From 38f11442c9fafd3b3540f0fb2bdc1ca9f465a0d6 Mon Sep 17 00:00:00 2001
From: dbr <dbr.onix@gmail.com>
Date: Wed, 4 Jan 2023 19:00:56 +1030
Subject: [PATCH] Self-contained example for glutin [#691]

---
 imgui-glium-renderer/Cargo.toml               |  3 +
 .../examples/glium_01_basic.rs                | 98 +++++++++++++++++++
 2 files changed, 101 insertions(+)
 create mode 100644 imgui-glium-renderer/examples/glium_01_basic.rs

diff --git a/imgui-glium-renderer/Cargo.toml b/imgui-glium-renderer/Cargo.toml
index 6338966..65d9cac 100644
--- a/imgui-glium-renderer/Cargo.toml
+++ b/imgui-glium-renderer/Cargo.toml
@@ -12,3 +12,6 @@ categories = ["gui", "rendering"]
 [dependencies]
 glium = { version = "0.32.1", default-features = false }
 imgui = { version = "0.9.0", path = "../imgui" }
+
+[dev-dependencies]
+imgui-winit-support = {path = "../imgui-winit-support"}
diff --git a/imgui-glium-renderer/examples/glium_01_basic.rs b/imgui-glium-renderer/examples/glium_01_basic.rs
new file mode 100644
index 0000000..2e06b65
--- /dev/null
+++ b/imgui-glium-renderer/examples/glium_01_basic.rs
@@ -0,0 +1,98 @@
+use glium::glutin::event::{Event, WindowEvent};
+use glium::glutin::event_loop::{ControlFlow, EventLoop};
+use glium::Surface;
+
+const TITLE: &str = "Hello, imgui-rs!";
+
+fn main() {
+    // Common setup for creating a winit window and imgui context, not specifc
+    // to this renderer at all except that glutin is used to create the window
+    // since it will give us access to a GL context
+    let (event_loop, display) = create_window();
+    let (mut winit_platform, mut imgui_context) = imgui_init(&display);
+
+    // Create renderer from this crate
+    let mut renderer = imgui_glium_renderer::Renderer::init(&mut imgui_context, &display).expect("Failed to initialize renderer");
+
+    // Timer for FPS calculation
+    let mut last_frame = std::time::Instant::now();
+
+    // Standard winit event loop
+    event_loop.run(move |event, _, control_flow| match event {
+            Event::NewEvents(_) => {
+                let now = std::time::Instant::now();
+                imgui_context.io_mut().update_delta_time(now - last_frame);
+                last_frame = now;
+            }
+            Event::MainEventsCleared => {
+                let gl_window = display.gl_window();
+                winit_platform
+                    .prepare_frame(imgui_context.io_mut(), gl_window.window())
+                    .expect("Failed to prepare frame");
+                gl_window.window().request_redraw();
+            }
+            Event::RedrawRequested(_) => {
+                // Create frame for the all important `&imgui::Ui`
+                let ui = imgui_context.frame();
+
+                // Draw our example content
+                ui.show_demo_window(&mut true);
+
+                // Setup for drawing
+                let gl_window = display.gl_window();
+                let mut target = display.draw();
+
+                // Renderer doesn't automatically clear window
+                target.clear_color_srgb(1.0, 1.0, 1.0, 1.0);
+
+                // Perform rendering
+                winit_platform.prepare_render(ui, gl_window.window());
+                let draw_data = imgui_context.render();
+                renderer
+                    .render(&mut target, draw_data)
+                    .expect("Rendering failed");
+                target.finish().expect("Failed to swap buffers");
+            }
+            Event::WindowEvent {
+                event: WindowEvent::CloseRequested,
+                ..
+            } => *control_flow = ControlFlow::Exit,
+            event => {
+                let gl_window = display.gl_window();
+                winit_platform.handle_event(imgui_context.io_mut(), gl_window.window(), &event);
+            }
+    });
+}
+
+fn create_window() -> (EventLoop<()>, glium::Display) {
+    let event_loop = EventLoop::new();
+    let context = glium::glutin::ContextBuilder::new().with_vsync(true);
+    let builder = glium::glutin::window::WindowBuilder::new()
+        .with_title(TITLE.to_owned())
+        .with_inner_size(glium::glutin::dpi::LogicalSize::new(1024f64, 768f64));
+    let display =
+        glium::Display::new(builder, context, &event_loop).expect("Failed to initialize display");
+
+    (event_loop, display)
+}
+
+
+fn imgui_init(display: &glium::Display) -> (imgui_winit_support::WinitPlatform, imgui::Context) {
+    let mut imgui_context = imgui::Context::create();
+    imgui_context.set_ini_filename(None);
+
+    let mut winit_platform = imgui_winit_support::WinitPlatform::init(&mut imgui_context);
+
+    let gl_window = display.gl_window();
+    let window = gl_window.window();
+
+    let dpi_mode = imgui_winit_support::HiDpiMode::Default;
+
+    winit_platform.attach_window(imgui_context.io_mut(), window, dpi_mode);
+
+    imgui_context
+        .fonts()
+        .add_font(&[imgui::FontSource::DefaultFontData { config: None }]);
+
+    (winit_platform, imgui_context)
+}