diff --git a/kitty/shaders.c b/kitty/shaders.c
index e555b43fd..eaf0c6a24 100644
--- a/kitty/shaders.c
+++ b/kitty/shaders.c
@@ -628,7 +628,7 @@ draw_cells_impl(ssize_t vao_idx, GLfloat xstart, GLfloat ystart, GLfloat dx, GLf
 #define UL(name) cell_uniform_locations[CELL_##name]
     bind_program(CELL_PROGRAM); 
     bind_vao_uniform_buffer(vao_idx, 2, cell_color_table_block_index);
-    static GLuint dimensions[8];
+    static GLuint dimensions[9];
     dimensions[0] = screen->columns; dimensions[1] = screen->lines; dimensions[2] = cx; dimensions[3] = cy; dimensions[4] = cx + MAX(1, screen_current_char_width(screen)) - 1;
     screen_url_range(screen, dimensions + 5);
     glUniform1uiv(UL(dimensions), sizeof(dimensions) / sizeof(dimensions[0]), dimensions);