Fix gizmo cut previews

When using legacy hole drilling algorithm

src/libslic3r/CSGMesh/TriangleMeshAdapter.hpp

@@ -0,0 +1,95 @@
+#ifndef TRIANGLEMESHADAPTER_HPP
+#define TRIANGLEMESHADAPTER_HPP
+
+#include "CSGMesh.hpp"
+
+#include "libslic3r/TriangleMesh.hpp"
+
+namespace Slic3r { namespace csg {
+
+// Provide default overloads for indexed_triangle_set to be usable as a plain
+// CSGPart with an implicit union operation
+
+inline CSGType get_operation(const indexed_triangle_set &part)
+{
+    return CSGType::Union;
+}
+
+inline CSGStackOp get_stack_operation(const indexed_triangle_set &part)
+{
+    return CSGStackOp::Continue;
+}
+
+inline const indexed_triangle_set * get_mesh(const indexed_triangle_set &part)
+{
+    return ∂
+}
+
+inline Transform3f get_transform(const indexed_triangle_set &part)
+{
+    return Transform3f::Identity();
+}
+
+inline CSGType get_operation(const indexed_triangle_set *const part)
+{
+    return CSGType::Union;
+}
+
+inline CSGStackOp get_stack_operation(const indexed_triangle_set *const part)
+{
+    return CSGStackOp::Continue;
+}
+
+inline const indexed_triangle_set * get_mesh(const indexed_triangle_set *const part)
+{
+    return part;
+}
+
+inline Transform3f get_transform(const indexed_triangle_set *const part)
+{
+    return Transform3f::Identity();
+}
+
+inline CSGType get_operation(const TriangleMesh &part)
+{
+    return CSGType::Union;
+}
+
+inline CSGStackOp get_stack_operation(const TriangleMesh &part)
+{
+    return CSGStackOp::Continue;
+}
+
+inline const indexed_triangle_set * get_mesh(const TriangleMesh &part)
+{
+    return &part.its;
+}
+
+inline Transform3f get_transform(const TriangleMesh &part)
+{
+    return Transform3f::Identity();
+}
+
+inline CSGType get_operation(const TriangleMesh * const part)
+{
+    return CSGType::Union;
+}
+
+inline CSGStackOp get_stack_operation(const TriangleMesh * const part)
+{
+    return CSGStackOp::Continue;
+}
+
+inline const indexed_triangle_set * get_mesh(const TriangleMesh * const part)
+{
+    return &part->its;
+}
+
+inline Transform3f get_transform(const TriangleMesh * const part)
+{
+    return Transform3f::Identity();
+}
+
+}} // namespace Slic3r::csg
+
+#endif // TRIANGLEMESHADAPTER_HPP