fix: Regression in mesh bounds calculation introduced through #2858 (#2952)

Co-authored-by: Eideren <contact@eideren.com>

Author: 2 people

sources/engine/Stride.Graphics/VertexBufferHelper.cs

@@ -241,7 +241,7 @@ public bool Read<TSemantic, TDest, TReader>(Span<TDest> destination, TReader rea
         IConverter<Color, TDest>,
         ISemantic 
         where TDest : unmanaged
-        where TReader : IReader<TDest>
+        where TReader : IReader<TDest>, allows ref struct
     {
         if (Binding.Declaration.TryGetElement(TSemantic.Name, semanticIndex, out var elementData))
         {
@@ -267,7 +267,7 @@ public bool Read<TSemantic, TDest, TReader>(Span<TDest> destination, TReader rea
     private unsafe void InnerRead<TConverter, TReader, TSource, TDest>(Span<TDest> destination, TReader reader, VertexElementWithOffset element) 
         where TConverter : IConverter<TSource, TDest> 
         where TSource : unmanaged
-        where TReader : IReader<TDest>
+        where TReader : IReader<TDest>, allows ref struct
     {
         if (sizeof(TSource) != element.Size)
             throw new ArgumentException($"{typeof(TSource)} does not match element size ({sizeof(TSource)} != {element.Size})");

sources/engine/Stride.Rendering/Extensions/BoundingExtensions.cs

@@ -16,22 +16,22 @@ public static BoundingBox ComputeBounds(this VertexBufferBinding vertexBufferBin
         {
             var helper = new VertexBufferHelper(vertexBufferBinding, vertexBufferBinding.Buffer.GetSerializationData().Content, out _);
 
-            var computeBoundsStruct = new ComputeBoundsStruct
+            var box = BoundingBox.Empty;
+            boundingSphere = BoundingSphere.Empty;
+            var computeBounds = new ComputeBoundsHelper
             {
-                Box = BoundingBox.Empty, 
-                Sphere = new BoundingSphere(),
+                Box = ref box, 
+                Sphere = ref boundingSphere,
                 Matrix = matrix
             };
-            helper.Read<PositionSemantic, Vector3, ComputeBoundsStruct>(default, computeBoundsStruct);
-
-            boundingSphere = computeBoundsStruct.Sphere;
-            return computeBoundsStruct.Box;
+            helper.Read<PositionSemantic, Vector3, ComputeBoundsHelper>(default, computeBounds);
+            return box;
         }
 
-        struct ComputeBoundsStruct : VertexBufferHelper.IReader<Vector3>
+        ref struct ComputeBoundsHelper : VertexBufferHelper.IReader<Vector3>
         {
-            public required BoundingBox Box;
-            public required BoundingSphere Sphere;
+            public required ref BoundingBox Box;
+            public required ref BoundingSphere Sphere;
             public required Matrix Matrix;
 
             public unsafe void Read<TConverter, TSource>(byte* startPointer, int elementCount, int stride, Span<Vector3> destination) where TConverter : IConverter<TSource, Vector3> where TSource : unmanaged