vendor

egui/crates/egui_glium/examples/native_texture.rs

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+#![cfg_attr(not(debug_assertions), windows_subsystem = "windows")] // hide console window on Windows in release
+
+use glium::glutin;
+
+fn main() {
+    let event_loop = glutin::event_loop::EventLoopBuilder::with_user_event().build();
+    let display = create_display(&event_loop);
+
+    let mut egui_glium = egui_glium::EguiGlium::new(&display, &event_loop);
+
+    let png_data = include_bytes!("../../../examples/retained_image/src/rust-logo-256x256.png");
+    let image = load_glium_image(png_data);
+    let image_size = egui::vec2(image.width as f32, image.height as f32);
+    // Load to gpu memory
+    let glium_texture = glium::texture::SrgbTexture2d::new(&display, image).unwrap();
+    // Allow us to share the texture with egui:
+    let glium_texture = std::rc::Rc::new(glium_texture);
+    // Allocate egui's texture id for GL texture
+    let texture_id = egui_glium
+        .painter
+        .register_native_texture(glium_texture, Default::default());
+    // Setup button image size for reasonable image size for button container.
+    let button_image_size = egui::vec2(32_f32, 32_f32);
+
+    event_loop.run(move |event, _, control_flow| {
+        let mut redraw = || {
+            let mut quit = false;
+
+            let repaint_after = egui_glium.run(&display, |egui_ctx| {
+                egui::SidePanel::left("my_side_panel").show(egui_ctx, |ui| {
+                    if ui
+                        .add(egui::Button::image_and_text(
+                            texture_id,
+                            button_image_size,
+                            "Quit",
+                        ))
+                        .clicked()
+                    {
+                        quit = true;
+                    }
+                });
+                egui::Window::new("NativeTextureDisplay").show(egui_ctx, |ui| {
+                    ui.image(texture_id, image_size);
+                });
+            });
+
+            *control_flow = if quit {
+                glutin::event_loop::ControlFlow::Exit
+            } else if repaint_after.is_zero() {
+                display.gl_window().window().request_redraw();
+                glutin::event_loop::ControlFlow::Poll
+            } else if let Some(repaint_after_instant) =
+                std::time::Instant::now().checked_add(repaint_after)
+            {
+                glutin::event_loop::ControlFlow::WaitUntil(repaint_after_instant)
+            } else {
+                glutin::event_loop::ControlFlow::Wait
+            };
+
+            {
+                use glium::Surface as _;
+                let mut target = display.draw();
+
+                let color = egui::Rgba::from_rgb(0.1, 0.3, 0.2);
+                target.clear_color(color[0], color[1], color[2], color[3]);
+
+                // draw things behind egui here
+
+                egui_glium.paint(&display, &mut target);
+
+                // 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, .. } => {
+                use glutin::event::WindowEvent;
+                if matches!(event, WindowEvent::CloseRequested | WindowEvent::Destroyed) {
+                    *control_flow = glutin::event_loop::ControlFlow::Exit;
+                }
+
+                let event_response = egui_glium.on_event(&event);
+
+                if event_response.repaint {
+                    display.gl_window().window().request_redraw();
+                }
+            }
+            glutin::event::Event::NewEvents(glutin::event::StartCause::ResumeTimeReached {
+                ..
+            }) => {
+                display.gl_window().window().request_redraw();
+            }
+
+            _ => (),
+        }
+    });
+}
+
+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_stencil_buffer(0)
+        .with_vsync(true);
+
+    glium::Display::new(window_builder, context_builder, event_loop).unwrap()
+}
+
+fn load_glium_image(png_data: &[u8]) -> glium::texture::RawImage2d<'_, u8> {
+    // Load image using the image crate:
+    let image = image::load_from_memory(png_data).unwrap().to_rgba8();
+    let image_dimensions = image.dimensions();
+
+    // Premultiply alpha:
+    let pixels: Vec<_> = image
+        .into_vec()
+        .chunks_exact(4)
+        .map(|p| egui::Color32::from_rgba_unmultiplied(p[0], p[1], p[2], p[3]))
+        .flat_map(|color| color.to_array())
+        .collect();
+
+    // Convert to glium image:
+    glium::texture::RawImage2d::from_raw_rgba(pixels, image_dimensions)
+}