3 files changed, 17 insertions, 3 deletions
diff --git a/autoload/polyglot/detect.vim b/autoload/polyglot/detect.vim
index cac826cf..2b1900e6 100644
--- a/autoload/polyglot/detect.vim
+++ b/autoload/polyglot/detect.vim
@@ -134,6 +134,18 @@ func! polyglot#detect#Fs(...)
   set ft=forth | return
 endfunc
 
+func! polyglot#detect#Frag(...)
+  if a:0 != 1 && did_filetype()
+    return
+  endif
+  for lnum in range(1, min([line("$"), 50]))
+    let line = getline(lnum)
+    if line =~# '\s*\(#version\|precision\|uniform\|varying\|vec[234]\)'
+      set ft=glsl | return
+    endif
+  endfor
+endfunc
+
 func! polyglot#detect#Re(...)
   if a:0 != 1 && did_filetype()
     return
diff --git a/autoload/polyglot/ft.vim b/autoload/polyglot/ft.vim
index 56012da1..2ba69ed1 100644
--- a/autoload/polyglot/ft.vim
+++ b/autoload/polyglot/ft.vim
@@ -1,7 +1,7 @@
 " Vim functions for file type detection
 "
 " Maintainer:	Bram Moolenaar <Bram@vim.org>
-" Last Change:	2021 Nov 27
+" Last Change:	2021 Dec 17
 
 " These functions are moved here from runtime/filetype.vim to make startup
 " faster.
diff --git a/autoload/polyglot/init.vim b/autoload/polyglot/init.vim
index 1457f11a..353da7e4 100644
--- a/autoload/polyglot/init.vim
+++ b/autoload/polyglot/init.vim
@@ -2319,7 +2319,8 @@ if !has_key(g:polyglot_is_disabled, 'jsx')
 endif
 
 if !has_key(g:polyglot_is_disabled, 'javascript')
-  au BufNewFile,BufRead *._js,*.bones,*.cjs,*.es,*.es6,*.frag,*.gs,*.jake,*.javascript,*.js,*.jsb,*.jscad,*.jsfl,*.jsm,*.jss,*.jsx,*.mjs,*.njs,*.pac,*.sjs,*.ssjs,*.xsjs,*.xsjslib,Jakefile setf javascript
+  au! BufNewFile,BufRead,BufWritePost *.frag call polyglot#detect#Frag()
+  au BufNewFile,BufRead *._js,*.bones,*.cjs,*.es,*.es6,*.gs,*.jake,*.javascript,*.js,*.jsb,*.jscad,*.jsfl,*.jsm,*.jss,*.jsx,*.mjs,*.njs,*.pac,*.sjs,*.ssjs,*.xsjs,*.xsjslib,Jakefile setf javascript
   au BufNewFile,BufRead *.flow setf flow
 endif
 
@@ -2339,7 +2340,8 @@ endif
 
 if !has_key(g:polyglot_is_disabled, 'glsl')
   au! BufNewFile,BufRead,BufWritePost *.fs call polyglot#detect#Fs()
-  au BufNewFile,BufRead *.comp,*.fp,*.frag,*.frg,*.fsh,*.fshader,*.geo,*.geom,*.glsl,*.glslf,*.glslv,*.gs,*.gshader,*.rchit,*.rmiss,*.shader,*.tesc,*.tese,*.vert,*.vrx,*.vsh,*.vshader setf glsl
+  au! BufNewFile,BufRead,BufWritePost *.frag call polyglot#detect#Frag()
+  au BufNewFile,BufRead *.comp,*.fp,*.frg,*.fsh,*.fshader,*.geo,*.geom,*.glsl,*.glslf,*.glslv,*.gs,*.gshader,*.rchit,*.rmiss,*.shader,*.tesc,*.tese,*.vert,*.vrx,*.vsh,*.vshader setf glsl
 endif
 
 if !has_key(g:polyglot_is_disabled, 'git')