Samuel Hopkins
Just confirming that the patch from Andreas (attachment 1715 [details]) works for me under SDL 2.0.3 with xmonad.
Stas Sergeev
Confirming that the patch in this ticket fixes the full-screen switching for dosemu2 on ubuntu-16.04. Note that I am not using xmonad, so this bug appears to be generic.
This gracefully recovers when a device format is changed, and will switch
to the new default device if the current one is unplugged, etc.
This does not handle when a new default device is added; it only notices
if the current default goes away. That will be fixed by implementing the
stubbed-out MMNotificationClient_OnDefaultDeviceChanged() function.
"ISO C90 forbids mixed declarations and code [-Werror=declaration-after-statement]"
Moving some variable declarations to the top of Android_SetScreenResolution()
* alsa hotplug thread is low priority
* give a chance for other threads to catch up when audio playback is not progressing
* use nonblocking for alsa audio capture
There is a bug with SDL hanging when an audio capture USB device is removed, because poll never returns
We will throw away the data anyhow, but some apps depend on the callback
firing to make progress; testmultiaudio.c, if nothing else, is an example
of this.
Capture also will now fire the callback in these conditions, offering nothing
but silence.
Apps can check SDL_GetAudioDeviceStatus() or listen for the
SDL_AUDIODEVICEREMOVED event if they want to gracefully deal with
an opened audio device that has been unexpectedly lost.
This is just enough to get you through a file that just used the extended
header for float or int data. It doesn't handle all the other things that
you expect from this header, like 24-bit samples inside a 32-bit container
or speaker masks.
This should remain binary compatible with Windows XP, as we dynamically
load anything we need and fall back to DirectSound/WinMM/XAudio2 if not
available.
Like other C runtimes, it should probably produce the string "(null)".
This bug probably only affected Windows, as most platforms use their standard
C runtime's snprintf().
Walter van Niftrik
We have found that since SDL 2.0.5 the audio callback thread is created with a very small stack size. In our application this is leading to stack overflows.
We believe there is a bug at http://hg.libsdl.org/SDL/file/391fd532f79e/src/audio/SDL_audio.c#l1132, where the is_internal_thread flag appears to be inverted.
Volumetric
In X11 the SDL error "Unknown touch device" can occur after which the application stops recognizing touch events. For a kiosk-type application this results in a hang as far as the user is concerned. This is reproducible on HP Z220/Z230/Z240 workstations by swapping USB cables for a while and it also occurs with no physical changes, probably due to USB device power management. A workaround is to make SDL re-enumerate the touch devices like it does at startup. A patch is attached.
Matthew
Its possible to set SDL_CaptureMouse() so you continue receiving mouse input while the mouse is outside your window. This works however There is then a gap where no messages send, which is when the mouse is hovering the title bar and the window edges.
X11 seemed to be confused by the broad definition, so WEIGHT_NAME,
SLANT and SETWIDTH_NAME were defined, thus fixing the font lookup
on some systems (tested on Mageia 6 with X11 1.19.1).
Fixes bug 3571.
Tom Seddon
GL_ActivateRenderer may call GL_UpdateViewport, which leaves the GL_PROJECTION matrix selected. But after GL_ResetState, the GL_MODELVIEW matrix is selected, suggesting that's the intended default state.
It seems at least like these should be consistent. Presumably GL_UpdateViewport should be doing a glMatrixMode(GL_MODELVIEW) before it finishes.
Also updates the naming of these Xbox Wireless Controllers connected via USB (and thus the third-party Xbox Controller Driver) to match.
The Xbox Wireless Controller entries are now listed, in order, via USB, bia Bluetooh (with older firmware) and via Bluetooth (with firmware 3.1.1221.0).
This is a bleeding edge API, added to Windows 10 Anniversary Edition (build
1607, specifically).
https://msdn.microsoft.com/en-us/library/windows/desktop/mt774976(v=vs.85).aspx
Nothing supports this yet, including WinDbg, Visual Studio, minidumps, etc,
so we still need to also use the RaiseException hack. But presumably tools
will use this API as a more robust and universal way to get thread names
sooner or later, so we'll start broadcasting to it now.
Firmware revision 3.1.1221.0 changes the mapping of the Xbox One S
controller in Bluetooth mode. Aside from changing the layout of
other buttons, this revision also changes the triggers to act as
Accelerator and Brake axes from the simulation controls page.
