Hand tracking

Signed-off-by: Slendi <slendi@socopon.com>

src/Application.cpp

@@ -479,6 +479,12 @@ struct OpenXrState {
 	PFN_xrGetVulkanGraphicsDeviceKHR get_graphics_device { nullptr };
 	PFN_xrGetVulkanGraphicsRequirements2KHR get_requirements2 { nullptr };
 	PFN_xrGetVulkanGraphicsRequirementsKHR get_requirements { nullptr };
+	bool hand_tracking_supported { false };
+	XrHandTrackerEXT left_hand_tracker { XR_NULL_HANDLE };
+	XrHandTrackerEXT right_hand_tracker { XR_NULL_HANDLE };
+	PFN_xrCreateHandTrackerEXT create_hand_tracker { nullptr };
+	PFN_xrDestroyHandTrackerEXT destroy_hand_tracker { nullptr };
+	PFN_xrLocateHandJointsEXT locate_hand_joints { nullptr };
 };
 
 Application::Application()
@@ -1012,6 +1018,10 @@ auto Application::run() -> void
 
 			gl.set_transform(view_projection);
 			gl.draw_sphere(m_camera.target, 0.01f);
+
+			if (m_openxr && m_openxr->hand_tracking_supported) {
+				render_hands(gl, view_projection);
+			}
 		};
 
 		if (xr_active) {
@@ -1145,6 +1155,13 @@ auto Application::init_openxr() -> void
 		m_openxr->use_vulkan_enable2 = true;
 	}
 
+	bool const has_hand_tracking
+	    = has_extension(XR_EXT_HAND_TRACKING_EXTENSION_NAME);
+	if (has_hand_tracking) {
+		extensions.push_back(XR_EXT_HAND_TRACKING_EXTENSION_NAME);
+		m_openxr->hand_tracking_supported = true;
+	}
+
 	create_info.enabledExtensionCount
 	    = static_cast<uint32_t>(extensions.size());
 	create_info.enabledExtensionNames = extensions.data();
@@ -1276,6 +1293,35 @@ auto Application::init_openxr() -> void
 		}
 	}
 
+	if (m_openxr->hand_tracking_supported) {
+		auto create_result = xrGetInstanceProcAddr(m_openxr->instance,
+		    "xrCreateHandTrackerEXT",
+		    reinterpret_cast<PFN_xrVoidFunction *>(
+		        &m_openxr->create_hand_tracker));
+		if (XR_FAILED(create_result) || !m_openxr->create_hand_tracker) {
+			m_logger.warn("OpenXR hand tracking create function unavailable");
+			m_openxr->hand_tracking_supported = false;
+		}
+
+		auto destroy_result = xrGetInstanceProcAddr(m_openxr->instance,
+		    "xrDestroyHandTrackerEXT",
+		    reinterpret_cast<PFN_xrVoidFunction *>(
+		        &m_openxr->destroy_hand_tracker));
+		if (XR_FAILED(destroy_result) || !m_openxr->destroy_hand_tracker) {
+			m_logger.warn("OpenXR hand tracking destroy function unavailable");
+			m_openxr->hand_tracking_supported = false;
+		}
+
+		auto locate_result
+		    = xrGetInstanceProcAddr(m_openxr->instance, "xrLocateHandJointsEXT",
+		        reinterpret_cast<PFN_xrVoidFunction *>(
+		            &m_openxr->locate_hand_joints));
+		if (XR_FAILED(locate_result) || !m_openxr->locate_hand_joints) {
+			m_logger.warn("OpenXR hand tracking locate function unavailable");
+			m_openxr->hand_tracking_supported = false;
+		}
+	}
+
 	m_logger.info("OpenXR system detected");
 }
 
