bevy 案例分析 window_settings.rs

对应的路径 bevy/examples/window/window_settings.rs

使用方式

运行程序后：
窗口会在3帧后显示
按 空格键：切换光标可见性和抓取模式
按 V 键：切换垂直同步
按 T 键：切换窗口层级
按 F 键：切换亮/暗主题
按 1/2/3 键：切换窗口控制按钮
鼠标左键/右键：循环切换光标图标

标题会实时显示运行时间

完整的代码

//! Illustrates how to change window settings and shows how to affect
//! the mouse pointer in various ways.

#[cfg(feature = "custom_cursor")]
use bevy::winit::cursor::{CustomCursor, CustomCursorImage};
use bevy::{
    diagnostic::{FrameCount, FrameTimeDiagnosticsPlugin, LogDiagnosticsPlugin},
    prelude::*,
    window::{CursorGrabMode, PresentMode, SystemCursorIcon, WindowLevel, WindowTheme},
    winit::cursor::CursorIcon,
};

fn main() {
    App::new()
        .add_plugins((
            DefaultPlugins.set(WindowPlugin {
                primary_window: Some(Window {
                    title: "I am a window!".into(),
                    name: Some("bevy.app".into()),
                    resolution: (500., 300.).into(),
                    present_mode: PresentMode::AutoVsync,
                    // Tells Wasm to resize the window according to the available canvas
                    fit_canvas_to_parent: true,
                    // Tells Wasm not to override default event handling, like F5, Ctrl+R etc.
                    prevent_default_event_handling: false,
                    window_theme: Some(WindowTheme::Dark),
                    enabled_buttons: bevy::window::EnabledButtons {
                        maximize: false,
                        ..Default::default()
                    },
                    // This will spawn an invisible window
                    // The window will be made visible in the make_visible() system after 3 frames.
                    // This is useful when you want to avoid the white window that shows up before the GPU is ready to render the app.
                    visible: false,
                    ..default()
                }),
                ..default()
            }),
            LogDiagnosticsPlugin::default(),
            FrameTimeDiagnosticsPlugin::default(),
        ))
        .add_systems(Startup, init_cursor_icons)
        .add_systems(
            Update,
            (
                change_title,
                toggle_theme,
                toggle_cursor,
                toggle_vsync,
                toggle_window_controls,
                cycle_cursor_icon,
                switch_level,
                make_visible,
            ),
        )
        .run();
}

fn make_visible(mut window: Single<&mut Window>, frames: Res<FrameCount>) {
    // The delay may be different for your app or system.
    if frames.0 == 3 {
        // At this point the gpu is ready to show the app so we can make the window visible.
        // Alternatively, you could toggle the visibility in Startup.
        // It will work, but it will have one white frame before it starts rendering
        window.visible = true;
    }
}

/// This system toggles the vsync mode when pressing the button V.
/// You'll see fps increase displayed in the console.
fn toggle_vsync(input: Res<ButtonInput<KeyCode>>, mut window: Single<&mut Window>) {
    if input.just_pressed(KeyCode::KeyV) {
        window.present_mode = if matches!(window.present_mode, PresentMode::AutoVsync) {
            PresentMode::AutoNoVsync
        } else {
            PresentMode::AutoVsync
        };
        info!("PRESENT_MODE: {:?}", window.present_mode);
    }
}

/// This system switches the window level when pressing the T button
/// You'll notice it won't be covered by other windows, or will be covered by all the other
/// windows depending on the level.
///
/// This feature only works on some platforms. Please check the
/// [documentation](https://docs.rs/bevy/latest/bevy/prelude/struct.Window.html#structfield.window_level)
/// for more details.
fn switch_level(input: Res<ButtonInput<KeyCode>>, mut window: Single<&mut Window>) {
    if input.just_pressed(KeyCode::KeyT) {
        window.window_level = match window.window_level {
            WindowLevel::AlwaysOnBottom => WindowLevel::Normal,
            WindowLevel::Normal => WindowLevel::AlwaysOnTop,
            WindowLevel::AlwaysOnTop => WindowLevel::AlwaysOnBottom,
        };
        info!("WINDOW_LEVEL: {:?}", window.window_level);
    }
}

/// This system toggles the window controls when pressing buttons 1, 2 and 3
///
/// This feature only works on some platforms. Please check the
/// [documentation](https://docs.rs/bevy/latest/bevy/prelude/struct.Window.html#structfield.enabled_buttons)
/// for more details.
fn toggle_window_controls(input: Res<ButtonInput<KeyCode>>, mut window: Single<&mut Window>) {
    let toggle_minimize = input.just_pressed(KeyCode::Digit1);
    let toggle_maximize = input.just_pressed(KeyCode::Digit2);
    let toggle_close = input.just_pressed(KeyCode::Digit3);

    if toggle_minimize || toggle_maximize || toggle_close {
        if toggle_minimize {
            window.enabled_buttons.minimize = !window.enabled_buttons.minimize;
        }
        if toggle_maximize {
            window.enabled_buttons.maximize = !window.enabled_buttons.maximize;
        }
        if toggle_close {
            window.enabled_buttons.close = !window.enabled_buttons.close;
        }
    }
}

