Page 1 of 1
StartDrawing(): The specified output is NULL (0 value)
Posted: Fri Mar 30, 2018 12:25 pm
by Shield
Hey
I have to use OSX for work and wanted to see how well PB works on it.
Was off to a great start, but I soon encountered a problem I have no solution for:
StartDrawing(): The specified output is NULL (0 value).
Code: Select all
Debug InitSprite()
Debug OpenWindow(0, 0, 0, 800, 600, "")
Debug OpenWindowedScreen(WindowID(0), 0, 0, 800, 600)
Repeat
If WindowEvent() = #PB_Event_CloseWindow
Break
EndIf
ClearScreen(0)
StartDrawing(ScreenOutput())
DrawText(10, 10, "TEST")
StopDrawing()
FlipBuffers()
ForEver
The weird thing is, it sometimes works properly and sometimes crashes with the error above.
Initialization is always successful.
Am I missing something silly or has this happened to anyone else?
Re: StartDrawing(): The specified output is NULL (0 value)
Posted: Fri Mar 30, 2018 12:56 pm
by Wolfram
The lines beginning with Debug will only compiled if the debugger is turned on.
Code: Select all
Debug InitSprite()
Debug OpenWindow(0, 0, 0, 800, 600, "")
Debug OpenWindowedScreen(WindowID(0), 0, 0, 800, 600)
if you want to see the result of a function you can do it in this way.
Code: Select all
status =InitSprite()
Debug status
status =OpenWindow(0, 0, 0, 800, 600, "")
Debug status
status =OpenWindowedScreen(WindowID(0), 0, 0, 800, 600)
Debug status
Re: StartDrawing(): The specified output is NULL (0 value)
Posted: Fri Mar 30, 2018 1:28 pm
by mk-soft
Works by me...
Code: Select all
If InitSprite() = 0
MessageRequester("Error", "InitSprite", #PB_MessageRequester_Error)
End
EndIf
If OpenWindow(0, 0, 0, 800, 600, "") = 0
MessageRequester("Error", "Openwindow", #PB_MessageRequester_Error)
End
EndIf
If OpenWindowedScreen(WindowID(0), 0, 0, 800, 600) = 0
MessageRequester("Error", "OpenWindowedScreen", #PB_MessageRequester_Error)
End
EndIf
#Framerate = 30
AddWindowTimer(0, 1, 1000/#Framerate)
Global trigger
Global lasttime, time, sync
lasttime = ElapsedMilliseconds()
Repeat
Select WaitWindowEvent()
Case #PB_Event_CloseWindow
Break
Case #PB_Event_Timer
Select EventTimer()
Case 1
time = ElapsedMilliseconds() - lasttime
sync = 1000/#Framerate - time
trigger + 1
ClearScreen(0)
StartDrawing(ScreenOutput())
DrawText(10, 10, "Trigger " + trigger)
DrawText(10, 40, "Time " + time)
DrawText(10, 70, "Sync-Time " + sync)
StopDrawing()
FlipBuffers()
lasttime = ElapsedMilliseconds()
EndSelect
EndSelect
ForEver
CPU: App 16%
Re: StartDrawing(): The specified output is NULL (0 value)
Posted: Sun Apr 01, 2018 1:11 pm
by Shield
Wolfram wrote:The lines beginning with Debug will only compiled if the debugger is turned on.
Yes, I know.
I did that to check whether any of the Init/Open commands fail, they don't and they never do.
What I'm saying is: the code above works sometimes and sometimes doesn't, completely randomly,
and I have no idea why. Just rerunning it usually fixes the problem until it crashes again the next time I run it.
Re: StartDrawing(): The specified output is NULL (0 value)
Posted: Sun Apr 01, 2018 2:26 pm
by mk-soft
No Problem here...
PB v5.62 (x64)
Xcode 9.3
MacOS 10.13.4
Re: StartDrawing(): The specified output is NULL (0 value)
Posted: Sun Apr 01, 2018 5:36 pm
by Shield
@mk-soft
Your code from your first answer seems to work, however, when I remove the timer bit and change it to the following it starts crashing occasionally as well.
Could there some asynchronous initialization be going on behind the scenes where ScreenOutput sometimes gets called before everything is properly initialized?
Edit: Asked a friend to test and she encounters the same issue.
Code: Select all
If InitSprite() = 0
MessageRequester("Error", "InitSprite", #PB_MessageRequester_Error)
End
EndIf
If OpenWindow(0, 0, 0, 800, 600, "") = 0
MessageRequester("Error", "Openwindow", #PB_MessageRequester_Error)
End
EndIf
If OpenWindowedScreen(WindowID(0), 0, 0, 800, 600) = 0
MessageRequester("Error", "OpenWindowedScreen", #PB_MessageRequester_Error)
End
EndIf
Global trigger
Global lasttime, time, sync
lasttime = ElapsedMilliseconds()
Repeat
Select WaitWindowEvent()
Case #PB_Event_CloseWindow
Break
EndSelect
time = ElapsedMilliseconds() - lasttime
trigger + 1
ClearScreen(0)
StartDrawing(ScreenOutput())
DrawText(10, 10, "Trigger " + trigger)
DrawText(10, 40, "Time " + time)
DrawText(10, 70, "Sync-Time " + sync)
StopDrawing()
FlipBuffers()
lasttime = ElapsedMilliseconds()
ForEver
Re: StartDrawing(): The specified output is NULL (0 value)
Posted: Sun Apr 01, 2018 5:39 pm
by Shield
Alright, weird...
Really looks to me as if there is something asynchronous going on.
A Delay(200) just before the main loop seems to prevent the issue from occurring...