OpenXR: Make it possible to implement vendor extensions to hand tracking from GDExtension

modules/openxr/doc_classes/OpenXRExtensionWrapperExtension.xml

@@ -123,6 +123,14 @@
 				Called when the OpenXR session state is changed to visible. This means OpenXR is now ready to receive frames.
 			</description>
 		</method>
+		<method name="_set_hand_joint_locations_and_get_next_pointer" qualifiers="virtual">
+			<return type="int" />
+			<param index="0" name="hand_index" type="int" />
+			<param index="1" name="next_pointer" type="void*" />
+			<description>
+				Adds additional data structures when each hand tracker is created.
+			</description>
+		</method>
 		<method name="_set_instance_create_info_and_get_next_pointer" qualifiers="virtual">
 			<return type="int" />
 			<param index="0" name="next_pointer" type="void*" />

modules/openxr/extensions/openxr_extension_wrapper.h

@@ -60,6 +60,7 @@ class OpenXRExtensionWrapper {
 	virtual void *set_instance_create_info_and_get_next_pointer(void *p_next_pointer) { return p_next_pointer; } // Add additional data structures when we create our OpenXR instance.
 	virtual void *set_session_create_and_get_next_pointer(void *p_next_pointer) { return p_next_pointer; } // Add additional data structures when we create our OpenXR session.
 	virtual void *set_swapchain_create_info_and_get_next_pointer(void *p_next_pointer) { return p_next_pointer; } // Add additional data structures when creating OpenXR swap chains.
+	virtual void *set_hand_joint_locations_and_get_next_pointer(int p_hand_index, void *p_next_pointer) { return p_next_pointer; }
 
 	// `on_register_metadata` allows extensions to register additional controller metadata.
 	// This function is called even when OpenXRApi is not constructured as the metadata

modules/openxr/extensions/openxr_extension_wrapper_extension.cpp

@@ -38,6 +38,7 @@ void OpenXRExtensionWrapperExtension::_bind_methods() {
 	GDVIRTUAL_BIND(_set_instance_create_info_and_get_next_pointer, "next_pointer");
 	GDVIRTUAL_BIND(_set_session_create_and_get_next_pointer, "next_pointer");
 	GDVIRTUAL_BIND(_set_swapchain_create_info_and_get_next_pointer, "next_pointer");
+	GDVIRTUAL_BIND(_set_hand_joint_locations_and_get_next_pointer, "hand_index", "next_pointer");
 	GDVIRTUAL_BIND(_on_register_metadata);
 	GDVIRTUAL_BIND(_on_before_instance_created);
 	GDVIRTUAL_BIND(_on_instance_created, "instance");
@@ -117,6 +118,16 @@ void *OpenXRExtensionWrapperExtension::set_swapchain_create_info_and_get_next_po
 	return nullptr;
 }
 
+void *OpenXRExtensionWrapperExtension::set_hand_joint_locations_and_get_next_pointer(int p_hand_index, void *p_next_pointer) {
+	uint64_t pointer;
+
+	if (GDVIRTUAL_CALL(_set_hand_joint_locations_and_get_next_pointer, p_hand_index, GDExtensionPtr<void>(p_next_pointer), pointer)) {
+		return reinterpret_cast<void *>(pointer);
+	}
+
+	return nullptr;
+}
+
 void OpenXRExtensionWrapperExtension::on_register_metadata() {
 	GDVIRTUAL_CALL(_on_register_metadata);
 }

modules/openxr/extensions/openxr_extension_wrapper_extension.h

@@ -58,12 +58,14 @@ class OpenXRExtensionWrapperExtension : public Object, OpenXRExtensionWrapper {
 	virtual void *set_instance_create_info_and_get_next_pointer(void *p_next_pointer) override;
 	virtual void *set_session_create_and_get_next_pointer(void *p_next_pointer) override;
 	virtual void *set_swapchain_create_info_and_get_next_pointer(void *p_next_pointer) override;
+	virtual void *set_hand_joint_locations_and_get_next_pointer(int p_hand_index, void *p_next_pointer) override;
 
 	//TODO workaround as GDExtensionPtr<void> return type results in build error in godot-cpp
 	GDVIRTUAL1R(uint64_t, _set_system_properties_and_get_next_pointer, GDExtensionPtr<void>);
 	GDVIRTUAL1R(uint64_t, _set_instance_create_info_and_get_next_pointer, GDExtensionPtr<void>);
 	GDVIRTUAL1R(uint64_t, _set_session_create_and_get_next_pointer, GDExtensionPtr<void>);
 	GDVIRTUAL1R(uint64_t, _set_swapchain_create_info_and_get_next_pointer, GDExtensionPtr<void>);
+	GDVIRTUAL2R(uint64_t, _set_hand_joint_locations_and_get_next_pointer, int, GDExtensionPtr<void>);
 
 	virtual void on_register_metadata() override;
 	virtual void on_before_instance_created() override;

modules/openxr/extensions/openxr_hand_tracking_extension.cpp

@@ -179,6 +179,14 @@ void OpenXRHandTrackingExtension::on_process() {
 					next_pointer = &hand_trackers[i].data_source;
 				}
 
+				// Needed for vendor hand tracking extensions implemented from GDExtension.
+				for (OpenXRExtensionWrapper *wrapper : OpenXRAPI::get_singleton()->get_registered_extension_wrappers()) {
+					void *np = wrapper->set_hand_joint_locations_and_get_next_pointer(i, next_pointer);
+					if (np != nullptr) {
+						next_pointer = np;
+					}
+				}
+
 				hand_trackers[i].locations.type = XR_TYPE_HAND_JOINT_LOCATIONS_EXT;
 				hand_trackers[i].locations.next = next_pointer;
 				hand_trackers[i].locations.isActive = false;

modules/openxr/openxr_api.cpp

@@ -1415,6 +1415,10 @@ void OpenXRAPI::unregister_extension_wrapper(OpenXRExtensionWrapper *p_extension
 	registered_extension_wrappers.erase(p_extension_wrapper);
 }
 
+const Vector<OpenXRExtensionWrapper *> &OpenXRAPI::get_registered_extension_wrappers() {
+	return registered_extension_wrappers;
+}
+
 void OpenXRAPI::register_extension_metadata() {
 	for (OpenXRExtensionWrapper *extension_wrapper : registered_extension_wrappers) {
 		extension_wrapper->on_register_metadata();

modules/openxr/openxr_api.h

@@ -324,6 +324,7 @@ class OpenXRAPI {
 	void set_xr_interface(OpenXRInterface *p_xr_interface);
 	static void register_extension_wrapper(OpenXRExtensionWrapper *p_extension_wrapper);
 	static void unregister_extension_wrapper(OpenXRExtensionWrapper *p_extension_wrapper);
+	static const Vector<OpenXRExtensionWrapper *> &get_registered_extension_wrappers();
 	static void register_extension_metadata();
 	static void cleanup_extension_wrappers();