feat(server): ✨ Define draft libalvr API

alvr/server/Cargo.toml

@@ -22,6 +22,7 @@ alvr_server_io.workspace = true
 alvr_session.workspace = true
 alvr_sockets.workspace = true
 
+ash = "0.37"
 bincode = "1"
 bytes = "1"
 chrono = "0.4"

alvr/server/src/c_api.rs

@@ -0,0 +1,267 @@
+use ash::vk;
+use std::{
+    ffi::{c_char, CStr},
+    time::Instant,
+};
+
+#[repr(C)]
+#[derive(Clone, Copy)]
+pub struct AlvrFov {
+    /// Negative, radians
+    pub left: f32,
+    /// Positive, radians
+    pub right: f32,
+    /// Positive, radians
+    pub up: f32,
+    /// Negative, radians
+    pub down: f32,
+}
+
+#[repr(C)]
+#[derive(Clone, Copy)]
+pub struct AlvrQuat {
+    pub x: f32,
+    pub y: f32,
+    pub z: f32,
+    pub w: f32,
+}
+impl Default for AlvrQuat {
+    fn default() -> Self {
+        Self {
+            x: 0.0,
+            y: 0.0,
+            z: 0.0,
+            w: 1.0,
+        }
+    }
+}
+
+#[repr(C)]
+#[derive(Clone, Copy, Default)]
+pub struct AlvrPose {
+    orientation: AlvrQuat,
+    position: [f32; 3],
+}
+
+#[repr(C)]
+#[derive(Clone, Copy)]
+pub struct AlvrSpaceRelation {
+    pub pose: AlvrPose,
+    pub linear_velocity: [f32; 3],
+    pub angular_velocity: [f32; 3],
+    pub has_velocity: bool,
+}
+
+#[repr(C)]
+#[derive(Clone, Copy)]
+pub struct AlvrJoint {
+    relation: AlvrSpaceRelation,
+    radius: f32,
+}
+
+#[repr(C)]
+#[derive(Clone, Copy)]
+pub struct AlvrJointSet {
+    values: [AlvrJoint; 26],
+    global_hand_relation: AlvrSpaceRelation,
+    is_active: bool,
+}
+
+#[repr(C)]
+#[derive(Clone, Copy)]
+pub union AlvrInputValue {
+    pub bool_: bool,
+    pub float_: f32,
+}
+
+// the profile is implied
+#[repr(C)]
+#[derive(Clone, Copy)]
+pub struct AlvrInput {
+    pub id: u64,
+    pub value: AlvrInputValue,
+}
+
+#[repr(u8)]
+#[derive(Clone, Copy)]
+pub enum AlvrOutput {
+    Haptics {
+        frequency: f32,
+        amplitude: f32,
+        duration_ns: u64,
+    },
+}
+
+#[repr(C)]
+#[derive(Clone, Copy)]
+pub struct AlvrBatteryValue {
+    pub device_id: u64,
+    /// range [0, 1]
+    pub value: f32,
+}
+
+#[repr(C)]
+pub enum AlvrEvent {
+    Battery(AlvrBatteryValue),
+    Bounds([f32; 2]),
+    Restart,
+    Shutdown,
+}
+
+#[repr(C)]
+#[derive(Clone, Copy)]
+pub struct AlvrTargetConfig {
+    target_width: u32,
+    target_height: u32,
+}
+
+#[repr(C)]
+#[derive(Clone, Copy)]
+pub struct AlvrDeviceConfig {
+    device_id: u64,
+    interaction_profile_id: u64,
+}
+
+// Get ALVR server time. The libalvr user should provide timestamps in the provided time frame of
+// reference in the following functions
+#[no_mangle]
+pub unsafe extern "C" fn alvr_get_time_ns() -> u64 {
+    Instant::now().elapsed().as_nanos() as u64
+}
+
+// The libalvr user is responsible of interpreting values and calling functions using
+// device/input/output identifiers obtained using this function
+#[no_mangle]
+pub unsafe extern "C" fn alvr_path_to_id(path_string: *const c_char) -> u64 {
+    alvr_common::hash_string(CStr::from_ptr(path_string).to_str().unwrap())
+}
+
