egui_glow/
winit.rs

1pub use egui_winit::{self, EventResponse};
2
3use egui::{ViewportId, ViewportOutput};
4use egui_winit::winit;
5
6use crate::shader_version::ShaderVersion;
7
8/// Use [`egui`] from a [`glow`] app based on [`winit`].
9pub struct EguiGlow {
10    pub egui_ctx: egui::Context,
11    pub egui_winit: egui_winit::State,
12    pub painter: crate::Painter,
13
14    viewport_info: egui::ViewportInfo,
15
16    // output from the last update:
17    shapes: Vec<egui::epaint::ClippedShape>,
18    pixels_per_point: f32,
19    textures_delta: egui::TexturesDelta,
20}
21
22impl EguiGlow {
23    /// For automatic shader version detection set `shader_version` to `None`.
24    pub fn new(
25        event_loop: &winit::event_loop::ActiveEventLoop,
26        gl: std::sync::Arc<glow::Context>,
27        shader_version: Option<ShaderVersion>,
28        native_pixels_per_point: Option<f32>,
29        dithering: bool,
30    ) -> Self {
31        #[expect(clippy::unwrap_used)] // TODO(emilk): return error instead of unwrap
32        let painter = crate::Painter::new(gl, "", shader_version, dithering)
33            .map_err(|err| {
34                log::error!("error occurred in initializing painter:\n{err}");
35            })
36            .unwrap();
37
38        let egui_ctx = egui::Context::default();
39
40        let egui_winit = egui_winit::State::new(
41            egui_ctx.clone(),
42            ViewportId::ROOT,
43            event_loop,
44            native_pixels_per_point,
45            event_loop.system_theme(),
46            Some(painter.max_texture_side()),
47        );
48
49        Self {
50            egui_ctx,
51            egui_winit,
52            painter,
53            viewport_info: Default::default(),
54            shapes: Default::default(),
55            pixels_per_point: native_pixels_per_point.unwrap_or(1.0),
56            textures_delta: Default::default(),
57        }
58    }
59
60    pub fn on_window_event(
61        &mut self,
62        window: &winit::window::Window,
63        event: &winit::event::WindowEvent,
64    ) -> EventResponse {
65        self.egui_winit.on_window_event(window, event)
66    }
67
68    /// Call [`Self::paint`] later to paint.
69    pub fn run(&mut self, window: &winit::window::Window, run_ui: impl FnMut(&mut egui::Ui)) {
70        let raw_input = self.egui_winit.take_egui_input(window);
71
72        let egui::FullOutput {
73            platform_output,
74            textures_delta,
75            shapes,
76            pixels_per_point,
77            viewport_output,
78        } = self.egui_ctx.run_ui(raw_input, run_ui);
79
80        if viewport_output.len() > 1 {
81            log::warn!("Multiple viewports not yet supported by EguiGlow");
82        }
83        for (_, ViewportOutput { commands, .. }) in viewport_output {
84            let mut actions_requested = Default::default();
85            egui_winit::process_viewport_commands(
86                &self.egui_ctx,
87                &mut self.viewport_info,
88                commands,
89                window,
90                &mut actions_requested,
91            );
92            for action in actions_requested {
93                log::warn!("{action:?} not yet supported by EguiGlow");
94            }
95        }
96
97        self.egui_winit
98            .handle_platform_output(window, platform_output);
99
100        self.shapes = shapes;
101        self.pixels_per_point = pixels_per_point;
102        self.textures_delta.append(textures_delta);
103    }
104
105    /// Paint the results of the last call to [`Self::run`].
106    pub fn paint(&mut self, window: &winit::window::Window) {
107        let shapes = std::mem::take(&mut self.shapes);
108        let mut textures_delta = std::mem::take(&mut self.textures_delta);
109
110        for (id, image_delta) in textures_delta.set {
111            self.painter.set_texture(id, &image_delta);
112        }
113
114        let pixels_per_point = self.pixels_per_point;
115        let clipped_primitives = self.egui_ctx.tessellate(shapes, pixels_per_point);
116        let dimensions: [u32; 2] = window.inner_size().into();
117        self.painter
118            .paint_primitives(dimensions, pixels_per_point, &clipped_primitives);
119
120        for id in textures_delta.free.drain(..) {
121            self.painter.free_texture(id);
122        }
123    }
124
125    /// Call to release the allocated graphics resources.
126    pub fn destroy(&mut self) {
127        self.painter.destroy();
128    }
129}
egui_glow/winit.rs

egui_glow/
winit.rs
