virtualx-engine/modules/openxr/extensions/openxr_hand_tracking_extension.cpp

/*************************************************************************/
/*  openxr_hand_tracking_extension.cpp                                   */
/*************************************************************************/
/*                       This file is part of:                           */
/*                           GODOT ENGINE                                */
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#include "openxr_hand_tracking_extension.h"
#include "../openxr_api.h"
#include "core/string/print_string.h"
#include "servers/xr_server.h"

#include <openxr/openxr.h>

OpenXRHandTrackingExtension *OpenXRHandTrackingExtension::singleton = nullptr;

OpenXRHandTrackingExtension *OpenXRHandTrackingExtension::get_singleton() {
	return singleton;
}

OpenXRHandTrackingExtension::OpenXRHandTrackingExtension(OpenXRAPI *p_openxr_api) :
		OpenXRExtensionWrapper(p_openxr_api) {
	singleton = this;

	// Extensions we use for our hand tracking.
	request_extensions[XR_EXT_HAND_TRACKING_EXTENSION_NAME] = &hand_tracking_ext;
	request_extensions[XR_EXT_HAND_JOINTS_MOTION_RANGE_EXTENSION_NAME] = &hand_motion_range_ext;
	request_extensions[XR_FB_HAND_TRACKING_AIM_EXTENSION_NAME] = &hand_tracking_aim_state_ext;

	// Make sure this is cleared until we actually request it
	handTrackingSystemProperties.supportsHandTracking = false;
}

OpenXRHandTrackingExtension::~OpenXRHandTrackingExtension() {
	singleton = nullptr;
}

void OpenXRHandTrackingExtension::on_instance_created(const XrInstance p_instance) {
	if (hand_tracking_ext) {
		EXT_INIT_XR_FUNC(xrCreateHandTrackerEXT);
		EXT_INIT_XR_FUNC(xrDestroyHandTrackerEXT);
		EXT_INIT_XR_FUNC(xrLocateHandJointsEXT);

		hand_tracking_ext = xrCreateHandTrackerEXT_ptr && xrDestroyHandTrackerEXT_ptr && xrLocateHandJointsEXT_ptr;
	}
}

void OpenXRHandTrackingExtension::on_session_destroyed() {
	cleanup_hand_tracking();
}

void OpenXRHandTrackingExtension::on_instance_destroyed() {
	xrCreateHandTrackerEXT_ptr = nullptr;
	xrDestroyHandTrackerEXT_ptr = nullptr;
	xrLocateHandJointsEXT_ptr = nullptr;
}

void *OpenXRHandTrackingExtension::set_system_properties_and_get_next_pointer(void *p_next_pointer) {
	if (!hand_tracking_ext) {
		// not supported...
		return p_next_pointer;
	}

	handTrackingSystemProperties = {
		XR_TYPE_SYSTEM_HAND_TRACKING_PROPERTIES_EXT, // type
		p_next_pointer, // next
		false, // supportsHandTracking
	};

	return &handTrackingSystemProperties;
}

void OpenXRHandTrackingExtension::on_state_ready() {
	if (!handTrackingSystemProperties.supportsHandTracking) {
		// not supported...
		return;
	}

	// Setup our hands and reset data
	for (int i = 0; i < MAX_OPENXR_TRACKED_HANDS; i++) {
		// we'll do this later
		hand_trackers[i].is_initialised = false;
		hand_trackers[i].hand_tracker = XR_NULL_HANDLE;

		hand_trackers[i].aimState.aimPose = { { 0.0, 0.0, 0.0, 0.0 }, { 0.0, 0.0, 0.0 } };
		hand_trackers[i].aimState.pinchStrengthIndex = 0.0;
		hand_trackers[i].aimState.pinchStrengthMiddle = 0.0;
		hand_trackers[i].aimState.pinchStrengthRing = 0.0;
		hand_trackers[i].aimState.pinchStrengthLittle = 0.0;

		hand_trackers[i].locations.isActive = false;

		for (int j = 0; j < XR_HAND_JOINT_COUNT_EXT; j++) {
			hand_trackers[i].joint_locations[j] = { 0, { { 0.0, 0.0, 0.0, 0.0 }, { 0.0, 0.0, 0.0 } }, 0.0 };
			hand_trackers[i].joint_velocities[j] = { 0, { 0.0, 0.0, 0.0 }, { 0.0, 0.0, 0.0 } };
		}
	}
}

void OpenXRHandTrackingExtension::on_process() {
	if (!handTrackingSystemProperties.supportsHandTracking) {
		// not supported...
		return;
	}

	// process our hands
	const XrTime time = openxr_api->get_next_frame_time(); // This data will be used for the next frame we render

	XrResult result;

	for (int i = 0; i < MAX_OPENXR_TRACKED_HANDS; i++) {
		if (hand_trackers[i].hand_tracker == XR_NULL_HANDLE) {
			XrHandTrackerCreateInfoEXT createInfo = {
				XR_TYPE_HAND_TRACKER_CREATE_INFO_EXT, // type
				nullptr, // next
				i == 0 ? XR_HAND_LEFT_EXT : XR_HAND_RIGHT_EXT, // hand
				XR_HAND_JOINT_SET_DEFAULT_EXT, // handJointSet
			};

