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In my Win32 application, I register several window classes, each class have a different message procedure. Then, I create several windows.
I call SetTimer(m_hWnd, SPECIFIC_MESSAGE_CONSANT,1000, NULL);
As far as I know:
This should send a WM_TIMER with wParam = SPECIFIC_MESSAGE_CONSANT, with one second time delay.
To the message procedure of the window class that m_hWnd (HWND) was created from.
where SPECIFIC_MESSAGE_CONSANT = 11761
In my int APIENTRY _tWinMain()
I do:
MSG msg;
ZeroMemory( &msg, sizeof(msg) );
while( msg.message!=WM_QUIT )
{
if( PeekMessage( &msg, NULL, 0U, 0U, PM_REMOVE ) )
{
TranslateMessage( &msg );
DispatchMessage( &msg );
}
else
{
}
}
WM_TIMER never arrives to the place marked above.
I tried PostMessage(m_hWnd,WM_TIMER,SPECIFIC_MESSAGE_CONSANT,NULL) ->
got exactly where expected.
Still, I must have the time delay.
modified on Tuesday, February 26, 2008 6:20 AM
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Hanan888 wrote: if( PeekMessage( &msg, NULL, 0U, 0U, PM_REMOVE ) )
This can lead to busy loop, as peekmessage returns without waiting for messages. This may not be the problem. This can use significant processor time.
Hanan888 wrote: Then, I create several windows.
Are you creating the windows in the same thread as the message loop?
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Thank you.
Rajkumar R wrote: This can lead to busy loop, as peekmessage returns without waiting for messages. This may not be the problem. This can use significant processor time.
I was sure that my message peeking loop was pretty standard. I can't see the problem you indicated.
Please describe it if you have the time.
Rajkumar R wrote: Are you creating the windows in the same thread as the message loop?
I dont do any special threading now, working pretty standard so I guess I am creating the windows in the same thread.
please note: all other messages (automatic-win32-messages) arrive where I expect them.
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Hanan888 wrote: I was sure that my message peeking loop was pretty standard. I can't see the problem you indicated.
Please describe it if you have the time.
"pretty standard" please give the standard committee link for this.
typically, in win32 samples, i seen message loop with GetMessage() in winmain like,
while( (bRet = GetMessage( &msg, NULL, 0, 0 )) != 0)
{
if (bRet == -1)
{
// handle the error and possibly exit
}
else
{
TranslateMessage(&msg);
DispatchMessage(&msg);
}
}
PeekMessage is used, if you are doing some lengthy operation and want to examine the message queue in between.
Hanan888 wrote: Please describe it if you have the time.
just replace your message loop with GetMessage() and compare the processor usage in Task Manager.
In my HT machine, i am getting almost 0% using GetMessage(), and using your peekmessage() more than 50%, iam sure in single processor machine it will be more than 90%.
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Thank you for the info.
My way was standard in DirectX samples.
if PeekMessage() returns false (no messages in queue)
I do graphic rendering.
My recent check showed that if I do PostMessage() (instead of setTimer() )I get exactly where I wanted. Still, I must use timer to acheive the delay.
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Hanan888 wrote: I do graphic rendering.
That's it you are performing lengthy operation.
Hanan888 wrote: Still, I must use timer to acheive the delay.
in your rendering loop, you can find the elapsed time since last time message posted and find out the delay. And if you find that delay you actually don't need to post message, you can call the handler for WM_TIMER directly in the rendering loop.
but still i am not convinced why SetTimer() is not working.
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Thanks again.
Rajkumar R wrote: in your rendering loop, you can find the elapsed time since last time message posted and find out the delay. And if you find that delay you actually don't need to post message, you can call the handler for WM_TIMER directly in the rendering loop.
Yes, in rendering I check the time now and calculate the delay or something like that (some other from my team implemented these stuff).
But what I need is triggering some GUI and rendering and business-logic events, orchestrating them with time delays.
And it all worked before something got funky.
All messages (PAINT, LBUTTONDOWN,...) go exactly where I need them.
PostMessage(m_hWnd,WM_TIMER,SPECIFIC_CONST,NULL); get where I expect it to go.
only SetTimer(m_hWnd,SPECIFIC_CONST,1000,NULL)
never get to the case WM_TIMER:
Rajkumar R wrote: but still i am convinced why SetTimer() is not working.