The Darwin sysjoystick code didn't previously map anything at these
axes, making it impossible to detect input on these two buttons.
This defaults to the internal SDL resampler, since that's the likely default
without a system-wide install of libsamplerate, but those that need more can
tweak this.
This currently favors libsamplerate over the fast path (quality over speed),
but I'm not sure that's the correct approach, as there may be surprising
changes in performance metrics depending on what packages are available on
a user's system. That being said, currently, the only thing with access to
SDL_AudioStream is an SDL audio device's thread, and it might be mostly idle
otherwise, so maybe this is generally good.
Turns out that iterating from 0 to channels-1 was a serious performance hit!
These cases now tend to match or beat the original audio resampler's speed!
This allows us to avoid an extra copy, allocate less memory and reduce cache
pressure. On the downside: we have to do a lot of tapdancing to resample the
buffer in reverse when the output is growing.
It's expensive and (hopefully) unnecessary. If this becomes an overflow
problem, we could multiply both values by 0.5f before adding them, but let's
see if we can get by without the extra multiplication first.
We never seem to overflow the source buffer now; this might have been a
leftover from a bug that was covered by Vitaly's fixes?
Removing this conditional makes the resampler 10-20% faster. Left an
assert in there for debug builds, in case this still happens.
white.magic
The logic which decides if a device enumerated via the direct input system in the function EnumJoysticksCallback in SDL_dinputjoystick.c is processed is discarding valid joystick devices due to the assumption that devices of the type DI8DEVTYPE_SUPPLEMENTAL are not valid devices.
This change was added with 2.0.4 with this commit http://hg.libsdl.org/SDL/rev/1b9d40126645 that is linked to this bug report https://bugzilla.libsdl.org/show_bug.cgi?id=2460 which indicates that in that case devices of the type DI8DEVTYPE_SUPPLEMENTAL were not desirable as they caused a singular device to emit multiple "device added" events.
Since then there appear to have been a few fixes to handle devices that fall into various other classes in the following two commits:
http://hg.libsdl.org/SDL/rev/10ffb4787d7a and http://hg.libsdl.org/SDL/rev/6a2bbac05728
Two devices I have reports of failing to be listed when the DI8DEVTYPE_SUPPLEMENTAL type is excluded are ECS Gametric Throttle and Thrustmaster MFD Cougar.
Sam Lantinga
I verified that the OUYA controller shows up as a single device with this change, so I've reverted the change to ignore supplemental devices, leaving framework in place to easily add devices that we want to ignore.
Removed some needless things ("len / sizeof (Uint8)"), and made sure the
int32 -> float code uses doubles to avoid working with large integer values
in a 32-bit float.
Mark Callow
The attached patch does the following for the X11 and Windows platforms, the only ones where SDL attempts to use context_create_es_profile:
- Adds SDL_HINT_OPENGL_ES_DRIVER by which the application can
say to use the OpenGL ES driver & EGL rather than the Open GL
driver. (For bug #2570)
- Adds code to {WIN,X11}_GL_InitExtensions to determine the maximum
OpenGL ES version supported by the OpenGL driver (for bug #3145)
- Modifies the test that determines whether to use the OpenGL
driver or the real OpenGL ES driver to take into account the
hint, the requested and supported ES version and whether ES 1.X
is being requested. (For bug #2570 & bug #3145)
- Enables the testgles2 test for __WINDOWS__ and __LINUX__ and adds
the test to the VisualC projects.
With the fix in place I have run testdraw2, testgl and testgles2 without any issues and have run my own apps that use OpenGL, OpenGL ES 3 and OpenGL ES 1.1.
Lukasz Biel
Tried to compile SDL2 using newest version of VS.
Got:
SDL_audiocvt.obj : error LNK2019: unresolved external symbol memcpy referenced in function SDL_ResampleCVT
1>E:\Users\dotPo\Lib\SDL\VisualC\x64\Release\SDL2.dll : fatal error LNK1120: 1 unresolved externals
whole compilation process: http://pastebin.com/eWDAvBce
Steps to reproduce:
clone http://hg.libsdl.org/SDL using tortoise hg,
open SDL\VisualC\SDL.sln,
when promted if should retarget solution click ok,
select release x64 build type,
Build/Build Solution
attempt 2, using Visual Studio cmake support:
open folder SDL\
select release x64 build type,
run CMake\Build CMakeLists.txt
build fails
When switched to debug build type, buils succeeds in both cases.
