在 glium 中设置帧重绘率？

Question

我正在尝试使用 rust 中的 glium 制作游戏循环。我的目标是让屏幕每秒重绘 60 次。使用我拥有的当前事件循环代码，只有在窗口大小发生变化时才会重绘框架。我在 glutin docs 中读到，我需要在某个地方调用 request_redraw，但我不确定如何/在哪里。到目前为止，这是我的代码：

event_loop.run(move |event, _target, control_flow| match event {
    Event::LoopDestroyed => return,
    Event::WindowEvent {
        window_id: _window_id,
        event: winevent,
    } => match winevent {
        WindowEvent::Resized(physical_size) => display.gl_window().resize(physical_size),
        WindowEvent::CloseRequested => {
            *control_flow = ControlFlow::Exit;
        }
        _ => {}
    },
    Event::RedrawRequested(_window_id) => {
        let mut target = display.draw();
        target.clear_color_srgb(rng.gen(), rng.gen(), rng.gen(), 1.0);
        target.finish().unwrap();
    }
    _ => {}
});

Answer 1

我之前没有使用过glium（我已经有一段时间直接使用Vulkano 制作了一些图形应用程序）。但是，仔细阅读 API，您似乎可以通过一系列 api 从winit 获取您的 Window 句柄。我在下面的代码中概述了它们。像下面这样的东西应该适合你。关键是从winit 访问Window 句柄。滚动浏览Window API，您应该会看到：request_redraw。然后，您可以像这样在事件处理程序周围插入游戏循环逻辑：

use std::time::Instant;
use glium::Display;
use winit::event_loop::{EventLoop, ControlFlow};
use winit::event::{Event, WindowEvent};
use winit::window::Window;

const TARGET_FPS: u64 = 60;

/* ... some function for main loop ... */

let display: Display = ... /* glium Display instance */

event_loop.run(move |event, _target, control_flow| {
    let start_time = Instant::now();
    match event {
        Event::WindowEvent { event: WindowEvent::CloseRequested, .. } => {
            *control_flow = ControlFlow::Exit;
        },
        ...
    /*
     * Process events here
     */
    }
    match *control_flow {
        ControlFlow::Exit => (),
        _ => {
            /*
             * Grab window handle from the display (untested - based on API)
             */
            display.gl_window().window().request_redraw();
            /*
             * Below logic to attempt hitting TARGET_FPS.
             * Basically, sleep for the rest of our milliseconds
             */
            let elapsed_time = Instant::now().duration_since(start_time).as_millis() as u64;

            let wait_millis = match 1000 / TARGET_FPS >= elapsed_time {
                true => 1000 / TARGET_FPS - elapsed_time,
                false => 0
            };
            let new_inst = start_time + std::time::Duration::from_millis(wait_millis);
            *control_flow = ControlFlow::WaitUntil(new_inst);
        }
    }
});