Do you mean you're still not convinced ?
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if your task is to put a SPECIFIC_MSG into the message queue of a window then use PostMessage API instead of creating a timer with 0 time interval
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thank You.
I had some experience with PostMessage() and my problem was, that the message "passed-through" all other messages, and got ahead of them in the queue or something.
Anyhow, my typical usage is to set some time interval.
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You dont SEND the Timer message, you INSTALL a timer!!! You got to call KillTimer somewhere.
Try a delay in the Timer.
Greetings from Germany
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Thank You.
KarstenK wrote: You dont SEND the Timer message, you INSTALL a timer!!! You got to call KillTimer somewhere.
I do KillTimer(hWnd,SPECIFIC_CONST); in the message procedure when it arrives.
KarstenK wrote: Try a delay in the Timer.
Delay didn't change anything, WM_TIMER never arrives in the message procedure.
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Hanan888 wrote: with no time delay
You cannot be sure of that. The timer resulution in WinNT is about 10 ms, it could take as long as that before the first WM_TIMER is fired.
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Thank You.
I don't need any accuracy in the time delay.
My typical usage is to set the timer with several seconds delay.
My problem is that it never arrives, breakpoint in case WM_TIMER: never gets hit.
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Are you sure that the timer is getting created? Check the return value of ::SetTimer.
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Thank You, really I didn't think of checking the return value.
but now I checked and it seems alright
result = SetTimer(m_hWnd, SPECIFIC_CONSTANT ,10000, NULL);
after this,
result = SPECIFIC_CONSTANT .
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result = SetTimer(m_hWnd, SPECIFIC_CONSTANT ,10000, NULL);
You get WM_TIMER after 10 sec. 10000 ms. == 10 sec.
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Thank you and sorry if I'm mistakenly emphasized any need for no-delay.
It just that the messages never gets to the right place, whatever the delay is.
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Hm, you're using PM_REMOVE in PeekMessage, maybe it gets removed from the queue before it hits your message loop?
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Thanks.
As far as I know, it is removed from queue. But it gets in the msg variable, then processed.
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MSDN says "PeekMessage does not retrieve messages for windows that belong to other threads.". So, the messages from your queue will not be removed by others. They will be in queue till you Peek or Get messages. And you can not PeekMessage from a window queue, where the window is not created by your thread
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thanks.
ramana.g wrote: MSDN says "PeekMessage does not retrieve messages for windows that belong to other threads.". So, the messages from your queue will not be removed by others. They will be in queue till you Peek or Get messages. And you can not PeekMessage from a window queue, where the window is not created by your thread
AS far as I know, all my windows and all my application is one thread.
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Thank you all for help and invaluable knowledge !!!
I sure learned a lot.
It turns out, I stuck too much in the case WM_PAINT: ,
and that clogged the WM_TIMER messages.
I rendered all my windows on WM_PAINT (DirectX stuff).
Now, When I drag my windows some ungraceful visual effects happen, but I guess
I'll manage.
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I want to draw a 3D cube without using graphics libraries such as OpenGL. I`m not sure how I can draw the cube. I don`t know what I need to do to draw something 3D.
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See if you can pick yourself up a copy of the book 'Teach Yourself Computer Graphics' or something similar. This will show you how transform a 3D point x,y,z into a 2D point X,Y using a projection. The process uses matrices so you might want to be familiar with simple matrix transformations. Many texts on DirectX also explain this sort of thing but you don't have to use DirectX to take advantage of them if you're prepared to hand code the data structures yourself. Otherwise you might want to try old school drawing in VB6, you can draw directly onto a form pretty easily. I used this to port a simple 3D scene generator from QuickBasic to Windows quite a few years ago. Provided you can handle the mathematics 3D vector drawing is not really so difficult. When it comes to more complex stuff like lighting and shading you're going to need a good book you can follow as the algorithms can be tricky.
Nothing is exactly what it seems but everything with seems can be unpicked.
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You have to map cube 3D coords into screen 2D ones, you may choose, for instance, perspective transformation or (the simpler) isometric one.
If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler.
-- Alfonso the Wise, 13th Century King of Castile.
This is going on my arrogant assumptions. You may have a superb reason why I'm completely wrong.
-- Iain Clarke
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