VS 2017 is still beta.
It causes audio pops if you're converting in chunks (and needs to
allocate/initialize/free on each convert). We'll either adjust this interface
when we break ABI for 2.1 to make this usable, or publish the SDL_AudioStream
API for those that want a streaming solution.
In the meantime, the "simple" resampler produces "good enough" audio without
pops and doesn't have to be initialized, so that'll do for now on the
SDL_AudioCVT interface.
K_NORMTAB, K_SHIFTTAB, K_ALTTAB, K_ALTSHIFTTAB
In the normal case we'll load all the keymaps from the kernel, but this reduces the size of the SDL library for the fallback case when we can't get to the tty.
Mark Logan 2015-08-24 15:57:50 UTC
In SDL_windowsopengles.c, WIN_GLES_SetSwapInterval is as follows:
WIN_GLES_SetSwapInterval(_THIS, int interval)
{
/* FIXME: This should call SDL_EGL_SetSwapInterval, but ANGLE has a bug that prevents this
* from working if we do (the window contents freeze and don't swap properly). So, we ignore
* the request for now.
*/
SDL_Log("WARNING: Ignoring SDL_GL_SetSwapInterval call due to ANGLE bug");
return 0;
}
With a recent version of ANGLE (early July) calling SDL_EGL_SetSwapInterval with a D3D11 backend appears to work just fine. I am working on testing this with D3D9.
--
Alex Szpakowski
I found the bug, it was fixed in 2013. https://bugs.chromium.org/p/angleproject/issues/detail?id=481
In my opinion it should be safe to unconditionally use SetSwapInterval now. Anyone who encounters the bug should update their ANGLE to a version less than 3 years old, especially since they'd be using a SDL version that's 3+ years newer than their ANGLE version.
Rob
I've ran into an issue where I successfully receive SDL_KEY[UP,DOWN] events but not SDL_TEXTINPUT or SDL_TEXTEDITING. In my case the code in SDL_EVDEV_do_text_input() is returning early (on error) prior to calling SDL_SendKeyboardText(). I'm running on the RaspberryPi 3, without X11.
In SDL_EVDEV_do_text_input() there is a condition to check keysyms with a type value below 0xf0, then subtract 0xf0 from type. Without understanding the purpose of this code, I disabled it, recompiled, and I'm getting correct SDL_TEXTINPUT events. I'm going to guess that my hack/fix is going to be problematic in some other environment, but after some initial testing it looks like everything is running fine in my setup.
Richard Russell
Resuming from a suspended state results in a black screen. This only happens when using GLES 1.1 (GLES 2 resumes correctly) and when the render target has been changed using SDL_SetRenderTarget. This problem is new in 2.0.4.
The attached test case demonstrates the issue.
Sylvain Becker has apparently found a fix as follows:
"In the opengles leaf function (in 'src/render/opengles/SDL_render_gles.c'), it appears there is a call to 'GLES_ActivateRenderer' in 'GLES_SetRenderTarget', which is not present in opengles2. When commenting out this 'GLES_ActivateRenderer', it seems to resume fine".
This appears to fix the testcase perfectly, but I don't know whether it could have any undesirable side-effects.
tvc
I believe this patch should fix it, instead of looping through all the tty's and seemingly selecting the wrong one and corrupting the console I've just made SDL open /dev/tty which is the console attached to the current process anyway.
felix
Here's a snippet of SDL_DestroyRenderer from hg revision 10746:7540ff5d0e0e:
SDL_Texture *texture = NULL;
SDL_Texture *nexttexture = NULL;
/* ... */
for (texture = renderer->textures; texture; texture = nexttexture) {
nexttexture = texture->next;
SDL_DestroyTexture(texture);
}
SDL_DestroyTexture removes the texture from the linked list pointed to by the renderer and ends up calling SDL_DestroyTextureInternal, which contains this:
if (texture->native) {
SDL_DestroyTexture(texture->native);
}
If it happens that texture->native is an alias of nexttexture two stack frames up, SDL_DestroyRenderer will end up trying to destroy an already freed texture. I've had this very situation happen in dosemu2.
Bug introduced in revision 10650:a8253d439914, which has a somewhat ironic description of "Fixed all known static analysis bugs"...
