rendering code and api crate

crates/bevy_openxr/Cargo.toml

@@ -0,0 +1,25 @@
+[package]
+name = "bevy_openxr"
+version = "0.1.0"
+edition = "2021"
+
+[features]
+default = ["vulkan"]
+vulkan = ["dep:ash"]
+
+[dependencies]
+thiserror = "1.0.57"
+wgpu = "0.19.3"
+wgpu-hal = "0.19.3"
+
+bevy_xr.path = "../bevy_xr"
+bevy.workspace = true
+
+
+ash = { version = "0.37.3", optional = true }
+
+[target.'cfg(target_family = "unix")'.dependencies]
+openxr = { version = "0.18.0", features = ["mint"] }
+
+[target.'cfg(target_family = "windows")'.dependencies]
+openxr = { version = "0.18.0", features = ["mint", "static"] }

crates/bevy_openxr/examples/3d_scene.rs

@@ -0,0 +1,55 @@
+//! A simple 3D scene with light shining over a cube sitting on a plane.
+
+use bevy::{
+    prelude::*,
+    render::camera::{ManualTextureViewHandle, RenderTarget},
+};
+use bevy_openxr::{add_xr_plugins, render::XR_TEXTURE_INDEX};
+use bevy_xr::camera::XrCameraBundle;
+
+fn main() {
+    App::new()
+        .add_plugins(add_xr_plugins(DefaultPlugins))
+        .add_systems(Startup, setup)
+        .run();
+}
+
+/// set up a simple 3D scene
+fn setup(
+    mut commands: Commands,
+    mut meshes: ResMut<Assets<Mesh>>,
+    mut materials: ResMut<Assets<StandardMaterial>>,
+) {
+    // circular base
+    commands.spawn(PbrBundle {
+        mesh: meshes.add(Circle::new(4.0)),
+        material: materials.add(Color::WHITE),
+        transform: Transform::from_rotation(Quat::from_rotation_x(-std::f32::consts::FRAC_PI_2)),
+        ..default()
+    });
+    // cube
+    commands.spawn(PbrBundle {
+        mesh: meshes.add(Cuboid::new(1.0, 1.0, 1.0)),
+        material: materials.add(Color::rgb_u8(124, 144, 255)),
+        transform: Transform::from_xyz(0.0, 0.5, 0.0),
+        ..default()
+    });
+    // light
+    commands.spawn(PointLightBundle {
+        point_light: PointLight {
+            shadows_enabled: true,
+            ..default()
+        },
+        transform: Transform::from_xyz(4.0, 8.0, 4.0),
+        ..default()
+    });
+    // // camera
+    // commands.spawn(XrCameraBundle {
+    //     transform: Transform::from_xyz(-2.5, 4.5, 9.0).looking_at(Vec3::ZERO, Vec3::Y),
+    //     camera: Camera {
+    //         target: RenderTarget::TextureView(ManualTextureViewHandle(XR_TEXTURE_INDEX + 1)),
+    //         ..default()
+    //     },
+    //     ..default()
+    // });
+}

crates/bevy_openxr/src/error.rs

@@ -0,0 +1,66 @@
+use crate::graphics::GraphicsBackend;
+use std::borrow::Cow;
+use std::fmt;
+use thiserror::Error;
+
+#[derive(Error, Debug)]
+pub enum XrError {
+    #[error("OpenXR error: {0}")]
+    OpenXrError(#[from] openxr::sys::Result),
+    #[error("OpenXR loading error: {0}")]
+    OpenXrLoadingError(#[from] openxr::LoadError),
+    #[error("WGPU instance error: {0}")]
+    WgpuInstanceError(#[from] wgpu_hal::InstanceError),
+    #[error("WGPU device error: {0}")]
+    WgpuDeviceError(#[from] wgpu_hal::DeviceError),
+    #[error("WGPU request device error: {0}")]
+    WgpuRequestDeviceError(#[from] wgpu::RequestDeviceError),
+    #[error("Unsupported texture format: {0:?}")]
+    UnsupportedTextureFormat(wgpu::TextureFormat),
+    #[error("Vulkan error: {0}")]
+    VulkanError(#[from] ash::vk::Result),
+    #[error("Vulkan loading error: {0}")]
+    VulkanLoadingError(#[from] ash::LoadingError),
+    #[error("Graphics backend '{0:?}' is not available")]
+    UnavailableBackend(GraphicsBackend),
+    #[error("No compatible backend available")]
+    NoAvailableBackend,
+    #[error("No compatible view configuration available")]
+    NoAvailableViewConfiguration,
+    #[error("No compatible blend mode available")]
+    NoAvailableBlendMode,
+    #[error("No compatible format available")]
+    NoAvailableFormat,
+    #[error("OpenXR runtime does not support these extensions: {0}")]
+    UnavailableExtensions(UnavailableExts),
+    #[error("Could not meet graphics requirements for platform. See console for details")]
+    FailedGraphicsRequirements,
+    #[error(
+        "Tried to use item {item} with backend {backend}. Expected backend {expected_backend}"
+    )]
+    GraphicsBackendMismatch {
+        item: &'static str,
+        backend: &'static str,
+        expected_backend: &'static str,
+    },
+    #[error("Failed to create CString: {0}")]
+    NulError(#[from] std::ffi::NulError),
+}
+
+impl From<Vec<Cow<'static, str>>> for XrError {
+    fn from(value: Vec<Cow<'static, str>>) -> Self {
+        Self::UnavailableExtensions(UnavailableExts(value))
+    }
+}
+
+#[derive(Debug)]
+pub struct UnavailableExts(Vec<Cow<'static, str>>);
+
+impl fmt::Display for UnavailableExts {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        for s in &self.0 {
+            write!(f, "\t{s}")?;
+        }
+        Ok(())
+    }
+}

crates/bevy_openxr/src/extensions.rs

@@ -0,0 +1,322 @@
+use bevy::prelude::{Deref, DerefMut};
+use openxr::ExtensionSet;
+
+#[derive(Clone, Debug, Eq, PartialEq, Deref, DerefMut)]
+pub struct XrExtensions(ExtensionSet);
+impl XrExtensions {
+    pub fn raw_mut(&mut self) -> &mut ExtensionSet {
+        &mut self.0
+    }
+    pub fn raw(&self) -> &ExtensionSet {
+        &self.0
+    }
+    pub fn enable_fb_passthrough(&mut self) -> &mut Self {
+        self.0.fb_passthrough = true;
+        self
+    }
+    pub fn disable_fb_passthrough(&mut self) -> &mut Self {
+        self.0.fb_passthrough = false;
+        self
+    }
+    pub fn enable_hand_tracking(&mut self) -> &mut Self {
+        self.0.ext_hand_tracking = true;
+        self
+    }
+    pub fn disable_hand_tracking(&mut self) -> &mut Self {
+        self.0.ext_hand_tracking = false;
+        self
+    }
+    /// returns true if all of the extensions enabled are also available in `available_exts`
+    pub fn is_available(&self, available_exts: &XrExtensions) -> bool {
+        self.clone() & available_exts.clone() == *self
+    }
+}
+impl From<ExtensionSet> for XrExtensions {
+    fn from(value: ExtensionSet) -> Self {
+        Self(value)
+    }
+}
+impl From<XrExtensions> for ExtensionSet {
+    fn from(val: XrExtensions) -> Self {
+        val.0
+    }
+}
+impl Default for XrExtensions {
+    fn default() -> Self {
+        let exts = ExtensionSet::default();
+        //exts.ext_hand_tracking = true;
+        Self(exts)
+    }
+}
+
+macro_rules! unavailable_exts {
+    (
+        $exts:ty;
+        $(
+            $(
+                #[$meta:meta]
+            )*
+            $ident:ident
+        ),*
+        $(,)?
+    ) => {
+        impl $exts {
+            /// Returns any extensions needed by `required_exts` that aren't available in `self`
+            pub fn unavailable_exts(&self, required_exts: &Self) -> Vec<std::borrow::Cow<'static, str>> {
+                let mut exts = vec![];
+                $(
+                    $(
+                        #[$meta]
+                    )*
+                    if required_exts.0.$ident && !self.0.$ident {
+                        exts.push(std::borrow::Cow::Borrowed(stringify!($ident)))
+                    }
+                )*
+                for ext in required_exts.0.other.iter() {
+                    if !self.0.other.contains(ext) {
+                        exts.push(std::borrow::Cow::Owned(ext.clone()))
+                    }
+                }
+                exts
+            }
+        }
+    };
+}
+
+macro_rules! bitor {
+    (
+        $exts:ty;
+        $(
+            $(
+                #[$meta:meta]
+            )*
+            $ident:ident
+        ),*
+        $(,)?
+    ) => {
+        impl std::ops::BitOr for $exts {
+            type Output = Self;
+
+            fn bitor(self, rhs: Self) -> Self::Output {
+                let mut out = ExtensionSet::default();
+                $(
+                    $(
+                        #[$meta]
+                    )*
+                    {
+                        out.$ident = self.0.$ident || rhs.0.$ident;
+                    }
+
+                )*
+                out.other = self.0.other;
+                for ext in rhs.0.other {
+                    if !out.other.contains(&ext) {
+                        out.other.push(ext);
+                    }
+                }
+                Self(out)
+            }
+        }
+    };
+}
+
+macro_rules! bitand {
+    (
+        $exts:ty;
+        $(
+            $(
+                #[$meta:meta]
+            )*
+            $ident:ident
+        ),*
+        $(,)?
+    ) => {
+        impl std::ops::BitAnd for $exts {
+            type Output = Self;
+
+            fn bitand(self, rhs: Self) -> Self::Output {
+                let mut out = ExtensionSet::default();
+                $(
+                    $(
+                        #[$meta]
+                    )*
+                    {
+                        out.$ident = self.0.$ident && rhs.0.$ident;
+                    }
+
+                )*
+                for ext in self.0.other {
+                    if rhs.0.other.contains(&ext) {
+                        out.other.push(ext);
+                    }
+                }
+                Self(out)
+            }
+        }
+    };
+}
+
+macro_rules! impl_ext {
+    (
+        $(
+            $macro:ident
+        ),*
+
+    ) => {
+        $(
+            $macro! {
+                XrExtensions;
+                almalence_digital_lens_control,
+                bd_controller_interaction,
+                epic_view_configuration_fov,
+                ext_performance_settings,
+                ext_thermal_query,
+                ext_debug_utils,
+                ext_eye_gaze_interaction,
+                ext_view_configuration_depth_range,
+                ext_conformance_automation,
+                ext_hand_tracking,
+                #[cfg(windows)]
+                ext_win32_appcontainer_compatible,
+                ext_dpad_binding,
+                ext_hand_joints_motion_range,
+                ext_samsung_odyssey_controller,
+                ext_hp_mixed_reality_controller,
+                ext_palm_pose,
+                ext_uuid,
+                ext_hand_interaction,
+                ext_active_action_set_priority,
+                ext_local_floor,
+                ext_hand_tracking_data_source,
+                ext_plane_detection,
+                fb_composition_layer_image_layout,
+                fb_composition_layer_alpha_blend,
+                #[cfg(target_os = "android")]
+                fb_android_surface_swapchain_create,
+                fb_swapchain_update_state,
+                fb_composition_layer_secure_content,
+                fb_body_tracking,
+                fb_display_refresh_rate,
+                fb_color_space,
+                fb_hand_tracking_mesh,
+                fb_hand_tracking_aim,
+                fb_hand_tracking_capsules,
+                fb_spatial_entity,
+                fb_foveation,
+                fb_foveation_configuration,
+                fb_keyboard_tracking,
+                fb_triangle_mesh,
+                fb_passthrough,
+                fb_render_model,
+                fb_spatial_entity_query,
+                fb_spatial_entity_storage,
+                fb_foveation_vulkan,
+                #[cfg(target_os = "android")]
+                fb_swapchain_update_state_android_surface,
+                fb_swapchain_update_state_opengl_es,
+                fb_swapchain_update_state_vulkan,
+                fb_touch_controller_pro,
+                fb_spatial_entity_sharing,
+                fb_space_warp,
+                fb_haptic_amplitude_envelope,
+                fb_scene,
+                fb_scene_capture,
+                fb_spatial_entity_container,
+                fb_face_tracking,
+                fb_eye_tracking_social,
+                fb_passthrough_keyboard_hands,
+                fb_composition_layer_settings,
+                fb_touch_controller_proximity,
+                fb_haptic_pcm,
+                fb_composition_layer_depth_test,
+                fb_spatial_entity_storage_batch,
+                fb_spatial_entity_user,
+                htc_vive_cosmos_controller_interaction,
+                htc_facial_tracking,
+                htc_vive_focus3_controller_interaction,
+                htc_hand_interaction,
+                htc_vive_wrist_tracker_interaction,
+                htc_passthrough,
+                htc_foveation,
+                huawei_controller_interaction,
+                #[cfg(target_os = "android")]
+                khr_android_thread_settings,
+                #[cfg(target_os = "android")]
+                khr_android_surface_swapchain,
+                khr_composition_layer_cube,
+                #[cfg(target_os = "android")]
+                khr_android_create_instance,
+                khr_composition_layer_depth,
+                khr_vulkan_swapchain_format_list,
+                khr_composition_layer_cylinder,
+                khr_composition_layer_equirect,
+                khr_opengl_enable,
+                khr_opengl_es_enable,
+                khr_vulkan_enable,
+                #[cfg(windows)]
+                khr_d3d11_enable,
+                #[cfg(windows)]
+                khr_d3d12_enable,
+                khr_visibility_mask,
+                khr_composition_layer_color_scale_bias,
+                #[cfg(windows)]
+                khr_win32_convert_performance_counter_time,
+                khr_convert_timespec_time,
+                khr_loader_init,
+                #[cfg(target_os = "android")]
+                khr_loader_init_android,
+                khr_vulkan_enable2,
+                khr_composition_layer_equirect2,
+                khr_binding_modification,
+                khr_swapchain_usage_input_attachment_bit,
+                meta_foveation_eye_tracked,
+                meta_local_dimming,
+                meta_passthrough_preferences,
+                meta_virtual_keyboard,
+                meta_vulkan_swapchain_create_info,
+                meta_performance_metrics,
+                meta_headset_id,
+                meta_passthrough_color_lut,
+                ml_ml2_controller_interaction,
+                ml_frame_end_info,
+                ml_global_dimmer,
+                ml_compat,
+                ml_user_calibration,
+                mnd_headless,
+                mnd_swapchain_usage_input_attachment_bit,
+                msft_unbounded_reference_space,
+                msft_spatial_anchor,
+                msft_spatial_graph_bridge,
+                msft_hand_interaction,
+                msft_hand_tracking_mesh,
+                msft_secondary_view_configuration,
+                msft_first_person_observer,
+                msft_controller_model,
+                #[cfg(windows)]
+                msft_perception_anchor_interop,
+                #[cfg(windows)]
+                msft_holographic_window_attachment,
+                msft_composition_layer_reprojection,
+                msft_spatial_anchor_persistence,
+                #[cfg(target_os = "android")]
+                oculus_android_session_state_enable,
+                oculus_audio_device_guid,
+                oculus_external_camera,
+                oppo_controller_interaction,
+                qcom_tracking_optimization_settings,
+                ultraleap_hand_tracking_forearm,
+                valve_analog_threshold,
+                varjo_quad_views,
+                varjo_foveated_rendering,
+                varjo_composition_layer_depth_test,
+                varjo_environment_depth_estimation,
+                varjo_marker_tracking,
+                varjo_view_offset,
+                yvr_controller_interaction,
+            }
+        )*
+
+    };
+}
+
+impl_ext!(bitor, bitand, unavailable_exts);

