Geometry animation differs for shadow and window

[joaopauloalbq]

Platform

Manjaro 24.1 amd64

GPU, drivers, and screen setup

Intel UHD Graphics 620, mesa 24.2.4, xf96-video-intel 2.99.917+923+gb74b67f0, one laptop screen

glxinfo output

name of display: :0
display: :0  screen: 0
direct rendering: Yes
Extended renderer info (GLX_MESA_query_renderer):
    Vendor: Intel (0x8086)
    Device: Mesa Intel(R) UHD Graphics 620 (KBL GT2) (0x5917)
    Version: 24.2.4
    Accelerated: yes
    Video memory: 3913MB
    Unified memory: yes
    Preferred profile: core (0x1)
    Max core profile version: 4.6
    Max compat profile version: 4.6
    Max GLES1 profile version: 1.1
    Max GLES[23] profile version: 3.2
OpenGL vendor string: Intel
OpenGL renderer string: Mesa Intel(R) UHD Graphics 620 (KBL GT2)
OpenGL core profile version string: 4.6 (Core Profile) Mesa 24.2.4-arch1.0.1
OpenGL core profile shading language version string: 4.60
OpenGL core profile context flags: (none)
OpenGL core profile profile mask: core profile

OpenGL version string: 4.6 (Compatibility Profile) Mesa 24.2.4-arch1.0.1
OpenGL shading language version string: 4.60
OpenGL context flags: (none)
OpenGL profile mask: compatibility profile

OpenGL ES profile version string: OpenGL ES 3.2 Mesa 24.2.4-arch1.0.1
OpenGL ES profile shading language version string: OpenGL ES GLSL ES 3.20

Environment

Awesome WM

picom version

v12.3 (/startdir/picom revision 081510a)

Diagnostics

Version: v12.3 (/startdir/picom revision 081510a)

Extensions:

• Shape: Yes
• RandR: Yes
• Present: Present

Misc:

• Use Overlay: No (Another compositor is already running)
• Config file specified: None
• Config file used: /home/jp/.config/picom/picom.conf

Drivers (inaccurate):

modesetting

Backend: glx

• Driver vendors:
• GLX: Mesa Project and SGI
• GL: Intel
• GL renderer: Mesa Intel(R) UHD Graphics 620 (KBL GT2)
• Accelerated: 1 [ 12/11/2024 21:27:54.121 egl_init WARN ] The egl backend is still experimental, use with care.

Backend: egl

• Driver vendors:
• EGL: Mesa Project
• EGL driver: iris
• GL: Intel
• GL renderer: Mesa Intel(R) UHD Graphics 620 (KBL GT2)

Configuration:

Configuration file

backend = "glx"
corner-radius = 20
shadow = true
shadow-opacity = 0.90

animations = (
    {
        triggers = [ "geometry" ];
        scale-x = {
            curve = "cubic-bezier(0.07, 0.65, 0, 1)";
            duration = 3.0;
            start = "window-width-before / window-width";
            end = 1;
        };
        scale-y = {
            curve = "cubic-bezier(0.07, 0.65, 0, 1)";
            duration = 3.0;
            start = "window-height-before / window-height";
            end = 1;
        };
        shadow-scale-x = "scale-x";
        shadow-scale-y = "scale-y";
        offset-x = {
            curve = "cubic-bezier(0.07, 0.65, 0, 1)";
            duration = 3.0;
            start = "window-x-before - window-x";
            end = 0;
        };
        offset-y = {
            curve = "cubic-bezier(0.07, 0.65, 0, 1)";
            duration = 3.0;
            start = "window-y-before - window-y";
            end = 0;
        };
        shadow-offset-x = "offset-x";
        shadow-offset-y = "offset-y";
        saved-image-blend = 0;
    }
);

Steps of reproduction

1. Set corner-radius
2. Set shadow
3. Set animation for geometry change
4. Resize the window

---

(1) Expected behavior

The shadow animation should have the same timing as the window animation.

(1) Current Behavior

The shadow animation is delayed compared to the window animation.

---

(2) Expected behavior

Corners should not erase shadows.

(2) Current Behavior

Corners are erasing the shadows. Corner shadows are being animated (?)

---

OpenGL trace

picom.trace.zip

Other details

https://github.com/user-attachments/assets/e2b0a090-5e63-4dab-adb0-e060d1b2b3d0

[yshui]

hmm, i think this is probably because of interaction between saved-image-blend and rounded corners :thinking:

[yshui]

so i think first of all, shadow has different width & height from its window (i.e. shadow_width = window_width + 2 * shadow_radius). so it does have to have a different scaling factor. and it's more noticeable if the window itself is small.

besides that, the corners do look wrong but unsure what's happening there.

[yshui]

ok, i actually found the fix for the weird corners, but now i am baffled by the shadow detachment. it seems to only happen if the shadow offset is negative... so looks like my previous theory is wrong...

[joaopauloalbq]

yay \o/