diff --git a/pkgs/opengl/default.nix b/pkgs/opengl/default.nix
index 2b64d73..d79ad43 100644
--- a/pkgs/opengl/default.nix
+++ b/pkgs/opengl/default.nix
@@ -3,7 +3,7 @@
 # Add a setup hook to the mesa_noglu package that automatically adds
 # a libvglfaker.so dependency to executables that depend on libGL.so.
 
-{ super, lib, buildEnv, makeSetupHook, file, bash }:
+{ super, lib, buildEnv, makeSetupHook, file, bash, xorg }:
 
 let
   autoVirtualGLHook =
@@ -27,7 +27,7 @@ let
       makeSetupHook {
         name = "insert-virtualgl";
         deps = [ file virtualglLib ];
-        substitutions = { inherit virtualglLib; };
+        substitutions = { inherit virtualglLib bash; inherit (xorg) libXext; };
       } ./insert-virtualgl.sh;
 
 in {
diff --git a/pkgs/opengl/insert-virtualgl.sh b/pkgs/opengl/insert-virtualgl.sh
index c73b742..3b781e1 100755
--- a/pkgs/opengl/insert-virtualgl.sh
+++ b/pkgs/opengl/insert-virtualgl.sh
@@ -1,3 +1,10 @@
+# Quote the given arguement
+#
+VGL_quote() {
+  printf '%s' "${*@Q}"
+}
+
+
 # Stream producers
 #
 # These produce a stream of escaped new-line separated items
@@ -12,16 +19,22 @@ VGL_sourceS() {
 # Stream the results of find (correctly escapes all filenames)
 #
 VGL_findS() {
-  declare -a options=("$@") file
+  declare options=("$@") file
   find "${options[@]}" -print0 |
     while read -d '' -r file; do
       VGL_sourceS "$file"
     done
 }
 
-# Stream the closure of the list libraries from an elf file
+# Stream the list of directly required libraries from an elf file
 #
 VGL_elfLibsS() {
+  patchelf --print-needed "$1"
+}
+
+# Stream the resolved libraries from an elf file
+#
+VGL_elfLibsResolvedS() {
   declare file=$1 line
   ldd "$file" |
     while read line; do
@@ -42,6 +55,16 @@ VGL_elfLibsS() {
     done
 }
 
+# Stream the list of rpaths from an elf file
+#
+VGL_elfRPathS() {
+  declare file=$1 entry
+  patchelf --print-rpath "$file" |
+    while read -d ':' -r entry; do
+      VGL_sourceS "$entry"
+    done
+}
+
 
 
 # Stream transformers
@@ -49,30 +72,41 @@ VGL_elfLibsS() {
 # Take in a set of options and transform a stream of new-line separated items
 #
 
-# Group all items onto a single line separated by given deliminator (or space)
-#
-VGL_joinS() {
-  declare deliminator=${1- } next
-  if read next; then
-    printf '%q' "$next"
-    while read next; do
-      printf '%s%q' "$deliminator" "$next"
-    done
-    printf '\n'
-  fi
-}
-
 # Remove all items for which the given command returns false
 #
-VGL_filterS() {
-  declare command=("$@")
+VGL_testKeepS() {
+  declare command=$1 next
   while read next; do
-    if eval $(printf '%q ' "${command[@]}" "$next"); then
+    set -- "$next"
+    if (eval "$command"); then
       VGL_sourceS "$next"
     fi
   done
 }
 
+# Remove all items which match one of the given values
+#
+VGL_valuesRemoveS() {
+  declare -A values
+  declare value
+  for value in "$@"; do
+    values[$value]=
+  done
+  while read value; do
+    [[ ${values[$value]+yes} ]] \
+      || VGL_sourceS "$value"
+  done
+}
+
+# Add addition to end unless test succeeds on at least one
+#
+VGL_testSuffixNoneS() {
+  declare command=$1 addition=$2
+  eval "declare items=($(cat))"
+  VGL_sourceS "${items[@]}"
+  VGL_sourceS "${items[@]}" | VGL_isTestAnyS "$command" \
+    || VGL_sourceS "$addition"
+}
 
 
 # Stream consumers
@@ -82,10 +116,11 @@ VGL_filterS() {
 
 # Return true iff given command returns true for some item
 #
-VGL_anyS() {
-  declare command=("$@")
+VGL_isTestAnyS() {
+  declare command="$1" next
   while read next; do
-    if eval $(printf '%q ' "${command[@]}" "$next"); then
+    set -- "$next"
+    if (eval "$command"); then
       return 0
     fi
   done
@@ -93,6 +128,19 @@ VGL_anyS() {
 }
 
 
+# Return true iff given command returns true for all item
+#
+VGL_isTestAllS() {
+  declare command="$1" next
+  while read next; do
+    set -- "$next"
+    if ! (eval "$command"); then
+      return 1
+    fi
+  done
+  return 0
+}
+
 
 # Tests for the filter transformer
 #
@@ -123,33 +171,97 @@ VGL_isLibGL() {
 
 
 