Rob
When calling ioctl(fd, KDGKBTYPE, &type) in SDL_EVDEV_is_console(), we declare type as an 'int'. This should be a 'char'. The subsequent syscall, and kernel code, only writes the lower byte of the word.
See: http://lxr.free-electrons.com/source/drivers/tty/vt/vt_ioctl.c?v=4.4#L399
ucval = KB_101;
ret = put_user(ucval, (char __user *)arg);
I've observed intermittent behavior related to this, and I can force an error condition by using an int initialized to 0xFFFFFFFF. The resulting ioctl will set type to 0XFFFFFF02, and the conditional return in SDL_EVDEV_is_console() will fail.
Recommend changing to char, or masking off unused bits.
There was a draft of this where it did audio conversion into the final buffer,
if there was enough room available past what you asked for, but that interface
got removed, so the parameters didn't make sense (and we were using the
wrong one in any case, too!).
For example, if sR is 0 and dR is 255, we will get -255*sA casted to an unsigned value. Basically results are quite large numbers instead of the expected 0-255 range.
Fixed a case where partial trigger pull could be bound to another button
There is a fundamental problem not resolved by this commit:
Some controllers have axes (triggers, pedals, etc.) that don't start at zero, but we're guaranteed that if we get a value that it's correct. For these controllers, the current code works, where we take the first value we get and use that as the zero point and generate axis motion starting from that point on.
Other controllers have digital axes (D-pad) that assume a zero starting point, and the first value we get is the min or max axis value when the D-pad is moved. For these controllers, the current code thinks that the zero point is the axis value after the D-pad motion and this doesn't work.
My hypothesis is that the first class of devices is more common and that we should solve for that, and add an exception to SDL_JoystickAxesCenteredAtZero() as needed for the second class of devices.
Ryan C. Gordon
Kristian says you can't do it with Wayland, and that going forward, it'll just handle whatever you throw at it anyhow.
https://twitter.com/hoegsberg/status/816148272402165761
So I say we mark it SDL_PIXELFORMAT_RGB888, which is what my X11 display currently reports, and leave it at that.
kaisyu
In case of OpenGLES, the sequences of loading and unloading driver library should be like that:
SDL_Init
...
SDL_GL_LoadLibrary
SDL_EGL_LoadLibrary
...
SDL_Quit
...
SDL_GL_UnloadLibrary
SDL_EGL_UnloadLibrary
...
However, according to my test results, the varible '_this->gl_config.driver_loaded' does not allow 'SDL_GL_UnloadLibrary' to call 'SDL_EGL_UnloadLibrary'.
Coriiander
This notice is about a misplaced comment.
Often times when we use an #if #endif sequence, the #endif is followed by a comment to indicate what #if statement it belonged to. The SDL_xaudio2.c file contains a misplaced comment, as follows (I stripped the other comments):
#ifdef __GNUC__
# define SDL_XAUDIO2_HAS_SDK 1
#elif defined(__WINRT__)
# define SDL_XAUDIO2_HAS_SDK
#include "SDL_xaudio2.h"
#else
#if 0
#include <dxsdkver.h>
#if (!defined(_DXSDK_BUILD_MAJOR) || (_DXSDK_BUILD_MAJOR < 1284))
# pragma message("Your DirectX SDK is too old. Disabling XAudio2 support.")
#else
# define SDL_XAUDIO2_HAS_SDK 1
#endif
#endif
#endif /* 0 */
That final /* 0 */ should be moved one line up. Like this (I tabbed it out for you to make it more clear):
Tristan
The internal SDL_vsnprintf implementation accesses memory outside buffer. The bug existed also inside the format (%) processing, which was fixed with Bug 3441.
But there is still an invalid access, if we do not have any format inside the source string and the destination string is shorter than the format string. You can use any string for this test, as long it is longer than the buffer.
Example:
va_list argList;
char buffer[4];
SDL_vsnprintf(buffer, sizeof(buffer), "Testing", argList);
The bug is located on the 'else' branch of the format char test:
while (*fmt) {
if (*fmt == '%') {
...
} else {
if (left > 1) {
*text = *fmt;
--left;
}
++fmt;
++text;
}
}
if (left > 0) {
*text = '\0';
}
As you can see that text is always incremented, even when left is already one. When then on the last lines, *text is assigned the NULL char, the pointer is located outside bounds.
