compositor: only release swapchain image in Submit if one was acquired

src/compositor.rs

@@ -1271,8 +1271,10 @@ impl<G: GraphicsBackend> FrameController<G> {
 
         trace!("submitted {eye:?}");
         if self.eyes_submitted.iter().all(|eye| eye.is_some()) {
-            let mut swapchain_data = self.swapchain_data.as_mut();
-            if let Some(data) = &mut swapchain_data {
+            // If the session was restarted while no frame was begun, nothing has been acquired from the new swapchain yet, so there is nothing to release
+            if self.image_acquired
+                && let Some(data) = self.swapchain_data.as_mut()
+            {
                 trace!("releasing image");
                 data.swapchain.release_image().unwrap();
             }
@@ -1942,6 +1944,28 @@ mod tests {
         f.check_frame_state(fakexr::FrameState::Waited);
     }
 
+    #[test]
+    fn explicit_timing_submit_without_begun_frame() {
+        let f = Fixture::new();
+        f.comp.SetExplicitTimingMode(
+            vr::EVRCompositorTimingMode::Explicit_ApplicationPerformsPostPresentHandoff,
+        );
+
+        // The first Submit restarts the session while no frame has been begun, so the new swapchain has no acquired image when both eyes have been submitted
+        assert_eq!(f.wait_get_poses(), None);
+        assert_eq!(f.submit(vr::EVREye::Left), None);
+        assert_eq!(f.submit(vr::EVREye::Right), None);
+
+        // The next frame should proceed as usual
+        assert_eq!(f.wait_get_poses(), None);
+        assert_eq!(f.comp.SubmitExplicitTimingData(), None);
+        f.check_frame_state(fakexr::FrameState::Begun);
+        assert_eq!(f.submit(vr::EVREye::Left), None);
+        assert_eq!(f.submit(vr::EVREye::Right), None);
+        f.comp.PostPresentHandoff();
+        f.check_frame_state(fakexr::FrameState::Ended);
+    }
+
     #[test]
     fn explicit_timing_unfocused() {
         let f = Fixture::new();