+#[no_mangle]
+pub unsafe extern "C" fn alvr_initialize(target_config: *mut AlvrTargetConfig) {
+    todo!()
+}
+
+#[no_mangle]
+pub unsafe extern "C" fn alvr_poll_event(out_event: *mut AlvrEvent) -> bool {
+    todo!()
+}
+
+#[no_mangle]
+pub unsafe extern "C" fn alvr_shutdown() {
+    todo!()
+}
+
+// Device API:
+
+// Use the two-call pattern to first get the array length then the array data.
+#[no_mangle]
+pub unsafe extern "C" fn alvr_get_devices(out_device_configs: *mut AlvrDeviceConfig) -> u64 {
+    todo!()
+}
+
+// After this call, previous button and tracking data is discarded
+#[no_mangle]
+pub unsafe extern "C" fn alvr_update_inputs(device_id: u64) {
+    todo!()
+}
+
+// Use the two-call pattern to first get the array length then the array data.
+// Data is updated after a call to alvr_update_inputs.
+#[no_mangle]
+pub unsafe extern "C" fn alvr_get_inputs(
+    device_id: u64,
+    out_inputs_arr: *mut AlvrInput,
+    out_timestamp_ns: u64,
+) -> u64 {
+    todo!()
+}
+
+// pose_id is something like /user/hand/left/input/grip/pose
+#[no_mangle]
+pub unsafe extern "C" fn alvr_get_tracked_pose(
+    pose_id: u64,
+    timestamp_ns: u64,
+    out_relation: *mut AlvrSpaceRelation,
+) {
+    todo!()
+}
+
+#[no_mangle]
+pub unsafe extern "C" fn alvr_get_hand_tracking(
+    device_id: u64,
+    timestamp_ns: u64,
+    out_joint_set: *mut AlvrJointSet,
+) {
+    todo!()
+}
+
+// Currently only haptics is supported
+#[no_mangle]
+pub unsafe extern "C" fn alvr_set_output(output_id: u64, value: *const AlvrOutput) {
+    todo!()
+}
+
+#[no_mangle]
+pub unsafe extern "C" fn alvr_view_poses(
+    out_head_relation: *mut AlvrSpaceRelation,
+    out_fov_arr: *mut AlvrFov,            // 2 elements
+    out_relative_pose_arr: *mut AlvrPose, // 2 elements
+) {
+    todo!()
+}
+
+#[no_mangle]
+pub unsafe extern "C" fn alvr_destroy_device(device_id: u64) {
+    todo!()
+}
+
+// Compositor target API:
+
+// This should reflect the client current framerate
+#[no_mangle]
+pub unsafe extern "C" fn alvr_get_framerate() -> f32 {
+    todo!()
+}
+
+#[no_mangle]
+pub unsafe extern "C" fn alvr_pre_vulkan() {
+    todo!()
+}
+
+#[no_mangle]
+pub unsafe extern "C" fn alvr_post_vulkan() {
+    todo!()
+}
+
+#[no_mangle]
+pub unsafe extern "C" fn alvr_create_vk_target_swapchain(
+    width: u32,
+    height: u32,
+    color_format: vk::Format,
+    color_space: vk::ColorSpaceKHR,
+    image_usage: vk::ImageUsageFlags,
+    present_mode: vk::PresentModeKHR,
+    image_count: u64,
+) {
+    todo!()
+}
+
+#[no_mangle]
+pub unsafe extern "C" fn alvr_acquire_image(out_swapchain_index: u64) -> vk::Result {
+    todo!()
+}
+
+#[no_mangle]
+pub unsafe extern "C" fn alvr_present(
+    queue: vk::Queue,
+    swapchain_index: u64,
+    timeline_semaphore_value: u64,
+    timestamp_ns: u64,
+) -> vk::Result {
+    todo!()
+}
+
+#[no_mangle]
+pub unsafe extern "C" fn alvr_destroy_vk_target_swapchain() {
+    todo!()
+}

alvr/server/src/lib.rs

@@ -1,4 +1,5 @@
 mod bitrate;
+mod c_api;
 mod connection;
 mod face_tracking;
 mod hand_gestures;