非官方 Bevy 作弊书07-09

#[derive(Component)]
struct MyCameraMarker;fn setup_camera(mut commands: Commands) {commands.spawn((Camera2dBundle {transform: Transform::from_xyz(100.0, 200.0, 0.0),..default()},MyCameraMarker,));
}fn main() {App::new().add_plugins(DefaultPlugins).add_systems(Startup, setup_camera).run();
}

fn debug_projection(query_camera: Query<&OrthographicProjection, With<MyCameraMarker>>,
) {let projection = query_camera.single();// ... do something with the projection
}

commands.spawn((Camera2dBundle {projection: OrthographicProjection {// don't forget to set `near` and `far`// 别忘了设置`near`和`far`near: -1000.0,far: 1000.0,// ... any other settings you want to change .../ /……您还想更改其他设置吗?..default()},..default()},MyCameraMarker,
));

let mut camera_bundle = Camera2dBundle::default();
// change the settings we want to change:
// 更改我们想要更改的设置:
camera_bundle.projection.scale = 2.0;
camera_bundle.transform.rotate_z(30f32.to_radians());
// ...commands.spawn((camera_bundle,MyCameraMarker,
));

use bevy::render::camera::ScalingMode;let mut my_2d_camera_bundle = Camera2dBundle::default();
// For this example, let's make the screen/window height correspond to
// 在这个例子中，让我们将screen/window的高度设置为
// 1600.0 world units. The width will depend on the aspect ratio.
// 1600.0世界单位宽度取决于宽高比。
my_2d_camera_bundle.projection.scaling_mode = ScalingMode::FixedVertical(1600.0);
my_2d_camera_bundle.transform = Transform::from_xyz(100.0, 200.0, 0.0);commands.spawn((my_2d_camera_bundle,MyCameraMarker,
));

fn zoom_scale(mut query_camera: Query<&mut OrthographicProjection, With<MyCameraMarker>>,
) {let mut projection = query_camera.single_mut();// zoom in     // 放大projection.scale /= 1.25;// zoom out     // 缩小projection.scale *= 1.25;
}

fn zoom_scalingmode(mut query_camera: Query<&mut OrthographicProjection, With<MyCameraMarker>>,
) {use bevy::render::camera::ScalingMode;let mut projection = query_camera.single_mut();// 4 screen pixels to world/game pixel// 4个屏幕像素对应世界/游戏像素projection.scaling_mode = ScalingMode::WindowSize(4.0);// 6 screen pixels to world/game pixel// 6个屏幕像素对应世界/游戏像素projection.scaling_mode = ScalingMode::WindowSize(6.0);
}

fn main() {App::new().add_plugins(DefaultPlugins.set(ImagePlugin::default_nearest()))// ....run();
}

fn debug_projection(query_camera: Query<&Projection, With<MyCameraMarker>>,
) {let projection = query_camera.single();match projection {Projection::Perspective(persp) => {// we have a perspective projection// 我们有了一个透视投影}Projection::Orthographic(ortho) => {// we have an orthographic projection// 我们有一个正投影}}
}

commands.spawn((Camera3dBundle {projection: PerspectiveProjection {// We must specify the FOV in radians.// 我们必须以弧度指定FOV// Rust can convert degrees to radians for us.// Rust可以将度数转换为弧度fov: 60.0_f32.to_radians(),..default()}.into(),transform: Transform::from_xyz(10.0, 12.0, 16.0).looking_at(Vec3::ZERO, Vec3::Y),..default()},MyCameraMarker,
));

​

fn zoom_perspective(mut query_camera: Query<&mut Projection, With<MyCameraMarker>>,
) {// assume perspective. do nothing if orthographic.// 假设透视图如果正字法，什么都不做。let Projection::Perspective(persp) = query_camera.single_mut().into_inner() else {return;};// zoom in // 放大persp.fov /= 1.25;// zoom out  // 缩小persp.fov *= 1.25;
}

​

​

use bevy::render::camera::ScalingMode;commands.spawn((Camera3dBundle {projection: OrthographicProjection {// For this example, let's make the screen/window height// 在这个例子中，让我们设定屏幕/窗口的高度// correspond to 16.0 world units.// 对应16.0个世界单位scaling_mode: ScalingMode::FixedVertical(16.0),..default()}.into(),// the distance doesn't really matter for orthographic,// 对于正字法来说，距离并不重要，// it should look the same (though it might affect// 它看起来应该是一样的(尽管它可能会影响// shadows and clipping / culling)// 阴影和裁剪/剔除)transform: Transform::from_xyz(10.0, 12.0, 16.0).looking_at(Vec3::ZERO, Vec3::Y),..default()},MyCameraMarker,
));