crates/bevy_openxr/src/graphics.rs

@@ -0,0 +1,131 @@
+#[cfg(feature = "vulkan")]
+pub mod vulkan;
+
+use std::any::TypeId;
+
+use crate::extensions::XrExtensions;
+use crate::types::*;
+
+pub unsafe trait GraphicsExt: openxr::Graphics {
+    /// Wrap the graphics specific type into the [GraphicsWrap] enum
+    fn wrap<T: GraphicsType>(item: T::Inner<Self>) -> GraphicsWrap<T>;
+    /// Convert from wgpu format to the graphics format
+    fn from_wgpu_format(format: wgpu::TextureFormat) -> Option<Self::Format>;
+    /// Convert from the graphics format to wgpu format
+    fn to_wgpu_format(format: Self::Format) -> Option<wgpu::TextureFormat>;
+    /// Initialize graphics for this backend
+    fn init_graphics(
+        app_info: &AppInfo,
+        instance: &openxr::Instance,
+        system_id: openxr::SystemId,
+    ) -> Result<(WgpuGraphics, Self::SessionCreateInfo)>;
+    /// Convert a swapchain function
+    unsafe fn to_wgpu_img(
+        image: Self::SwapchainImage,
+        device: &wgpu::Device,
+        format: wgpu::TextureFormat,
+        resolution: UVec2,
+    ) -> Result<wgpu::Texture>;
+    fn required_exts() -> XrExtensions;
+}
+
+pub trait GraphicsType {
+    type Inner<G: GraphicsExt>;
+}
+
+impl GraphicsType for () {
+    type Inner<G: GraphicsExt> = ();
+}
+
+pub type GraphicsBackend = GraphicsWrap<()>;
+
+impl GraphicsBackend {
+    const ALL: &'static [Self] = &[Self::Vulkan(())];
+
+    pub fn available_backends(exts: &XrExtensions) -> Vec<Self> {
+        Self::ALL
+            .iter()
+            .copied()
+            .filter(|backend| backend.is_available(exts))
+            .collect()
+    }
+
+    pub fn is_available(&self, exts: &XrExtensions) -> bool {
+        self.required_exts().is_available(exts)
+    }
+
+    pub fn required_exts(&self) -> XrExtensions {
+        graphics_match!(
+            self;
+            _ => Api::required_exts()
+        )
+    }
+}
+
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+pub enum GraphicsWrap<T: GraphicsType> {
+    #[cfg(feature = "vulkan")]
+    Vulkan(T::Inner<openxr::Vulkan>),
+}
+
+impl<T: GraphicsType> GraphicsWrap<T> {
+    /// Returns the name of the graphics api this struct is using.
+    pub fn graphics_name(&self) -> &'static str {
+        graphics_match!(
+            self;
+            _ => std::any::type_name::<Api>()
+        )
+    }
+
+    fn graphics_type(&self) -> TypeId {
+        graphics_match!(
+            self;
+            _ => TypeId::of::<Api>()
+        )
+    }
+
+    /// Checks if this struct is using the wanted graphics api.
+    pub fn using_graphics<G: GraphicsExt + 'static>(&self) -> bool {
+        self.graphics_type() == TypeId::of::<G>()
+    }
+
+    /// Checks if the two values are both using the same graphics backend
+    pub fn using_graphics_of_val<V: GraphicsType>(&self, other: &GraphicsWrap<V>) -> bool {
+        self.graphics_type() == other.graphics_type()
+    }
+}
+
+macro_rules! graphics_match {
+    (
+        $field:expr;
+        $var:pat => $expr:expr $(=> $($return:tt)*)?
+    ) => {
+        match $field {
+            #[cfg(feature = "vulkan")]
+            $crate::graphics::GraphicsWrap::Vulkan($var) => {
+                #[allow(unused)]
+                type Api = openxr::Vulkan;
+                graphics_match!(@arm_impl Vulkan; $expr $(=> $($return)*)?)
+            },
+        }
+    };
+
+    (
+        @arm_impl
+        $variant:ident;
+        $expr:expr => $wrap_ty:ty
+    ) => {
+        GraphicsWrap::<$wrap_ty>::$variant($expr)
+    };
+
+    (
+        @arm_impl
+        $variant:ident;
+        $expr:expr
+    ) => {
+        $expr
+    };
+}
+
+use bevy::math::UVec2;
+pub(crate) use graphics_match;