@@ -1531,6 +1577,33 @@ auto Application::init_openxr_session() -> void
 	if (!m_openxr->swapchains.empty()) {
 		m_renderer->set_offscreen_extent(m_openxr->swapchains.front().extent);
 	}
+
+	if (m_openxr->hand_tracking_supported && m_openxr->create_hand_tracker) {
+		XrHandTrackerCreateInfoEXT left_info {};
+		left_info.type = XR_TYPE_HAND_TRACKER_CREATE_INFO_EXT;
+		left_info.next = nullptr;
+		left_info.hand = XR_HAND_LEFT_EXT;
+		left_info.handJointSet = XR_HAND_JOINT_SET_DEFAULT_EXT;
+		auto left_result = m_openxr->create_hand_tracker(
+		    m_openxr->session, &left_info, &m_openxr->left_hand_tracker);
+		if (XR_FAILED(left_result)) {
+			m_logger.warn("Failed to create left hand tracker");
+			m_openxr->left_hand_tracker = XR_NULL_HANDLE;
+		}
+
+		XrHandTrackerCreateInfoEXT right_info {};
+		right_info.type = XR_TYPE_HAND_TRACKER_CREATE_INFO_EXT;
+		right_info.next = nullptr;
+		right_info.hand = XR_HAND_RIGHT_EXT;
+		right_info.handJointSet = XR_HAND_JOINT_SET_DEFAULT_EXT;
+		auto right_result = m_openxr->create_hand_tracker(
+		    m_openxr->session, &right_info, &m_openxr->right_hand_tracker);
+		if (XR_FAILED(right_result)) {
+			m_logger.warn("Failed to create right hand tracker");
+			m_openxr->right_hand_tracker = XR_NULL_HANDLE;
+		}
+	}
+
 	m_logger.info("OpenXR session initialized");
 }
 
@@ -1548,6 +1621,18 @@ auto Application::shutdown_openxr() -> void
 	}
 	m_openxr->swapchains.clear();
 
+	if (m_openxr->left_hand_tracker != XR_NULL_HANDLE
+	    && m_openxr->destroy_hand_tracker) {
+		m_openxr->destroy_hand_tracker(m_openxr->left_hand_tracker);
+		m_openxr->left_hand_tracker = XR_NULL_HANDLE;
+	}
+
+	if (m_openxr->right_hand_tracker != XR_NULL_HANDLE
+	    && m_openxr->destroy_hand_tracker) {
+		m_openxr->destroy_hand_tracker(m_openxr->right_hand_tracker);
+		m_openxr->right_hand_tracker = XR_NULL_HANDLE;
+	}
+
 	if (m_openxr->app_space != XR_NULL_HANDLE) {
 		xrDestroySpace(m_openxr->app_space);
 		m_openxr->app_space = XR_NULL_HANDLE;
@@ -1666,6 +1751,8 @@ auto Application::render_openxr_frame(
 		return false;
 	}
 
+	update_hands(frame_state.predictedDisplayTime);
+
 	std::vector<XrCompositionLayerProjectionView> projection_views(view_count);
 	for (auto &projection_view : projection_views) {
 		projection_view = XrCompositionLayerProjectionView {};
@@ -1746,6 +1833,106 @@ auto Application::update_camera_from_xr_view(XrView const &view) -> void
 	m_cursor = PolarCoordinate::from_vec3(m_camera.target - m_camera.position);
 }
 
