# Scancodes vs keycodes

**URL:** <https://discourse.libsdl.org/t/scancodes-vs-keycodes/18036>\
**Category:** SDL Development\
**Created:** [March 11, 2011, 7:26pm UTC](https://discourse.libsdl.org/t/scancodes-vs-keycodes/18036 "2011-03-11T19:26:00Z")\
**Posts on this page:** 7\
**Page:** 1

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**Author:** ![slouken](https://discourse.libsdl.org/letter_avatar_proxy/v4/letter/s/ec9cab/32.png) [@slouken](https://discourse.libsdl.org/u/slouken)\
**Post date:** [March 11, 2011, 7:26pm UTC](https://discourse.libsdl.org/t/scancodes-vs-keycodes/18036/1 "2011-03-11T19:26:00Z")

</div>

In SDL 1.3 I introduced the concept of a scancode, which is keyboard mapping  
independent.  
e.g. WASD with scancodes will always be in an inverted T, while it might be  
remapped to different positions using keycodes on a French keyboard or  
Dvorak layout.

Unfortunately as you might imagine the scancodes are hardware dependent and  
so things are broken on unusual keyboards.

Is anybody using this distinction between scancodes and keycodes in SDL  
1.3? Or is it preferrable to go back to just using keycodes the way SDL 1.2  
works?

See ya!–  
-Sam Lantinga, Founder and CEO, Galaxy Gameworks

---

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**Author:** ![Patrick\_Baggett](https://discourse.libsdl.org/letter_avatar_proxy/v4/letter/p/f14d63/32.png) [@Patrick\_Baggett](https://discourse.libsdl.org/u/Patrick_Baggett)\
**Post date:** [March 11, 2011, 7:52pm UTC](https://discourse.libsdl.org/t/scancodes-vs-keycodes/18036/2 "2011-03-11T19:52:14Z")

</div>

I’ve found scancodes to be a terrible idea. I had code that worked on Win32  
system, reasonably worked on Linux/x86 systems, and went to hell when I ran  
it on Solaris/SPARC. Turns out just translating the windowing system  
messages into a platform independent message was the best way. While it is  
unfortunate that WASD doesn’t always translate depending on keymap, a real  
game would allow the user to remap the controls anyways and this would be  
done once and problem solved.

PatrickOn Fri, Mar 11, 2011 at 1:26 PM, Sam Lantinga wrote:

> In SDL 1.3 I introduced the concept of a scancode, which is keyboard  
> mapping independent.  
> e.g. WASD with scancodes will always be in an inverted T, while it might be  
> remapped to different positions using keycodes on a French keyboard or  
> Dvorak layout.
> 
> Unfortunately as you might imagine the scancodes are hardware dependent and  
> so things are broken on unusual keyboards.
> 
> Is anybody using this distinction between scancodes and keycodes in SDL  
> 1.3? Or is it preferrable to go back to just using keycodes the way SDL 1.2  
> works?
> 
> ## See ya!
> 
> ```
> -Sam Lantinga, Founder and CEO, Galaxy Gameworks
> 
> ```
> 
> * * *
> 
> SDL mailing list  
> SDL at [lists.libsdl.org](http://lists.libsdl.org)  
> [http://lists.libsdl.org/listinfo.cgi/sdl-libsdl.org](http://lists.libsdl.org/listinfo.cgi/sdl-libsdl.org)

---

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**Author:** ![David\_Olofson](https://discourse.libsdl.org/user_avatar/discourse.libsdl.org/david_olofson/32/115_2.png) [@David\_Olofson](https://discourse.libsdl.org/u/David_Olofson)\
**Post date:** [March 11, 2011, 7:57pm UTC](https://discourse.libsdl.org/t/scancodes-vs-keycodes/18036/3 "2011-03-11T19:57:56Z")

</div>

[…]

> While it is  
> unfortunate that WASD doesn’t always translate depending on keymap, a real  
> game would allow the user to remap the controls anyways and this would be  
> done once and problem solved.  
> […]