crates/bevy_openxr/src/graphics/vulkan.rs

@@ -0,0 +1,678 @@
+use std::ffi::{c_void, CString};
+
+use ash::vk::Handle;
+use bevy::log::error;
+use bevy::math::UVec2;
+use openxr::Version;
+use wgpu_hal::api::Vulkan;
+use wgpu_hal::Api;
+
+use crate::error::XrError;
+use crate::extensions::XrExtensions;
+use crate::types::*;
+
+use super::GraphicsExt;
+
+#[cfg(not(target_os = "android"))]
+const VK_TARGET_VERSION: Version = Version::new(1, 2, 0);
+#[cfg(target_os = "android")]
+const VK_TARGET_VERSION: Version = Version::new(1, 1, 0);
+
+const VK_TARGET_VERSION_ASH: u32 = ash::vk::make_api_version(
+    0,
+    VK_TARGET_VERSION.major() as u32,
+    VK_TARGET_VERSION.minor() as u32,
+    VK_TARGET_VERSION.patch() as u32,
+);
+
+unsafe impl GraphicsExt for openxr::Vulkan {
+    fn from_wgpu_format(format: wgpu::TextureFormat) -> Option<Self::Format> {
+        wgpu_to_vulkan(format).map(|f| f.as_raw() as _)
+    }
+
+    fn to_wgpu_format(format: Self::Format) -> Option<wgpu::TextureFormat> {
+        vulkan_to_wgpu(ash::vk::Format::from_raw(format as _))
+    }
+
+    fn init_graphics(
+        app_info: &AppInfo,
+        instance: &openxr::Instance,
+        system_id: openxr::SystemId,
+    ) -> Result<(WgpuGraphics, Self::SessionCreateInfo)> {
+        let reqs = instance.graphics_requirements::<openxr::Vulkan>(system_id)?;
+        if VK_TARGET_VERSION < reqs.min_api_version_supported
+            || VK_TARGET_VERSION.major() > reqs.max_api_version_supported.major()
+        {
+            error!(
+                "OpenXR runtime requires Vulkan version > {}, < {}.0.0",
+                reqs.min_api_version_supported,
+                reqs.max_api_version_supported.major() + 1
+            );
+            return Err(XrError::FailedGraphicsRequirements);
+        };
+        let vk_entry = unsafe { ash::Entry::load() }?;
+        let flags = wgpu::InstanceFlags::empty();
+        let extensions =
+            <Vulkan as Api>::Instance::desired_extensions(&vk_entry, VK_TARGET_VERSION_ASH, flags)?;
+        let device_extensions = vec![
+            ash::extensions::khr::Swapchain::name(),
+            ash::extensions::khr::DrawIndirectCount::name(),
+            #[cfg(target_os = "android")]
+            ash::extensions::khr::TimelineSemaphore::name(),
+        ];
+
+        let vk_instance = unsafe {
+            let extensions_cchar: Vec<_> = extensions.iter().map(|s| s.as_ptr()).collect();
+
+            let app_name = CString::new(app_info.name.clone().into_owned())?;
+            let vk_app_info = ash::vk::ApplicationInfo::builder()
+                .application_name(&app_name)
+                .application_version(1)
+                .engine_name(&app_name)
+                .engine_version(1)
+                .api_version(VK_TARGET_VERSION_ASH);
+
+            let vk_instance = instance
+                .create_vulkan_instance(
+                    system_id,
+                    std::mem::transmute(vk_entry.static_fn().get_instance_proc_addr),
+                    &ash::vk::InstanceCreateInfo::builder()
+                        .application_info(&vk_app_info)
+                        .enabled_extension_names(&extensions_cchar) as *const _
+                        as *const _,
+                )?
+                .map_err(ash::vk::Result::from_raw)?;
+
+            ash::Instance::load(
+                vk_entry.static_fn(),
+                ash::vk::Instance::from_raw(vk_instance as _),
+            )
+        };
+
+        let vk_instance_ptr = vk_instance.handle().as_raw() as *const c_void;
+
+        let vk_physical_device = ash::vk::PhysicalDevice::from_raw(unsafe {
+            instance.vulkan_graphics_device(system_id, vk_instance.handle().as_raw() as _)? as _
+        });
+        let vk_physical_device_ptr = vk_physical_device.as_raw() as *const c_void;
+
+        let vk_device_properties =
+            unsafe { vk_instance.get_physical_device_properties(vk_physical_device) };
+
+        if vk_device_properties.api_version < VK_TARGET_VERSION_ASH {
+            unsafe { vk_instance.destroy_instance(None) }
+            error!(
+                "Vulkan physical device doesn't support version {}.{}.{}",
+                VK_TARGET_VERSION.major(),
+                VK_TARGET_VERSION.minor(),
+                VK_TARGET_VERSION.patch()
+            );
+            return Err(XrError::FailedGraphicsRequirements);
+        }
+
+        let wgpu_vk_instance = unsafe {
+            <Vulkan as Api>::Instance::from_raw(
+                vk_entry.clone(),
+                vk_instance.clone(),
+                VK_TARGET_VERSION_ASH,
+                0,
+                None,
+                extensions,
+                flags,
+                false,
+                Some(Box::new(())),
+            )?
+        };
+
+        let wgpu_features = wgpu::Features::TEXTURE_ADAPTER_SPECIFIC_FORMAT_FEATURES
+            | wgpu::Features::MULTIVIEW
+            | wgpu::Features::MULTI_DRAW_INDIRECT_COUNT
+            | wgpu::Features::MULTI_DRAW_INDIRECT;
+
+        let Some(wgpu_exposed_adapter) = wgpu_vk_instance.expose_adapter(vk_physical_device) else {
+            error!("WGPU failed to provide an adapter");
+            return Err(XrError::FailedGraphicsRequirements);
+        };
+
+        let enabled_extensions = wgpu_exposed_adapter
+            .adapter
+            .required_device_extensions(wgpu_features);
+
+        let (wgpu_open_device, vk_device_ptr, queue_family_index) = {
+            let extensions_cchar: Vec<_> = device_extensions.iter().map(|s| s.as_ptr()).collect();
+            let mut enabled_phd_features = wgpu_exposed_adapter
+                .adapter
+                .physical_device_features(&enabled_extensions, wgpu_features);
+            let family_index = 0;
+            let family_info = ash::vk::DeviceQueueCreateInfo::builder()
+                .queue_family_index(family_index)
+                .queue_priorities(&[1.0])
+                .build();
+            let family_infos = [family_info];
+            let info = enabled_phd_features
+                .add_to_device_create_builder(
+                    ash::vk::DeviceCreateInfo::builder()
+                        .queue_create_infos(&family_infos)
+                        .push_next(&mut ash::vk::PhysicalDeviceMultiviewFeatures {
+                            multiview: ash::vk::TRUE,
+                            ..Default::default()
+                        }),
+                )
+                .enabled_extension_names(&extensions_cchar)
+                .build();
+            let vk_device = unsafe {
+                let vk_device = instance
+                    .create_vulkan_device(
+                        system_id,
+                        std::mem::transmute(vk_entry.static_fn().get_instance_proc_addr),
+                        vk_physical_device.as_raw() as _,
+                        &info as *const _ as *const _,
+                    )?
+                    .map_err(ash::vk::Result::from_raw)?;
+
+                ash::Device::load(
+                    vk_instance.fp_v1_0(),
+                    ash::vk::Device::from_raw(vk_device as _),
+                )
+            };
+            let vk_device_ptr = vk_device.handle().as_raw() as *const c_void;
+
+            let wgpu_open_device = unsafe {
+                wgpu_exposed_adapter.adapter.device_from_raw(
+                    vk_device,
+                    true,
+                    &enabled_extensions,
+                    wgpu_features,
+                    family_info.queue_family_index,
+                    0,
+                )
+            }?;
+
+            (
+                wgpu_open_device,
+                vk_device_ptr,
+                family_info.queue_family_index,
+            )
+        };
+
+        let wgpu_instance =
+            unsafe { wgpu::Instance::from_hal::<wgpu_hal::api::Vulkan>(wgpu_vk_instance) };
+        let wgpu_adapter = unsafe { wgpu_instance.create_adapter_from_hal(wgpu_exposed_adapter) };
+        let (wgpu_device, wgpu_queue) = unsafe {
+            wgpu_adapter.create_device_from_hal(
+                wgpu_open_device,
+                &wgpu::DeviceDescriptor {
+                    label: None,
+                    required_features: wgpu_features,
+                    required_limits: wgpu::Limits {
+                        max_bind_groups: 8,
+                        max_storage_buffer_binding_size: wgpu_adapter
+                            .limits()
+                            .max_storage_buffer_binding_size,
+                        max_push_constant_size: 4,
+                        ..Default::default()
+                    },
+                },
+                None,
+            )
+        }?;
+
+        Ok((
+            WgpuGraphics(
+                wgpu_device,
+                wgpu_queue,
+                wgpu_adapter.get_info(),
+                wgpu_adapter,
+                wgpu_instance,
+            ),
+            openxr::vulkan::SessionCreateInfo {
+                instance: vk_instance_ptr,
+                physical_device: vk_physical_device_ptr,
+                device: vk_device_ptr,
+                queue_family_index,
+                queue_index: 0,
+            },
+        ))
+    }
+
+    unsafe fn to_wgpu_img(
+        color_image: Self::SwapchainImage,
+        device: &wgpu::Device,
+        format: wgpu::TextureFormat,
+        resolution: UVec2,
+    ) -> Result<wgpu::Texture> {
+        let color_image = ash::vk::Image::from_raw(color_image);
+        let wgpu_hal_texture = unsafe {
+            <wgpu_hal::vulkan::Api as wgpu_hal::Api>::Device::texture_from_raw(
+                color_image,
+                &wgpu_hal::TextureDescriptor {
+                    label: Some("VR Swapchain"),
+                    size: wgpu::Extent3d {
+                        width: resolution.x,
+                        height: resolution.y,
+                        depth_or_array_layers: 2,
+                    },
+                    mip_level_count: 1,
+                    sample_count: 1,
+                    dimension: wgpu::TextureDimension::D2,
+                    format: format,
+                    usage: wgpu_hal::TextureUses::COLOR_TARGET | wgpu_hal::TextureUses::COPY_DST,
+                    memory_flags: wgpu_hal::MemoryFlags::empty(),
+                    view_formats: vec![],
+                },
+                None,
+            )
+        };
+        let texture = unsafe {
+            device.create_texture_from_hal::<wgpu_hal::vulkan::Api>(
+                wgpu_hal_texture,
+                &wgpu::TextureDescriptor {
+                    label: Some("VR Swapchain"),
+                    size: wgpu::Extent3d {
+                        width: resolution.x,
+                        height: resolution.y,
+                        depth_or_array_layers: 2,
+                    },
+                    mip_level_count: 1,
+                    sample_count: 1,
+                    dimension: wgpu::TextureDimension::D2,
+                    format: format,
+                    usage: wgpu::TextureUsages::RENDER_ATTACHMENT | wgpu::TextureUsages::COPY_DST,
+                    view_formats: &[],
+                },
+            )
+        };
+        Ok(texture)
+    }
+
+    fn required_exts() -> XrExtensions {
+        let mut extensions = openxr::ExtensionSet::default();
+        extensions.khr_vulkan_enable2 = true;
+        extensions.into()
+    }
+
+    fn wrap<T: super::GraphicsType>(item: T::Inner<Self>) -> super::GraphicsWrap<T> {
+        super::GraphicsWrap::Vulkan(item)
+    }
+}
+
+fn vulkan_to_wgpu(format: ash::vk::Format) -> Option<wgpu::TextureFormat> {
+    use ash::vk::Format as F;
+    use wgpu::TextureFormat as Tf;
+    use wgpu::{AstcBlock, AstcChannel};
+    Some(match format {
+        F::R8_UNORM => Tf::R8Unorm,
+        F::R8_SNORM => Tf::R8Snorm,
+        F::R8_UINT => Tf::R8Uint,
+        F::R8_SINT => Tf::R8Sint,
+        F::R16_UINT => Tf::R16Uint,
+        F::R16_SINT => Tf::R16Sint,
+        F::R16_UNORM => Tf::R16Unorm,
+        F::R16_SNORM => Tf::R16Snorm,
+        F::R16_SFLOAT => Tf::R16Float,
+        F::R8G8_UNORM => Tf::Rg8Unorm,
+        F::R8G8_SNORM => Tf::Rg8Snorm,
+        F::R8G8_UINT => Tf::Rg8Uint,
+        F::R8G8_SINT => Tf::Rg8Sint,
+        F::R16G16_UNORM => Tf::Rg16Unorm,
+        F::R16G16_SNORM => Tf::Rg16Snorm,
+        F::R32_UINT => Tf::R32Uint,
+        F::R32_SINT => Tf::R32Sint,
+        F::R32_SFLOAT => Tf::R32Float,
+        F::R16G16_UINT => Tf::Rg16Uint,
+        F::R16G16_SINT => Tf::Rg16Sint,
+        F::R16G16_SFLOAT => Tf::Rg16Float,
+        F::R8G8B8A8_UNORM => Tf::Rgba8Unorm,
+        F::R8G8B8A8_SRGB => Tf::Rgba8UnormSrgb,
+        F::B8G8R8A8_SRGB => Tf::Bgra8UnormSrgb,
+        F::R8G8B8A8_SNORM => Tf::Rgba8Snorm,
+        F::B8G8R8A8_UNORM => Tf::Bgra8Unorm,
+        F::R8G8B8A8_UINT => Tf::Rgba8Uint,
+        F::R8G8B8A8_SINT => Tf::Rgba8Sint,
+        F::A2B10G10R10_UINT_PACK32 => Tf::Rgb10a2Uint,
+        F::A2B10G10R10_UNORM_PACK32 => Tf::Rgb10a2Unorm,
+        F::B10G11R11_UFLOAT_PACK32 => Tf::Rg11b10Float,
+        F::R32G32_UINT => Tf::Rg32Uint,
+        F::R32G32_SINT => Tf::Rg32Sint,
+        F::R32G32_SFLOAT => Tf::Rg32Float,
+        F::R16G16B16A16_UINT => Tf::Rgba16Uint,
+        F::R16G16B16A16_SINT => Tf::Rgba16Sint,
+        F::R16G16B16A16_UNORM => Tf::Rgba16Unorm,
+        F::R16G16B16A16_SNORM => Tf::Rgba16Snorm,
+        F::R16G16B16A16_SFLOAT => Tf::Rgba16Float,
+        F::R32G32B32A32_UINT => Tf::Rgba32Uint,
+        F::R32G32B32A32_SINT => Tf::Rgba32Sint,
+        F::R32G32B32A32_SFLOAT => Tf::Rgba32Float,
+        F::D32_SFLOAT => Tf::Depth32Float,
+        F::D32_SFLOAT_S8_UINT => Tf::Depth32FloatStencil8,
+        F::D16_UNORM => Tf::Depth16Unorm,
+        F::G8_B8R8_2PLANE_420_UNORM => Tf::NV12,
+        F::E5B9G9R9_UFLOAT_PACK32 => Tf::Rgb9e5Ufloat,
+        F::BC1_RGBA_UNORM_BLOCK => Tf::Bc1RgbaUnorm,
+        F::BC1_RGBA_SRGB_BLOCK => Tf::Bc1RgbaUnormSrgb,
