1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144

/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at https://mozilla.org/MPL/2.0/. */

//! A modified version of EguiGlow [from egui_glow 0.22.0][0] that retains its shapes,
//! allowing [`EguiGlow::paint`] to be called multiple times.
//!
//! [0]: https://github.com/emilk/egui/blob/0.22.0/crates/egui_glow/src/winit.rs

// Copyright (c) 2018-2021 Emil Ernerfeldt <[email protected]>
//
// Permission is hereby granted, free of charge, to any
// person obtaining a copy of this software and associated
// documentation files (the "Software"), to deal in the
// Software without restriction, including without
// limitation the rights to use, copy, modify, merge,
// publish, distribute, sublicense, and/or sell copies of
// the Software, and to permit persons to whom the Software
// is furnished to do so, subject to the following
// conditions:
//
// The above copyright notice and this permission notice
// shall be included in all copies or substantial portions
// of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF
// ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED
// TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
// PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT
// SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
// CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
// OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR
// IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
// DEALINGS IN THE SOFTWARE.

use egui::{ViewportId, ViewportOutput};
use egui_glow::ShaderVersion;
pub use egui_winit;
use egui_winit::winit;
pub use egui_winit::EventResponse;

/// Use [`egui`] from a [`glow`] app based on [`winit`].
pub struct EguiGlow {
    pub egui_ctx: egui::Context,
    pub egui_winit: egui_winit::State,
    pub painter: egui_glow::Painter,

    shapes: Vec<egui::epaint::ClippedShape>,
    textures_delta: egui::TexturesDelta,
}

impl EguiGlow {
    /// For automatic shader version detection set `shader_version` to `None`.
    pub fn new(
        event_loop: &winit::event_loop::EventLoop<super::events_loop::WakerEvent>,
        gl: std::sync::Arc<glow::Context>,
        shader_version: Option<ShaderVersion>,
    ) -> Self {
        let painter = egui_glow::Painter::new(gl, "", shader_version, false)
            .map_err(|err| {
                log::error!("error occurred in initializing painter:\n{err}");
            })
            .unwrap();

        let egui_ctx = egui::Context::default();
        Self {
            egui_winit: egui_winit::State::new(
                egui_ctx.clone(),
                ViewportId::ROOT,
                event_loop,
                None,
                None,
                None,
            ),
            egui_ctx,
            painter,
            shapes: Default::default(),
            textures_delta: Default::default(),
        }
    }

    pub fn on_window_event(
        &mut self,
        window: &winit::window::Window,
        event: &winit::event::WindowEvent,
    ) -> EventResponse {
        self.egui_winit.on_window_event(window, event)
    }

    /// Returns the `Duration` of the timeout after which egui should be repainted even if there's no new events.
    ///
    /// Call [`Self::paint`] later to paint.
    pub fn run(
        &mut self,
        window: &winit::window::Window,
        run_ui: impl FnMut(&egui::Context),
    ) -> std::time::Duration {
        let raw_input = self.egui_winit.take_egui_input(window);
        let egui::FullOutput {
            platform_output,
            viewport_output,
            textures_delta,
            shapes,
            pixels_per_point: _pixels_per_point,
        } = self.egui_ctx.run(raw_input, run_ui);

        self.egui_winit
            .handle_platform_output(window, platform_output);

        self.shapes = shapes;
        self.textures_delta.append(textures_delta);
        match viewport_output.get(&ViewportId::ROOT) {
            Some(&ViewportOutput { repaint_delay, .. }) => repaint_delay,
            None => std::time::Duration::ZERO,
        }
    }

    /// Paint the results of the last call to [`Self::run`].
    pub fn paint(&mut self, window: &winit::window::Window) {
        /////// let shapes = std::mem::take(&mut self.shapes);
        let shapes = &self.shapes;
        let mut textures_delta = std::mem::take(&mut self.textures_delta);

        for (id, image_delta) in textures_delta.set {
            self.painter.set_texture(id, &image_delta);
        }

        let pixels_per_point = self.egui_ctx.pixels_per_point();
        /////// let clipped_primitives = self.egui_ctx.tessellate(shapes);
        let clipped_primitives = self.egui_ctx.tessellate(shapes.clone(), pixels_per_point);
        let dimensions: [u32; 2] = window.inner_size().into();
        self.painter
            .paint_primitives(dimensions, pixels_per_point, &clipped_primitives);

        for id in textures_delta.free.drain(..) {
            self.painter.free_texture(id);
        }
    }

    /// Call to release the allocated graphics resources.
    pub fn destroy(&mut self) {
        self.painter.destroy();
    }
}