Refactor: Remove 'in' modifier for small ID structs

- Removed `in` modifier from `B2ShapeId`, `B2BodyId`, and `B2ContactId` parameters in various functions and delegates.
- These structs are small (8 bytes or less), so passing them by value is more efficient than passing by reference.
- This change avoids potential pointer indirection overhead and aligns with C# performance best practices for small structs.

Author: ikpil

src/Box2D.NET.Samples/Samples/Benchmarks/BenchmarkCast.cs

@@ -163,7 +163,7 @@ void BuildScene()
         m_minTime = 1e6f;
     }
 
-    static float CastCallback(in B2ShapeId shapeId, B2Vec2 point, B2Vec2 normal, float fraction, object context)
+    static float CastCallback(B2ShapeId shapeId, B2Vec2 point, B2Vec2 normal, float fraction, object context)
     {
         CastResult result = context as CastResult;
         result.point = point;
@@ -173,7 +173,7 @@ static float CastCallback(in B2ShapeId shapeId, B2Vec2 point, B2Vec2 normal, flo
     }
 
 
-    static bool OverlapCallback(in B2ShapeId shapeId, object context)
+    static bool OverlapCallback(B2ShapeId shapeId, object context)
     {
         OverlapResult result = context as OverlapResult;
         if (result.count < 32)

src/Box2D.NET.Samples/Samples/Benchmarks/BenchmarkSensor.cs

@@ -143,7 +143,7 @@ void CreateRow(float y)
         }
     }
 
-    private bool Filter(in B2ShapeId idA, in B2ShapeId idB)
+    private bool Filter(B2ShapeId idA, B2ShapeId idB)
     {
         ShapeUserData userData = null;
         if (b2Shape_IsSensor(idA))
@@ -163,7 +163,7 @@ private bool Filter(in B2ShapeId idA, in B2ShapeId idB)
         return true;
     }
 
-    private static bool FilterFcn(in B2ShapeId idA, in B2ShapeId idB, object context)
+    private static bool FilterFcn(B2ShapeId idA, B2ShapeId idB, object context)
     {
         BenchmarkSensor self = context as BenchmarkSensor;
         return self.Filter(idA, idB);

src/Box2D.NET.Samples/Samples/Characters/Mover.cs

@@ -93,7 +93,7 @@ private static Sample Create(SampleContext context)
         return new Mover(context);
     }
 
-    private static float CastCallback(in B2ShapeId shapeId, B2Vec2 point, B2Vec2 normal, float fraction, object context)
+    private static float CastCallback(B2ShapeId shapeId, B2Vec2 point, B2Vec2 normal, float fraction, object context)
     {
         CastResult result = (CastResult)context;
         result.point = point;
@@ -497,7 +497,7 @@ public override void UpdateGui()
         ImGui.End();
     }
 
-    static bool PlaneResultFcn(in B2ShapeId shapeId, ref B2PlaneResult planeResult, object context)
+    static bool PlaneResultFcn(B2ShapeId shapeId, ref B2PlaneResult planeResult, object context)
     {
         B2_ASSERT(planeResult.hit == true);
 
@@ -521,7 +521,7 @@ static bool PlaneResultFcn(in B2ShapeId shapeId, ref B2PlaneResult planeResult,
         return true;
     }
 
-    static bool Kick(in B2ShapeId shapeId, object context)
+    static bool Kick(B2ShapeId shapeId, object context)
     {
         Mover self = (Mover)context;
         B2BodyId bodyId = b2Shape_GetBody(shapeId);

src/Box2D.NET.Samples/Samples/Collisions/CastWorld.cs

@@ -556,7 +556,7 @@ public override void Draw()
 
 
     // This callback finds the closest hit. This is the most common callback used in games.
-    static float RayCastClosestCallback(in B2ShapeId shapeId, B2Vec2 point, B2Vec2 normal, float fraction, object context)
+    static float RayCastClosestCallback(B2ShapeId shapeId, B2Vec2 point, B2Vec2 normal, float fraction, object context)
     {
         CastContext rayContext = (CastContext)context;
 
@@ -584,7 +584,7 @@ static float RayCastClosestCallback(in B2ShapeId shapeId, B2Vec2 point, B2Vec2 n
     // This callback finds any hit. For this type of query we are usually just checking for obstruction,
     // so the hit data is not relevant.
     // NOTE: shape hits are not ordered, so this may not return the closest hit
-    static float RayCastAnyCallback(in B2ShapeId shapeId, B2Vec2 point, B2Vec2 normal, float fraction, object context)
+    static float RayCastAnyCallback(B2ShapeId shapeId, B2Vec2 point, B2Vec2 normal, float fraction, object context)
     {
         CastContext rayContext = (CastContext)context;
 
