Refactor egui_glium with new EguiGlium wrapper and standalone example

egui_glium/examples/pure.rs

@@ -0,0 +1,89 @@
+//! Example how to use pure `egui_glium` without [`epi`].
+use glium::glutin;
+
+fn create_display(event_loop: &glutin::event_loop::EventLoop<()>) -> glium::Display {
+    let window_builder = glutin::window::WindowBuilder::new()
+        .with_resizable(true)
+        .with_inner_size(glutin::dpi::LogicalSize {
+            width: 800.0,
+            height: 600.0,
+        })
+        .with_title("egui_glium example");
+
+    let context_builder = glutin::ContextBuilder::new()
+        .with_depth_buffer(0)
+        .with_srgb(true)
+        .with_stencil_buffer(0)
+        .with_vsync(true);
+
+    glium::Display::new(window_builder, context_builder, &event_loop).unwrap()
+}
+
+fn main() {
+    let event_loop = glutin::event_loop::EventLoop::with_user_event();
+    let display = create_display(&&event_loop);
+
+    let mut egui = egui_glium::EguiGlium::new(&display);
+
+    event_loop.run(move |event, _, control_flow| {
+        let mut redraw = || {
+            egui.begin_frame(&display);
+
+            let mut quit = false;
+
+            egui::SidePanel::left("my_side_panel", 300.0).show(egui.ctx(), |ui| {
+                ui.heading("Hello World!");
+                if ui.button("Quit").clicked() {
+                    quit = true;
+                }
+            });
+
+            let (needs_repaint, shapes) = egui.end_frame(&display);
+
+            *control_flow = if quit {
+                glutin::event_loop::ControlFlow::Exit
+            } else if needs_repaint {
+                display.gl_window().window().request_redraw();
+                glutin::event_loop::ControlFlow::Poll
+            } else {
+                glutin::event_loop::ControlFlow::Wait
+            };
+
+            {
+                use glium::Surface as _;
+                let mut target = display.draw();
+
+                let clear_color = egui::Rgba::from_rgb(0.1, 0.3, 0.2);
+                target.clear_color(
+                    clear_color[0],
+                    clear_color[1],
+                    clear_color[2],
+                    clear_color[3],
+                );
+
+                // draw things behind egui here
+
+                egui.paint(&display, &mut target, shapes);
+
+                // draw things on top of egui here
+
+                target.finish().unwrap();
+            }
+        };
+
+        match event {
+            // Platform-dependent event handlers to workaround a winit bug
+            // See: https://github.com/rust-windowing/winit/issues/987
+            // See: https://github.com/rust-windowing/winit/issues/1619
+            glutin::event::Event::RedrawEventsCleared if cfg!(windows) => redraw(),
+            glutin::event::Event::RedrawRequested(_) if !cfg!(windows) => redraw(),
+
+            glutin::event::Event::WindowEvent { event, .. } => {
+                egui.on_event(event, control_flow);
+                display.gl_window().window().request_redraw(); // TODO: ask egui if the events warrants a repaint instead
+            }
+
+            _ => (),
+        }
+    });
+}