diff --git a/kitty/fonts/render.py b/kitty/fonts/render.py
index f5b2c9fe2..217187c32 100644
--- a/kitty/fonts/render.py
+++ b/kitty/fonts/render.py
@@ -400,10 +400,13 @@ def prerender_function(
         render_cursor, cursor_beam_thickness=cursor_beam_thickness,
         cursor_underline_thickness=cursor_underline_thickness, cell_width=cell_width,
         cell_height=cell_height, dpi_x=dpi_x, dpi_y=dpi_y)
-    cells = list(map(f, range(1, NUM_UNDERLINE_STYLES + 1)))
-    cells.append(f(0, strikethrough=True))
-    cells.append(f(missing=True))
-    cells.extend((c(1), c(2), c(3)))
+    # If you change the mapping of these cells you will need to change
+    # NUM_UNDERLINE_STYLES and BEAM_IDX in shader.c and STRIKE_SPRITE_INDEX in
+    # window.py and MISSING_GLYPH in font.c
+    cells = list(map(f, range(1, NUM_UNDERLINE_STYLES + 1)))  # underline sprites
+    cells.append(f(0, strikethrough=True))  # strikethrough sprite
+    cells.append(f(missing=True))  # missing glyph
+    cells.extend((c(1), c(2), c(3)))  # cursor glyphs
     tcells = tuple(cells)
     return tuple(map(ctypes.addressof, tcells)), tcells
 
diff --git a/kitty/shaders.c b/kitty/shaders.c
index d99166ff0..a4ae4e905 100644
--- a/kitty/shaders.c
+++ b/kitty/shaders.c
@@ -314,7 +314,7 @@ cell_update_uniform_block(ssize_t vao_idx, Screen *screen, int uniform_buffer, c
     }
     rd->use_cell_for_selection_bg = IS_SPECIAL_COLOR(highlight_bg) ? 1. : 0.;
     // Cursor position
-    enum { BLOCK_IDX = 0, BEAM_IDX = 8, UNDERLINE_IDX = 9, UNFOCUSED_IDX = 10 };
+    enum { BLOCK_IDX = 0, BEAM_IDX = NUM_UNDERLINE_STYLES + 3, UNDERLINE_IDX = NUM_UNDERLINE_STYLES + 4, UNFOCUSED_IDX = NUM_UNDERLINE_STYLES + 5 };
     if (cursor->is_visible) {
         rd->cursor_x = screen->cursor->x, rd->cursor_y = screen->cursor->y;
         if (cursor->is_focused) {