android-activity/examples/agdk-egui/src/lib.rs

use log::Level;
use winit::event_loop::{EventLoop, EventLoopBuilder, EventLoopWindowTarget};

#[cfg(target_os = "android")]
use android_activity::AndroidApp;
#[cfg(target_os = "android")]
use winit::platform::android::EventLoopBuilderExtAndroid;

use winit::event_loop::ControlFlow;

use egui_wgpu::winit::Painter;
use egui_winit::State;
//use egui_winit_platform::{Platform, PlatformDescriptor};
use winit::event::Event::*;
const INITIAL_WIDTH: u32 = 1920;
const INITIAL_HEIGHT: u32 = 1080;

/// A custom event type for the winit app.
enum Event {
    RequestRedraw,
}

/// Enable egui to request redraws via a custom Winit event...
#[derive(Clone)]
struct RepaintSignal(std::sync::Arc<std::sync::Mutex<winit::event_loop::EventLoopProxy<Event>>>);

fn create_window<T>(
    event_loop: &EventLoopWindowTarget<T>,
    state: &mut State,
    painter: &mut Painter,
) -> winit::window::Window {
    let window = winit::window::WindowBuilder::new()
        .with_decorations(true)
        .with_resizable(true)
        .with_transparent(false)
        .with_title("egui winit + wgpu example")
        .with_inner_size(winit::dpi::PhysicalSize {
            width: INITIAL_WIDTH,
            height: INITIAL_HEIGHT,
        })
        .build(&event_loop)
        .unwrap();

    unsafe { painter.set_window(Some(&window)) };

    // NB: calling set_window will lazily initialize render state which
    // means we will be able to query the maximum supported texture
    // dimensions
    if let Some(max_size) = painter.max_texture_side() {
        state.set_max_texture_side(max_size);
    }

    let pixels_per_point = window.scale_factor() as f32;
    state.set_pixels_per_point(pixels_per_point);

    window.request_redraw();

    window
}

fn _main(event_loop: EventLoop<Event>) {
    let ctx = egui::Context::default();
    let repaint_signal = RepaintSignal(std::sync::Arc::new(std::sync::Mutex::new(
        event_loop.create_proxy(),
    )));
    ctx.set_request_repaint_callback(move || {
        repaint_signal
            .0
            .lock()
            .unwrap()
            .send_event(Event::RequestRedraw)
            .ok();
    });

    let mut state = State::new(&event_loop);
    let mut painter = Painter::new(
        wgpu::Backends::all(),
        wgpu::PowerPreference::LowPower,
        wgpu::DeviceDescriptor {
            label: None,
            features: wgpu::Features::default(),
            limits: wgpu::Limits::default(),
        },
        wgpu::PresentMode::Fifo,
        1,
    );
    let mut window: Option<winit::window::Window> = None;
    let mut egui_demo_windows = egui_demo_lib::DemoWindows::default();

    // On most platforms we can immediately create a winit window. On Android we manage
    // window + surface state according to Resumed/Paused events.
    #[cfg(not(target_os = "android"))]
    {
        window = Some(create_window(&event_loop, &mut state, &mut painter));
    }

    event_loop.run(move |event, event_loop, control_flow| match event {
        #[cfg(target_os = "android")]
        Resumed => match window {
            None => {
                window = Some(create_window(event_loop, &mut state, &mut painter));
            }
            Some(ref window) => {
                unsafe { painter.set_window(Some(window)) };
                window.request_redraw();
            }
        },

        #[cfg(target_os = "android")]
        Suspended => {
            window = None;
        }

        RedrawRequested(..) => {
            if let Some(window) = window.as_ref() {
                let raw_input = state.take_egui_input(window);

                let full_output = ctx.run(raw_input, |ctx| {
                    egui_demo_windows.ui(ctx);
                });
                state.handle_platform_output(window, &ctx, full_output.platform_output);

                painter.paint_and_update_textures(
                    state.pixels_per_point(),
                    egui::Rgba::default(),
                    &ctx.tessellate(full_output.shapes),
                    &full_output.textures_delta,
                );

                if full_output.repaint_after.is_zero() {
                    window.request_redraw();
                }
            }
        }
        MainEventsCleared | UserEvent(Event::RequestRedraw) => {
            if let Some(window) = window.as_ref() {
                window.request_redraw();
            }
        }
        WindowEvent { event, .. } => {
            if state.on_event(&ctx, &event) == false {
                match event {
                    winit::event::WindowEvent::Resized(size) => {
                        painter.on_window_resized(size.width, size.height);
                    }
                    winit::event::WindowEvent::CloseRequested => {
                        *control_flow = ControlFlow::Exit;
                    }
                    _ => {}
                }
            }
        }
        _ => (),
    });
}

#[cfg(target_os = "android")]
#[no_mangle]
fn android_main(app: AndroidApp) {
    android_logger::init_once(android_logger::Config::default().with_min_level(Level::Trace));

    let event_loop = EventLoopBuilder::with_user_event()
        .with_android_app(app)
        .build();
    _main(event_loop);
}

#[cfg(not(target_os = "android"))]
fn main() {
    env_logger::builder()
        .filter_level(log::LevelFilter::Warn) // Default Log Level
        .parse_default_env()
        .init();

    let event_loop = EventLoopBuilder::with_user_event().build();
    _main(event_loop);
}