[gonwe]

GNOME Shell 51 no longer provides the Shell.GLSLEffect interfaces used by the radial effect. This ports the effect to Clutter.ShaderEffect, supplies its fragment shader through a Cogl.Snippet, updates uniforms with set_uniform_value(), and adds 51 to the supported shell versions in metadata.

[LavaTiger99]

Adding test evidence and an additional GNOME 51 shader compatibility finding. This concerns the failure reported in #317.

Environment: CachyOS, GNOME Shell 51.0, Mutter 51.0, Wayland, after upgrading from GNOME 50.5. The runtime checks below used a separately launched headless GNOME 51 session with isolated settings.

An equivalent local radial shader port fixed the import failure:

TypeError: class heritage (intermediate value).GLSLEffect is not an object or null

The optional src/effects/color_effect.js and src/effects/glitch_effect.js also call set_shader_source(), which is unavailable in GNOME 51's Clutter.ShaderEffect. The file list of this PR currently includes only the radial shader and metadata, so these two effects need a port as well.

The attached patch ports all three effects: static Cogl.Snippet construction via Cogl.Snippet.new(), vfunc_get_static_snippet(), and named radial uniforms. For color/glitch, it separates the existing GLSL declarations from the main() body and supplies the body as snippet replacement code.

Checks passed in the isolated session:

• Extension enabled.
• Background shading was made visible.
• Color and glitch effects were instantiated on visible actors without shader errors.
• With two temporary GTK windows, the switcher opened, moved next/previous, and activated the selected window without extension errors.

This validates our local patch, not this PR's exact branch. Multiple monitors, physical touchpad navigation, every animation/setting, and older GNOME versions were not tested. No source build/lint run is claimed.

The affected source files matched upstream commit aee3b83769dc870c52ba123c673ad07bd404a3c8. The reference patch below intentionally declares only 51; it is suitable for a 51-specific release or adaptation by the maintainer, not a claim that these shader changes support older GNOME releases.

Migration reference: https://gjs.guide/extensions/upgrading/gnome-shell-51.html

Reference GNOME 51-only source patch

diff --git a/metadata.json b/metadata.json
index 4027178..a4a4e84 100644
--- a/metadata.json
+++ b/metadata.json
@@ -7,7 +7,7 @@
     "gettext-domain": "CoverflowAltTab@palatis.blogspot.com",
     "name": "Coverflow Alt-Tab",
     "settings-schema": "org.gnome.shell.extensions.coverflowalttab",
-    "shell-version": ["50"],
+    "shell-version": ["51"],
     "uuid": "CoverflowAltTab@palatis.blogspot.com",
     "description": "Replacement of Alt-Tab, iterates through windows in a cover-flow manner.",
     "url": "https://github.com/dsheeler/CoverflowAltTab"
diff --git a/src/effects/color_effect.js b/src/effects/color_effect.js
index 993aa31..f9c0803 100644
--- a/src/effects/color_effect.js
+++ b/src/effects/color_effect.js
@@ -3,6 +3,7 @@
 //'use strict';
 
 import Clutter from 'gi://Clutter';
+import Cogl from 'gi://Cogl';
 import Shell from 'gi://Shell';
 import GObject from 'gi://GObject';
 import GLib from 'gi://GLib';
@@ -73,11 +74,6 @@ export const ColorEffect = new GObject.registerClass({
         this._blue = null;
         this._blend = null;
 
-        // set shader source
-        this._source = get_shader_source();
-
-        if (this._source)
-            this.set_shader_source(this._source);
 
         // set shader color
         if (_color)
@@ -157,6 +153,20 @@ export const ColorEffect = new GObject.registerClass({
     }
 
 
+    vfunc_get_static_snippet() {
+        const source = get_shader_source();
+        if (!source)
+            throw new Error('Unable to load Coverflow shader');
+        const main = /void\s+main\s*\(\s*\)\s*\{/.exec(source);
+        if (!main)
+            throw new Error('Coverflow shader has no main function');
+        const declarations = source.slice(0, main.index);
+        const body = source.slice(main.index + main[0].length, source.lastIndexOf('}'));
+        const snippet = Cogl.Snippet.new(Cogl.SnippetHook.FRAGMENT, declarations, null);
+        snippet.set_replace(body);
+        return snippet;
+    }
+
     vfunc_paint_target(paint_node = null, paint_context = null) {
         this.set_uniform_value("tex", 0);
 
diff --git a/src/effects/glitch_effect.js b/src/effects/glitch_effect.js
index 6d297a6..c221a70 100644
--- a/src/effects/glitch_effect.js
+++ b/src/effects/glitch_effect.js
@@ -3,6 +3,7 @@
 //'use strict';
 
