The open source OpenXR runtime
comp: Transition to visible/focused after xrEndFrame, not xrWaitFrame
The application synchronizes its frame loop by "by calling xrWaitFrame,
xrBeginFrame and xrEndFrame in a loop."
Applications can discard frames by not calling xrEndFrame. If initial
frames are discarded, we should not consider the frame loop synchronized.
Previously a sequence like
xrBeginFrame, xrWaitFrame, xrBeginFrame, xrWaitFrame, xrPollEvent, xrBeginFrame
failed because xrPollEvent the compositor emitted transitions to visible
and focused but they were not emitted in the state tracker, because the
oxr session had not internally tranisitioned to the synchronized state.
+12
-10
+6
-9
src/xrt/compositor/main/comp_compositor.c
+6
-9
src/xrt/compositor/main/comp_compositor.c
···
210
210
*predicted_display_time = c->last_next_display_time;
211
211
*out_frame_id = c->last_next_display_time;
212
212
213
-
if (c->state == COMP_STATE_PREPARED) {
214
-
c->state = COMP_STATE_WAITED;
215
-
}
216
213
return XRT_SUCCESS;
217
214
}
218
215
···
245
242
*out_frame_id = c->last_next_display_time;
246
243
247
244
c->last_next_display_time = next_display_time;
248
-
249
-
if (c->state == COMP_STATE_PREPARED) {
250
-
c->state = COMP_STATE_WAITED;
251
-
}
252
245
return XRT_SUCCESS;
253
246
}
254
247
}
···
514
507
c->expected_app_duration_ns =
515
508
c->app_profiling.last_end - c->app_profiling.last_begin;
516
509
510
+
if (c->state == COMP_STATE_PREPARED) {
511
+
c->state = COMP_STATE_COMMITTED;
512
+
}
513
+
517
514
// Now is a good point to garbage collect.
518
515
comp_compositor_garbage_collect(c);
519
516
return XRT_SUCCESS;
···
535
532
case COMP_STATE_PREPARED:
536
533
out_xce->state.type = XRT_COMPOSITOR_EVENT_NONE;
537
534
break;
538
-
case COMP_STATE_WAITED:
539
-
COMP_DEBUG(c, "WAITED -> VISIBLE");
535
+
case COMP_STATE_COMMITTED:
536
+
COMP_DEBUG(c, "COMMITTED -> VISIBLE");
540
537
out_xce->state.type = XRT_COMPOSITOR_EVENT_STATE_CHANGE;
541
538
out_xce->state.visible = true;
542
539
c->state = COMP_STATE_VISIBLE;
+1
-1
src/xrt/compositor/main/comp_compositor.h
+1
-1
src/xrt/compositor/main/comp_compositor.h
+5
src/xrt/state_trackers/oxr/oxr_session.c
+5
src/xrt/state_trackers/oxr/oxr_session.c
···
1898
1898
1899
1899
do_synchronize_state_change(log, sess);
1900
1900
1901
+
// For emitting state changes, the compositor has to know
1902
+
// whether the client is synchronized, i.e. has called
1903
+
// xrEndFrame, even with 0 layers.
1904
+
CALL_CHK(xrt_comp_layer_commit(xc, -1));
1905
+
1901
1906
return oxr_session_success_result(sess);
1902
1907
}
1903
1908