​

fn zoom_orthographic(mut query_camera: Query<&mut Projection, With<MyCameraMarker>>,
) {// assume orthographic. do nothing if perspective.// 假设正字法。什么都不做，如果透视。let Projection::Orthographic(ortho) = query_camera.single_mut().into_inner() else {return;};// zoom in  // 放大ortho.scale /= 1.25;// zoom out  // 缩小ortho.scale *= 1.25;
}

​

Keyboard - Unofficial Bevy Cheat Book

fn keyboard_input(keys: Res<Input<KeyCode>>,
) {if keys.just_pressed(KeyCode::Space) {// Space was pressed// 空格被按下}if keys.just_released(KeyCode::LControl) {// Left Ctrl was released// 左侧Ctrl被释放}if keys.pressed(KeyCode::W) {// W is being held down// W被按住}// we can check multiple at once with `.any_*`if keys.any_pressed([KeyCode::LShift, KeyCode::RShift]) {// Either the left or right shift are being held down//要么是左移，要么是右移}if keys.any_just_pressed([KeyCode::Delete, KeyCode::Back]) {// Either delete or backspace was just pressed// 只是按下了delete或backspace}
}

fn keyboard_events(mut key_evr: EventReader<KeyboardInput>,
) {use bevy::input::ButtonState;for ev in key_evr.iter() {match ev.state {ButtonState::Pressed => {println!("Key press: {:?} ({})", ev.key_code, ev.scan_code);}ButtonState::Released => {println!("Key release: {:?} ({})", ev.key_code, ev.scan_code);}}}
}

fn mouse_button_input(buttons: Res<Input<MouseButton>>,
) {if buttons.just_pressed(MouseButton::Left) {// Left button was pressed// 左键被按下}if buttons.just_released(MouseButton::Left) {// Left Button was released// 左键被释放}if buttons.pressed(MouseButton::Right) {// Right Button is being held down// 右键被持续按下}// we can check multiple at once with `.any_*`// 我们可以一次检查多个 `.any_*`if buttons.any_just_pressed([MouseButton::Left, MouseButton::Right]) {// Either the left or the right button was just pressed// 左键或右键刚被按下}
}

fn mouse_button_iter(buttons: Res<Input<MouseButton>>,
) {for button in buttons.get_pressed() {println!("{:?} is currently held down", button);}for button in buttons.get_just_pressed() {println!("{:?} was pressed", button);}for button in buttons.get_just_released() {println!("{:?} was released", button);}
}

use bevy::input::mouse::MouseButtonInput;fn mouse_button_events(mut mousebtn_evr: EventReader<MouseButtonInput>,
) {use bevy::input::ButtonState;for ev in mousebtn_evr.iter() {match ev.state {ButtonState::Pressed => {println!("Mouse button press: {:?}", ev.button);}ButtonState::Released => {println!("Mouse button release: {:?}", ev.button);}}}
}

use bevy::input::common_conditions::*;app.add_systems(Update, (handle_middleclick.run_if(input_just_pressed(MouseButton::Middle)),handle_drag.run_if(input_pressed(MouseButton::Left)),
));

use bevy::input::mouse::MouseWheel;fn scroll_events(mut scroll_evr: EventReader<MouseWheel>,
) {use bevy::input::mouse::MouseScrollUnit;for ev in scroll_evr.iter() {match ev.unit {MouseScrollUnit::Line => {println!("Scroll (line units): vertical: {}, horizontal: {}", ev.y, ev.x);//  println!("滚轮滚动（线单位）：垂直：{}, 水平：{}", ev.y, ev.x);}MouseScrollUnit::Pixel => {println!("Scroll (pixel units): vertical: {}, horizontal: {}", ev.y, ev.x);//  println!("滚轮滚动（像素单位）：垂直：{}, 水平：{}", ev.y, ev.x);}}}
}

use bevy::input::mouse::MouseMotion;fn mouse_motion(mut motion_evr: EventReader<MouseMotion>,
) {for ev in motion_evr.iter() {println!("Mouse moved: X: {} px, Y: {} px", ev.delta.x, ev.delta.y);//  println!("鼠标移动：X: {} px, Y: {} px", ev.delta.x, ev.delta.y);}
}

