examples: add gjs example

Reviewed-by: Neil Roberts <neil@linux.intel.com>

examples/Makefile.am

@@ -126,6 +126,7 @@ noinst_PROGRAMS = $(programs)
 endif
 
 EXTRA_DIST = \
+	cogl-gjs.js \
 	crate.jpg \
 	emscripten-example-js.h \
 	emscripten-example-js-library.js \

examples/cogl-gjs.js

@@ -0,0 +1,46 @@
+const Cogl = imports.gi.Cogl;
+const GLib = imports.gi.GLib;
+const Lang = imports.lang;
+
+let renderer = new Cogl.Renderer();
+let display = new Cogl.Display(renderer, new Cogl.OnscreenTemplate(new Cogl.SwapChain()));
+let ctx = new Cogl.Context(display);
+
+// Should be able to replace the 3 previous lines with :
+// let ctx = new Cogl.Context(null);
+// But crashing for some reason.
+
+// GLib mainloop integration
+let gsource = Cogl.glib_renderer_source_new(renderer, 0);
+let loop = GLib.MainLoop.new(null, false);
+gsource.attach(loop.get_context());
+
+// Onscreen creation
+let onscreen = new Cogl.Onscreen(ctx, 800, 600);
+onscreen.show();
+
+// Drawing pipeline
+let crate = Cogl.Texture2D.new_from_file(ctx, 'crate.jpg');
+let pipeline = new Cogl.Pipeline(ctx);
+pipeline.set_layer_texture(0, crate);
+let clearColor = new Cogl.Color();
+clearColor.init_from_4f(0, 0, 0, 1.0);
+
+// Redraw callback
+let closure = onscreen.add_dirty_callback(Lang.bind(this, function() {
+    onscreen.clear(Cogl.BufferBit.COLOR, clearColor);
+    onscreen.draw_rectangle(pipeline, -1, -1, 1, 1);
+    onscreen.swap_buffers();
+    return true;
+}), null);
+
+// Quit after 5s
+let tm = GLib.timeout_source_new(5000);
+tm.set_callback(Lang.bind(this, function() {
+    loop.quit();
+    return false;
+}), null);
+tm.attach(loop.get_context());
+
+// Run!
+loop.run();