+# Update elf files
+#
+
+# Run given stream element on rpath stream and write result to file if differs from original
+#
+VGL_elfFilterRPathS() {
+  declare file=$1 command=$2
+  eval "declare pathsOld=($(VGL_elfRPathS "$file"))"
+  eval "declare pathsNew=($(VGL_sourceS "${pathsOld[@]}" | eval "$command"))"
+  [[ ${pathsNew[@]@Q} = ${pathsOld[@]@Q} ]] \
+    || if (( ${#pathsNew[@]} > 0 ));
+       then ( IFS=:; set -x; patchelf --set-rpath "${pathsNew[*]}" "$file" )
+       else ( set -x; patchelf --remove-rpath "$file" )
+       fi
+}
+
+# Run given stream element on directly required libraries stream and write result to file if differs from original
+#
+VGL_elfFilterLibsS() {
+  declare file=$1 command=$2
+  eval "declare libsOld=($(VGL_elfLibsS "$file"))"
+  eval "declare libsNew=($(VGL_sourceS "${libsOld[@]}" | eval "$command"))"
+  eval "declare libs=($(VGL_sourceS "${libsOld[@]}" | VGL_valuesRemoveS "${libsNew[@]}"))"
+  (( ${#libs[@]} < 1 )) \
+    || ( eval "set -x; patchelf$(printf ' --remove-needed %q' "${libs[@]}") ${file@Q}")
+  eval "declare libs=($(VGL_sourceS "${libsNew[@]}" | VGL_valuesRemoveS "${libsOld[@]}"))"
+  (( ${#libs[@]} < 1 )) \
+    || ( eval "set -x; patchelf$(printf ' --add-needed %q' "${libs[@]}") ${file@Q}")
+}
+
+# Patch elf file to be able to use OpenGL properly (not a stream function so can be called in normal way)
+#
+VGL_patch() {
+  declare files=("$@") file
+  for file in "${files[@]}"; do
+    # glibc 2.3 ld.so supports a --preload option that would make this just a simple wrapper
+    #
+    # mv "$file" "${file%/*}/.${file##*/}.vgl"
+    # cat > "$file" <<EOF
+    #! @bash@/bin/bash
+    # exec -a "\$0" "$(patchelf --print-interpreter "${file%/*}/.${file##*/}.vgl")" \${VGL_DISPLAY:+--preload "@virtualglLib@/lib/libvglfaker.so"} "${file%/*}/.${file##*/}.vgl" "\$@"
+    # EOF
+    # chmod +x "$file"
+
+    # VGL version may need fixing up to ensure libglfaker.so gets loaded at the start
+
+    printf 'Wrapping and patching for VirtualGL: %q\n' "$file" >&2
+    cp -a "$file" "${file%/*}/.${file##*/}.vgl-yes"
+    VGL_elfFilterLibsS "${file%/*}/.${file##*/}.vgl-yes" 'VGL_testSuffixNoneS '"$(VGL_quote '[[ $1 =~ ^(.*/)?libvglfaker.so ]]')"' @virtualglLib@/lib/libvglfaker.so'
+    # patchelf --add-needed @virtualglLib@/lib/libvglfaker.so "${file%/*}/.${file##*/}.vgl-yes"
+
+    # Non-VGL versions may need fixing to load libXext so NVIDIA binary libs are happy
+    #
+    # Ugly, but putting this here instead of with the NVIDIA libs, allows us not to to fix one version for all
+
+    mv "$file" "${file%/*}/.${file##*/}.vgl-no"
+    VGL_elfFilterLibsS "${file%/*}/.${file##*/}.vgl-no" 'VGL_testSuffixNoneS '"$(VGL_quote '[[ $1 =~ ^(.*/)?libXext.so ]]')"' libXext.so.6'
+    VGL_elfFilterRPathS "${file%/*}/.${file##*/}.vgl-no" 'VGL_testSuffixNoneS '"$(VGL_quote '[[ $1 = @libXext@/lib ]]')"' @libXext@/lib'
+
+    # Replace with chooser script based on whether VGL_DISPLAY is set or not
+    cat > "$file" <<EOF
+#! @bash@/bin/bash
+
+if [ -z "\$VGL_DISPLAY" ]; then
+  exec -a "\$0" "${file%/*}/.${file##*/}.vgl-no" "\$@"
+else
+  exec -a "\$0" "${file%/*}/.${file##*/}.vgl-yes" "\$@"
+fi
+EOF
+    chmod +x "$file"
+  done
+}
+
+
 # Setup hook
 #
 
-# Find all executables that depend on libGL and add a libvglfaker.so dependency
+# Find all executables that depend on libGL and replace with a wrapper script that either executes the original
+# executable or a copy with an added libvglfaker.so dependency depending on whether VGL_DISPLAY is set or not.
 #
 VGL_autoAddVGL() {
   declare opts=$(shopt -p) output
   set +o pipefail
 
   echo "Inserting VirtualGL into OpenGL executables in $prefix..." >&2
-
+  set -x
   for output in $outputs; do
-    VGL_findS "${!output}" -type f | VGL_filterS VGL_isElfBin | {
-      declare file
-      while read file; do
-        VGL_elfLibsS "$file" |
-          if VGL_anyS VGL_isLibGL; then
-            VGL_sourceS "$file"
-          fi
-      done
-    } | {
-      declare file
-      while read file; do
-        printf 'patchelf --add-needed @virtualglLib@/lib/libvglfaker.so %q\n' "$file" >&2
-        patchelf --add-needed @virtualglLib@/lib/libvglfaker.so "$file"
-      done
-    }
+    VGL_findS "${!output}" -type f \
+    | VGL_testKeepS 'VGL_isElfBin "$1"' \
+    | VGL_testKeepS 'VGL_elfLibsResolvedS "$1" | VGL_isTestAnyS '"$(VGL_quote 'VGL_isLibGL "$1"')" \
+    | VGL_isTestAllS 'VGL_patch "$1"'
   done
 
   eval "$opts"