+        F::BC2_UNORM_BLOCK => Tf::Bc2RgbaUnorm,
+        F::BC2_SRGB_BLOCK => Tf::Bc2RgbaUnormSrgb,
+        F::BC3_UNORM_BLOCK => Tf::Bc3RgbaUnorm,
+        F::BC3_SRGB_BLOCK => Tf::Bc3RgbaUnormSrgb,
+        F::BC4_UNORM_BLOCK => Tf::Bc4RUnorm,
+        F::BC4_SNORM_BLOCK => Tf::Bc4RSnorm,
+        F::BC5_UNORM_BLOCK => Tf::Bc5RgUnorm,
+        F::BC5_SNORM_BLOCK => Tf::Bc5RgSnorm,
+        F::BC6H_UFLOAT_BLOCK => Tf::Bc6hRgbUfloat,
+        F::BC6H_SFLOAT_BLOCK => Tf::Bc6hRgbFloat,
+        F::BC7_UNORM_BLOCK => Tf::Bc7RgbaUnorm,
+        F::BC7_SRGB_BLOCK => Tf::Bc7RgbaUnormSrgb,
+        F::ETC2_R8G8B8_UNORM_BLOCK => Tf::Etc2Rgb8Unorm,
+        F::ETC2_R8G8B8_SRGB_BLOCK => Tf::Etc2Rgb8UnormSrgb,
+        F::ETC2_R8G8B8A1_UNORM_BLOCK => Tf::Etc2Rgb8A1Unorm,
+        F::ETC2_R8G8B8A1_SRGB_BLOCK => Tf::Etc2Rgb8A1UnormSrgb,
+        F::ETC2_R8G8B8A8_UNORM_BLOCK => Tf::Etc2Rgba8Unorm,
+        F::ETC2_R8G8B8A8_SRGB_BLOCK => Tf::Etc2Rgba8UnormSrgb,
+        F::EAC_R11_UNORM_BLOCK => Tf::EacR11Unorm,
+        F::EAC_R11_SNORM_BLOCK => Tf::EacR11Snorm,
+        F::EAC_R11G11_UNORM_BLOCK => Tf::EacRg11Unorm,
+        F::EAC_R11G11_SNORM_BLOCK => Tf::EacRg11Snorm,
+        F::ASTC_4X4_UNORM_BLOCK => Tf::Astc {
+            block: AstcBlock::B4x4,
+            channel: AstcChannel::Unorm,
+        },
+        F::ASTC_5X4_UNORM_BLOCK => Tf::Astc {
+            block: AstcBlock::B5x4,
+            channel: AstcChannel::Unorm,
+        },
+        F::ASTC_5X5_UNORM_BLOCK => Tf::Astc {
+            block: AstcBlock::B5x5,
+            channel: AstcChannel::Unorm,
+        },
+        F::ASTC_6X5_UNORM_BLOCK => Tf::Astc {
+            block: AstcBlock::B6x5,
+            channel: AstcChannel::Unorm,
+        },
+        F::ASTC_6X6_UNORM_BLOCK => Tf::Astc {
+            block: AstcBlock::B6x6,
+            channel: AstcChannel::Unorm,
+        },
+        F::ASTC_8X5_UNORM_BLOCK => Tf::Astc {
+            block: AstcBlock::B8x5,
+            channel: AstcChannel::Unorm,
+        },
+        F::ASTC_8X6_UNORM_BLOCK => Tf::Astc {
+            block: AstcBlock::B8x6,
+            channel: AstcChannel::Unorm,
+        },
+        F::ASTC_8X8_UNORM_BLOCK => Tf::Astc {
+            block: AstcBlock::B8x8,
+            channel: AstcChannel::Unorm,
+        },
+        F::ASTC_10X5_UNORM_BLOCK => Tf::Astc {
+            block: AstcBlock::B10x5,
+            channel: AstcChannel::Unorm,
+        },
+        F::ASTC_10X6_UNORM_BLOCK => Tf::Astc {
+            block: AstcBlock::B10x6,
+            channel: AstcChannel::Unorm,
+        },
+        F::ASTC_10X8_UNORM_BLOCK => Tf::Astc {
+            block: AstcBlock::B10x8,
+            channel: AstcChannel::Unorm,
+        },
+        F::ASTC_10X10_UNORM_BLOCK => Tf::Astc {
+            block: AstcBlock::B10x10,
+            channel: AstcChannel::Unorm,
+        },
+        F::ASTC_12X10_UNORM_BLOCK => Tf::Astc {
+            block: AstcBlock::B12x10,
+            channel: AstcChannel::Unorm,
+        },
+        F::ASTC_12X12_UNORM_BLOCK => Tf::Astc {
+            block: AstcBlock::B12x12,
+            channel: AstcChannel::Unorm,
+        },
+        F::ASTC_4X4_SRGB_BLOCK => Tf::Astc {
+            block: AstcBlock::B4x4,
+            channel: AstcChannel::UnormSrgb,
+        },
+        F::ASTC_5X4_SRGB_BLOCK => Tf::Astc {
+            block: AstcBlock::B5x4,
+            channel: AstcChannel::UnormSrgb,
+        },
+        F::ASTC_5X5_SRGB_BLOCK => Tf::Astc {
+            block: AstcBlock::B5x5,
+            channel: AstcChannel::UnormSrgb,
+        },
+        F::ASTC_6X5_SRGB_BLOCK => Tf::Astc {
+            block: AstcBlock::B6x5,
+            channel: AstcChannel::UnormSrgb,
+        },
+        F::ASTC_6X6_SRGB_BLOCK => Tf::Astc {
+            block: AstcBlock::B6x6,
+            channel: AstcChannel::UnormSrgb,
+        },
+        F::ASTC_8X5_SRGB_BLOCK => Tf::Astc {
+            block: AstcBlock::B8x5,
+            channel: AstcChannel::UnormSrgb,
+        },
+        F::ASTC_8X6_SRGB_BLOCK => Tf::Astc {
+            block: AstcBlock::B8x6,
+            channel: AstcChannel::UnormSrgb,
+        },
+        F::ASTC_8X8_SRGB_BLOCK => Tf::Astc {
+            block: AstcBlock::B8x8,
+            channel: AstcChannel::UnormSrgb,
+        },
+        F::ASTC_10X5_SRGB_BLOCK => Tf::Astc {
+            block: AstcBlock::B10x5,
+            channel: AstcChannel::UnormSrgb,
+        },
+        F::ASTC_10X6_SRGB_BLOCK => Tf::Astc {
+            block: AstcBlock::B10x6,
+            channel: AstcChannel::UnormSrgb,
+        },
+        F::ASTC_10X8_SRGB_BLOCK => Tf::Astc {
+            block: AstcBlock::B10x8,
+            channel: AstcChannel::UnormSrgb,
+        },
+        F::ASTC_10X10_SRGB_BLOCK => Tf::Astc {
+            block: AstcBlock::B10x10,
+            channel: AstcChannel::UnormSrgb,
+        },
+        F::ASTC_12X10_SRGB_BLOCK => Tf::Astc {
+            block: AstcBlock::B12x10,
+            channel: AstcChannel::UnormSrgb,
+        },
+        F::ASTC_12X12_SRGB_BLOCK => Tf::Astc {
+            block: AstcBlock::B12x12,
+            channel: AstcChannel::UnormSrgb,
+        },
+        F::ASTC_4X4_SFLOAT_BLOCK_EXT => Tf::Astc {
+            block: AstcBlock::B4x4,
+            channel: AstcChannel::Hdr,
+        },
+        F::ASTC_5X4_SFLOAT_BLOCK_EXT => Tf::Astc {
+            block: AstcBlock::B5x4,
+            channel: AstcChannel::Hdr,
+        },
+        F::ASTC_5X5_SFLOAT_BLOCK_EXT => Tf::Astc {
+            block: AstcBlock::B5x5,
+            channel: AstcChannel::Hdr,
+        },
+        F::ASTC_6X5_SFLOAT_BLOCK_EXT => Tf::Astc {
+            block: AstcBlock::B6x5,
+            channel: AstcChannel::Hdr,
+        },
+        F::ASTC_6X6_SFLOAT_BLOCK_EXT => Tf::Astc {
+            block: AstcBlock::B6x6,
+            channel: AstcChannel::Hdr,
+        },
+        F::ASTC_8X5_SFLOAT_BLOCK_EXT => Tf::Astc {
+            block: AstcBlock::B8x5,
+            channel: AstcChannel::Hdr,
+        },
+        F::ASTC_8X6_SFLOAT_BLOCK_EXT => Tf::Astc {
+            block: AstcBlock::B8x6,
+            channel: AstcChannel::Hdr,
+        },
+        F::ASTC_8X8_SFLOAT_BLOCK_EXT => Tf::Astc {
+            block: AstcBlock::B8x8,
+            channel: AstcChannel::Hdr,
+        },
+        F::ASTC_10X5_SFLOAT_BLOCK_EXT => Tf::Astc {
+            block: AstcBlock::B10x5,
+            channel: AstcChannel::Hdr,
+        },
+        F::ASTC_10X6_SFLOAT_BLOCK_EXT => Tf::Astc {
+            block: AstcBlock::B10x6,
+            channel: AstcChannel::Hdr,
+        },
+        F::ASTC_10X8_SFLOAT_BLOCK_EXT => Tf::Astc {
+            block: AstcBlock::B10x8,
+            channel: AstcChannel::Hdr,
+        },
+        F::ASTC_10X10_SFLOAT_BLOCK_EXT => Tf::Astc {
+            block: AstcBlock::B10x10,
+            channel: AstcChannel::Hdr,
+        },
+        F::ASTC_12X10_SFLOAT_BLOCK_EXT => Tf::Astc {
+            block: AstcBlock::B12x10,
+            channel: AstcChannel::Hdr,
+        },
+        F::ASTC_12X12_SFLOAT_BLOCK_EXT => Tf::Astc {
+            block: AstcBlock::B12x12,
+            channel: AstcChannel::Hdr,
+        },
+        _ => return None,
+    })
+}
+
+fn wgpu_to_vulkan(format: wgpu::TextureFormat) -> Option<ash::vk::Format> {
+    // Copied with minor modification from:
+    // https://github.com/gfx-rs/wgpu/blob/a7defb723f856d946d6d220e9897d20dbb7b8f61/wgpu-hal/src/vulkan/conv.rs#L5-L151
+    // license: MIT OR Apache-2.0
+    use ash::vk::Format as F;
+    use wgpu::TextureFormat as Tf;
+    use wgpu::{AstcBlock, AstcChannel};
+    Some(match format {
+        Tf::R8Unorm => F::R8_UNORM,
+        Tf::R8Snorm => F::R8_SNORM,
+        Tf::R8Uint => F::R8_UINT,
+        Tf::R8Sint => F::R8_SINT,
+        Tf::R16Uint => F::R16_UINT,
+        Tf::R16Sint => F::R16_SINT,
+        Tf::R16Unorm => F::R16_UNORM,
+        Tf::R16Snorm => F::R16_SNORM,
+        Tf::R16Float => F::R16_SFLOAT,
+        Tf::Rg8Unorm => F::R8G8_UNORM,
+        Tf::Rg8Snorm => F::R8G8_SNORM,
+        Tf::Rg8Uint => F::R8G8_UINT,
+        Tf::Rg8Sint => F::R8G8_SINT,
+        Tf::Rg16Unorm => F::R16G16_UNORM,
+        Tf::Rg16Snorm => F::R16G16_SNORM,
+        Tf::R32Uint => F::R32_UINT,
+        Tf::R32Sint => F::R32_SINT,
+        Tf::R32Float => F::R32_SFLOAT,
+        Tf::Rg16Uint => F::R16G16_UINT,
+        Tf::Rg16Sint => F::R16G16_SINT,
+        Tf::Rg16Float => F::R16G16_SFLOAT,
+        Tf::Rgba8Unorm => F::R8G8B8A8_UNORM,
+        Tf::Rgba8UnormSrgb => F::R8G8B8A8_SRGB,
+        Tf::Bgra8UnormSrgb => F::B8G8R8A8_SRGB,
+        Tf::Rgba8Snorm => F::R8G8B8A8_SNORM,
+        Tf::Bgra8Unorm => F::B8G8R8A8_UNORM,
+        Tf::Rgba8Uint => F::R8G8B8A8_UINT,
+        Tf::Rgba8Sint => F::R8G8B8A8_SINT,
+        Tf::Rgb10a2Uint => F::A2B10G10R10_UINT_PACK32,
+        Tf::Rgb10a2Unorm => F::A2B10G10R10_UNORM_PACK32,
+        Tf::Rg11b10Float => F::B10G11R11_UFLOAT_PACK32,
+        Tf::Rg32Uint => F::R32G32_UINT,
+        Tf::Rg32Sint => F::R32G32_SINT,
+        Tf::Rg32Float => F::R32G32_SFLOAT,
+        Tf::Rgba16Uint => F::R16G16B16A16_UINT,
+        Tf::Rgba16Sint => F::R16G16B16A16_SINT,
+        Tf::Rgba16Unorm => F::R16G16B16A16_UNORM,
+        Tf::Rgba16Snorm => F::R16G16B16A16_SNORM,
+        Tf::Rgba16Float => F::R16G16B16A16_SFLOAT,
+        Tf::Rgba32Uint => F::R32G32B32A32_UINT,
+        Tf::Rgba32Sint => F::R32G32B32A32_SINT,
+        Tf::Rgba32Float => F::R32G32B32A32_SFLOAT,
+        Tf::Depth32Float => F::D32_SFLOAT,
+        Tf::Depth32FloatStencil8 => F::D32_SFLOAT_S8_UINT,
+        Tf::Depth24Plus | Tf::Depth24PlusStencil8 | Tf::Stencil8 => return None, // Dependent on device properties
+        Tf::Depth16Unorm => F::D16_UNORM,
+        Tf::NV12 => F::G8_B8R8_2PLANE_420_UNORM,
+        Tf::Rgb9e5Ufloat => F::E5B9G9R9_UFLOAT_PACK32,
+        Tf::Bc1RgbaUnorm => F::BC1_RGBA_UNORM_BLOCK,
+        Tf::Bc1RgbaUnormSrgb => F::BC1_RGBA_SRGB_BLOCK,
+        Tf::Bc2RgbaUnorm => F::BC2_UNORM_BLOCK,
+        Tf::Bc2RgbaUnormSrgb => F::BC2_SRGB_BLOCK,
+        Tf::Bc3RgbaUnorm => F::BC3_UNORM_BLOCK,
+        Tf::Bc3RgbaUnormSrgb => F::BC3_SRGB_BLOCK,
+        Tf::Bc4RUnorm => F::BC4_UNORM_BLOCK,
+        Tf::Bc4RSnorm => F::BC4_SNORM_BLOCK,
+        Tf::Bc5RgUnorm => F::BC5_UNORM_BLOCK,
+        Tf::Bc5RgSnorm => F::BC5_SNORM_BLOCK,
+        Tf::Bc6hRgbUfloat => F::BC6H_UFLOAT_BLOCK,
+        Tf::Bc6hRgbFloat => F::BC6H_SFLOAT_BLOCK,
+        Tf::Bc7RgbaUnorm => F::BC7_UNORM_BLOCK,
+        Tf::Bc7RgbaUnormSrgb => F::BC7_SRGB_BLOCK,
+        Tf::Etc2Rgb8Unorm => F::ETC2_R8G8B8_UNORM_BLOCK,
+        Tf::Etc2Rgb8UnormSrgb => F::ETC2_R8G8B8_SRGB_BLOCK,
+        Tf::Etc2Rgb8A1Unorm => F::ETC2_R8G8B8A1_UNORM_BLOCK,
+        Tf::Etc2Rgb8A1UnormSrgb => F::ETC2_R8G8B8A1_SRGB_BLOCK,
+        Tf::Etc2Rgba8Unorm => F::ETC2_R8G8B8A8_UNORM_BLOCK,
+        Tf::Etc2Rgba8UnormSrgb => F::ETC2_R8G8B8A8_SRGB_BLOCK,
+        Tf::EacR11Unorm => F::EAC_R11_UNORM_BLOCK,
+        Tf::EacR11Snorm => F::EAC_R11_SNORM_BLOCK,
+        Tf::EacRg11Unorm => F::EAC_R11G11_UNORM_BLOCK,
+        Tf::EacRg11Snorm => F::EAC_R11G11_SNORM_BLOCK,
+        Tf::Astc { block, channel } => match channel {
+            AstcChannel::Unorm => match block {
+                AstcBlock::B4x4 => F::ASTC_4X4_UNORM_BLOCK,
+                AstcBlock::B5x4 => F::ASTC_5X4_UNORM_BLOCK,
+                AstcBlock::B5x5 => F::ASTC_5X5_UNORM_BLOCK,
+                AstcBlock::B6x5 => F::ASTC_6X5_UNORM_BLOCK,
+                AstcBlock::B6x6 => F::ASTC_6X6_UNORM_BLOCK,
+                AstcBlock::B8x5 => F::ASTC_8X5_UNORM_BLOCK,
+                AstcBlock::B8x6 => F::ASTC_8X6_UNORM_BLOCK,
+                AstcBlock::B8x8 => F::ASTC_8X8_UNORM_BLOCK,
+                AstcBlock::B10x5 => F::ASTC_10X5_UNORM_BLOCK,
+                AstcBlock::B10x6 => F::ASTC_10X6_UNORM_BLOCK,
+                AstcBlock::B10x8 => F::ASTC_10X8_UNORM_BLOCK,
+                AstcBlock::B10x10 => F::ASTC_10X10_UNORM_BLOCK,
+                AstcBlock::B12x10 => F::ASTC_12X10_UNORM_BLOCK,
+                AstcBlock::B12x12 => F::ASTC_12X12_UNORM_BLOCK,
+            },
+            AstcChannel::UnormSrgb => match block {
+                AstcBlock::B4x4 => F::ASTC_4X4_SRGB_BLOCK,
+                AstcBlock::B5x4 => F::ASTC_5X4_SRGB_BLOCK,
+                AstcBlock::B5x5 => F::ASTC_5X5_SRGB_BLOCK,
+                AstcBlock::B6x5 => F::ASTC_6X5_SRGB_BLOCK,
+                AstcBlock::B6x6 => F::ASTC_6X6_SRGB_BLOCK,
+                AstcBlock::B8x5 => F::ASTC_8X5_SRGB_BLOCK,
+                AstcBlock::B8x6 => F::ASTC_8X6_SRGB_BLOCK,
+                AstcBlock::B8x8 => F::ASTC_8X8_SRGB_BLOCK,
+                AstcBlock::B10x5 => F::ASTC_10X5_SRGB_BLOCK,
+                AstcBlock::B10x6 => F::ASTC_10X6_SRGB_BLOCK,
+                AstcBlock::B10x8 => F::ASTC_10X8_SRGB_BLOCK,
+                AstcBlock::B10x10 => F::ASTC_10X10_SRGB_BLOCK,
+                AstcBlock::B12x10 => F::ASTC_12X10_SRGB_BLOCK,
+                AstcBlock::B12x12 => F::ASTC_12X12_SRGB_BLOCK,
+            },
+            AstcChannel::Hdr => match block {
+                AstcBlock::B4x4 => F::ASTC_4X4_SFLOAT_BLOCK_EXT,
+                AstcBlock::B5x4 => F::ASTC_5X4_SFLOAT_BLOCK_EXT,
+                AstcBlock::B5x5 => F::ASTC_5X5_SFLOAT_BLOCK_EXT,
+                AstcBlock::B6x5 => F::ASTC_6X5_SFLOAT_BLOCK_EXT,
+                AstcBlock::B6x6 => F::ASTC_6X6_SFLOAT_BLOCK_EXT,
+                AstcBlock::B8x5 => F::ASTC_8X5_SFLOAT_BLOCK_EXT,
+                AstcBlock::B8x6 => F::ASTC_8X6_SFLOAT_BLOCK_EXT,
+                AstcBlock::B8x8 => F::ASTC_8X8_SFLOAT_BLOCK_EXT,
+                AstcBlock::B10x5 => F::ASTC_10X5_SFLOAT_BLOCK_EXT,
+                AstcBlock::B10x6 => F::ASTC_10X6_SFLOAT_BLOCK_EXT,
+                AstcBlock::B10x8 => F::ASTC_10X8_SFLOAT_BLOCK_EXT,
+                AstcBlock::B10x10 => F::ASTC_10X10_SFLOAT_BLOCK_EXT,
+                AstcBlock::B12x10 => F::ASTC_12X10_SFLOAT_BLOCK_EXT,
+                AstcBlock::B12x12 => F::ASTC_12X12_SFLOAT_BLOCK_EXT,
+            },
+        },
+    })
+}

