Fixed pointer indirection in the PtrToArg template for Object arguments.

[ghost]

Object pointer arguments for virtual function callbacks are not correctly converted by the PtrToArg template in godot-cpp. It is missing one level of pointer indirection, passing the void* wrapper directly to the gdnative_object_get_instance_binding implementation, which expects a Object*.

This patch adds the additional pointer dereference, which brings it in line with the core Godot PtrToArg template.

This fixes #651

[saki7]

This patch fixes the similar case #655 for PtrToArg<const Ref<T>&> and PtrToArg<Ref<T>>

--- a/include/godot_cpp/classes/ref.hpp
+++ b/include/godot_cpp/classes/ref.hpp
@@ -240,7 +240,7 @@ public:
 template <class T>
 struct PtrToArg<Ref<T>> {
        _FORCE_INLINE_ static Ref<T> convert(const void *p_ptr) {
-               return Ref<T>(godot::internal::gdn_interface->object_get_instance_binding((void *)p_ptr, godot::internal::token, &T::___binding_callbacks));
+               return Ref<T>(reinterpret_cast<T*>(godot::internal::gdn_interface->object_get_instance_binding(*(const GDNativeObjectPtr *)p_ptr, godot::internal::token, &T::___binding_callbacks)));
        }

        typedef Ref<T> EncodeT;
@@ -255,7 +255,7 @@ struct PtrToArg<const Ref<T> &> {
        typedef Ref<T> EncodeT;

        _FORCE_INLINE_ static Ref<T> convert(const void *p_ptr) {
-               return Ref<T>(godot::internal::gdn_interface->object_get_instance_binding((void *)p_ptr, godot::internal::token, &T::___binding_callbacks));
+               return Ref<T>(reinterpret_cast<T*>(godot::internal::gdn_interface->object_get_instance_binding(*(const GDNativeObjectPtr *)p_ptr, godot::internal::token, &T::___binding_callbacks)));
        }
 };

@lukas-toenne Could you include this in your PR?

[saki7]

Thanks!
Having these two commits together, I've confirmed overriding virtual function works without any other workarounds.

[ghost]

I can also confirm that these two commits fix #655

[Faless]

It took me a bit to fully understand what was going on, but this is correct.
Really excellent work both 🏅 🎆 !
And sorry for the very late review :/ it's been some crazy times, but we are finally moving into stabilization :).

[Faless]

Note to self, we should probably add a test for this, I had one, but it's not great for CI, maybe an _input/_gui_input with synthetic source from GDScript.