From 142b6fcc003bc9712fe4d0a546e926c5fd86f1e4 Mon Sep 17 00:00:00 2001
From: Kovid Goyal <kovid@kovidgoyal.net>
Date: Wed, 1 Dec 2021 22:51:12 +0530
Subject: [PATCH] Use symbolic names

---
 kitty/bgimage_vertex.glsl | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

diff --git a/kitty/bgimage_vertex.glsl b/kitty/bgimage_vertex.glsl
index 707000af2..7c7f07426 100644
--- a/kitty/bgimage_vertex.glsl
+++ b/kitty/bgimage_vertex.glsl
@@ -7,6 +7,10 @@
 #define tex_top 0
 #define tex_right 1
 #define tex_bottom 1
+#define x_axis 0
+#define y_axis 1
+#define window i
+#define image i + 2
 
 uniform float adjust_scale;
 uniform vec2 transform;  // [ pos_left_relative, pos_top_relative ]
@@ -29,15 +33,18 @@ const vec2 tex_map[] = vec2[4](
 
 
 float scaling_factor(int i) {
-    return adjust_scale * (sizes[i] / sizes[i + 2]) + (1 - adjust_scale);
+    return adjust_scale * (sizes[window] / sizes[image]) + (1 - adjust_scale);
 }
 
 float position_divisor(int i) {
-    return (sizes[i] - sizes[i + 2]) * transform[i] / sizes[i + 2];
+    return (sizes[window] - sizes[image]) * transform[i] / sizes[image];
 }
 
 void main() {
     vec2 tex_coords = tex_map[gl_VertexID];
-    texcoord = vec2(tex_coords[0] * scaling_factor(0) - position_divisor(0), tex_coords[1] * scaling_factor(1) - position_divisor(1));
+    texcoord = vec2(
+        tex_coords[x_axis] * scaling_factor(x_axis) - position_divisor(x_axis),
+        tex_coords[y_axis] * scaling_factor(y_axis) - position_divisor(y_axis)
+    );
     gl_Position = vec4(pos_map[gl_VertexID], 0, 1);
 }