fix issue #166: graphics do not update between PSET calls - using ununderstood workaround of double sleep(0) call

robhagemans · robhagemans · commit 8d1ae6f083e0 · 2022-06-30T22:13:54.000+01:00
diff --git a/pcbasic/basic/eventcycle.py b/pcbasic/basic/eventcycle.py
@@ -130,8 +130,11 @@ def check_events(self, event_check_input=()):
         """Main event cycle."""
         # sleep(0) is needed for responsiveness, e.g. even trapping in programs with tight loops
         # i.e. 100 goto 100 with event traps active)
+        # this also allows the screen to update between statements
         # it does slow the interpreter down by about 20% in FOR loops
         time.sleep(0)
+        # bizarrely, we need sleep(0) twice. I don't know why.
+        time.sleep(0)
         self._check_input(event_check_input)
 
     def _check_input(self, event_check_input):