Intellectual Kitty
In SDL_video.c, on line #1756, in SDL_SetWindowPosition (from today's distribution, 12-31-2016, https://hg.libsdl.org/SDL/shortlog/bf19e0c84483):
if (displayIndex > _this->num_displays) {
should be:
if (displayIndex >= _this->num_displays) {
felix
Compiling even a simple SDL2 'hello world' program with gcc -Wstrict-prototypes (GCC 6.2.1) results in warnings like:
/usr/include/SDL2/SDL_gamecontroller.h:143:1: attention : function declaration isn't a prototype [-Wstrict-prototypes]
extern DECLSPEC int SDLCALL SDL_GameControllerNumMappings();
^~~~~~
It seems there is a missing 'void' between the parentheses.
This was a leftover of simplifying the resamplers down from autogenerated
code; I forgot to make something that the generator hardcoded into something
variable.
Fixes Bugzilla #3507.
Ozkan Sezer
http://hg.libsdl.org/SDL/rev/464a2676d8ab seems to have
forgotten removing the return from SDL_dynapi_procs.h, and this patch
does that. Without it, MSVC warns:
c:\sdl2\src\dynapi\SDL_dynapi_procs.h(598) : warning C4098:
'SDL_GL_SwapWindow_DEFAULT' : 'void' function returning a value
c:\sdl2\src\dynapi\SDL_dynapi_procs.h(598) : warning C4098:
'SDL_GL_SwapWindow' : 'void' function returning a value
Ozkan Sezer
This adds the name 'ad' to two unnamed unions in edid.h
and adjusts edid-parse.c for it. Nameless unions are not supported in
ancient gcc, which I happened to use on one of my ancient setups.
These fixes are lumped into two categories:
1. add new file, SDL_dataqueue.c, to UWP/WinRT build-inputs (via MSVC project
files)
2. implement a temporary, hack-fix for a build error in SDL_xinputjoystick.c.
Win32's Raw Input APIs are, unfortunately, not available for use in UWP/WinRT
APIs. There does appear to be a replacement API, available in the
Windows.Devices.HumanInterfaceDevice namespace.
This fix should be sufficient to get SDL compiling again, without affecting
Win32 builds, however using the UWP/WinRT API (in UWP/WinRT builds) would
almost certainly be better (for UWP/WinRT builds).
TODO: research Windows.Devices.HumanInterfaceDevice, and use that if and as
appropriate.
This currently doesn't affect absolute motion, which would need to be implemented on each windowing system so the cursor matches the reported mouse coordinates.
Diego
I was previously unaware that rotating the device to a different orientation when the keyboard is shown causes a keyboardWillHide followed by a keyboardWillShow notification. The previous patch would then mistakenly StopTextInput when rotating. This patch fixes that by checking if the device is rotating before stopping text input.
Ozkan Sezer
With rev. 10651, i.e. http://hg.libsdl.org/SDL/rev/747a6a795b21 ,
SDL2 - OS X builds fail to run on 10.6 (my setup: i686 / 10.6.8)
because the symbol _IOPMAssertionCreateWithDescription is missing.
The SDK listing it for 10.7+ does seem correct. Reverting r10651
and rebuilding makes it to function again.
Simon Hug
The SDL_BlitScaled function runs into an access violation for specific blit coordinates and surface sizes. The attached testcase blits a 800x600 surface to a 1280x720 surface at the coordinates -640,-345 scaled to 1280x720. The blit function that moves the data then runs over and reads after the pixel data from the src surface causing an access violation.
I can't say where exactly it goes wrong, but I think it could have something to do with the rounding in SDL_UpperBlitScaled. final_src.y is 288 and final_src.h is 313. Together that's 601, which I believe is one too much, but I just don't know the code enough to make sure that's the problem.
Sylvain
I think this patch fix the issue, but maybe it's worth re-writing "SDL_UpperBlitScaled" using SDL_FRect.
The non-deprecated approach (IOPMAssertion) already exists in SDL, and is
available in Mac OS X 10.6 and later (although it was incorrectly listed as
10.7 and later in SDL). Since SDL now requires 10.6 or later, this is no
longer conditionally used.
realitix
SDL2 allows to create widow and to get information through SDL_SysWMinfo.
But it misses something, with Vulkan, you need the HWND and HINSTANCE of the window for Win32 system.
Sadly, SDL2 provides only HWND but not HINSTANCE.
In some context, it can be difficult to get the HINSTANCE, indeed, I'm using pySDL2 (Python) and I can only access properties that SDL2 gives me.
