refactor: create OxrSessionConfig and make that the only way to configure things like BlendModes

Signed-off-by: Schmarni <marnistromer@gmail.com>

crates/bevy_openxr/examples/3d_scene.rs

@@ -1,27 +1,28 @@
 //! A simple 3D scene with light shining over a cube sitting on a plane.
 
 use bevy::{prelude::*, render::pipelined_rendering::PipelinedRenderingPlugin};
-use bevy_mod_openxr::{add_xr_plugins, init::OxrInitPlugin};
+use bevy_mod_openxr::{add_xr_plugins, resources::OxrSessionConfig};
 use openxr::EnvironmentBlendMode;
 
-fn main() {
+fn main() -> AppExit {
     App::new()
-        .add_plugins(
-            add_xr_plugins(DefaultPlugins.build().disable::<PipelinedRenderingPlugin>()).set(
-                OxrInitPlugin {
-                    blend_modes: Some(vec![
-                        EnvironmentBlendMode::ALPHA_BLEND,
-                        EnvironmentBlendMode::ADDITIVE,
-                        EnvironmentBlendMode::OPAQUE,
-                    ]),
-                    ..Default::default()
-                },
-            ),
-        )
+        .add_plugins(add_xr_plugins(
+            // Disabling Pipelined Rendering should reduce latency a little bit for button inputs
+            // and increase accuracy for hand tracking, controller positions and similar,
+            // the views are updated right before rendering so they are as accurate as possible
+            DefaultPlugins.build().disable::<PipelinedRenderingPlugin>(),
+        ))
+        .insert_resource(OxrSessionConfig {
+            blend_modes: Some(vec![
+                EnvironmentBlendMode::ALPHA_BLEND,
+                EnvironmentBlendMode::OPAQUE,
+            ]),
+            ..default()
+        })
         .add_plugins(bevy_xr_utils::hand_gizmos::HandGizmosPlugin)
         .add_systems(Startup, setup)
         .insert_resource(ClearColor(Color::NONE))
-        .run();
+        .run()
 }
 
 /// set up a simple 3D scene