			result = xrCreateHandTrackerEXT(openxr_api->get_session(), &createInfo, &hand_trackers[i].hand_tracker);
			if (XR_FAILED(result)) {
				// not successful? then we do nothing.
				print_line("OpenXR: Failed to obtain hand tracking information [", openxr_api->get_error_string(result), "]");
				hand_trackers[i].is_initialised = false;
			} else {
				void *next_pointer = nullptr;
				if (hand_tracking_aim_state_ext) {
					hand_trackers[i].aimState.type = XR_TYPE_HAND_TRACKING_AIM_STATE_FB;
					hand_trackers[i].aimState.next = next_pointer;
					hand_trackers[i].aimState.status = 0;
					hand_trackers[i].aimState.aimPose = { { 0.0, 0.0, 0.0, 0.0 }, { 0.0, 0.0, 0.0 } };
					hand_trackers[i].aimState.pinchStrengthIndex = 0.0;
					hand_trackers[i].aimState.pinchStrengthMiddle = 0.0;
					hand_trackers[i].aimState.pinchStrengthRing = 0.0;
					hand_trackers[i].aimState.pinchStrengthLittle = 0.0;

					next_pointer = &hand_trackers[i].aimState;
				}

				hand_trackers[i].velocities.type = XR_TYPE_HAND_JOINT_VELOCITIES_EXT;
				hand_trackers[i].velocities.next = next_pointer;
				hand_trackers[i].velocities.jointCount = XR_HAND_JOINT_COUNT_EXT;
				hand_trackers[i].velocities.jointVelocities = hand_trackers[i].joint_velocities;
				next_pointer = &hand_trackers[i].velocities;

				hand_trackers[i].locations.type = XR_TYPE_HAND_JOINT_LOCATIONS_EXT;
				hand_trackers[i].locations.next = next_pointer;
				hand_trackers[i].locations.isActive = false;
				hand_trackers[i].locations.jointCount = XR_HAND_JOINT_COUNT_EXT;
				hand_trackers[i].locations.jointLocations = hand_trackers[i].joint_locations;

				hand_trackers[i].is_initialised = true;
			}
		}

		if (hand_trackers[i].is_initialised) {
			void *next_pointer = nullptr;

			XrHandJointsMotionRangeInfoEXT motionRangeInfo;

			if (hand_motion_range_ext) {
				motionRangeInfo.type = XR_TYPE_HAND_JOINTS_MOTION_RANGE_INFO_EXT;
				motionRangeInfo.next = next_pointer;
				motionRangeInfo.handJointsMotionRange = hand_trackers[i].motion_range;

				next_pointer = &motionRangeInfo;
			}

			XrHandJointsLocateInfoEXT locateInfo = {
				XR_TYPE_HAND_JOINTS_LOCATE_INFO_EXT, // type
				next_pointer, // next
				openxr_api->get_play_space(), // baseSpace
				time, // time
			};

			result = xrLocateHandJointsEXT(hand_trackers[i].hand_tracker, &locateInfo, &hand_trackers[i].locations);
			if (XR_FAILED(result)) {
				// not successful? then we do nothing.
				print_line("OpenXR: Failed to get tracking for hand", i, "[", openxr_api->get_error_string(result), "]");
				continue;
			}

			// For some reason an inactive controller isn't coming back as inactive but has coordinates either as NAN or very large
			const XrPosef &palm = hand_trackers[i].joint_locations[XR_HAND_JOINT_PALM_EXT].pose;
			if (
					!hand_trackers[i].locations.isActive || isnan(palm.position.x) || palm.position.x < -1000000.00 || palm.position.x > 1000000.00) {
				hand_trackers[i].locations.isActive = false; // workaround, make sure its inactive
			}

			/* TODO change this to managing the controller from openxr_interface
			if (hand_tracking_aim_state_ext && hand_trackers[i].locations.isActive && check_bit(XR_HAND_TRACKING_AIM_VALID_BIT_FB, hand_trackers[i].aimState.status)) {
				// Controllers are updated based on the aim state's pose and pinches' strength
				if (hand_trackers[i].aim_state_godot_controller == -1) {
					hand_trackers[i].aim_state_godot_controller =
							arvr_api->godot_arvr_add_controller(
									const_cast<char *>(hand_controller_names[i]),
									i + HAND_CONTROLLER_ID_OFFSET,
									true,
									true);
				}
			}
			*/
		}
	}
}

void OpenXRHandTrackingExtension::on_state_stopping() {
	// cleanup
	cleanup_hand_tracking();
}

void OpenXRHandTrackingExtension::cleanup_hand_tracking() {
	XRServer *xr_server = XRServer::get_singleton();
	ERR_FAIL_NULL(xr_server);

	for (int i = 0; i < MAX_OPENXR_TRACKED_HANDS; i++) {
		if (hand_trackers[i].hand_tracker != XR_NULL_HANDLE) {
			xrDestroyHandTrackerEXT(hand_trackers[i].hand_tracker);

			hand_trackers[i].is_initialised = false;
			hand_trackers[i].hand_tracker = XR_NULL_HANDLE;
		}
	}
}

bool OpenXRHandTrackingExtension::get_active() {
	return handTrackingSystemProperties.supportsHandTracking;
}

const OpenXRHandTrackingExtension::HandTracker *OpenXRHandTrackingExtension::get_hand_tracker(uint32_t p_hand) const {
	ERR_FAIL_UNSIGNED_INDEX_V(p_hand, MAX_OPENXR_TRACKED_HANDS, nullptr);

	return &hand_trackers[p_hand];
}

XrHandJointsMotionRangeEXT OpenXRHandTrackingExtension::get_motion_range(uint32_t p_hand) const {
	ERR_FAIL_UNSIGNED_INDEX_V(p_hand, MAX_OPENXR_TRACKED_HANDS, XR_HAND_JOINTS_MOTION_RANGE_MAX_ENUM_EXT);

	return hand_trackers[p_hand].motion_range;
}

void OpenXRHandTrackingExtension::set_motion_range(uint32_t p_hand, XrHandJointsMotionRangeEXT p_motion_range) {
	ERR_FAIL_UNSIGNED_INDEX(p_hand, MAX_OPENXR_TRACKED_HANDS);
	hand_trackers[p_hand].motion_range = p_motion_range;
}