voxel mesher test

            float voxelSize = 1.0f;

            DMeshSO meshSO = CotangentUI.ActiveScene.FindSceneObjectsOfType<DMeshSO>()[0];
            AxisAlignedBox3f bounds = meshSO.GetTransformedBoundingBox();
            bounds.Expand(2*voxelSize);

            Vector3i gridSize = (Vector3i)(bounds.Diagonal / voxelSize);
            Bitmap3d bitmap = new Bitmap3d(gridSize);

            foreach ( Vector3i idx in bitmap.Indices() ) {
                Vector3f v = (Vector3f)idx * voxelSize;
                v += bounds.Min;
                if (meshSO.Spatial.IsInside(v))
                    bitmap.Set(idx, true);
            }


            VoxelSurfaceGenerator gen = new VoxelSurfaceGenerator() {
                Voxels = bitmap, Clockwise = false
            };
            gen.Generate();
            DMesh3 mesh = gen.Mesh;

            MeshTransforms.Scale(mesh, voxelSize);
            MeshTransforms.Translate(mesh, bounds.Min);

            mesh.EnableVertexColors(Colorf.White);
            AxisAlignedBox3d meshBox = mesh.CachedBounds;
            foreach (int vid in mesh.VertexIndices()) {
                Vector3d v = mesh.GetVertex(vid);
                double t = (v.y - meshBox.Min.y) / meshBox.Height;
                mesh.SetVertexColor(vid, Colorf.Lerp(Colorf.White, Colorf.Red, (float)t));
            }

            DMeshSO voxelSO = new DMeshSO();
            voxelSO.Create(mesh, CotangentUI.ActiveScene.DefaultMeshSOMaterial);
            CotangentUI.ActiveScene.AddSceneObject(voxelSO, false);