Add setting to try OpenGL ES first

glutin/src/application.rs

@@ -61,11 +61,23 @@ where
             settings.id,
         );
 
-        let context = ContextBuilder::new()
+        let opengl_builder = ContextBuilder::new()
             .with_vsync(true)
-            // .with_gl(glutin::GlRequest::Specific(glutin::Api::OpenGlEs, (2, 0)))
-            .with_multisampling(C::sample_count(&compositor_settings) as u16)
-            .build_windowed(builder, &event_loop)
+            .with_multisampling(C::sample_count(&compositor_settings) as u16);
+
+        let opengles_builder = opengl_builder.clone().with_gl(
+            glutin::GlRequest::Specific(glutin::Api::OpenGlEs, (2, 0)),
+        );
+
+        let (first_builder, second_builder) = if settings.try_opengles_first {
+            (opengles_builder, opengl_builder)
+        } else {
+            (opengl_builder, opengles_builder)
+        };
+
+        let context = first_builder
+            .build_windowed(builder.clone(), &event_loop)
+            .or_else(|_| second_builder.build_windowed(builder, &event_loop))
             .map_err(|error| {
                 use glutin::CreationError;
 

src/settings.rs

@@ -55,6 +55,15 @@ pub struct Settings<Flags> {
     ///
     /// [`Application`]: crate::Application
     pub exit_on_close_request: bool,
+
+    /// Whether the [`Application`] should try to build the context
+    /// using OpenGL ES first then OpenGL.
+    ///
+    /// By default, it is disabled.
+    /// **Note:** Only works for the `glow` backend.
+    ///
+    /// [`Application`]: crate::Application
+    pub try_opengles_first: bool,
 }
 
 impl<Flags> Settings<Flags> {
@@ -73,6 +82,7 @@ impl<Flags> Settings<Flags> {
             text_multithreading: default_settings.text_multithreading,
             antialiasing: default_settings.antialiasing,
             exit_on_close_request: default_settings.exit_on_close_request,
+            try_opengles_first: default_settings.try_opengles_first,
         }
     }
 }
@@ -91,6 +101,7 @@ where
             text_multithreading: false,
             antialiasing: false,
             exit_on_close_request: true,
+            try_opengles_first: false,
         }
     }
 }
@@ -103,6 +114,7 @@ impl<Flags> From<Settings<Flags>> for iced_winit::Settings<Flags> {
             window: settings.window.into(),
             flags: settings.flags,
             exit_on_close_request: settings.exit_on_close_request,
+            try_opengles_first: settings.try_opengles_first,
         }
     }
 }

winit/src/settings.rs

@@ -38,6 +38,12 @@ pub struct Settings<Flags> {
     /// Whether the [`Application`] should exit when the user requests the
     /// window to close (e.g. the user presses the close button).
     pub exit_on_close_request: bool,
+
+    /// Whether the [`Application`] should try to build the context
+    /// using OpenGL ES first then OpenGL.
+    ///
+    /// NOTE: Only works for the `glow` backend.
+    pub try_opengles_first: bool,
 }
 
 /// The window settings of an application.