/// This system will then change the title during execution
fn change_title(mut window: Single<&mut Window>, time: Res<Time>) {
    window.title = format!(
        "Seconds since startup: {}",
        time.elapsed().as_secs_f32().round()
    );
}

fn toggle_cursor(mut window: Single<&mut Window>, input: Res<ButtonInput<KeyCode>>) {
    if input.just_pressed(KeyCode::Space) {
        window.cursor_options.visible = !window.cursor_options.visible;
        window.cursor_options.grab_mode = match window.cursor_options.grab_mode {
            CursorGrabMode::None => CursorGrabMode::Locked,
            CursorGrabMode::Locked | CursorGrabMode::Confined => CursorGrabMode::None,
        };
    }
}

// This system will toggle the color theme used by the window
fn toggle_theme(mut window: Single<&mut Window>, input: Res<ButtonInput<KeyCode>>) {
    if input.just_pressed(KeyCode::KeyF) {
        if let Some(current_theme) = window.window_theme {
            window.window_theme = match current_theme {
                WindowTheme::Light => Some(WindowTheme::Dark),
                WindowTheme::Dark => Some(WindowTheme::Light),
            };
        }
    }
}

#[derive(Resource)]
struct CursorIcons(Vec<CursorIcon>);

fn init_cursor_icons(
    mut commands: Commands,
    #[cfg(feature = "custom_cursor")] asset_server: Res<AssetServer>,
) {
    commands.insert_resource(CursorIcons(vec![
        SystemCursorIcon::Default.into(),
        SystemCursorIcon::Pointer.into(),
        SystemCursorIcon::Wait.into(),
        SystemCursorIcon::Text.into(),
        #[cfg(feature = "custom_cursor")]
        CustomCursor::Image(CustomCursorImage {
            handle: asset_server.load("branding/icon.png"),
            hotspot: (128, 128),
            ..Default::default()
        })
        .into(),
    ]));
}

/// This system cycles the cursor's icon through a small set of icons when clicking
fn cycle_cursor_icon(
    mut commands: Commands,
    window: Single<Entity, With<Window>>,
    input: Res<ButtonInput<MouseButton>>,
    mut index: Local<usize>,
    cursor_icons: Res<CursorIcons>,
) {
    if input.just_pressed(MouseButton::Left) {
        *index = (*index + 1) % cursor_icons.0.len();
        commands
            .entity(*window)
            .insert(cursor_icons.0[*index].clone());
    } else if input.just_pressed(MouseButton::Right) {
        *index = if *index == 0 {
            cursor_icons.0.len() - 1
        } else {
            *index - 1
        };
        commands
            .entity(*window)
            .insert(cursor_icons.0[*index].clone());
    }
}

这段代码是一个 Bevy 引擎示例，展示了如何控制窗口的各种设置以及如何操作鼠标指针。以下是详细解释：

fn main() {
    App::new()
        .add_plugins((
            DefaultPlugins.set(WindowPlugin {
                primary_window: Some(Window {
                    title: "I am a window!".into(), // 初始标题
                    name: Some("bevy.app".into()),  // 窗口系统标识名
                    resolution: (500., 300.).into(), // 初始分辨率
                    present_mode: PresentMode::AutoVsync, // 垂直同步模式
                    fit_canvas_to_parent: true,     // 在 Web 上适配父容器
                    prevent_default_event_handling: false, // 允许默认事件处理
                    window_theme: Some(WindowTheme::Dark), // 深色主题
                    enabled_buttons: bevy::window::EnabledButtons {
                        maximize: false,            // 禁用最大化按钮
                        ..Default::default()
                    },
                    visible: false,                 // 初始不可见
                    ..default()
                }),
                ..default()
            }),
            LogDiagnosticsPlugin::default(),    // 日志诊断插件
            FrameTimeDiagnosticsPlugin::default(), // 帧时间诊断插件
        ))
        // ... 系统注册 ...
        .run();
}

这段代码干了这些事情：

创建了一个初始不可见的窗口（visible: false）

设置了深色主题（WindowTheme::Dark）

禁用了最大化按钮

添加了性能诊断插件

2. 使窗口可见的系统

fn make_visible(mut window: Single<&mut Window>, frames: Res<FrameCount>) {
    if frames.0 == 3 {
        window.visible = true; // 3帧后显示窗口
    }
}

解决启动时可能出现的白屏问题
等待GPU准备就绪后显示窗口

3. 窗口设置切换系统

3.1 3.1 垂直同步切换

fn toggle_vsync(input: Res<ButtonInput<KeyCode>>, mut window: Single<&mut Window>) {
    if input.just_pressed(KeyCode::KeyV) {
        window.present_mode = match window.present_mode {
            PresentMode::AutoVsync => PresentMode::AutoNoVsync,
            _ => PresentMode::AutoVsync,
        };
    }
}