wp_viewporter subsurface scaling is broken

[Cloudef]

Hyprland version

v0.56.0

Is this a regression?

Don't know

What's the bug?

Subsurfaces do not scale properly using wp_viewporter protocol. It seems the rendering clips to the buffer dimensions.

Hyprland:

Weston:

Sway (wlroots):

COSMIC-comp (smithay):

Reproduction steps

git clone git@github.com:Cloudef/swiv.git
cd swiv
git checkout -f hyprland-bug-1
nix run . -- qoi/zero.qoi
# or without nix, install zig 0.15.2
zig build run -- qoi/zero.qoi

Attachments

No response

I acknowledge that:

• I have searched all (open and closed) discussions and issues and my problem is not there.

• I have read the Code of Conduct and agree to follow it.

• I wrote this request with my own hands, my own keyboard, and in my own words.

[Cloudef]

Other weirdness is that subsurfaces can escape the parent surface.

This seems to happen on weston too but not on others.. fun times
According to docs weston / hyprland behavior for this is correct.

[Cloudef]

Doing surface_attach when updating the viewporter transform seems to fix it for hyprland. But there seems to still be some weirdness with viewporter if set_destination is large, can be reproduced by zooming in with the scroll wheel in the example app.

I pushed the original bug to hyprland-bug-1 branch and edited the original description