crates/bevy_openxr/src/init.rs

@@ -0,0 +1,455 @@
+use bevy::app::{App, First, Plugin, PreUpdate};
+use bevy::ecs::event::EventWriter;
+use bevy::ecs::schedule::common_conditions::{not, on_event};
+use bevy::ecs::schedule::IntoSystemConfigs;
+use bevy::ecs::system::{Commands, Res, ResMut, Resource};
+use bevy::ecs::world::World;
+use bevy::log::{error, info};
+use bevy::math::{uvec2, UVec2};
+use bevy::render::camera::ManualTextureViews;
+use bevy::render::extract_resource::ExtractResourcePlugin;
+use bevy::render::renderer::{
+    RenderAdapter, RenderAdapterInfo, RenderDevice, RenderInstance, RenderQueue,
+};
+use bevy::render::settings::RenderCreation;
+use bevy::render::{ExtractSchedule, MainWorld, RenderApp, RenderPlugin};
+use bevy_xr::session::{
+    BeginXrSession, CreateXrSession, XrInstanceCreated, XrInstanceDestroyed, XrSessionState,
+};
+
+use crate::error::XrError;
+use crate::graphics::GraphicsBackend;
+use crate::resources::*;
+use crate::types::*;
+
+pub struct XrInitPlugin {
+    /// Information about the app this is being used to build.
+    pub app_info: AppInfo,
+    /// Extensions wanted for this session.
+    // TODO!() This should be changed to take a simpler list of features wanted that this crate supports. i.e. hand tracking
+    pub exts: XrExtensions,
+    /// List of blend modes the openxr session can use. If [None], pick the first available blend mode.
+    pub blend_modes: Option<Vec<EnvironmentBlendMode>>,
+    /// List of backends the openxr session can use. If [None], pick the first available backend.
+    pub backends: Option<Vec<GraphicsBackend>>,
+    /// List of formats the openxr session can use. If [None], pick the first available format
+    pub formats: Option<Vec<wgpu::TextureFormat>>,
+    /// List of resolutions that the openxr swapchain can use. If [None] pick the first available resolution.
+    pub resolutions: Option<Vec<UVec2>>,
+    /// Passed into the render plugin when added to the app.
+    pub synchronous_pipeline_compilation: bool,
+}
+
+pub fn instance_created(status: Option<Res<XrStatus>>) -> bool {
+    status.is_some_and(|status| status.instance_created)
+}
+
+pub fn session_created(status: Option<Res<XrStatus>>) -> bool {
+    status.is_some_and(|status| status.session_created)
+}
+
+pub fn session_running(status: Option<Res<XrStatus>>) -> bool {
+    status.is_some_and(|status| status.session_running)
+}
+
+pub fn session_ready(status: Option<Res<XrStatus>>) -> bool {
+    status.is_some_and(|status| status.session_ready)
+}
+
+impl Plugin for XrInitPlugin {
+    fn build(&self, app: &mut App) {
+        if let Err(e) = init_xr(&self, app) {
+            error!("Failed to initialize openxr instance: {e}.");
+            app.add_plugins(RenderPlugin::default())
+                .insert_resource(XrStatus::UNINITIALIZED);
+        }
+    }
+}
+
+fn xr_entry() -> Result<XrEntry> {
+    #[cfg(windows)]
+    let entry = openxr::Entry::linked();
+    #[cfg(not(windows))]
+    let entry = unsafe { openxr::Entry::load()? };
+    Ok(XrEntry(entry))
+}
+
+fn init_xr(config: &XrInitPlugin, app: &mut App) -> Result<()> {
+    let entry = xr_entry()?;
+
+    let available_exts = entry.enumerate_extensions()?;
+
+    // check available extensions and send a warning for any wanted extensions that aren't available.
+    for ext in available_exts.unavailable_exts(&config.exts) {
+        error!(
+            "Extension \"{ext}\" not available in the current OpenXR runtime. Disabling extension."
+        );
+    }
+
+    let available_backends = GraphicsBackend::available_backends(&available_exts);
+
+    // Backend selection
+    let backend = if let Some(wanted_backends) = &config.backends {
+        let mut backend = None;
+        for wanted_backend in wanted_backends {
+            if available_backends.contains(wanted_backend) {
+                backend = Some(*wanted_backend);
+                break;
+            }
+        }
+        backend
+    } else {
+        available_backends.first().copied()
+    }
+    .ok_or(XrError::NoAvailableBackend)?;
+
+    let exts = config.exts.clone() & available_exts;
+
+    let instance = entry.create_instance(config.app_info.clone(), exts, backend)?;
+    let instance_props = instance.properties()?;
+
+    info!(
+        "Loaded OpenXR runtime: {} {}",
+        instance_props.runtime_name, instance_props.runtime_version
+    );
+
+    let system_id = instance.system(openxr::FormFactor::HEAD_MOUNTED_DISPLAY)?;
+    let system_props = instance.system_properties(system_id)?;
+
+    info!(
+        "Using system: {}",
+        if system_props.system_name.is_empty() {
+            "<unnamed>"
+        } else {
+            &system_props.system_name
+        }
+    );
+
+    let (WgpuGraphics(device, queue, adapter_info, adapter, wgpu_instance), create_info) =
+        instance.init_graphics(system_id)?;
+
+    app.world.send_event(XrInstanceCreated);
+    app.add_plugins((
+        RenderPlugin {
+            render_creation: RenderCreation::manual(
+                device.into(),
+                RenderQueue(queue.into()),
+                RenderAdapterInfo(adapter_info),
+                RenderAdapter(adapter.into()),
+                RenderInstance(wgpu_instance.into()),
+            ),
+            synchronous_pipeline_compilation: config.synchronous_pipeline_compilation,
+        },
+        ExtractResourcePlugin::<XrTime>::default(),
+        ExtractResourcePlugin::<XrStatus>::default(),
+    ))
+    .insert_resource(instance.clone())
+    .insert_resource(SystemId(system_id))
+    .insert_resource(XrStatus {
+        instance_created: true,
+        ..Default::default()
+    })
+    .insert_non_send_resource(XrSessionInitConfig {
+        blend_modes: config.blend_modes.clone(),
+        formats: config.formats.clone(),
+        resolutions: config.resolutions.clone(),
+        create_info,
+    })
+    .add_systems(
+        First,
+        (
+            poll_events.run_if(instance_created),
+            create_xr_session
+                .run_if(not(session_created))
+                .run_if(on_event::<CreateXrSession>()),
+            begin_xr_session
+                .run_if(session_ready)
+                .run_if(on_event::<BeginXrSession>()),
+        ),
+    )
+    .sub_app_mut(RenderApp)
+    .insert_resource(instance)
+    .insert_resource(SystemId(system_id))
+    .add_systems(
+        ExtractSchedule,
+        transfer_xr_resources.run_if(not(session_running)),
+    );
+
+    Ok(())
+}
+
+/// This is used to store information from startup that is needed to create the session after the instance has been created.
+struct XrSessionInitConfig {
+    /// List of blend modes the openxr session can use. If [None], pick the first available blend mode.
+    blend_modes: Option<Vec<EnvironmentBlendMode>>,
+    /// List of formats the openxr session can use. If [None], pick the first available format
+    formats: Option<Vec<wgpu::TextureFormat>>,
+    /// List of resolutions that the openxr swapchain can use. If [None] pick the first available resolution.
+    resolutions: Option<Vec<UVec2>>,
+    /// Graphics info used to create a session.
+    create_info: SessionCreateInfo,
+}
+
+pub fn create_xr_session(world: &mut World) {
+    let Some(create_info) = world.remove_non_send_resource() else {
+        error!(
+            "Failed to retrive SessionCreateInfo. This is likely due to improper initialization."
+        );
+        return;
+    };
+
+    let Some(instance) = world.get_resource().cloned() else {
+        error!("Failed to retrieve XrInstance. This is likely due to improper initialization.");
+        return;
+    };
+
+    let Some(system_id) = world.get_resource::<SystemId>().cloned() else {
+        error!("Failed to retrieve SystemId. THis is likely due to improper initialization");
+        return;
+    };
+
+    if let Err(e) = init_xr_session(world, instance, *system_id, create_info) {
+        error!("Failed to initialize XrSession: {e}");
+    }
+}
+
+fn init_xr_session(
+    world: &mut World,
+    instance: XrInstance,
+    system_id: openxr::SystemId,
+    config: XrSessionInitConfig,
+) -> Result<()> {
+    let (session, frame_waiter, frame_stream) =
+        unsafe { instance.create_session(system_id, config.create_info)? };
+
+    // TODO!() support other view configurations
+    let available_view_configurations = instance.enumerate_view_configurations(system_id)?;
+    if !available_view_configurations.contains(&openxr::ViewConfigurationType::PRIMARY_STEREO) {
+        return Err(XrError::NoAvailableViewConfiguration);
+    }
+
+    let view_configuration_type = openxr::ViewConfigurationType::PRIMARY_STEREO;
+
+    let view_configuration_views =
+        instance.enumerate_view_configuration_views(system_id, view_configuration_type)?;
+
+    let (resolution, _view) = if let Some(resolutions) = &config.resolutions {
+        let mut preferred = None;
+        for resolution in resolutions {
+            for view_config in view_configuration_views.iter() {
+                if view_config.recommended_image_rect_height == resolution.y
+                    && view_config.recommended_image_rect_width == resolution.x
+                {
+                    preferred = Some((*resolution, *view_config));
+                }
+            }
+        }
+
+        if preferred.is_none() {
+            for resolution in resolutions {
+                for view_config in view_configuration_views.iter() {
+                    if view_config.max_image_rect_height >= resolution.y
+                        && view_config.max_image_rect_width >= resolution.x
+                    {
+                        preferred = Some((*resolution, *view_config));
+                    }
+                }
+            }
+        }
+
+        preferred
+    } else {
+        if let Some(config) = view_configuration_views.first() {
+            Some((
+                uvec2(
+                    config.recommended_image_rect_width,
+                    config.recommended_image_rect_height,
+                ),
+                *config,
+            ))
+        } else {
+            None
+        }
+    }
+    .ok_or(XrError::NoAvailableViewConfiguration)?;
+
+    let available_formats = session.enumerate_swapchain_formats()?;
+
+    let format = if let Some(formats) = &config.formats {
+        let mut format = None;
+        for wanted_format in formats {
+            if available_formats.contains(wanted_format) {
+                format = Some(*wanted_format);
+            }
+        }
+        format
+    } else {
+        available_formats.first().copied()
+    }
+    .ok_or(XrError::NoAvailableFormat)?;
+
+    let mut swapchain = session.create_swapchain(SwapchainCreateInfo {
+        create_flags: SwapchainCreateFlags::EMPTY,
+        usage_flags: SwapchainUsageFlags::COLOR_ATTACHMENT | SwapchainUsageFlags::SAMPLED,
+        format,
+        // TODO() add support for multisampling
+        sample_count: 1,
+        width: resolution.x,
+        height: resolution.y,
+        face_count: 1,
+        array_size: 2,
+        mip_count: 1,
+    })?;
+
+    let images = swapchain.enumerate_images(
+        world.resource::<RenderDevice>().wgpu_device(),
+        format,
+        resolution,
+    )?;
+
+    let available_blend_modes =
+        instance.enumerate_environment_blend_modes(system_id, view_configuration_type)?;
+
+    // blend mode selection
+    let blend_mode = if let Some(wanted_blend_modes) = &config.blend_modes {
+        let mut blend_mode = None;
+        for wanted_blend_mode in wanted_blend_modes {
+            if available_blend_modes.contains(wanted_blend_mode) {
+                blend_mode = Some(*wanted_blend_mode);
+                break;
+            }
+        }
+        blend_mode
+    } else {
+        available_blend_modes.first().copied()
+    }
+    .ok_or(XrError::NoAvailableBackend)?;
+
+    let stage = XrStage(
+        session
+            .create_reference_space(openxr::ReferenceSpaceType::STAGE, openxr::Posef::IDENTITY)?
+            .into(),
+    );
+
+    let graphics_info = XrGraphicsInfo {
+        blend_mode,
+        resolution,
+        format,
+    };
+
+    world.resource_mut::<XrStatus>().session_created = true;
+    world.insert_resource(session.clone());
+    world.insert_resource(frame_waiter);
+    world.insert_resource(images.clone());
+    world.insert_resource(graphics_info.clone());
+    world.insert_resource(stage.clone());
+    world.insert_resource(XrRenderResources {
+        session,
+        frame_stream,
+        swapchain,
+        images,
+        graphics_info,
+        stage,
+    });
+
+    Ok(())
+}
+
+pub fn begin_xr_session(
+    session: Res<XrSession>,
+    mut session_state: EventWriter<XrSessionState>,
+    mut status: ResMut<XrStatus>,
+) {
+    session
+        .begin(openxr::ViewConfigurationType::PRIMARY_STEREO)
+        .expect("Failed to begin session");
+    status.session_running = true;
+    session_state.send(XrSessionState::Running);
+}
+
+/// This is used solely to transport resources from the main world to the render world.
+#[derive(Resource)]
+struct XrRenderResources {
+    session: XrSession,
+    frame_stream: XrFrameStream,
+    swapchain: XrSwapchain,
+    images: XrSwapchainImages,
+    graphics_info: XrGraphicsInfo,
+    stage: XrStage,
+}
+
+pub fn transfer_xr_resources(mut commands: Commands, mut world: ResMut<MainWorld>) {
+    let Some(XrRenderResources {
+        session,
+        frame_stream,
+        swapchain,
+        images,
+        graphics_info,
+        stage,
+    }) = world.remove_resource()
+    else {
+        return;
+    };
+
+    commands.insert_resource(session);
+    commands.insert_resource(frame_stream);
+    commands.insert_resource(swapchain);
+    commands.insert_resource(images);
+    commands.insert_resource(graphics_info);
+    commands.insert_resource(stage);
+}
+
+pub fn poll_events(
+    instance: Res<XrInstance>,
+    session: Option<Res<XrSession>>,
+    mut session_state: EventWriter<XrSessionState>,
+    mut instance_destroyed: EventWriter<XrInstanceDestroyed>,
+    mut status: ResMut<XrStatus>,
+) {
+    let mut buffer = Default::default();
+    while let Some(event) = instance
+        .poll_event(&mut buffer)
+        .expect("Failed to poll event")
+    {
+        use openxr::Event::*;
+        match event {
+            SessionStateChanged(e) => {
+                if let Some(ref session) = session {
+                    info!("entered XR state {:?}", e.state());
+                    use openxr::SessionState;
+
+                    match e.state() {
+                        SessionState::IDLE => {
+                            status.session_ready = false;
+                            session_state.send(XrSessionState::Idle);
+                        }
+                        SessionState::READY => {
+                            status.session_ready = true;
+                            session_state.send(XrSessionState::Ready);
+                        }
+                        SessionState::STOPPING => {
+                            status.session_running = false;
+                            status.session_ready = false;
+                            session.end().expect("Failed to end session");
+                            session_state.send(XrSessionState::Stopping);
+                        }
+                        // TODO: figure out how to destroy the session
+                        SessionState::EXITING | SessionState::LOSS_PENDING => {
+                            status.session_running = false;
+                            status.session_created = false;
+                            status.session_ready = false;
+                            session.end().expect("Failed to end session");
+                            session_state.send(XrSessionState::Destroyed);
+                        }
+                        _ => {}
+                    }
+                }
+            }
+            InstanceLossPending(_) => {
+                *status = XrStatus::UNINITIALIZED;
+                instance_destroyed.send_default();
+            }
+            _ => {}
+        }
+    }
+}