+auto Application::update_hands(XrTime display_time) -> void
+{
+	if (!m_openxr || !m_openxr->hand_tracking_supported) {
+		m_left_hand_valid = false;
+		m_right_hand_valid = false;
+		return;
+	}
+
+	if (m_openxr->left_hand_tracker != XR_NULL_HANDLE
+	    && m_openxr->locate_hand_joints) {
+		XrHandJointsLocateInfoEXT locate_info {};
+		locate_info.type = XR_TYPE_HAND_JOINTS_LOCATE_INFO_EXT;
+		locate_info.next = nullptr;
+		locate_info.baseSpace = m_openxr->app_space;
+		locate_info.time = display_time;
+
+		XrHandJointLocationEXT locations[XR_HAND_JOINT_COUNT_EXT];
+		XrHandJointLocationsEXT locations_info {};
+		locations_info.type = XR_TYPE_HAND_JOINT_LOCATIONS_EXT;
+		locations_info.next = nullptr;
+		locations_info.jointCount = XR_HAND_JOINT_COUNT_EXT;
+		locations_info.jointLocations = locations;
+
+		if (XR_SUCCEEDED(m_openxr->locate_hand_joints(
+		        m_openxr->left_hand_tracker, &locate_info, &locations_info))) {
+			m_left_hand_valid = (locations[0].locationFlags
+			                        & XR_SPACE_LOCATION_POSITION_VALID_BIT)
+			    != 0;
+			if (m_left_hand_valid) {
+				for (uint32_t j = 0; j < XR_HAND_JOINT_COUNT_EXT; j++) {
+					m_left_joints[j]
+					    = smath::Vec3 { locations[j].pose.position.x,
+						      locations[j].pose.position.y,
+						      locations[j].pose.position.z };
+				}
+			}
+		} else {
+			m_left_hand_valid = false;
+		}
+	}
+
+	if (m_openxr->right_hand_tracker != XR_NULL_HANDLE
+	    && m_openxr->locate_hand_joints) {
+		XrHandJointsLocateInfoEXT locate_info {};
+		locate_info.type = XR_TYPE_HAND_JOINTS_LOCATE_INFO_EXT;
+		locate_info.next = nullptr;
+		locate_info.baseSpace = m_openxr->app_space;
+		locate_info.time = display_time;
+
+		XrHandJointLocationEXT locations[XR_HAND_JOINT_COUNT_EXT];
+		XrHandJointLocationsEXT locations_info {};
+		locations_info.type = XR_TYPE_HAND_JOINT_LOCATIONS_EXT;
+		locations_info.next = nullptr;
+		locations_info.jointCount = XR_HAND_JOINT_COUNT_EXT;
+		locations_info.jointLocations = locations;
+
+		if (XR_SUCCEEDED(m_openxr->locate_hand_joints(
+		        m_openxr->right_hand_tracker, &locate_info, &locations_info))) {
+			m_right_hand_valid = (locations[0].locationFlags
+			                         & XR_SPACE_LOCATION_POSITION_VALID_BIT)
+			    != 0;
+			if (m_right_hand_valid) {
+				for (uint32_t j = 0; j < XR_HAND_JOINT_COUNT_EXT; j++) {
+					m_right_joints[j]
+					    = smath::Vec3 { locations[j].pose.position.x,
+						      locations[j].pose.position.y,
+						      locations[j].pose.position.z };
+				}
+			}
+		} else {
+			m_right_hand_valid = false;
+		}
+	}
+}
+
+auto Application::render_hands(
+    VulkanRenderer::GL &gl, smath::Mat4 const &view_projection) -> void
+{
+	gl.set_texture(&m_renderer->white_texture());
+	float const radius = 0.005f;
+
+	if (m_left_hand_valid) {
+		for (uint32_t j = 0; j < XR_HAND_JOINT_COUNT_EXT; j++) {
+			smath::Vec3 const &pos = m_left_joints[j];
+			gl.set_transform(view_projection * smath::translate(pos));
+			gl.draw_sphere(smath::Vec3 { 0.0f, 0.0f, 0.0f }, radius, 8, 16,
+			    smath::Vec4 { 1.0f, 0.0f, 0.0f, 1.0f });
+		}
+	}
+
+	if (m_right_hand_valid) {
+		for (uint32_t j = 0; j < XR_HAND_JOINT_COUNT_EXT; j++) {
+			smath::Vec3 const &pos = m_right_joints[j];
+			gl.set_transform(view_projection * smath::translate(pos));
+			gl.draw_sphere(smath::Vec3 { 0.0f, 0.0f, 0.0f }, radius, 8, 16,
+			    smath::Vec4 { 1.0f, 0.0f, 0.0f, 1.0f });
+		}
+	}
+}
+
 auto Application::process_libinput_events() -> void
 {
 	if (!m_libinput)

src/Application.h

@@ -13,6 +13,8 @@
 #include <linux/input-event-codes.h>
 #include <openxr/openxr.h>
 
+#include "smath.hpp"
+
 #include "Loader.h"
 #include "Logger.h"
 #include "Skybox.h"
@@ -73,6 +75,9 @@ private:
 	    std::function<void(VulkanRenderer::GL &)> const &record,
 	    float dt_seconds) -> bool;
 	auto update_camera_from_xr_view(XrView const &view) -> void;
+	auto update_hands(XrTime display_time) -> void;
+	auto render_hands(
+	    VulkanRenderer::GL &gl, smath::Mat4 const &view_projection) -> void;
 
