Xbmc: libretro: OpenGL support not implemented

[rozhuk-im]

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I'm trying to port Play! - PlayStation 2 emulator: https://github.com/rozhuk-im/game.libretro.play
https://purei.org/
https://github.com/jpd002/Play-

It is compiled (with FreeBSD port system, with some private hacks) and run but Kodi (from master) crash because OpenGL in libretro not implemented.

@lrusak , @a1rwulf, @AlwinEsch , @garbear I see some progress in your git repos, but can some one make PR with this with latest changes?

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[a1rwulf]

Not a real duplicate of: https://github.com/xbmc/xbmc/issues/15874
But it's basically the same :)
@rozhuk-im Thx for bringing it up again, I'll try to find some motiviation to give it another try.

[rozhuk-im]

@a1rwulf Thanks for response, I see #15874, but start this bug as discussion/chat with all who work with it.

At this time I stick with:
Error: Missing GL version
after:

    glewExperimental = GL_TRUE;
    auto result = glewInit();

This is in

    g_hw_render.context_type = RETRO_HW_CONTEXT_OPENGL_CORE;
    g_hw_render.version_major = 3;
    g_hw_render.version_minor = 2;
    g_hw_render.context_reset = retro_context_reset;
    g_hw_render.context_destroy = retro_context_destroy;
    g_hw_render.cache_context = false;
    g_hw_render.bottom_left_origin = true;
    g_hw_render.depth = true;
...
    g_environ_cb(RETRO_ENVIRONMENT_SET_HW_RENDER, &g_hw_render);

retro_context_reset() function, I'm add call into retro_run() as qiuck hack.

[a1rwulf]

There's more to it.
I need to verify @garbear's work in the game.libretro core library and fix the remaining issues we have inside Kodi.

[montvid]

Would be nice to have opengl and vulkan support - kodi retroplayer is a good idea!

[AlwinEsch]

About Vulkan, that could for me really a perfect thing for a GSOC project. This has a so big improvement against GL, specially to have App/Process Independent use about them and a Zerocopy inside GPU.

By them can be easily (about his supported parts) a sandbox system added where the parts can use Kodi's GUI in perfect performance and runs safe.

Has looked to it some times ago about the webbrowser thing (hope to start again soon on them), but with a big lack of experience in Vulkan no chance to make byself (only becomed Kodi partly working with a Vulkan <-> GLES emulation library).

Only hard thing then that Kodi must be use them alone without any GL support itself, maybe DX can be still used, but should then also maybe makes sense to change. To allow GLES (e.g. for addons) are some wrapper libs available on Web.