Can't load OpenGL

[fperrad]

When I try to load OpenGL from Lua, I obtain the following error :

Could not find non-existent sub _gl_func_list
    current instr.: 'lua;OpenGL;_wrap_opengl_entry_points' pc 193 (runtime\parrot\library\OpenGL.pir:197)
    called from Sub 'lua;OpenGL;_opengl_init' pc 18 (runtime\parrot\library\OpenGL.pir:93)
    called from Sub 'lua;glut;luaopen_glut' pc 9 (src\lib\glut.pir:33)
    called from Sub 'lua;package;require' pc 59368 (src/lib/luapackage.pir:495)
    called from Sub '&main_10' pc 110 (EVAL_1:47)
    called from Sub 'docall' pc 53370 (src/lib/luaaux.pir:999)
    called from Sub 'handle_script' pc 51155 (lua.pir:303)
    called from Sub 'main' pc 50642 (lua.pir:123)

The attached patch fixes this issue, OpenGL_funcs.pir becomes an included part of OpenGL.pir instead of an independent PBC file.

In a long term step, we could refactor config/gen/opengl.pm with template, and merge OpenGL.pir & OpenGL_funcs.pir in an single file.

[japhb]

This is effectively a partial reversion of NotFound's commit (r38693) that does the opposite:

https://trac.parrot.org/parrot/changeset/38693

I originally used .include, as you have it in the patch, but NotFound went through and converted it to runtime load ... I don't know his reasoning.

[NotFound]

I'll take a look at it tomorrow.

[japhb]

From #parrot, with minor edits:

<fperrad> japhb, what do you think about a refactor of config/gen/opengl.pm with template ? <japhb> fperrad: I like having OpenGL.pir and OpenGL_funcs.pir separate, because OpenGL.pir is hand-written code, and OpenGL_funcs.pir is completely generated. It makes it easy to be clear about what is safe to hand-edit and what is not. It also makes clear what parts opengl.pm alters and what it does not. That's why I went with separate files and a .include. There is also the GLUT callbacks library, which is pseudo-templated; but there's not a whole lot I can do about that cleanly. The GLUT callbacks library is an abomination, and definitely not thread- or interpreter-safe, but there's just no other way with current Parrot NCI. <japhb> Adding this Q/A to ticket .... <fperrad> japhb, OK for the record

[japhb]

More from #parrot:

<japhb> fperrad: I'm also curious why this problem affects Lua and not Rakudo or pure PIR ...?

<japhb> When NotFound made his original patch, I was OK with it because it didn't seem to have any obvious negative impact at the time (and thus I had no real reason to object).

<fperrad> japhb, OpenGL.pir uses the namespace 'OpenGL', but OpenGL_funcs.pir not

I try to add this namespace in OpenGL_funcs.pir, but it isn't enought

<japhb> Oh interesting ... That sounds buggish.

[NotFound]

I've been unable to reproduce the problem. Maybe I'm building lua in a wrong way.

I added an example of using opengl from HLL in r40167. Maybe the differences between static-triangle and static-triangle-hll might explain, or help to diagnose, the problem.

[NotFound]

Reason to no use include:

If you include a file from the library directory you need to specify his path, and then you have problems about deprecated search paths and about build tree vs installed paths.

If you really need to use include, better put the file in the include directory.

[fperrad]

Replying to NotFound:

I've been unable to reproduce the problem. Maybe I'm building lua in a wrong way. I added an example of using opengl from HLL in r40167. Maybe the differences between static-triangle and static-triangle-hll might explain, or help to diagnose, the problem.

I refactor Lua with this new example. See  http://github.com/fperrad/lua/commit/517eef4331b706973d88aa4deeea6d1e12990d9d

Thanks.

François