Fixed bug 1272 - Bogus numlock key up/down events being reported on MacOS X
Vern Jensen
The problem is that in certain situations I'm getting THREE keyUp/keyDown events when I push certain keys.
In my event code I added:
case SDL_KEYUP:
printf("SDL KeyScanCode for KEYUP event: %d\n", event->key.keysym.scancode );
…
and
case SDL_KEYDOWN:
printf("SDL KeyScanCode for KEYDOWN event: %d\n", event->key.keysym.scancode );
…
The result of one test run where I push 2 keys and then release them is this:
SDL KeyScanCode for KEYDOWN event: 92 // Pushed keypad 4
SDL KeyScanCode for KEYDOWN event: 83 // Pushed left shift
SDL KeyScanCode for KEYUP event: 83
SDL KeyScanCode for KEYDOWN event: 225
SDL KeyScanCode for KEYUP event: 92 // Released keypad 4
SDL KeyScanCode for KEYDOWN event: 83
SDL KeyScanCode for KEYUP event: 83
SDL KeyScanCode for KEYUP event: 225 // Released left shift
There *should* be only a total of 4 events above… 2 for each key being pushed, and 2 for each being released. But instead some bogus events for numlock being pushed/released are sent from SDL. These events did not occur. I did not push numlock. The value above for numlock is 83. Comments above show when I pushed each key. As you can see, when I push left shift, THREE events are instantly sent to my application, keyDown and then keyUp for numlock, and then the valid event for left shift (the key that was actually pushed).
You could replace keypad 4 with pretty much any keyPad key and it'll still happen. You can also replace it with any arrow key and it'll happen. However, when trying it with normal letter keys on the main keyboard it didn't.
It happens with other modifier keys too, not just left shift.
The order in which the keys are pressed matter. For instance, if I do:
1) keypad 4
2) left shift
3) release left shift
4) release keypad 4
Then at step 2, I get the 3 events above (when there should be only one), but steps 3 and 4 work properly… I don't get extra keyUp/keyDown events for steps 3 or 4. Thereas if the order of steps 3 and 4 are reversed, I get the bogus extra events for numlock.
Also, the problem can occur even when pushing just a single key by itself. If I push left shift, then keypad 4, then release left shift, then release keypad 4, then the following push of left shift will cause the bug. If I continue pushing and releasing left shift though, it won't happen again until I again involve keypad keys.
---
Sam Lantinga
According to the Apple documentation, NSNumericPadKeyMask is set for any arrow or numeric keypad event. Indeed this is what's happening.
I verified that we get the correct events for the numlock key and the mod state gets set correcly, so it should be safe to remove this bogus code.
<HTML>
<HEAD>
<TITLE>Using SDL with Microsoft Visual C++</TITLE>
</HEAD>
<BODY>
<H1>
Using SDL with Microsoft Visual C++
</H1>
<H3>
by <A HREF="mailto:snowlion@sprynet.com">Lion Kimbro </A>and additions by <A HREF="mailto:james@conceptofzero.net">
James Turk</A>
</H3>
<p>
You can either use the precompiled libraries from <A HREF="http://www.libsdl.org/download.php"> the SDL Download web site </A>, or you can build SDL yourself.
</p>
<H3>
Building SDL
</H3>
<P>
Go into the VisualC directory and double-click on the Visual Studio solution for your version of Visual Studio, e.g. <CODE>SDL_VS2008.sln</CODE> This should open up the IDE.
</P>
<P>
There are different solution files for the various
versions of the IDE. Please use the appropiate version
2008, 2010 or 2012; the 2010EE and 2012EE files
should be used with the "Express Edition" releases.
</P>
<P>
Build the <CODE>.dll</CODE> and <CODE>.lib</CODE> files.
</P>
<P>
This is done by right clicking on each project in turn (Projects are listed in
the Workspace panel in the FileView tab), and selecting "Build".
</P>
<P>
You may get a few warnings, but you should not get any errors. You do have to
have at least the DirectX 9 SDK installed, however. The latest
version of DirectX can be downloaded from <A HREF="http://www.microsoft.com">Microsoft</A>.
</P>
<P>
Later, we will refer to the following .lib and .dll files that have just been
generated:
</P>
<ul>
<li> SDL2.dll</li>
<li> SDL2.lib</li>
<li> SDL2main.lib</li>
</ul>
<P>
Search for these using the Windows Find (Windows-F) utility inside the VisualC directory.
</P>
<H3>
Creating a Project with SDL
</H3>
<P>
Create a project as a Win32 Application.
</P>
<P>
Create a C++ file for your project.
</P>
<P>
Set the C runtime to "Multi-threaded DLL" in the menu: <CODE>Project|Settings|C/C++
tab|Code Generation|Runtime Library </CODE>.
</P>
<P>
Add the SDL <CODE>include</CODE> directory to your list of includes in the
menu: <CODE>Project|Settings|C/C++ tab|Preprocessor|Additional include directories </CODE>
.
<br>
<STRONG><FONT color="#009900">VC7 Specific: Instead of doing this I find it easier to
add the include and library directories to the list that VC7 keeps. Do this by
selecting Tools|Options|Projects|VC++ Directories and under the "Show
Directories For:" dropbox select "Include Files", and click the "New Directory
Icon" and add the [SDLROOT]\include directory (e.g. If you installed to
c:\SDL\ add c:\SDL\include). Proceed to change the
dropbox selection to "Library Files" and add [SDLROOT]\lib.</FONT></STRONG>
</P>
<P>
The "include directory" I am referring to is the <CODE>include</CODE> folder
within the main SDL directory (the one that this HTML file located within).
</P>
<P>
Now we're going to use the files that we had created earlier in the Build SDL
step.
</P>
<P>
Copy the following files into your Project directory:
</P>
<ul>
<li> SDL2.dll</li>
</ul>
<P>
Add the following files to your project (It is not necessary to copy them to
your project directory):
</P>
<ul>
<li> SDL2.lib </li>
<li> SDL2main.lib</li>
</ul>
<P>
(To add them to your project, right click on your project, and select "Add
files to project")
</P>
<P><STRONG><FONT color="#009900">Instead of adding the files to your project it is more
desireable to add them to the linker options: Project|Properties|Linker|Command
Line and type the names of the libraries to link with in the "Additional
Options:" box. Note: This must be done for each build
configuration (e.g. Release,Debug).</FONT></STRONG></P>
<H3>
SDL 101, First Day of Class
</H3>
<P>
Now create the basic body of your project. The body of your program should take
the following form: <CODE>
<PRE>
#include "SDL.h"
int main( int argc, char* argv[] )
{
// Body of the program goes here.
return 0;
}
</PRE>
</CODE>
<P></P>
<H3>
That's it!
</H3>
<P>
I hope that this document has helped you get through the most difficult part of
using the SDL: installing it. Suggestions for improvements to this document
should be sent to the writers of this document.
</P>
<P>
Thanks to Paulus Esterhazy (pesterhazy@gmx.net), for the work on VC++ port.
</P>
<P>
This document was originally called "VisualC.txt", and was written by <A HREF="mailto:slouken@libsdl.org">
Sam Lantinga</A>.
</P>
<P>
Later, it was converted to HTML and expanded into the document that you see
today by <A HREF="mailto:snowlion@sprynet.com">Lion Kimbro</A>.
</P>
<P>Minor Fixes and Visual C++ 7 Information (In Green) was added by <A HREF="mailto:james@conceptofzero.net">James Turk</A>
</P>
</BODY>
</HTML>