The game does not run for me:
```
STYLE-WARNING: Undefined alien: "SDL_main"
STYLE-WARNING: Undefined alien: "gk_create"
STYLE-WARNING: Undefined alien: "gk_destroy"
STYLE-WARNING: Undefined alien: "gk_process"
STYLE-WARNING: Undefined alien: "SDL_main"
Unhandled SDL2::SDL-RC-ERROR in thread #<SB-THREAD:THREAD "main thread" RUNNING
{1005266DF3}>:
SDL Error (-1): That operation is not supported
```
I have libsdl2 installed
Here the backtrace:
Backtrace for: #<SB-THREAD:THREAD "main thread" RUNNING {1005266DF3}>
0: (SB-DEBUG::DEBUGGER-DISABLED-HOOK #<SDL2::SDL-RC-ERROR {10053278B3}> #<unavailable argument>)
1: (SB-DEBUG::RUN-HOOK *INVOKE-DEBUGGER-HOOK* #<SDL2::SDL-RC-ERROR {10053278B3}>)
2: (INVOKE-DEBUGGER #<SDL2::SDL-RC-ERROR {10053278B3}>)
3: (ERROR SDL2::SDL-RC-ERROR :RC -1 :STRING "That operation is not supported")
4: (SDL2:GL-SET-ATTR :CONTEXT-MAJOR-VERSION 3)
5: ((LAMBDA NIL :IN NINJA-SPHERE:RUN))
6: (NINJA-SPHERE:RUN :W 1536 :H 864)
7: ((LAMBDA NIL :IN "/home/rpav/vcs/git/common-lisp/ninja-sphere/build.lisp"))
8: (SDL2::HANDLE-MESSAGE (#<FUNCTION (LAMBDA NIL :IN "/home/rpav/vcs/git/common-lisp/ninja-sphere/build.lisp") {100006D94B}>))
9: (SDL2::SDL-MAIN-THREAD)
10: ((FLET #:WITHOUT-INTERRUPTS-BODY-82 :IN SAVE-LISP-AND-DIE))
11: ((LABELS SB-IMPL::RESTART-LISP :IN SAVE-LISP-AND-DIE))
unhandled condition in --disable-debugger mode, quitting
My pc should support opengl up to version 4.5
Looks like an error setting the version though (see frame 4); make sure your glxinfo shows 4.5 and/or you haven't updated nvidia drivers and not restarted Xorg or something? This is a common problem with me when using nvidia drivers. For AMD/Intel, not sure. I'm not sure it's possible to support 4.5 and not support 3.3, but maybe.
