Add support for SDL 2.0

[DerekBronson]

The first release of Linux platform support introduced SDL 1.3 to the engine. While functional, it limits features and is "ugly" according to the author. Implementing SDL 2.0 would fix some issues and be far prettier. A question that popped up was whether SDL 2.0 should be implemented across all platforms. The author suggested it would be helpful, but not a high priority.

T2D Linux First Release Blog: http://www.garagegames.com/community/blog/view/22545/1
Comment on SDL 2.0: http://www.garagegames.com/community/blogs/view/22545/1#comment-195505

[MichPerry-GG]

Updated original post to clarify the origin of this issue.

[tapir]

Currrently Torque2D 3.0 does not even build in Linux although it's claimed that it works for Linux.
The make error is: "/.../Torque2D/engine/compilers/Make/../../source/platformX86UNIX/x86UNIXInputManager.cc:71: undefined reference to `X11_KeyToUnicode'" and is related to SDL 1.3 (which is a development version)

[camporter]

Unfortunately I wasn't able to get a keybinding fix in place for the 3.0 release. The X11_KeyToUnicode function is only available in the older SDL 1.2 releases (even though it shouldn't have been used at all). SDL 1.3 is essentially the pre-release of 2.0, which has an entirely different interface. I believe @Syrup84 meant to say SDL 1.2.

Let me know if you have any other problems. Extra details such as which compiler, architecture, kernel/distro version and graphics driver/card are also appreciated!

[tapir]

So how do we build Torque in Linux? Sorry to hijack this bug report but it seems to be related.

[lilligreen]

Build guide is available on the wiki: https://github.com/GarageGames/Torque2D/wiki/Linux-Development-Guide

If anything in the guide is unclear, needs correcting, etc, please let me know either via the T2D forums or by opening up a new issue.

[tapir]

Well that guide doesn't mention "X11_KeyToUnicode" issue.
Created a new issue #185

[camporter]

Could you provide more information about your environment? SDL 1.2 is the only supported version. I am currently linking against SDL 1.2.5. Here's the change in libSDL for the fix that was made two years ago: https://hg.libsdl.org/SDL/rev/900a0fae90ca

[tapir]

I'm on Arch linux with SDL 1.2.15.

SDL 1.2.5 is very old (2002-2003?) and on any modern linux distro, you
won't find it. Did you maybe mean 1.2.15 also?

EDIT: I've looked at 1.2.15 source (SDL_x11events.c to be exact) and I don't see that X11_KetToUnicode() is exported as a library function.
From the patch you've sent: "extern DECLSPEC Uint16 SDLCALL X11_KeyToUnicode(SDLKey, SDLMod);". This line is missing in 1.2.15 source. Am I missing something?

EDIT2: Turns out that patch was commited after 1.2.15 release of SDL which is the latest official release.
In this case I suggest avoiding the linux support claim of Torque2D 3.0. Unless you compile SDL yourself or use an ancient version, Torque2D won't compile in linux.

On 6 May 2014 02:25, "Cameron Porter" [email protected] wrote:

Could you provide more information about your environment? SDL 1.2 is the
only supported version. I am currently linking against SDL 1.2.5. Here's
the change in libSDL for the fix that was made two years ago:
https://hg.libsdl.org/SDL/rev/900a0fae90ca

—
Reply to this email directly or view it on GitHubhttps://github.com//issues/173#issuecomment-42252734
.

[raichu]

Same here. It seems Ubuntu people patched this themselves:
https://launchpad.net/ubuntu/+source/libsdl1.2/+bug/66217

Unless they mean Linux support only means Ubuntu, they should indeed either fix it or remove the claim.

[tapir]

On a side note, why not get rid of all the platform specific code?
SDL 2.0 supports all the big platforms. From the website:

SDL officially supports Windows, Mac OS X, Linux, iOS, and Android

For the web, we can keep using emscripten.

[camporter]

I've dusted off the SDL2 code that I have, most of the input code is working, window handling and rendering are working as well. Just have to rip out the remaining Xlib junk, then try to make the whole thing more intelligible and try to document what's going on as well.

At the time of testing for T2D 3.0, we didn't have anyone on other distributions to test, so unfortunately the missing symbol was never noticed (except by the nag message built in with having used it).

If you can't wait for SDL2 support, you have a few options:

• Copy the implementation of X11_KeyToUnicode from SDL.
• Statically link SDL with the patch into your build to ensure that it will work on any distribution. SDL is zlib licensed, so no problems there. I haven't tried this, but presumably it should work.
• Change the input mapping code to do similar behavior to what the emscripten code does, and set your own maps.

If I make good progress this weekend, the PR could be up as well.

[lilligreen]

Torque 3D also has Linux using SDL2, not sure if it is worth looking at any of their platform code: https://github.com/BeamNG/Torque3D/tree/dev_linux_opengl

On a side note, why not get rid of all the platform specific code?

The idea is good, I'm guessing the amount of work to get there has kept anyone from attempting this yet.

[tapir]

@camporter Instead I've sent the patch to my distro's bugzilla and now it's fixed (https://bugs.archlinux.org/task/40292)

@lilligreen I'm guessing once the switch is done from SDL-1.2 to 2.0 for linux, it shouldn't be that much work to make it run in other platforms.

[camporter]

Here is my initial commit for SDL2: camporter@94ed1af

Not that this is still being tested, and keyboard input is currently broken. Extra window shows up because I'm not yet saving a ref to the SDL_Window. That will be the next task.

[tapir]

@camporter That's some work! I can't wait to see it finished.

[tapir]

Any updates on when we can have SDL 2.0 support?