I have to use a dirty trick like that to get the HINSTANCE: (https://raw.githubusercontent.com/bglgwyng/pyVulkan/master/examples/win32misc.py)
felix
Building SDL 2.0.5, or even the Mercurial snapshot (r10608) with GCC 6.2.1 and --enable-video-directfb generates a number of compiler diagnostics and fails.
Simon Hug
The software renderer produces incorrect results when blending textures at an angle with certain blend modes. It seems that there were some edge cases that weren't considered when the SW_RenderCopyEx function was last changed. Or another bug possibly covered up the problem. (More on that in another bug report.)
Most of the issues come from the fact that the rotating function sets a black colorkey. This is problematic because black is most likely appearing in the surface and the final blit will ignore these pixels. Unless a colorkey is already set (the software renderer currently never sets one), it's very hard to find a free color. Of course it could scan over the whole image until one is found, but that seems inefficient.
The following blend modes have issues when drawn at an angle.
NONE: The black pixels get ignored, making them essentially transparent. This breaks the 'dstRGBA = srcRGBA' definition of the NONE blend mode.
MOD: Again, the black pixels get ignored. This also breaks the 'dstRGB = dstRGB * srcRGB' definition of the MOD blend mode, where black pixels would make the destination black as well. A white colorkey will work though, with some preparations.
BLEND: There are some issues when blending a texture with a translucent RGBA target texture. I - uh - forgot what the problem here exactly is.
This patch fixes the issues mentioned above. It mainly changes the code so it tries to do things without the colorkey and removes the automatic format conversion part from the SDLgfx_rotateSurface function. Getting the format right is something the caller has to do now and the required code has been added to the SW_RenderCopyEx function.
There's a small change to the SW_CreateTexture function. RLE encoding a surface with an alpha mask can be a lossy process. Depending on how the user uses the RGBA channels, this may be undesired. The change that surfaces with an alpha mask don't get encoded makes the software renderer consistent with the other renderers.
The SW_RenderCopyEx function now does these steps: Lock the source surface if necessary. Create a clone of the source by using the pixel buffer directly. Check the format and set a flag if a conversion is necessary. Check if scaling or cropping is necessary and set the flag for that as well. Check if color and alpha modulation has to be done before the rotate. Check if the source is an opaque surface. If not, it creates a mask surface that is necessary for the NONE blend mode. If any of the flags were set, a new surface is created and the source will be converted, scaled, cropped, and modulated. The rest of the function stays somewhat the same. The mask also needs to be rotated of course and then there is the NONE blend mode...
It's surprisingly hard to get the pixel from a rotated surface to the destination buffer without affecting the pixel outside the rotated area. I found a way to do this with three blits which is pretty hard on the performance. Perhaps someone has an idea how to do this faster?
As mentioned above, the SDLgfx_rotateSurface now only takes 8-bit paletted or 32-bit with alpha mask surfaces. It additionally sets the new surfaces up for the MOD blend mode.
I shortly tested the 8-bit path of SDLgfx_rotateSurface and it seemed to work so far. This path is not used by the software renderer anyway.
Vitaly Novichkov
Okay, when I researched code and algorithm, I tried to replace condition "while(dst >= target)" with "while(dst > target)" and crashes are gone.
Seems on some moments it tries to write into the place before memory block begin, therefore phantom crashes appearing after some moments.
Sylvain 2016-11-07 08:49:34 UTC
when rotated +90 or -90, some transparent lines appears, though there is no Alpha or ColorKey.
if you set a dummy colorkey, it will remove the line ...
if you set a some alpha mod, the +90/-90 get transparent but not the 0/180 ...
x414e54
It is a bit of a pain to update the library or rely on whatever version the user has on their computer for default mappings.
So providing an easily updatable text file via SDL_GameControllerAddMappingsFromFile is still currently the most viable way. However using this replaces all mappings provided by the SDL_HINT_GAMECONTROLLERCONFIG environment variable which may have come from the user's custom Steam mapping.
There should be an easy way for games to supply extra game controller mappings to fill in the differences between SDL versions without it clobbering the SDL_HINT_GAMECONTROLLERCONFIG environment variable.
Internally the mappings could use a priority system and if the priority is lower then it will not overwrite the mappings.
For now it just assumes SDL_HINT_GAMECONTROLLERCONFIG is the highest priority, the default hardcoded are the lowest and anything set via the API is medium.
