[gnome-shell/gnome-41] lightbox: GLSL requires real numbers, not integers

[Marge Bot <marge-bot src gnome org>]

commit 06ad30f54cc46a59e98d1d860f9bcc8c6f1e2b5d
Author: Daniel van Vugt <daniel van vugt canonical com>
Date:   Tue Jan 25 17:06:49 2022 +0800

    lightbox: GLSL requires real numbers, not integers
    
    At least backward-compatible GLSL requires real numbers only. It's a
    fatal shader compilation error to use integers in GLES and older GL
    versions like that of i915.
    
    Fixes: https://gitlab.gnome.org/GNOME/mutter/-/issues/2115
    (cherry picked from commit e38a41624679cee2331f460de36c3d8314a362c0)
    
    Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/2180>

 js/ui/lightbox.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/js/ui/lightbox.js b/js/ui/lightbox.js
index cf68ea828c..08bf5641d2 100644
--- a/js/ui/lightbox.js
+++ b/js/ui/lightbox.js
@@ -20,7 +20,7 @@ vec2 position = cogl_tex_coord_in[0].xy - 0.5;\n\
 float t = length(2.0 * position);\n\
 t = clamp(t, 0.0, 1.0);\n\
 float pixel_brightness = mix(1.0, 1.0 - vignette_sharpness, t);\n\
-cogl_color_out.a = cogl_color_out.a * (1 - pixel_brightness * brightness);';
+cogl_color_out.a = cogl_color_out.a * (1.0 - pixel_brightness * brightness);';
 
 var RadialShaderEffect = GObject.registerClass({
     Properties: {