From f8dac2c13619952bd6679db19fd5b49be1e744fb Mon Sep 17 00:00:00 2001
From: Kovid Goyal <kovid@kovidgoyal.net>
Date: Tue, 26 Aug 2025 12:09:30 +0530
Subject: [PATCH] Write foreground output only at end of shader

---
 kitty/cell_fragment.glsl |  4 ++--
 kitty/cell_vertex.glsl   | 12 ++++++++----
 2 files changed, 10 insertions(+), 6 deletions(-)

diff --git a/kitty/cell_fragment.glsl b/kitty/cell_fragment.glsl
index 88ba50b3d..877da11d0 100644
--- a/kitty/cell_fragment.glsl
+++ b/kitty/cell_fragment.glsl
@@ -16,7 +16,7 @@ in vec3 underline_pos;
 in vec3 cursor_pos;
 in vec3 strike_pos;
 flat in uint underline_exclusion_pos;
-in vec3 foreground;
+in vec3 cell_foreground;
 in vec4 cursor_color_premult;
 in vec3 decoration_fg;
 in float colored_sprite;
@@ -62,7 +62,7 @@ vec4 load_text_foreground_color() {
     // For colored sprites use the color from the sprite rather than the text foreground
     // Return non-premultiplied foreground color
     vec4 text_fg = texture(sprites, sprite_pos);
-    return vec4(mix(foreground, text_fg.rgb, colored_sprite), text_fg.a);
+    return vec4(mix(cell_foreground, text_fg.rgb, colored_sprite), text_fg.a);
 }
 
 vec4 calculate_premul_foreground_from_sprites(vec4 text_fg) {
diff --git a/kitty/cell_vertex.glsl b/kitty/cell_vertex.glsl
index f35a5d3a8..043bca9a7 100644
--- a/kitty/cell_vertex.glsl
+++ b/kitty/cell_vertex.glsl
@@ -47,16 +47,16 @@ const uint cursor_shape_map[] = uint[5](  // maps cursor shape to foreground spr
 out vec3 background;
 out vec4 effective_background_premul;
 #ifndef ONLY_BACKGROUND
+out float effective_text_alpha;
 out vec3 sprite_pos;
 out vec3 underline_pos;
 out vec3 cursor_pos;
-out vec4 cursor_color_premult;
 out vec3 strike_pos;
 flat out uint underline_exclusion_pos;
-out vec3 foreground;
+out vec3 cell_foreground;
+out vec4 cursor_color_premult;
 out vec3 decoration_fg;
 out float colored_sprite;
-out float effective_text_alpha;
 #endif
 
 
@@ -261,7 +261,7 @@ void main() {
     // Foreground {{{
 #ifndef ONLY_BACKGROUND // background does not depend on foreground
     fg_as_uint = has_mark * color_table[NUM_COLORS + MARK_MASK + mark] + (ONE - has_mark) * fg_as_uint;
-    foreground = color_to_vec(fg_as_uint);
+    vec3 foreground = color_to_vec(fg_as_uint);
     float has_dim = float((text_attrs >> DIM_SHIFT) & ONE), has_blink = float((text_attrs >> BLINK_SHIFT) & ONE);
     effective_text_alpha = inactive_text_alpha * if_one_then(has_dim, dim_opacity, 1.0) * if_one_then(
             has_blink, blink_opacity, 1.0);
@@ -320,4 +320,8 @@ void main() {
     bgpremul *= draw_bg;
     effective_background_premul = bgpremul;
 #endif
+
+#ifndef ONLY_BACKGROUND
+    cell_foreground = foreground;
+#endif
 }