add prelude

src/prelude.rs

@@ -0,0 +1,15 @@
+use bevy::ecs::schedule::{IntoSystemConfigs, SystemConfigs};
+
+use crate::xr_init::xr_only;
+pub use crate::xr_input::{QuatConv, Vec2Conv, Vec3Conv};
+pub use crate::xr_init::schedules::XrSetup;
+
+pub trait XrSystems<Marker> {
+    fn xr_only(self) -> SystemConfigs;
+}
+
+impl<T: IntoSystemConfigs<M>, M> XrSystems<M> for T {
+    fn xr_only(self) -> SystemConfigs {
+        self.into_configs().run_if(xr_only())
+    }
+}