 import Clutter from 'gi://Clutter';
+import Cogl from 'gi://Cogl';
 import Shell from 'gi://Shell';
 import GObject from 'gi://GObject';
 import GLib from 'gi://GLib';
@@ -34,15 +35,24 @@ export const GlitchEffect = new GObject.registerClass({
     constructor(params) {
         super(params);
         this._timeOffset = Math.random() * 1000000;
-        // set shader source
-        this._source = get_shader_source();
-
-        if (this._source)
-            this.set_shader_source(this._source);
 
         this.set_enabled(true);
     }
 
+    vfunc_get_static_snippet() {
+        const source = get_shader_source();
+        if (!source)
+            throw new Error('Unable to load Coverflow shader');
+        const main = /void\s+main\s*\(\s*\)\s*\{/.exec(source);
+        if (!main)
+            throw new Error('Coverflow shader has no main function');
+        const declarations = source.slice(0, main.index);
+        const body = source.slice(main.index + main[0].length, source.lastIndexOf('}'));
+        const snippet = Cogl.Snippet.new(Cogl.SnippetHook.FRAGMENT, declarations, null);
+        snippet.set_replace(body);
+        return snippet;
+    }
+
     vfunc_paint_target(paint_node = null, paint_context = null) {
         const time = this._timeOffset + GLib.get_monotonic_time() / GLib.USEC_PER_SEC;
         this.set_uniform_value("time", time);
diff --git a/src/effects/radialShader.js b/src/effects/radialShader.js
index 47f01e4..4d6a821 100644
--- a/src/effects/radialShader.js
+++ b/src/effects/radialShader.js
@@ -1,4 +1,4 @@
-import Shell from 'gi://Shell'
+import Clutter from 'gi://Clutter'
 import GObject from 'gi://GObject'
 import Cogl from 'gi://Cogl'
 
@@ -29,22 +29,21 @@ export const MyRadialShaderEffect = GObject.registerClass({
             GObject.ParamFlags.READWRITE,
             0, 1, 0),
     },
-}, class MyRadialShaderEffect extends Shell.GLSLEffect {
+}, class MyRadialShaderEffect extends Clutter.ShaderEffect {
     constructor(params) {
         super(params);
         this._brightness = undefined;
         this._sharpness = undefined;
 
-        this._brightnessLocation = this.get_uniform_location('brightness');
-        this._sharpnessLocation = this.get_uniform_location('vignette_sharpness');
 
         this.brightness = 1.0;
         this.sharpness = 0.0;
     }
 
-    vfunc_build_pipeline() {
-        this.add_glsl_snippet(Cogl.SnippetHook.FRAGMENT,
-            VIGNETTE_DECLARATIONS, VIGNETTE_CODE, true);
+    vfunc_get_static_snippet() {
+        const snippet = Cogl.Snippet.new(Cogl.SnippetHook.FRAGMENT, VIGNETTE_DECLARATIONS, null);
+        snippet.set_replace(VIGNETTE_CODE);
+        return snippet;
     }
 
     get brightness() {
@@ -55,7 +54,7 @@ export const MyRadialShaderEffect = GObject.registerClass({
         if (this._brightness === v)
             return;
         this._brightness = v;
-        this.set_uniform_float(this._brightnessLocation,
+        this.set_uniform_float('brightness',
             1, [this._brightness]);
         this.notify('brightness');
     }
@@ -68,7 +67,7 @@ export const MyRadialShaderEffect = GObject.registerClass({
         if (this._sharpness === v)
             return;
         this._sharpness = v;
-        this.set_uniform_float(this._sharpnessLocation,
+        this.set_uniform_float('vignette_sharpness',
             1, [this._sharpness]);
         this.notify('sharpness');
     }

[camiloeferrera]

Opened #319 with a corrected version of this port after reproducing both API issues on a final GNOME 51.0 system (CachyOS, Wayland):

• new Cogl.Snippet(...) throws Argument to the constructor of Snippet should be a plain JS object with properties to set — and produces a corrupt snippet that can crash the compositor.
• set_uniform_value('brightness', <number>) throws Expected type gfloat for Argument 'value' but got type 'number'.

#319 uses Cogl.Snippet.new(hook, declarations, null) and named set_uniform_float(name, 1, [v]), and also ports the color/glitch effects discussed here (#318's file list only covers the radial shader). Thanks for the original port — it pointed the way.

[dsheeler]

@gonwe, thanks so much for the pr. I am going to close this one and merge #319. Thanks @LavaTiger99 and @camiloeferrera for furthering the effort!