+1

There isn’t really any proper way around making it configurable. Not everyone  
wants to use WASD either, even if it’s in the “right” place.On Friday 11 March 2011, at 20.52.14, Patrick Baggett \<baggett.patrick at [gmail.com](http://gmail.com)\> wrote:

–  
//David Olofson - Consultant, Developer, Artist, Open Source Advocate

.— Games, examples, libraries, scripting, sound, music, graphics —.  
| [http://consulting.olofson.net](http://consulting.olofson.net)[http://olofsonarcade.com](http://olofsonarcade.com) |  
‘---------------------------------------------------------------------’

---

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**Author:** ![Jean-Francois\_Severe](https://discourse.libsdl.org/letter_avatar_proxy/v4/letter/j/a4c791/32.png) [@Jean-Francois\_Severe](https://discourse.libsdl.org/u/Jean-Francois_Severe)\
**Post date:** [March 11, 2011, 8:24pm UTC](https://discourse.libsdl.org/t/scancodes-vs-keycodes/18036/4 "2011-03-11T20:24:38Z")

</div>

Having a concept of a key position is actually more relevant in a game than  
key label. If I want to use the number bar, I don’t care if the 3 key is  
labeled 3 or ", what I’m interested in is the physical position of the key  
as that position is meaningful in terms of gameplay. Same goes for WASD.

Having to remap the keys, usually right after the introduction cinematic,  
make the game look unprofessional, and it breaks the player’s immersion at  
the very beginning of the game.  
If you see it that way, scancodes may be broken on some platforms, but most  
gameplays are broken on non US keyboards when using keycodes.

There are some solutions to avoid that. The first is to have SDL give us a  
portable way to query the keyboard layout. Then we would adapt the default  
configuration to that.  
Another would be to ask the user either when downloading the game or when  
the game starts for the first time. But I believe it’s wrong to rely on the  
user.

As for weird keyboards, not much we can do about that, we game developers  
have to manually plan for each of those we wish to support manually anyways.

The best solution in my mind would be to remap the weird platforms to a  
standard set of scancodes (solaris/sparc, and more). That way the behaviour  
described by patrick would be an SDL bug. That way have some overhead  
though. But even if it’s not fully portable, please keep the scancodes. My  
target platforms are Windows/Linux/Mac, so if it works for those, I’ll take  
it !

2011/3/11 Patrick Baggett \<baggett.patrick at [gmail.com](http://gmail.com)\>\> I’ve found scancodes to be a terrible idea. I had code that worked on Win32

> system, reasonably worked on Linux/x86 systems, and went to hell when I ran  
> it on Solaris/SPARC. Turns out just translating the windowing system  
> messages into a platform independent message was the best way. While it is  
> unfortunate that WASD doesn’t always translate depending on keymap, a real  
> game would allow the user to remap the controls anyways and this would be  
> done once and problem solved.
> 
> Patrick
> 
> On Fri, Mar 11, 2011 at 1:26 PM, Sam Lantinga wrote:
> 
> > In SDL 1.3 I introduced the concept of a scancode, which is keyboard  
> > mapping independent.  
> > e.g. WASD with scancodes will always be in an inverted T, while it might  
> > be remapped to different positions using keycodes on a French keyboard or  
> > Dvorak layout.
> > 
> > Unfortunately as you might imagine the scancodes are hardware dependent  
> > and so things are broken on unusual keyboards.
> > 
> > Is anybody using this distinction between scancodes and keycodes in SDL  
> > 1.3? Or is it preferrable to go back to just using keycodes the way SDL 1.2  
> > works?
> > 
> > ## See ya!
> > 
> > ```
> > -Sam Lantinga, Founder and CEO, Galaxy Gameworks
> > 
> > ```
> > 
> > * * *
> > 
> > SDL mailing list  
> > SDL at [lists.libsdl.org](http://lists.libsdl.org)  
> > [http://lists.libsdl.org/listinfo.cgi/sdl-libsdl.org](http://lists.libsdl.org/listinfo.cgi/sdl-libsdl.org)
> 
> * * *
> 
> SDL mailing list  
> SDL at [lists.libsdl.org](http://lists.libsdl.org)  
> [http://lists.libsdl.org/listinfo.cgi/sdl-libsdl.org](http://lists.libsdl.org/listinfo.cgi/sdl-libsdl.org)

