Get mesh data

src/Stride.CommunityToolkit/Extensions/ModelComponentExtensions.cs

@@ -1,3 +1,6 @@
+using Stride.Games;
+using Stride.Rendering;
+
 namespace Stride.Engine;
 
 public static class ModelComponentExtensions
@@ -29,4 +32,84 @@ public static Vector3 GetMeshHWL(this ModelComponent modelComponent)
 
         return new Vector3(height, width, length);
     }
+
+    /// <summary>
+    /// Gets the ModelComponents Mesh data as vertices and indices.
+    /// </summary>
+    /// <param name="model"></param>
+    /// <param name="game"></param>
+    /// <returns></returns>
+    public static (List<Vector3> verts, List<int> indices) GetMeshVerticesAndIndices(this ModelComponent model, IGame game)
+    {
+        return GetMeshData(model.Model, game.Services, game);
+    }
+
+    static unsafe (List<Vector3> verts, List<int> indices) GetMeshData(Model model, IServiceRegistry services, IGame game)
+    {
+        Matrix[] nodeTransforms = null;
+
+        int totalVerts = 0, totalIndices = 0;
+        foreach (var meshData in model.Meshes)
+        {
+            totalVerts += meshData.Draw.VertexBuffers[0].Count;
+            totalIndices += meshData.Draw.IndexBuffer.Count;
+        }
+
+        var combinedVerts = new List<Vector3>(totalVerts);
+        var combinedIndices = new List<int>(totalIndices);
+
+        foreach (var meshData in model.Meshes)
+        {
+            var vBuffer = meshData.Draw.VertexBuffers[0].Buffer;
+            var iBuffer = meshData.Draw.IndexBuffer.Buffer;
+            byte[] verticesBytes = vBuffer.GetData<byte>(game.GraphicsContext.CommandList); ;
+            byte[] indicesBytes = iBuffer.GetData<byte>(game.GraphicsContext.CommandList); ;
+
+            if ((verticesBytes?.Length ?? 0) == 0 || (indicesBytes?.Length ?? 0) == 0)
+            {
+                // returns empty lists if there is an issue
+                return (combinedVerts, combinedIndices);
+            }
+
+            int vertMappingStart = combinedVerts.Count;
+
+            fixed (byte* bytePtr = verticesBytes)
+            {
+                var vBindings = meshData.Draw.VertexBuffers[0];
+                int count = vBindings.Count;
+                int stride = vBindings.Declaration.VertexStride;
+                for (int i = 0, vHead = vBindings.Offset; i < count; i++, vHead += stride)
+                {
+                    var pos = *(Vector3*)(bytePtr + vHead);
+                    if (nodeTransforms != null)
+                    {
+                        Matrix posMatrix = Matrix.Translation(pos);
+                        Matrix.Multiply(ref posMatrix, ref nodeTransforms[meshData.NodeIndex], out var finalMatrix);
+                        pos = finalMatrix.TranslationVector;
+                    }
+
+                    combinedVerts.Add(pos);
+                }
+            }
+
+            fixed (byte* bytePtr = indicesBytes)
+            {
+                if (meshData.Draw.IndexBuffer.Is32Bit)
+                {
+                    foreach (int i in new Span<int>(bytePtr + meshData.Draw.IndexBuffer.Offset, meshData.Draw.IndexBuffer.Count))
+                    {
+                        combinedIndices.Add(vertMappingStart + i);
+                    }
+                }
+                else
+                {
+                    foreach (ushort i in new Span<ushort>(bytePtr + meshData.Draw.IndexBuffer.Offset, meshData.Draw.IndexBuffer.Count))
+                    {
+                        combinedIndices.Add(vertMappingStart + i);
+                    }
+                }
+            }
+        }
+        return (combinedVerts, combinedIndices);
+    }
 }

src/Stride.CommunityToolkit/Stride.CommunityToolkit.csproj

@@ -1,6 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
     <PropertyGroup>
         <AssemblyName>Stride.CommunityToolkit</AssemblyName>
+        <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
     </PropertyGroup>
 
     <Import Project="..\CommonSettings.props" />