; i < 4; i++)
         {
-            float dot = JVector.Dot(direction, bodies[i].Position);
+            float dot = JVector.Dot(direction, Bodies[i].Position);
             if (dot > maxDot)
             {
                 maxDot = dot;
                 furthest = i;
             }
         }
 
-        result = bodies[furthest].Position;
+        result = Bodies[furthest].Position;
     }
 }

src/Jitter2/World.Step.cs

@@ -264,7 +264,7 @@ private void UpdateBodiesCallback(Parallel.Batch batch)
 
             if (body.sleepTime < body.deactivationTimeThreshold)
             {
-                body.island.markedAsActive = true;
+                body.island.MarkedAsActive = true;
             }
 
             if (!rigidBody.IsStatic && rigidBody.IsActive)
@@ -760,17 +760,17 @@ private void CheckDeactivation()
         {
             Island island = islands[i];
 
-            bool deactivateIsland = !island.markedAsActive;
+            bool deactivateIsland = !island.MarkedAsActive;
             if (!AllowDeactivation) deactivateIsland = false;
 
             // Mark the island as inactive
             // Next frame one active body will be enough to set
             // MarkedAsActive back to true;
-            island.markedAsActive = false;
+            island.MarkedAsActive = false;
 
-            if (!deactivateIsland && !island.needsUpdate) continue;
+            if (!deactivateIsland && !island.NeedsUpdate) continue;
 
-            island.needsUpdate = false;
+            island.NeedsUpdate = false;
 
             foreach (RigidBody body in island.bodies)
             {

src/Jitter2/World.cs

@@ -439,8 +439,8 @@ internal void DeactivateBodyNextStep(RigidBody body)
 
     private void AddToActiveList(Island island)
     {
-        island.markedAsActive = true;
-        island.needsUpdate = true;
+        island.MarkedAsActive = true;
+        island.NeedsUpdate = true;
         islands.MoveToActive(island);
     }