crates/bevy_openxr/src/layer_builder.rs

@@ -0,0 +1,169 @@
+use std::mem;
+
+use openxr::{sys, CompositionLayerFlags, Fovf, Posef, Rect2Di, Space};
+
+use crate::graphics::graphics_match;
+use crate::resources::XrSwapchain;
+
+#[derive(Copy, Clone)]
+pub struct SwapchainSubImage<'a> {
+    inner: sys::SwapchainSubImage,
+    swapchain: Option<&'a XrSwapchain>,
+}
+
+impl<'a> SwapchainSubImage<'a> {
+    #[inline]
+    pub fn new() -> Self {
+        Self {
+            inner: sys::SwapchainSubImage {
+                ..unsafe { mem::zeroed() }
+            },
+            swapchain: None,
+        }
+    }
+    #[inline]
+    pub fn into_raw(self) -> sys::SwapchainSubImage {
+        self.inner
+    }
+    #[inline]
+    pub fn as_raw(&self) -> &sys::SwapchainSubImage {
+        &self.inner
+    }
+    #[inline]
+    pub fn swapchain(mut self, value: &'a XrSwapchain) -> Self {
+        graphics_match!(
+            &value.0;
+            swap => self.inner.swapchain = swap.as_raw()
+        );
+        self.swapchain = Some(value);
+        self
+    }
+    #[inline]
+    pub fn image_rect(mut self, value: Rect2Di) -> Self {
+        self.inner.image_rect = value;
+        self
+    }
+    #[inline]
+    pub fn image_array_index(mut self, value: u32) -> Self {
+        self.inner.image_array_index = value;
+        self
+    }
+}
+
+impl<'a> Default for SwapchainSubImage<'a> {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
+#[derive(Copy, Clone)]
+pub struct CompositionLayerProjectionView<'a> {
+    inner: sys::CompositionLayerProjectionView,
+    swapchain: Option<&'a XrSwapchain>,
+}
+
+impl<'a> CompositionLayerProjectionView<'a> {
+    #[inline]
+    pub fn new() -> Self {
+        Self {
+            inner: sys::CompositionLayerProjectionView {
+                ty: sys::StructureType::COMPOSITION_LAYER_PROJECTION_VIEW,
+                ..unsafe { mem::zeroed() }
+            },
+            swapchain: None,
+        }
+    }
+    #[inline]
+    pub fn into_raw(self) -> sys::CompositionLayerProjectionView {
+        self.inner
+    }
+    #[inline]
+    pub fn as_raw(&self) -> &sys::CompositionLayerProjectionView {
+        &self.inner
+    }
+    #[inline]
+    pub fn pose(mut self, value: Posef) -> Self {
+        self.inner.pose = value;
+        self
+    }
+    #[inline]
+    pub fn fov(mut self, value: Fovf) -> Self {
+        self.inner.fov = value;
+        self
+    }
+    #[inline]
+    pub fn sub_image(mut self, value: SwapchainSubImage<'a>) -> Self {
+        self.inner.sub_image = value.inner;
+        self.swapchain = value.swapchain;
+        self
+    }
+}
+impl<'a> Default for CompositionLayerProjectionView<'a> {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+pub unsafe trait CompositionLayer<'a> {
+    fn swapchain(&self) -> Option<&'a XrSwapchain>;
+    fn header(&self) -> &'a sys::CompositionLayerBaseHeader;
+}
+#[derive(Clone)]
+pub struct CompositionLayerProjection<'a> {
+    inner: sys::CompositionLayerProjection,
+    swapchain: Option<&'a XrSwapchain>,
+    views: Vec<sys::CompositionLayerProjectionView>,
+}
+impl<'a> CompositionLayerProjection<'a> {
+    #[inline]
+    pub fn new() -> Self {
+        Self {
+            inner: sys::CompositionLayerProjection {
+                ty: sys::StructureType::COMPOSITION_LAYER_PROJECTION,
+                ..unsafe { mem::zeroed() }
+            },
+            swapchain: None,
+            views: Vec::new(),
+        }
+    }
+    #[inline]
+    pub fn into_raw(self) -> sys::CompositionLayerProjection {
+        self.inner
+    }
+    #[inline]
+    pub fn as_raw(&self) -> &sys::CompositionLayerProjection {
+        &self.inner
+    }
+    #[inline]
+    pub fn layer_flags(mut self, value: CompositionLayerFlags) -> Self {
+        self.inner.layer_flags = value;
+        self
+    }
+    #[inline]
+    pub fn space(mut self, value: &'a Space) -> Self {
+        self.inner.space = value.as_raw();
+        self
+    }
+    #[inline]
+    pub fn views(mut self, value: &'a [CompositionLayerProjectionView<'a>]) -> Self {
+        for view in value {
+            self.views.push(view.inner.clone());
+        }
+        self.inner.views = self.views.as_slice().as_ptr() as *const _ as _;
+        self.inner.view_count = value.len() as u32;
+        self
+    }
+}
+unsafe impl<'a> CompositionLayer<'a> for CompositionLayerProjection<'a> {
+    fn swapchain(&self) -> Option<&'a XrSwapchain> {
+        self.swapchain
+    }
+
+    fn header(&self) -> &'a sys::CompositionLayerBaseHeader {
+        unsafe { std::mem::transmute(&self.inner) }
+    }
+}
+impl<'a> Default for CompositionLayerProjection<'a> {
+    fn default() -> Self {
+        Self::new()
+    }
+}

crates/bevy_openxr/src/lib.rs

@@ -0,0 +1,36 @@
+use bevy::{
+    app::{PluginGroup, PluginGroupBuilder},
+    render::RenderPlugin,
+    utils::default,
+};
+use bevy_xr::camera::XrCameraPlugin;
+use init::XrInitPlugin;
+use render::XrRenderPlugin;
+
+pub mod camera;
+pub mod error;
+pub mod extensions;
+pub mod graphics;
+pub mod init;
+pub mod layer_builder;
+pub mod render;
+pub mod resources;
+pub mod types;
+
+pub fn add_xr_plugins<G: PluginGroup>(plugins: G) -> PluginGroupBuilder {
+    plugins
+        .build()
+        .disable::<RenderPlugin>()
+        .add_before::<RenderPlugin, _>(bevy_xr::session::XrSessionPlugin)
+        .add_before::<RenderPlugin, _>(XrInitPlugin {
+            app_info: default(),
+            exts: default(),
+            blend_modes: default(),
+            backends: default(),
+            formats: Some(vec![wgpu::TextureFormat::Rgba8UnormSrgb]),
+            resolutions: default(),
+            synchronous_pipeline_compilation: default(),
+        })
+        .add(XrRenderPlugin)
+        .add(XrCameraPlugin)
+}

