video/wayland: use EGL_EXT_present_opaque when available

[1ace]

Description

This should fix the issue with the games requesting alpha configs and not filling the alpha channel all the way to 100%

Existing Issue(s)

@flibitijibibo I couldn't find any GitHub issue for this issue; let me know if there was one and I'll add Closes #123 here :)

checklist:

• EGL extension spec
• Mesa implementation

[flibitijibibo]

Added a hint of top of this to support transparent windows, in case someone ever needs it:

flibitijibibo@a9d90f2

[1ace]

Good idea; I added your commit to the PR 👍

[flibitijibibo]

EGL_EXT_protected_content

Only just realized this is copied from the extension below it... the Mesa patch has this too!

[1ace]

Ah yes, guilty as charged 😅

Thanks for noticing that, I'll fix it 👍

[1ace]

Btw, this src/video/khronos/EGL/eglext.h change was only meant to reflect the real change that will be to pull this file from upstream once the extension lands (and when I do that, other things in this file will change, starting with the date in the header, and possibly other changes that hadn't been carried over yet).

[flibitijibibo]

I'll have to check and see how we do header updates here... sometimes we use the header and sometimes we define it in SDL_egl.c, I'm actually not sure what the rule is there. Ryan or Sam might know though.

[Cacodemon345]

The hint documentation seems to be misleading for non-EGL platforms.

[flibitijibibo]

It's probably worth re-wording to ALLOW_TRANSPARENCY to fall more in line with the extension spec's wording - once the extension is finalized I'll redo the commit.

[flibitijibibo]

The EGL extension has been merged into the registry - with that in mind I've redone the hint patch to be worded more in line with what the extension suggests:

flibitijibibo@0c8947c

Which leaves one last question... @slouken, @icculus, how should we integrate the new attrib define? Is it enough to update the Khronos headers in our repo, or do we need to add it to SDL_egl.c as well to account for older EGL headers outside of the ones we provide?

[flibitijibibo]

Checked this on flibitBuild and it appears we will indeed need to define this in SDL_egl.c as well. @1ace, I believe this is all that's needed at this point:

1. First commit can be an update of the official header
2. Second commit needs the definition copied in SDL_egl.c
3. Third commit can be replaced with flibitijibibo@0c8947c

Once that's all in place I'll get this in!

[1ace]

@flibitijibibo Thanks!

I just had a go at updating the local SDL copy of the EGL headers, and they're massively out of date, to the point where I'm not confident the update won't break something. I think I'll make a separate PR to update them, and only do your points 2 & 3 in this PR :)

[1ace]

Alright, PR updated 👍

[flibitijibibo]

Looks great, thanks for putting this whole extension together btw!