[GDExtension] Missing methods, classes and API discrepancies.

[bruvzg]

godot-cpp: ad11bbb5845a454551d490812631922c33b7601c
godot: godotengine/godot#52192

Some missing API functions and discrepancies found during attempt to port TextServerAdvanced to the GDExtension (as part of godotengine/godot#52192):

• String:
  • missing ptr, ptrw methods.
  • missing +, += operators.
• StringName do not expose < and > operators, and unusable as map key.
• Packed*Arrray:
  • missing ptr, ptrw methods.
  • [] operator API difference with the engine ([] vs .write[]).
• Dictionary:
  • missing [] operator.
  • seems to have no methods to write value at all.
• Char*String:
  • no public constructors.
• RID:
  • no is_valid method.
  • no RID_*_Owner implementation, can be copy-pasted locally from the engine with minimal changes, but probably should be part of godot-cpp. Included in Port a bunch of Godot container templates to GDExtension. #701.
• Mutex and Semaphore:
  • lock and unlock methods aren't const.
  • no MutexLock class and _THREAD_SAFE_ macros defined (can be added locally, but probably should be part of godot-cpp). Included in Port a bunch of Godot container templates to GDExtension. #701.
• memnew, memdelete aren't working with non-Godot classes.
• no memalloc, memfree macros defined (can be added locally):

  #define memalloc(m_size) Memory::alloc_static(m_size)
  #define memrealloc(m_mem, m_size) Memory::realloc_static(m_mem, m_size)
  #define memfree(m_mem) Memory::free_static(m_mem)
  

• Enum type return values can't be bound on the engine side.
• Enum type argument types can't be bound, unless conversion macros is added manually - MAKE_PTRARGCONV(TextServer::Direction, int64_t);.
• Missing math defines, MAX, MIN, CLAMP etc.
• No conversion for custom native pointer types, can be fixed locally by adding GDVIRTUAL_NATIVE_PTR(Glyph *); macro.
• No templates for Vector, Map, List, HashMap, Set, not a critical issue, but would be convenient to have for better module <-> GDExtension portability. Included in Port a bunch of Godot container templates to GDExtension. #701.

[akien-mga]

Most of the discrepancy in core classes comes from the fact that GDExtension uses the API registered in ClassDB, i.e. the proxy classes defined in core/core_bind.cpp. Some of the differences are probably oversights (core class refactored, but not the core_bind.cpp version), and others might be for technical reasons. For example Thread and core_bind::Thread have a somewhat different API (e.g. Thread::is_started() vs core_bind::Thread::is_active()).

I ran into most of the above too when attempting to port the opensimplex module to an extension (just for testing purposes). Some others I ran into:

• RS alias for RenderingServer is not defined (might be worth considering whether we should still use it at all upstream).
• RenderingServer::free() is exposed as RenderingServer::free_rid(). That's a good candidate for renaming upstream to use free_rid consistently IMO (also PhysicsServer* and TextServer)
• SNAME is not available to create and reference static stringnames.
• callable_mp is not available either. It could likely be copied from core/object/callable_method_pointer.h and adapted to work in godot-cpp.
• vformat not available
• DEFVAL not defined. It's a no-op upstream but used for readability: Remove DEFVAL godot#46903. Either that PR should be reassessed (remove DEFVAL), or it should be added here for consistency.
• Image constructors missing.
• OBJ_SAVE_TYPE and GDREGISTER_CLASS missing.

I also had issues with a class extending Texture2D. It's an abstract virtual class upstream, and my derived class is still seen as abstract in Godot so it can't be instantiated. That's probably the same cause as godotengine/godot#35484 for GDScript/C# custom nodes.

Also related, using the override keyword in that class extending Texture2D didn't work, as apparently godot-cpp couldn't see that I'm indeed overriding virtual methods from the base class. That might be an expected limitation though.

[Zylann]

Missing math defines, MAX, MIN, CLAMP etc.

For these ones I believe they should stop being used. In C++ max/min/clamp already exist as inline templates in Math:: and in STL so I see no reason to use macros for that stuff.

RS alias for RenderingServer is not defined (might be worth considering whether we should still use it at all upstream).

Such shortcuts shouldn't need to exist IMO, at least not globally. It's a 2-letter macro whose sole purpose is shortening something that isn't that long and not used often (depends of the area of course), and being explicit would be much better. If the singleton is repeated a lot then it can be placed in a local reference.

[Xrayez]

• No templates for Vector, Map, List, HashMap, Set, not a critical issue, but would be convenient to have for better module <-> GDExtension portability.

I use those all the time in https://github.com/goostengine/goost, even templates like LocalVector.

I also had issues with a class extending Texture2D. It's an abstract virtual class upstream, and my derived class is still seen as abstract in Godot so it can't be instantiated. That's probably the same cause as godotengine/godot#35484 for GDScript/C# custom nodes.

See godotengine/godot#42830.

[Razoric480]

The ClassDB object allows for registering but doesn't give access to any of its methods as defined in the version GDscript has access to: https://docs.godotengine.org/en/latest/classes/class_classdb.html

[2shady4u]

Another method of String that went missing in GDExtension:

alloc_c_string()

EDIT: Also, I can't seem to find an equivalent to the String::num_int64()-method in the new GDExtension API.

[bruvzg]

Another method of String that went missing in GDExtension: alloc_c_string()

There's no such method in the Godot ether, what's it supposed to do?

Also, I can't seem to find an equivalent to the String::num_int64()-method in the new GDExtension API.

This is fixed.

---

Updated the first comment, most of the stuff in the original issue is already fixed, or (in case of templates) will be added by #701

[2shady4u]

It's supposed to be an easy way of converting a Godot String to a char*.
This can be worked around by first going to CharString and then getting a char* from that.

char *String::alloc_c_string() const {
	godot_char_string contents = godot::api->godot_string_utf8(&_godot_string);

	int length = godot::api->godot_char_string_length(&contents);

	char *result = (char *)godot::api->godot_alloc(length + 1);

	if (result) {
		memcpy(result, godot::api->godot_char_string_get_data(&contents), length + 1);
	}

	godot::api->godot_char_string_destroy(&contents);

	return result;
}