crates/bevy_openxr/src/render.rs

@@ -0,0 +1,332 @@
+use bevy::{
+    prelude::*,
+    render::{
+        camera::{ManualTextureView, ManualTextureViewHandle, ManualTextureViews, RenderTarget},
+        renderer::render_system,
+        Render, RenderApp, RenderSet,
+    },
+};
+use bevy_xr::camera::{XrCameraBundle, XrProjection, XrView};
+use openxr::CompositionLayerFlags;
+
+use crate::layer_builder::*;
+use crate::resources::*;
+
+use crate::init::session_running;
+
+pub struct XrRenderPlugin;
+
+impl Plugin for XrRenderPlugin {
+    fn build(&self, app: &mut App) {
+        app.add_systems(
+            PreUpdate,
+            (
+                init_views.run_if(resource_added::<XrGraphicsInfo>),
+                wait_frame.run_if(session_running),
+            ),
+        );
+        // .add_systems(Startup, init_views);
+        app.sub_app_mut(RenderApp).add_systems(
+            Render,
+            (
+                (begin_frame, insert_texture_views)
+                    .chain()
+                    .in_set(RenderSet::PrepareAssets)
+                    .before(render_system),
+                end_frame.in_set(RenderSet::Cleanup),
+            )
+                .run_if(session_running),
+        );
+    }
+}
+
+pub const XR_TEXTURE_INDEX: u32 = 3383858418;
+
+/// This is needed to properly initialize the texture views so that bevy will set them to the correct resolution despite them being updated in the render world.
+pub fn init_views(
+    graphics_info: Res<XrGraphicsInfo>,
+    mut manual_texture_views: ResMut<ManualTextureViews>,
+    swapchain_images: Res<XrSwapchainImages>,
+    mut commands: Commands,
+) {
+    let temp_tex = swapchain_images.first().unwrap();
+    // this for loop is to easily add support for quad or mono views in the future.
+    let mut views = vec![];
+    for index in 0..2 {
+        info!("{}", graphics_info.resolution);
+        let view_handle =
+            add_texture_view(&mut manual_texture_views, temp_tex, &graphics_info, index);
+
+        let entity = commands
+            .spawn(XrCameraBundle {
+                camera: Camera {
+                    target: RenderTarget::TextureView(view_handle),
+                    ..Default::default()
+                },
+                ..Default::default()
+            })
+            .id();
+        views.push(entity);
+    }
+    commands.insert_resource(XrViews(views));
+}
+
+pub fn wait_frame(mut frame_waiter: ResMut<XrFrameWaiter>, mut commands: Commands) {
+    let state = frame_waiter.wait().expect("Failed to wait frame");
+    commands.insert_resource(XrTime(openxr::Time::from_nanos(
+        state.predicted_display_time.as_nanos() + state.predicted_display_period.as_nanos(),
+    )));
+}
+
+pub fn update_views(
+    mut views: Query<(&mut Transform, &mut XrProjection), With<XrView>>,
+    view_entities: Res<XrViews>,
+    session: Res<XrSession>,
+    stage: Res<XrStage>,
+    time: Res<XrTime>,
+) {
+    let (_flags, xr_views) = session
+        .locate_views(
+            openxr::ViewConfigurationType::PRIMARY_STEREO,
+            **time,
+            &stage,
+        )
+        .expect("Failed to locate views");
+
+    for (i, view) in xr_views.iter().enumerate() {
+        if let Some((mut transform, mut projection)) = view_entities
+            .0
+            .get(i)
+            .and_then(|entity| views.get_mut(*entity).ok())
+        {
+            let projection_matrix = calculate_projection(projection.near, view.fov);
+            projection.projection_matrix = projection_matrix;
+
+            let openxr::Quaternionf { x, y, z, w } = view.pose.orientation;
+            let rotation = Quat::from_xyzw(x, y, z, w);
+            transform.rotation = rotation;
+            let openxr::Vector3f { x, y, z } = view.pose.position;
+            let translation = Vec3::new(x, y, z);
+            transform.translation = translation;
+        }
+    }
+}
+
+fn calculate_projection(near_z: f32, fov: openxr::Fovf) -> Mat4 {
+    //  symmetric perspective for debugging
+    // let x_fov = (self.fov.angle_left.abs() + self.fov.angle_right.abs());
+    // let y_fov = (self.fov.angle_up.abs() + self.fov.angle_down.abs());
+    // return Mat4::perspective_infinite_reverse_rh(y_fov, x_fov / y_fov, self.near);
+
+    let is_vulkan_api = false; // FIXME wgpu probably abstracts this
+    let far_z = -1.; //   use infinite proj
+                     // let far_z = self.far;
+
+    let tan_angle_left = fov.angle_left.tan();
+    let tan_angle_right = fov.angle_right.tan();
+
+    let tan_angle_down = fov.angle_down.tan();
+    let tan_angle_up = fov.angle_up.tan();
+
+    let tan_angle_width = tan_angle_right - tan_angle_left;
+
+    // Set to tanAngleDown - tanAngleUp for a clip space with positive Y
+    // down (Vulkan). Set to tanAngleUp - tanAngleDown for a clip space with
+    // positive Y up (OpenGL / D3D / Metal).
+    // const float tanAngleHeight =
+    //     graphicsApi == GRAPHICS_VULKAN ? (tanAngleDown - tanAngleUp) : (tanAngleUp - tanAngleDown);
+    let tan_angle_height = if is_vulkan_api {
+        tan_angle_down - tan_angle_up
+    } else {
+        tan_angle_up - tan_angle_down
+    };
+
+    // Set to nearZ for a [-1,1] Z clip space (OpenGL / OpenGL ES).
+    // Set to zero for a [0,1] Z clip space (Vulkan / D3D / Metal).
+    // const float offsetZ =
+    //     (graphicsApi == GRAPHICS_OPENGL || graphicsApi == GRAPHICS_OPENGL_ES) ? nearZ : 0;
+    // FIXME handle enum of graphics apis
+    let offset_z = 0.;
+
+    let mut cols: [f32; 16] = [0.0; 16];
+
+    if far_z <= near_z {
+        // place the far plane at infinity
+        cols[0] = 2. / tan_angle_width;
+        cols[4] = 0.;
+        cols[8] = (tan_angle_right + tan_angle_left) / tan_angle_width;
+        cols[12] = 0.;
+
+        cols[1] = 0.;
+        cols[5] = 2. / tan_angle_height;
+        cols[9] = (tan_angle_up + tan_angle_down) / tan_angle_height;
+        cols[13] = 0.;
+
+        cols[2] = 0.;
+        cols[6] = 0.;
+        cols[10] = -1.;
+        cols[14] = -(near_z + offset_z);
+
+        cols[3] = 0.;
+        cols[7] = 0.;
+        cols[11] = -1.;
+        cols[15] = 0.;
+
+        //  bevy uses the _reverse_ infinite projection
+        //  https://dev.theomader.com/depth-precision/
+        let z_reversal = Mat4::from_cols_array_2d(&[
+            [1f32, 0., 0., 0.],
+            [0., 1., 0., 0.],
+            [0., 0., -1., 0.],
+            [0., 0., 1., 1.],
+        ]);
+
+        return z_reversal * Mat4::from_cols_array(&cols);
+    } else {
+        // normal projection
+        cols[0] = 2. / tan_angle_width;
+        cols[4] = 0.;
+        cols[8] = (tan_angle_right + tan_angle_left) / tan_angle_width;
+        cols[12] = 0.;
+
+        cols[1] = 0.;
+        cols[5] = 2. / tan_angle_height;
+        cols[9] = (tan_angle_up + tan_angle_down) / tan_angle_height;
+        cols[13] = 0.;
+
+        cols[2] = 0.;
+        cols[6] = 0.;
+        cols[10] = -(far_z + offset_z) / (far_z - near_z);
+        cols[14] = -(far_z * (near_z + offset_z)) / (far_z - near_z);
+
+        cols[3] = 0.;
+        cols[7] = 0.;
+        cols[11] = -1.;
+        cols[15] = 0.;
+    }
+
+    Mat4::from_cols_array(&cols)
+}
+
+pub fn begin_frame(mut frame_stream: ResMut<XrFrameStream>) {
+    frame_stream.begin().expect("Failed to begin frame");
+}
+
+pub fn insert_texture_views(
+    swapchain_images: Res<XrSwapchainImages>,
+    mut swapchain: ResMut<XrSwapchain>,
+    mut manual_texture_views: ResMut<ManualTextureViews>,
+    graphics_info: Res<XrGraphicsInfo>,
+) {
+    let index = swapchain.acquire_image().expect("Failed to acquire image");
+    swapchain
+        .wait_image(openxr::Duration::INFINITE)
+        .expect("Failed to wait image");
+    let image = &swapchain_images[index as usize];
+
+    for i in 0..2 {
+        add_texture_view(&mut manual_texture_views, image, &graphics_info, i);
+    }
+    // let left = image.create_view(&wgpu::TextureViewDescriptor {
+    //     dimension: Some(wgpu::TextureViewDimension::D2),
+    //     array_layer_count: Some(1),
+    //     ..Default::default()
+    // });
+    // let right = image.create_view(&wgpu::TextureViewDescriptor {
+    //     dimension: Some(wgpu::TextureViewDimension::D2),
+    //     array_layer_count: Some(1),
+    //     base_array_layer: 1,
+    //     ..Default::default()
+    // });
+    // let resolution = graphics_info.resolution;
+    // let format = graphics_info.format;
+    // let left = ManualTextureView {
+    //     texture_view: left.into(),
+    //     size: resolution,
+    //     format: format,
+    // };
+    // let right = ManualTextureView {
+    //     texture_view: right.into(),
+    //     size: resolution,
+    //     format: format,
+    // };
+    // manual_texture_views.insert(LEFT_XR_TEXTURE_HANDLE, left);
+    // manual_texture_views.insert(RIGHT_XR_TEXTURE_HANDLE, right);
+}
+
+pub fn add_texture_view(
+    manual_texture_views: &mut ManualTextureViews,
+    texture: &wgpu::Texture,
+    info: &XrGraphicsInfo,
+    index: u32,
+) -> ManualTextureViewHandle {
+    let view = texture.create_view(&wgpu::TextureViewDescriptor {
+        dimension: Some(wgpu::TextureViewDimension::D2),
+        array_layer_count: Some(1),
+        base_array_layer: index,
+        ..default()
+    });
+    let view = ManualTextureView {
+        texture_view: view.into(),
+        size: info.resolution,
+        format: info.format,
+    };
+    let handle = ManualTextureViewHandle(XR_TEXTURE_INDEX + index);
+    manual_texture_views.insert(handle, view);
+    handle
+}
+
+pub fn end_frame(
+    mut frame_stream: ResMut<XrFrameStream>,
+    session: Res<XrSession>,
+    mut swapchain: ResMut<XrSwapchain>,
+    stage: Res<XrStage>,
+    display_time: Res<XrTime>,
+    graphics_info: Res<XrGraphicsInfo>,
+) {
+    swapchain.release_image().unwrap();
+    let (_flags, views) = session
+        .locate_views(
+            openxr::ViewConfigurationType::PRIMARY_STEREO,
+            **display_time,
+            &stage,
+        )
+        .expect("Failed to locate views");
+
+    let rect = openxr::Rect2Di {
+        offset: openxr::Offset2Di { x: 0, y: 0 },
+        extent: openxr::Extent2Di {
+            width: graphics_info.resolution.x as _,
+            height: graphics_info.resolution.y as _,
+        },
+    };
+    frame_stream
+        .end(
+            **display_time,
+            graphics_info.blend_mode,
+            &[&CompositionLayerProjection::new()
+                .layer_flags(CompositionLayerFlags::BLEND_TEXTURE_SOURCE_ALPHA)
+                .space(&stage)
+                .views(&[
+                    CompositionLayerProjectionView::new()
+                        .pose(views[0].pose)
+                        .fov(views[0].fov)
+                        .sub_image(
+                            SwapchainSubImage::new()
+                                .swapchain(&swapchain)
+                                .image_array_index(0)
+                                .image_rect(rect),
+                        ),
+                    CompositionLayerProjectionView::new()
+                        .pose(views[1].pose)
+                        .fov(views[1].fov)
+                        .sub_image(
+                            SwapchainSubImage::new()
+                                .swapchain(&swapchain)
+                                .image_array_index(1)
+                                .image_rect(rect),
+                        ),
+                ])],
+        )
+        .expect("Failed to end stream");
+}

crates/bevy_openxr/src/resources.rs

@@ -0,0 +1,281 @@
+use std::sync::Arc;
+
+use crate::error::XrError;
+use crate::graphics::*;
+use crate::layer_builder::CompositionLayer;
+use crate::types::*;
+use bevy::prelude::*;
+use bevy::render::extract_resource::ExtractResource;
+use openxr::AnyGraphics;
+
+#[derive(Deref, Clone)]
+pub struct XrEntry(pub openxr::Entry);
+
+impl XrEntry {
+    pub fn enumerate_extensions(&self) -> Result<XrExtensions> {
+        Ok(self.0.enumerate_extensions().map(Into::into)?)
+    }
+
+    pub fn create_instance(
+        &self,
+        app_info: AppInfo,
+        exts: XrExtensions,
+        backend: GraphicsBackend,
+    ) -> Result<XrInstance> {
+        let available_exts = self.enumerate_extensions()?;
+
+        if !backend.is_available(&available_exts) {
+            return Err(XrError::UnavailableBackend(backend));
+        }
+
+        let required_exts = exts | backend.required_exts();
+
+        let instance = self.0.create_instance(
+            &openxr::ApplicationInfo {
+                application_name: &app_info.name,
+                application_version: app_info.version.to_u32(),
+                engine_name: "Bevy",
+                engine_version: Version::BEVY.to_u32(),
+            },
+            &required_exts.into(),
+            &[],
+        )?;
+
+        Ok(XrInstance(instance, backend, app_info))
+    }
+
+    pub fn available_backends(&self) -> Result<Vec<GraphicsBackend>> {
+        Ok(GraphicsBackend::available_backends(
+            &self.enumerate_extensions()?,
+        ))
+    }
+}
+
+#[derive(Resource, Deref, Clone)]
+pub struct XrInstance(
+    #[deref] pub openxr::Instance,
+    pub(crate) GraphicsBackend,
+    pub(crate) AppInfo,
+);
+
+impl XrInstance {
+    pub fn init_graphics(
+        &self,
+        system_id: openxr::SystemId,
+    ) -> Result<(WgpuGraphics, SessionCreateInfo)> {
+        graphics_match!(
+            self.1;
+            _ => {
+                let (graphics, session_info) = Api::init_graphics(&self.2, &self, system_id)?;
+
+                Ok((graphics, SessionCreateInfo(Api::wrap(session_info))))
+            }
+        )
+    }
+
+    /// # Safety
+    ///
+    /// `info` must contain valid handles for the graphics api
+    pub unsafe fn create_session(
+        &self,
+        system_id: openxr::SystemId,
+        info: SessionCreateInfo,
+    ) -> Result<(XrSession, XrFrameWaiter, XrFrameStream)> {
+        if !info.0.using_graphics_of_val(&self.1) {
+            return Err(XrError::GraphicsBackendMismatch {
+                item: std::any::type_name::<SessionCreateInfo>(),
+                backend: info.0.graphics_name(),
+                expected_backend: self.1.graphics_name(),
+            });
+        }
+        graphics_match!(
+            info.0;
+            info => {
+                let (session, frame_waiter, frame_stream) = self.0.create_session::<Api>(system_id, &info)?;
+                Ok((session.into(), XrFrameWaiter(frame_waiter), XrFrameStream(Api::wrap(frame_stream))))
+            }
+        )
+    }
+}
+
+pub struct SessionCreateInfo(pub(crate) GraphicsWrap<Self>);
+
+impl GraphicsType for SessionCreateInfo {
+    type Inner<G: GraphicsExt> = G::SessionCreateInfo;
+}
+
+impl GraphicsType for XrSession {
+    type Inner<G: GraphicsExt> = openxr::Session<G>;
+}
+
+#[derive(Resource, Deref, Clone)]
+pub struct XrSession(
+    #[deref] pub(crate) openxr::Session<AnyGraphics>,
+    pub(crate) GraphicsWrap<Self>,
+);
+
+impl<G: GraphicsExt> From<openxr::Session<G>> for XrSession {
+    fn from(value: openxr::Session<G>) -> Self {
+        Self(value.clone().into_any_graphics(), G::wrap(value))
+    }
+}
+
+impl XrSession {
+    pub fn enumerate_swapchain_formats(&self) -> Result<Vec<wgpu::TextureFormat>> {
+        graphics_match!(
+            &self.1;
+            session => Ok(session.enumerate_swapchain_formats()?.into_iter().filter_map(Api::to_wgpu_format).collect())
+        )
+    }
+
+    pub fn create_swapchain(&self, info: SwapchainCreateInfo) -> Result<XrSwapchain> {
+        Ok(XrSwapchain(graphics_match!(
+            &self.1;
+            session => session.create_swapchain(&info.try_into()?)? => XrSwapchain
+        )))
+    }
+}
+
+#[derive(Resource)]
+pub struct XrFrameStream(pub(crate) GraphicsWrap<Self>);
+
+impl GraphicsType for XrFrameStream {
+    type Inner<G: GraphicsExt> = openxr::FrameStream<G>;
+}
+
+impl XrFrameStream {
+    pub fn begin(&mut self) -> openxr::Result<()> {
+        graphics_match!(
+            &mut self.0;
+            stream => stream.begin()
+        )
+    }
+
+    pub fn end(
+        &mut self,
+        display_time: openxr::Time,
+        environment_blend_mode: openxr::EnvironmentBlendMode,
+        layers: &[&dyn CompositionLayer],
+    ) -> Result<()> {
+        graphics_match!(
+            &mut self.0;
+            stream => {
+                let mut new_layers = vec![];
+
+                for (i, layer) in layers.into_iter().enumerate() {
+                    if let Some(swapchain) = layer.swapchain() {
+                        if !swapchain.0.using_graphics::<Api>() {
+                            error!(
+                                "Composition layer {i} is using graphics api '{}', expected graphics api '{}'. Excluding layer from frame submission.",
+                                swapchain.0.graphics_name(),
+                                std::any::type_name::<Api>(),
+                            );
+                            continue;
+                        }
+                    }
+                    new_layers.push(unsafe { std::mem::transmute(layer.header()) });
+                }
+
+                Ok(stream.end(display_time, environment_blend_mode, new_layers.as_slice())?)
+            }
+        )
+    }
+}
+
+#[derive(Resource, Deref, DerefMut)]
+pub struct XrFrameWaiter(pub openxr::FrameWaiter);
+
+#[derive(Resource)]
+pub struct XrSwapchain(pub(crate) GraphicsWrap<Self>);
+
+impl GraphicsType for XrSwapchain {
+    type Inner<G: GraphicsExt> = openxr::Swapchain<G>;
+}
+
+impl XrSwapchain {
+    pub fn acquire_image(&mut self) -> Result<u32> {
+        graphics_match!(
+            &mut self.0;
+            swap => Ok(swap.acquire_image()?)
+        )
+    }
+
+    pub fn wait_image(&mut self, timeout: openxr::Duration) -> Result<()> {
+        graphics_match!(
+            &mut self.0;
+            swap => Ok(swap.wait_image(timeout)?)
+        )
+    }
+
+    pub fn release_image(&mut self) -> Result<()> {
+        graphics_match!(
+            &mut self.0;
+            swap => Ok(swap.release_image()?)
+        )
+    }
+
+    pub fn enumerate_images(
+        &mut self,
+        device: &wgpu::Device,
+        format: wgpu::TextureFormat,
+        resolution: UVec2,
+    ) -> Result<XrSwapchainImages> {
+        graphics_match!(
+            &mut self.0;
+            swap => {
+                let mut images = vec![];
+                for image in swap.enumerate_images()? {
+                    unsafe {
+                        images.push(Api::to_wgpu_img(image, device, format, resolution)?);
+                    }
+                }
+                Ok(XrSwapchainImages(images.into()))
+            }
+        )
+    }
+}
+
+#[derive(Deref, Clone, Resource)]
+pub struct XrStage(pub Arc<openxr::Space>);
+
+#[derive(Debug, Deref, Resource, Clone)]
+pub struct XrSwapchainImages(pub Arc<Vec<wgpu::Texture>>);
+
+#[derive(Copy, Clone, Eq, PartialEq, Deref, DerefMut, Resource, ExtractResource)]
+pub struct XrTime(pub openxr::Time);
+
+#[derive(Copy, Clone, Eq, PartialEq, Resource)]
+pub struct XrSwapchainInfo {
+    pub format: wgpu::TextureFormat,
+    pub resolution: UVec2,
+}
+
+#[derive(Debug, Copy, Clone, Deref, Default, Eq, PartialEq, Ord, PartialOrd, Hash, Resource)]
+pub struct SystemId(pub openxr::SystemId);
+
+#[derive(Clone, Copy, Eq, PartialEq, Default, Resource, ExtractResource)]
+pub struct XrStatus {
+    pub instance_created: bool,
+    pub session_created: bool,
+    pub session_ready: bool,
+    pub session_running: bool,
+}
+
+impl XrStatus {
+    pub const UNINITIALIZED: Self = Self {
+        instance_created: false,
+        session_created: false,
+        session_ready: false,
+        session_running: false,
+    };
+}
+
+#[derive(Clone, Copy, Resource)]
+pub struct XrGraphicsInfo {
+    pub blend_mode: EnvironmentBlendMode,
+    pub resolution: UVec2,
+    pub format: wgpu::TextureFormat,
+}
+
+#[derive(Clone, Resource)]
+pub struct XrViews(pub Vec<Entity>);