---

<div class="post-metadata">

**Author:** ![Patrick\_Baggett](https://discourse.libsdl.org/letter_avatar_proxy/v4/letter/p/f14d63/32.png) [@Patrick\_Baggett](https://discourse.libsdl.org/u/Patrick_Baggett)\
**Post date:** [March 11, 2011, 9:18pm UTC](https://discourse.libsdl.org/t/scancodes-vs-keycodes/18036/5 "2011-03-11T21:18:26Z")

</div>

2011/3/11 Jean-Fran?ois S?v?re

> Having a concept of a key position is actually more relevant in a game than  
> key label. If I want to use the number bar, I don’t care if the 3 key is  
> labeled 3 or ", what I’m interested in is the physical position of the key  
> as that position is meaningful in terms of gameplay. Same goes for WASD.
> 
> Having to remap the keys, usually right after the introduction cinematic,  
> make the game look unprofessional, and it breaks the player’s immersion at  
> the very beginning of the game.  
> If you see it that way, scancodes may be broken on some platforms, but most  
> gameplays are broken on non US keyboards when using keycodes.
> 
> There are some solutions to avoid that. The first is to have SDL give us a  
> portable way to query the keyboard layout. Then we would adapt the default  
> configuration to that.  
> Another would be to ask the user either when downloading the game or when  
> the game starts for the first time. But I believe it’s wrong to rely on the  
> user.
> 
> As for weird keyboards, not much we can do about that, we game developers  
> have to manually plan for each of those we wish to support manually anyways.
> 
> The best solution in my mind would be to remap the weird platforms to a  
> standard set of scancodes (solaris/sparc, and more). That way the behaviour  
> described by patrick would be an SDL bug. That way have some overhead  
> though. But even if it’s not fully portable, please keep the scancodes. My  
> target platforms are Windows/Linux/Mac, so if it works for those, I’ll take  
> it !

I disagree with pretty much everything you’ve said, but if someone can write  
a function like ScancodeForKey(row, col), then more power to them. I don’t  
see any X11 or Win32 APIs to do this though. If there are none, then this  
leaves your “position based” solution dead in the water and we’re back to  
hard-coded scancode which may or may not map the proper position depending  
on the keyboard layout/vendor/OS (yes, the same OS can produce different  
scancodes for the exact same hardware, usually for the less frequently used  
keys, e.g. F11 / scroll lock). I don’t even know how this solution would  
work on iOS based devices though.

The map between “weird” platforms and “common” platforms scancodes is just  
wrong. My results weren’t a bug, they were a natural result of what I asked  
for. Scancodes are just that, integers that uniquely identify a key on a  
keyboard. They can and should be arbitrary values depending on  
platform/layout. Easiest example of platform specific scancode conversion  
failing: Solaris – plug in a standard USB keyboard in addition to the Sun  
keyboard – boom all of your scancodes are wrong. This sort of hell is why  
events and messages happen with symbolic constants that contain TRANSLATED  
scancode values. Don’t fight it, just love it.

Patrick

---

<div class="post-metadata">

**Author:** ![Jean-Francois\_Severe](https://discourse.libsdl.org/letter_avatar_proxy/v4/letter/j/a4c791/32.png) [@Jean-Francois\_Severe](https://discourse.libsdl.org/u/Jean-Francois_Severe)\
**Post date:** [March 11, 2011, 11:41pm UTC](https://discourse.libsdl.org/t/scancodes-vs-keycodes/18036/6 "2011-03-11T23:41:05Z")

</div>

I don’t understand Patrick, what you’re saying is that it’s difficult, but I  
believe Sam is saying that scancodes in 1.3 are already designed as position  
indicators. The question is whether or not it makes sense, it’s whether or  
not it’s usefull. I had no idea 1.3 had revised the scancode concept, but  
should Sam choose to keep it, I’ll definitely use it.  
As for the problem with solaris and other OS, just document the cases/OS  
that don’t work. If you only target platforms that work, it’s a usefull  
feature.