 	SDL_Window *m_window { nullptr };
 	Backend m_backend { Backend::SDL };
@@ -104,6 +109,13 @@ private:
 
 	Camera m_camera;
 	PolarCoordinate m_cursor;
+
+	static inline std::array<smath::Vec3, XR_HAND_JOINT_COUNT_EXT>
+	    m_left_joints {};
+	static inline std::array<smath::Vec3, XR_HAND_JOINT_COUNT_EXT>
+	    m_right_joints {};
+	static inline bool m_left_hand_valid { false };
+	static inline bool m_right_hand_valid { false };
 };
 
 } // namespace Lunar

src/VulkanRenderer.cpp

@@ -426,37 +426,66 @@ auto VulkanRenderer::GL::draw_sphere(smath::Vec3 center, float radius,
 	if (sphere_color.has_value())
 		color(*sphere_color);
 
+	begin(GeometryKind::Triangles);
+
 	for (int y = 0; y < rings; y++) {
-		float const v = static_cast<float>(y + 1) / static_cast<float>(rings);
+		float const v1 = static_cast<float>(y) / static_cast<float>(rings);
+		float const v2 = static_cast<float>(y + 1) / static_cast<float>(rings);
 
-		float const theta = v * pi;
+		float const theta1 = v1 * pi;
+		float const theta2 = v2 * pi;
 
-		float const s = std::sin(theta);
+		float const s1 = std::sin(theta1);
-		float const c = std::cos(theta);
+		float const c1 = std::cos(theta1);
+		float const s2 = std::sin(theta2);
+		float const c2 = std::cos(theta2);
 
-		begin(GeometryKind::TriangleStrip);
+		for (int x = 0; x < segments; x++) {
-
+			float const u1
-		for (int x = 0; x <= segments; x++) {
-			float const u
 			    = static_cast<float>(x) / static_cast<float>(segments);
-			float const phi = u * (2.0f * pi);
+			float const u2
+			    = static_cast<float>(x + 1) / static_cast<float>(segments);
 
-			float const sp = std::sin(phi);
+			float const phi1 = u1 * (2.0f * pi);
-			float const cp = std::cos(phi);
+			float const phi2 = u2 * (2.0f * pi);
 
-			// Vertex on ring y+1
+			float const sp1 = std::sin(phi1);
-			{
+			float const cp1 = std::cos(phi1);
-				smath::Vec3 n { s * cp, c, s * sp };
+			float const sp2 = std::sin(phi2);
-				normal(n);
+			float const cp2 = std::cos(phi2);
-				uv(smath::Vec2 { u, 1.0f - v });
 
-				smath::Vec3 p { center + n * radius };
+			smath::Vec3 n1 { s1 * cp1, c1, s1 * sp1 };
-				vert(p);
+			smath::Vec3 n2 { s1 * cp2, c1, s1 * sp2 };
+			smath::Vec3 n3 { s2 * cp1, c2, s2 * sp1 };
+			smath::Vec3 n4 { s2 * cp2, c2, s2 * sp2 };
+
+			normal(n1);
+			uv(smath::Vec2 { u1, 1.0f - v1 });
+			vert(center + n1 * radius);
+
+			normal(n2);
+			uv(smath::Vec2 { u2, 1.0f - v1 });
+			vert(center + n2 * radius);
+
+			normal(n3);
+			uv(smath::Vec2 { u1, 1.0f - v2 });
+			vert(center + n3 * radius);
+
+			normal(n2);
+			uv(smath::Vec2 { u2, 1.0f - v1 });
+			vert(center + n2 * radius);
+
+			normal(n4);
+			uv(smath::Vec2 { u2, 1.0f - v2 });
+			vert(center + n4 * radius);
+
+			normal(n3);
+			uv(smath::Vec2 { u1, 1.0f - v2 });
+			vert(center + n3 * radius);
 		}
 	}
 
 	end();
-	}
 }
 
 auto VulkanRenderer::GL::draw_mesh(GPUMeshBuffers const &mesh,