@@ -614,7 +614,7 @@ static float RayCastAnyCallback(in B2ShapeId shapeId, B2Vec2 point, B2Vec2 norma
     // NOTE: shape hits are not ordered, so this may return hits in any order. This means that
     // if you limit the number of results, you may discard the closest hit. You can see this
     // behavior in the sample.
-    static float RayCastMultipleCallback(in B2ShapeId shapeId, B2Vec2 point, B2Vec2 normal, float fraction, object context)
+    static float RayCastMultipleCallback(B2ShapeId shapeId, B2Vec2 point, B2Vec2 normal, float fraction, object context)
     {
         CastContext rayContext = (CastContext)context;
 
@@ -648,7 +648,7 @@ static float RayCastMultipleCallback(in B2ShapeId shapeId, B2Vec2 point, B2Vec2
     }
 
     // This ray cast collects multiple hits along the ray and sorts them.
-    static float RayCastSortedCallback(in B2ShapeId shapeId, B2Vec2 point, B2Vec2 normal, float fraction, object context)
+    static float RayCastSortedCallback(B2ShapeId shapeId, B2Vec2 point, B2Vec2 normal, float fraction, object context)
     {
         CastContext rayContext = (CastContext)context;
 

src/Box2D.NET.Samples/Samples/Collisions/OverlapWorld.cs

@@ -64,7 +64,7 @@ private static Sample Create(SampleContext context)
     }
 
 
-    static bool OverlapResultFcn(in B2ShapeId shapeId, object context)
+    static bool OverlapResultFcn(B2ShapeId shapeId, object context)
     {
         ShapeUserData userData = b2Shape_GetUserData(shapeId).GetRef<ShapeUserData>();
         if (userData != null && userData.ignore)

src/Box2D.NET.Samples/Samples/Events/Platform.cs

@@ -116,7 +116,7 @@ public Platform(SampleContext context) : base(context)
         m_jumping = false;
     }
 
-    private static bool PreSolveStatic(in B2ShapeId shapeIdA, in B2ShapeId shapeIdB, B2Vec2 point, B2Vec2 normal, object context)
+    private static bool PreSolveStatic(B2ShapeId shapeIdA, B2ShapeId shapeIdB, B2Vec2 point, B2Vec2 normal, object context)
     {
         Platform self = context as Platform;
         return self.PreSolve(shapeIdA, shapeIdB, point, normal);
@@ -125,7 +125,7 @@ private static bool PreSolveStatic(in B2ShapeId shapeIdA, in B2ShapeId shapeIdB,
     // This callback must be thread-safe. It may be called multiple times simultaneously.
     // Notice how this method is constant and doesn't change any data. It also
     // does not try to access any values in the world that may be changing, such as contact data.
-    public bool PreSolve(in B2ShapeId shapeIdA, in B2ShapeId shapeIdB, B2Vec2 point, B2Vec2 normal)
+    public bool PreSolve(B2ShapeId shapeIdA, B2ShapeId shapeIdB, B2Vec2 point, B2Vec2 normal)
     {
         B2_ASSERT(b2Shape_IsValid(shapeIdA));
         B2_ASSERT(b2Shape_IsValid(shapeIdB));

src/Box2D.NET.Samples/Samples/Events/SensorHits.cs

@@ -189,7 +189,7 @@ public override void UpdateGui()
         ImGui.End();
     }
 
-    void CollectTransforms(in B2ShapeId sensorShapeId)
+    void CollectTransforms(B2ShapeId sensorShapeId)
     {
         const int capacity = 5;
         Span<B2ShapeId> visitorIds = stackalloc B2ShapeId[capacity];

src/Box2D.NET.Samples/Samples/Events/SensorTypes.cs

@@ -139,7 +139,7 @@ public SensorTypes(SampleContext context) : base(context)
         }
     }
 
-    void PrintOverlaps(in B2ShapeId sensorShapeId, string prefix)
+    void PrintOverlaps(B2ShapeId sensorShapeId, string prefix)
     {
         // Determine the necessary capacity
         int capacity = b2Shape_GetSensorCapacity(sensorShapeId);

src/Box2D.NET.Samples/Samples/Issues/ShapeCastChain.cs

@@ -234,7 +234,7 @@ private bool ShapeCastSingle(ref PhysicsHitQueryResult2D outResult, B2Vec2 start
         return false;
     }
 
-    private static float b2CastResult_Closest(in B2ShapeId shapeId, B2Vec2 point, B2Vec2 normal, float fraction, object c)
+    private static float b2CastResult_Closest(B2ShapeId shapeId, B2Vec2 point, B2Vec2 normal, float fraction, object c)
     {
         CastContext_Single context = c as CastContext_Single;
 

src/Box2D.NET.Samples/Samples/Sample.cs

@@ -251,7 +251,7 @@ public void ResetText()
         m_textLine = m_textIncrement;
     }
 
-    public bool QueryCallback(in B2ShapeId shapeId, object context)
+    public bool QueryCallback(B2ShapeId shapeId, object context)
     {
         QueryContext queryContext = context as QueryContext;