2011/3/11 Patrick Baggett \<baggett.patrick at [gmail.com](http://gmail.com)\>\>

> 2011/3/11 Jean-Fran?ois S?v?re \<@Jean-Francois\_Severe\>
> 
> Having a concept of a key position is actually more relevant in a game than
> 
> > key label. If I want to use the number bar, I don’t care if the 3 key is  
> > labeled 3 or ", what I’m interested in is the physical position of the key  
> > as that position is meaningful in terms of gameplay. Same goes for WASD.
> > 
> > Having to remap the keys, usually right after the introduction cinematic,  
> > make the game look unprofessional, and it breaks the player’s immersion at  
> > the very beginning of the game.  
> > If you see it that way, scancodes may be broken on some platforms, but  
> > most gameplays are broken on non US keyboards when using keycodes.
> > 
> > There are some solutions to avoid that. The first is to have SDL give us a  
> > portable way to query the keyboard layout. Then we would adapt the default  
> > configuration to that.  
> > Another would be to ask the user either when downloading the game or when  
> > the game starts for the first time. But I believe it’s wrong to rely on the  
> > user.
> > 
> > As for weird keyboards, not much we can do about that, we game developers  
> > have to manually plan for each of those we wish to support manually anyways.
> > 
> > The best solution in my mind would be to remap the weird platforms to a  
> > standard set of scancodes (solaris/sparc, and more). That way the behaviour  
> > described by patrick would be an SDL bug. That way have some overhead  
> > though. But even if it’s not fully portable, please keep the scancodes. My  
> > target platforms are Windows/Linux/Mac, so if it works for those, I’ll take  
> > it !
> 
> I disagree with pretty much everything you’ve said, but if someone can  
> write a function like ScancodeForKey(row, col), then more power to them. I  
> don’t see any X11 or Win32 APIs to do this though. If there are none, then  
> this leaves your “position based” solution dead in the water and we’re back  
> to hard-coded scancode which may or may not map the proper position  
> depending on the keyboard layout/vendor/OS (yes, the same OS can produce  
> different scancodes for the exact same hardware, usually for the less  
> frequently used keys, e.g. F11 / scroll lock). I don’t even know how this  
> solution would work on iOS based devices though.
> 
> The map between “weird” platforms and “common” platforms scancodes is just  
> wrong. My results weren’t a bug, they were a natural result of what I asked  
> for. Scancodes are just that, integers that uniquely identify a key on a  
> keyboard. They can and should be arbitrary values depending on  
> platform/layout. Easiest example of platform specific scancode conversion  
> failing: Solaris – plug in a standard USB keyboard in addition to the Sun  
> keyboard – boom all of your scancodes are wrong. This sort of hell is why  
> events and messages happen with symbolic constants that contain TRANSLATED  
> scancode values. Don’t fight it, just love it.
> 
> Patrick
> 
> * * *
> 
> SDL mailing list  
> SDL at [lists.libsdl.org](http://lists.libsdl.org)  
> [http://lists.libsdl.org/listinfo.cgi/sdl-libsdl.org](http://lists.libsdl.org/listinfo.cgi/sdl-libsdl.org)

---

<div class="post-metadata">

**Author:** ![Rainer\_Deyke](https://discourse.libsdl.org/letter_avatar_proxy/v4/letter/r/a9a28c/32.png) [@Rainer\_Deyke](https://discourse.libsdl.org/u/Rainer_Deyke)\
**Post date:** [March 12, 2011, 3:49am UTC](https://discourse.libsdl.org/t/scancodes-vs-keycodes/18036/7 "2011-03-12T03:49:28Z")

</div>

I’m using it. It’s my main reason for using SDL 1.3 instead of sticking  
to SDL 1.2.On 3/11/2011 12:26, Sam Lantinga wrote:

> Is anybody using this distinction between scancodes and keycodes in SDL  
> 1.3? Or is it preferrable to go back to just using keycodes the way SDL 1.2  
> works?

–  
Rainer Deyke - rainerd at [eldwood.com](http://eldwood.com)