[FX Renderer] Add blur

[ErikReider]

Fixes: #14
Supersedes: #22

TODO:

• Add global config options (per surface blur won't work due to the damage calculations)
• Add latest blur features from SwayFX
• Add "optimized" blur

[WillPower3309]

Some small comments, can you explain at a high level how we handle blur ignore transparent in scene? Reviewing from my phone and that bit of logic is the only one I'm having a nuisance tracking

[WillPower3309]

Thanks for your patience in waiting for a review!

[ErikReider]

an you explain at a high level how we handle blur ignore transparent in scene?

It's actually pretty simple, the comp needs to call the wlr_scene_buffer_set_backdrop_blur_ignore_transparent function for the wlr_scene_buffer node:

https://github.com/ErikReider/fx-comp/blob/80a2c853a62dafecef149b00c6888f7622c2a643/src/desktop/xdg.c#L39

The actual wlr_scene part of it is the same as we do in SwayFX where we pass a bool to the blur function indicating whether we want to ignore the transparent regions or not. (Render the surface texture and stencil it, etc…)

[ErikReider]

What we can do is to separate the renderer impl and the scene impl into separate PRs to make it easier for you to review. What do you think of that idea @WillPower3309 ?

[WillPower3309]

What we can do is to separate the renderer impl and the scene impl into separate PRs to make it easier for you to review. What do you think of that idea @WillPower3309 ?

If you don't mind that would be great!

[ErikReider]

What we can do is to separate the renderer impl and the scene impl into separate PRs to make it easier for you to review. What do you think of that idea @WillPower3309 ?

If you don't mind that would be great!

Done :)

[WillPower3309]

Just a couple minor comments, otherwise LGTM

[ErikReider]

Done! :)