crates/bevy_openxr/src/types.rs

@@ -0,0 +1,77 @@
+use std::borrow::Cow;
+
+use crate::error::XrError;
+pub use crate::extensions::XrExtensions;
+use crate::graphics::GraphicsExt;
+
+pub use openxr::{EnvironmentBlendMode, SwapchainCreateFlags, SwapchainUsageFlags};
+
+pub type Result<T> = std::result::Result<T, XrError>;
+
+pub struct WgpuGraphics(
+    pub wgpu::Device,
+    pub wgpu::Queue,
+    pub wgpu::AdapterInfo,
+    pub wgpu::Adapter,
+    pub wgpu::Instance,
+);
+
+#[derive(Clone, Copy, Debug, Default, PartialEq)]
+pub struct Version(pub u8, pub u8, pub u16);
+
+impl Version {
+    pub const BEVY: Self = Self(0, 12, 1);
+
+    pub const fn to_u32(self) -> u32 {
+        let major = (self.0 as u32) << 24;
+        let minor = (self.1 as u32) << 16;
+        self.2 as u32 | major | minor
+    }
+}
+
+#[derive(Clone, Debug, PartialEq)]
+pub struct AppInfo {
+    pub name: Cow<'static, str>,
+    pub version: Version,
+}
+
+impl Default for AppInfo {
+    fn default() -> Self {
+        Self {
+            name: "Bevy".into(),
+            version: Version::BEVY,
+        }
+    }
+}
+
+#[derive(Debug, Copy, Clone)]
+pub struct SwapchainCreateInfo {
+    pub create_flags: SwapchainCreateFlags,
+    pub usage_flags: SwapchainUsageFlags,
+    pub format: wgpu::TextureFormat,
+    pub sample_count: u32,
+    pub width: u32,
+    pub height: u32,
+    pub face_count: u32,
+    pub array_size: u32,
+    pub mip_count: u32,
+}
+
+impl<G: GraphicsExt> TryFrom<SwapchainCreateInfo> for openxr::SwapchainCreateInfo<G> {
+    type Error = XrError;
+
+    fn try_from(value: SwapchainCreateInfo) -> Result<Self> {
+        Ok(openxr::SwapchainCreateInfo {
+            create_flags: value.create_flags,
+            usage_flags: value.usage_flags,
+            format: G::from_wgpu_format(value.format)
+                .ok_or(XrError::UnsupportedTextureFormat(value.format))?,
+            sample_count: value.sample_count,
+            width: value.width,
+            height: value.height,
+            face_count: value.face_count,
+            array_size: value.array_size,
+            mip_count: value.mip_count,
+        })
+    }
+}

crates/bevy_xr/Cargo.toml

@@ -0,0 +1,9 @@
+[package]
+name = "bevy_xr"
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+bevy.workspace = true

crates/bevy_xr/src/camera.rs

@@ -0,0 +1,102 @@
+use bevy::app::{App, Plugin};
+use bevy::core_pipeline::core_3d::graph::Core3d;
+use bevy::core_pipeline::core_3d::Camera3d;
+use bevy::core_pipeline::tonemapping::{DebandDither, Tonemapping};
+use bevy::ecs::bundle::Bundle;
+use bevy::ecs::component::Component;
+use bevy::ecs::reflect::ReflectComponent;
+use bevy::math::{Mat4, Vec3A};
+use bevy::reflect::Reflect;
+use bevy::render::camera::{
+    Camera, CameraMainTextureUsages, CameraProjection, CameraProjectionPlugin, CameraRenderGraph,
+    Exposure,
+};
+use bevy::render::primitives::Frustum;
+use bevy::render::view::{ColorGrading, VisibleEntities};
+use bevy::transform::components::{GlobalTransform, Transform};
+
+pub struct XrCameraPlugin;
+
+impl Plugin for XrCameraPlugin {
+    fn build(&self, app: &mut App) {
+        app.add_plugins(CameraProjectionPlugin::<XrProjection>::default());
+    }
+}
+
+#[derive(Clone, Copy, Component, Reflect, Debug)]
+#[reflect(Component)]
+pub struct XrProjection {
+    pub projection_matrix: Mat4,
+    pub near: f32,
+    pub far: f32,
+}
+
+impl Default for XrProjection {
+    fn default() -> Self {
+        Self {
+            near: 0.1,
+            far: 1000.,
+            projection_matrix: Mat4::IDENTITY,
+        }
+    }
+}
+
+/// Marker component for an XR view. It is the backends responsibility to update this.
+#[derive(Clone, Copy, Component, Debug, Default)]
+pub struct XrView;
+
+impl CameraProjection for XrProjection {
+    fn get_projection_matrix(&self) -> Mat4 {
+        self.projection_matrix
+    }
+
+    fn update(&mut self, _width: f32, _height: f32) {}
+
+    fn far(&self) -> f32 {
+        self.far
+    }
+
+    // TODO calculate this properly
+    fn get_frustum_corners(&self, _z_near: f32, _z_far: f32) -> [Vec3A; 8] {
+        Default::default()
+    }
+}
+
+#[derive(Bundle)]
+pub struct XrCameraBundle {
+    pub camera: Camera,
+    pub camera_render_graph: CameraRenderGraph,
+    pub projection: XrProjection,
+    pub visible_entities: VisibleEntities,
+    pub frustum: Frustum,
+    pub transform: Transform,
+    pub global_transform: GlobalTransform,
+    pub camera_3d: Camera3d,
+    pub tonemapping: Tonemapping,
+    pub dither: DebandDither,
+    pub color_grading: ColorGrading,
+    pub exposure: Exposure,
+    pub main_texture_usages: CameraMainTextureUsages,
+    pub view: XrView,
+}
+
+impl Default for XrCameraBundle {
+    fn default() -> Self {
+        Self {
+            camera_render_graph: CameraRenderGraph::new(Core3d),
+            camera: Default::default(),
+            projection: Default::default(),
+            visible_entities: Default::default(),
+            frustum: Default::default(),
+            transform: Default::default(),
+            global_transform: Default::default(),
+            camera_3d: Default::default(),
+            tonemapping: Default::default(),
+            color_grading: Default::default(),
+            exposure: Default::default(),
+            main_texture_usages: Default::default(),
+            dither: DebandDither::Enabled,
+            view: XrView,
+        }
+    }
+}

crates/bevy_xr/src/lib.rs

@@ -0,0 +1,2 @@
+pub mod camera;
+pub mod session;

crates/bevy_xr/src/session.rs

@@ -0,0 +1,89 @@
+use bevy::app::{App, Plugin, PreUpdate};
+use bevy::ecs::event::{Event, EventReader, EventWriter};
+use bevy::ecs::system::Local;
+
+pub struct XrSessionPlugin;
+
+impl Plugin for XrSessionPlugin {
+    fn build(&self, app: &mut App) {
+        app.add_event::<CreateXrSession>()
+            .add_event::<BeginXrSession>()
+            .add_event::<EndXrSession>()
+            .add_event::<XrSessionState>()
+            .add_event::<XrInstanceCreated>()
+            .add_event::<XrInstanceDestroyed>()
+            .add_systems(PreUpdate, handle_xr_events);
+    }
+}
+
+pub fn handle_xr_events(
+    mut instance_created: EventReader<XrInstanceCreated>,
+    mut session_state: EventReader<XrSessionState>,
+    mut instance_destroyed: EventReader<XrInstanceDestroyed>,
+    mut create_session: EventWriter<CreateXrSession>,
+    mut begin_session: EventWriter<BeginXrSession>,
+    mut has_instance: Local<bool>,
+    mut local_session_state: Local<Option<XrSessionState>>,
+) {
+    // Don't do anything if no events recieved
+    if instance_created.is_empty() && instance_destroyed.is_empty() && session_state.is_empty() {
+        return;
+    }
+    if !instance_created.is_empty() {
+        *has_instance = true;
+        instance_created.clear();
+    }
+    if !instance_destroyed.is_empty() {
+        *has_instance = false;
+        instance_destroyed.clear();
+    }
+    for state in session_state.read() {
+        *local_session_state = Some(*state);
+    }
+    if *has_instance {
+        if local_session_state.is_none() {
+            create_session.send_default();
+        } else if matches!(*local_session_state, Some(XrSessionState::Ready)) {
+            begin_session.send_default();
+        }
+    }
+}
+
+/// Event sent to backends to create an XR session
+#[derive(Event, Clone, Copy, Default)]
+pub struct CreateXrSession;
+
+/// Event sent to backends to begin an XR session
+#[derive(Event, Clone, Copy, Default)]
+pub struct BeginXrSession;
+
+/// Event sent to backends to end an XR session.
+#[derive(Event, Clone, Copy, Default)]
+pub struct EndXrSession;
+
+// /// Event sent to backends to destroy an XR session.
+// #[derive(Event, Clone, Copy, Default)]
+// pub struct DestroyXrSession;
+
+/// Event sent from backends to inform the frontend of the session state.
+#[derive(Event, Clone, Copy)]
+pub enum XrSessionState {
+    /// The session is in an idle state. Either just created or stopped
+    Idle,
+    /// The session is ready. You may send a [`BeginXrSession`] event.
+    Ready,
+    /// The session is running.
+    Running,
+    /// The session is being stopped
+    Stopping,
+    /// The session is destroyed
+    Destroyed,
+}
+
+/// Event sent from backends to inform the frontend that the instance was created.
+#[derive(Event, Clone, Copy, Default)]
+pub struct XrInstanceCreated;
+
+/// Event sent from backends to inform the frontend that the instance was destroyed.
+#[derive(Event, Clone, Copy, Default)]
+pub struct XrInstanceDestroyed;