From 6d39fb0a652bf963d1d6a33907cd883015e98003 Mon Sep 17 00:00:00 2001
From: awtterpip <zach.spams0508@gmail.com>
Date: Fri, 29 Dec 2023 17:02:48 -0600
Subject: [PATCH] oxr backend progress

---
 xr_api/Cargo.toml                         |  1 +
 xr_api/src/backend/oxr.rs                 | 77 ++++++++++++++++++++++-
 xr_api/src/backend/oxr/graphics.rs        | 17 +++++
 xr_api/src/backend/oxr/graphics/vulkan.rs |  9 +++
 xr_api/src/backend/oxr/utils.rs           |  7 +++
 xr_api/src/types.rs                       |  9 ++-
 6 files changed, 115 insertions(+), 5 deletions(-)
 create mode 100644 xr_api/src/backend/oxr/graphics.rs
 create mode 100644 xr_api/src/backend/oxr/graphics/vulkan.rs

diff --git a/xr_api/Cargo.toml b/xr_api/Cargo.toml
index 435029c..cff3494 100644
--- a/xr_api/Cargo.toml
+++ b/xr_api/Cargo.toml
@@ -8,6 +8,7 @@ default = ["linked"]
 linked = ["openxr/linked"]
 
 [dependencies]
+ash = "0.37.3"
 futures = "0.3.29"
 glam = "0.25.0"
 thiserror = "1.0.51"
diff --git a/xr_api/src/backend/oxr.rs b/xr_api/src/backend/oxr.rs
index 9bad4b4..42d0361 100644
--- a/xr_api/src/backend/oxr.rs
+++ b/xr_api/src/backend/oxr.rs
@@ -1,3 +1,8 @@
+mod graphics;
+mod utils;
+
+use std::sync::Mutex;
+
 use crate::prelude::*;
 
 pub struct OXrEntry(openxr::Entry);
@@ -11,6 +16,14 @@ impl OXrEntry {
     }
 }
 
+impl Into<openxr::ExtensionSet> for ExtensionSet {
+    fn into(self) -> openxr::ExtensionSet {
+        let mut set = openxr::ExtensionSet::default();
+        set.khr_vulkan_enable2 = self.vulkan;
+        set
+    }
+}
+
 impl EntryTrait for OXrEntry {
     fn available_extensions(&self) -> Result<ExtensionSet> {
         // self.0.enumerate_extensions();
@@ -18,11 +31,25 @@ impl EntryTrait for OXrEntry {
     }
 
     fn create_instance(&self, exts: ExtensionSet) -> Result<Instance> {
-        todo!()
+        #[allow(unused_mut)]
+        let mut enabled_extensions: openxr::ExtensionSet = exts.into();
+        #[cfg(target_os = "android")]
+        {
+            enabled_extensions.khr_android_create_instance = true;
+        }
+        let xr_instance = self.0.create_instance(
+            &openxr::ApplicationInfo {
+                application_name: "bevy",
+                ..Default::default()
+            },
+            &enabled_extensions,
+            &[],
+        )?;
+        Ok(OXrInstance(xr_instance, exts).into())
     }
 }
 
-pub struct OXrInstance(openxr::Instance);
+pub struct OXrInstance(openxr::Instance, ExtensionSet);
 
 impl InstanceTrait for OXrInstance {
     fn entry(&self) -> Entry {
@@ -30,10 +57,54 @@ impl InstanceTrait for OXrInstance {
     }
 
     fn enabled_extensions(&self) -> ExtensionSet {
-        todo!()
+        self.1
     }
 
     fn create_session(&self, info: SessionCreateInfo) -> Result<Session> {
+        graphics::init_oxr_graphics(self.0.clone(), self.1, info.texture_format).map(Into::into)
+    }
+}
+
+pub struct OXrSession {
+    pub(crate) instance: Instance,
+    pub(crate) session: openxr::Session<openxr::AnyGraphics>,
+    pub(crate) render_resources: Mutex<
+        Option<(
+            wgpu::Device,
+            wgpu::Queue,
+            wgpu::AdapterInfo,
+            wgpu::Adapter,
+            wgpu::Instance,
+        )>,
+    >,
+}
+
+impl SessionTrait for OXrSession {
+    fn instance(&self) -> &Instance {
+        &self.instance
+    }
+
+    fn get_render_resources(
+        &self,
+    ) -> Option<(
+        wgpu::Device,
+        wgpu::Queue,
+        wgpu::AdapterInfo,
+        wgpu::Adapter,
+        wgpu::Instance,
+    )> {
+        std::mem::take(&mut self.render_resources.lock().unwrap())
+    }
+
+    fn create_input(&self, bindings: Bindings) -> Result<Input> {
+        todo!()
+    }
+
+    fn begin_frame(&self) -> Result<(View, View)> {
+        todo!()
+    }
+
+    fn end_frame(&self) -> Result<()> {
         todo!()
     }
 }
diff --git a/xr_api/src/backend/oxr/graphics.rs b/xr_api/src/backend/oxr/graphics.rs
new file mode 100644
index 0000000..34f221a
--- /dev/null
+++ b/xr_api/src/backend/oxr/graphics.rs
@@ -0,0 +1,17 @@
+mod vulkan;
+
+use super::OXrSession;
+use crate::error::{Result, XrError};
+use crate::types::ExtensionSet;
+
+pub fn init_oxr_graphics(
+    instance: openxr::Instance,
+    extensions: ExtensionSet,
+    format: wgpu::TextureFormat,
+) -> Result<OXrSession> {
+    if extensions.vulkan {
+        return vulkan::init_oxr_graphics(instance, format);
+    }
+
+    Err(XrError::Placeholder)
+}
diff --git a/xr_api/src/backend/oxr/graphics/vulkan.rs b/xr_api/src/backend/oxr/graphics/vulkan.rs
new file mode 100644
index 0000000..21392af
--- /dev/null
+++ b/xr_api/src/backend/oxr/graphics/vulkan.rs
@@ -0,0 +1,9 @@
+use crate::backend::oxr::OXrSession;
+use crate::error::Result;
+
+pub fn init_oxr_graphics(
+    instance: openxr::Instance,
+    format: wgpu::TextureFormat,
+) -> Result<OXrSession> {
+    todo!()
+}
diff --git a/xr_api/src/backend/oxr/utils.rs b/xr_api/src/backend/oxr/utils.rs
index e69de29..f5b569c 100644
--- a/xr_api/src/backend/oxr/utils.rs
+++ b/xr_api/src/backend/oxr/utils.rs
@@ -0,0 +1,7 @@
+use crate::error::XrError;
+
+impl From<openxr::sys::Result> for XrError {
+    fn from(value: openxr::sys::Result) -> Self {
+        XrError::Placeholder
+    }
+}
diff --git a/xr_api/src/types.rs b/xr_api/src/types.rs
index 219d651..8e598be 100644
--- a/xr_api/src/types.rs
+++ b/xr_api/src/types.rs
@@ -5,9 +5,14 @@ use crate::api_traits::{ActionInputTrait, HapticTrait, InputTrait};
 use crate::error::Result;
 
 #[derive(Clone, Copy, Debug, Default, PartialEq, Eq)]
-pub struct ExtensionSet {}
+pub struct ExtensionSet {
+    pub vulkan: bool,
+}
 
-pub enum SessionCreateInfo {}
+pub struct SessionCreateInfo {
+    /// preferred texture format
+    pub texture_format: wgpu::TextureFormat,
+}
 
 pub struct Bindings {}