nixpkgs/pkgs/development/libraries/mesa/stubs.nix

{ stdenv
, libglvnd
, mesa
, OpenGL
, testers
}:

stdenv.mkDerivation (finalAttrs: {
  pname = "libGL";
  inherit (if stdenv.hostPlatform.isDarwin then mesa else libglvnd) version;
  outputs = [ "out" "dev" ];

  # On macOS, libglvnd is not supported, so we just use what mesa
  # build. We need to also include OpenGL.framework, and some
  # extra tricks to go along with. We add mesa’s libGLX to support
  # the X extensions to OpenGL.
  buildCommand = if stdenv.hostPlatform.isDarwin then ''
    mkdir -p $out/nix-support $dev
    echo ${OpenGL} >> $out/nix-support/propagated-build-inputs
    ln -s ${mesa.out}/lib $out/lib

    mkdir -p $dev/lib/pkgconfig $dev/nix-support
    echo "$out" > $dev/nix-support/propagated-build-inputs
    ln -s ${mesa.dev}/include $dev/include

    cat <<EOF >$dev/lib/pkgconfig/gl.pc
  Name: gl
  Description: gl library
  Version: ${mesa.version}
  Libs: -L${mesa.out}/lib -lGL
  Cflags: -I${mesa.dev}/include
  EOF

    cat <<EOF >$dev/lib/pkgconfig/glesv1_cm.pc
  Name: glesv1_cm
  Description: glesv1_cm library
  Version: ${mesa.version}
  Libs: -L${mesa.out}/lib -lGLESv1_CM
  Cflags: -I${mesa.dev}/include
  EOF

    cat <<EOF >$dev/lib/pkgconfig/glesv2.pc
  Name: glesv2
  Description: glesv2 library
  Version: ${mesa.version}
  Libs: -L${mesa.out}/lib -lGLESv2
  Cflags: -I${mesa.dev}/include
  EOF
  ''

  # Otherwise, setup gl stubs to use libglvnd.
  else ''
    mkdir -p $out/nix-support
    ln -s ${libglvnd.out}/lib $out/lib

    mkdir -p $dev/{,lib/pkgconfig,nix-support}
    echo "$out ${libglvnd} ${libglvnd.dev}" > $dev/nix-support/propagated-build-inputs
    ln -s ${libglvnd.dev}/include $dev/include

    genPkgConfig() {
      local name="$1"
      local lib="$2"

      cat <<EOF >$dev/lib/pkgconfig/$name.pc
    Name: $name
    Description: $lib library
    Version: ${libglvnd.version}
    Libs: -L${libglvnd.out}/lib -l$lib
    Cflags: -I${libglvnd.dev}/include
    EOF
    }

    genPkgConfig gl GL
    genPkgConfig egl EGL
    genPkgConfig glesv1_cm GLESv1_CM
    genPkgConfig glesv2 GLESv2
  '';

  passthru.tests.pkg-config = testers.testMetaPkgConfig finalAttrs.finalPackage;

  meta = {
    description = "Stub bindings using " + (if stdenv.hostPlatform.isDarwin then "mesa" else "libglvnd");
    pkgConfigModules = [ "gl" "egl" "glesv1_cm" "glesv2" ];
  } // {
    inherit (if stdenv.hostPlatform.isDarwin then mesa.meta else libglvnd.meta) homepage license platforms;
  };
})