use bevy::window::PrimaryWindow;fn cursor_position(q_windows: Query<&Window, With<PrimaryWindow>>,
) {// Games typically only have one window (the primary window)// 游戏通常只有一个窗口（主窗口）if let Some(position) = q_windows.single().cursor_position() {println!("Cursor is inside the primary window, at {:?}", position);//  println!("光标位于主窗口内，在{:?}", position);} else {println!("Cursor is not in the game window.");// println!("光标不在游戏窗口内。");}
}

fn cursor_events(mut cursor_evr: EventReader<CursorMoved>,
) {for ev in cursor_evr.iter() {println!("New cursor position: X: {}, Y: {}, in Window ID: {:?}",//  "新的光标位置：X: {}, Y: {}, 在窗口ID: {:?}",ev.position.x, ev.position.y, ev.window);}
}

use bevy::input::touchpad::{TouchpadMagnify, TouchpadRotate};// these only work on macOS
// 这些只在macOS上工作
fn touchpad_gestures(mut evr_touchpad_magnify: EventReader<TouchpadMagnify>,mut evr_touchpad_rotate: EventReader<TouchpadRotate>,
) {for ev_magnify in evr_touchpad_magnify.iter() {// Positive numbers are zooming in   // 正数表示放大// Negative numbers are zooming out  // 负数表示缩小println!("Touchpad zoom by {}", ev_magnify.0);}for ev_rotate in evr_touchpad_rotate.iter() {// Positive numbers are anticlockwise  // 正数表示逆时针// Negative numbers are clockwise      // 负数表示顺时针println!("Touchpad rotate by {}", ev_rotate.0);}
}

Text / Character - Unofficial Bevy Cheat Book

非官方 Bevy 作弊书

9.3 文本/字符输入

相关官方示例： char_input_events、 text_input。

如果您想在 Bevy 应用程序中实现文本输入，请使用此功能（而不是 键盘输入）。这样，一切都会按照用户期望的操作系统运行，包括 Unicode 支持。

Bevy 将为来自操作系统的每个 Unicode 代码点生成一个ReceivedCharacter 事件。

此示例演示如何让用户将文本输入到字符串中（此处存储为本地资源）。

fn text_input(mut evr_char: EventReader<ReceivedCharacter>,kbd: Res<Input<KeyCode>>,mut string: Local<String>,
) {if kbd.just_pressed(KeyCode::Return) {println!("Text input: {}", &*string);string.clear();}if kbd.just_pressed(KeyCode::Back) {string.pop();}for ev in evr_char.iter() {// ignore control (special) characters// 忽略控制（特殊）字符if !ev.char.is_control() {string.push(ev.char);}}
}

注意：我们使用 Bevy 的常规键盘输入来处理 Enter 和 Backspace 键的按下。当按下这些键时也会发送字符事件（它们会产生特殊的控制字符，如 ASCII 换行符\n），因此，如果我们不希望将它们保存到字符串中，则需要忽略它们。

在您自己的应用程序中，您可能还希望以适合您的 UI 的方式处理箭头键等操作。

输入法支持

Bevy 支持 IME（输入法编辑器），这是人们在具有更复杂文字的语言（如东亚语言）中执行文本输入的方式。但是，它需要您进行一些特殊处理。

IME 通过使用特殊的“缓冲区”来工作，它显示当前正在进行的文本建议，并允许用户在确认之前选择正确的字符。文本建议/自动完成由操作系统提供，但您的应用程序需要向用户显示它们。

如果您希望所有国际用户都能够用他们的语言输入文本（就像他们在操作系统上的其他 GUI 应用程序中通常所做的那样），您应该支持 IME。

为此，每当您希望用户输入文本时，您都需要在窗口上启用“IME 模式”，然后再将其禁用。例如，如果您在玩游戏之前提示用户输入姓名，则您可以在提示处于活动状态时启用 IME 模式。

启用“IME 模式”后，如果用户使用 IME，您将收到 Ime事件，而不是ReceivedCharacter 常规键盘输入。但是，如果用户没有使用 IME，那么即使启用了“IME 模式”，一切也会正常运行。

当用户有正在进行的文本时，您将收到Ime::Preedit事件，告诉您“临时缓冲区”的当前内容以及需要显示的有关光标/突出显示的信息，以便用户可以看到他们正在做什么。

当用户确认他们的输入时，您将收到一个Ime::Commit事件，告诉您用户希望插入到应用程序中的文本。

// for this simple example, we will just enable/disable IME mode on mouse click
// 对于这个简单的例子，我们只需要在鼠标点击时启用/禁用IME模式
fn ime_toggle(mousebtn: Res<Input<MouseButton>>,mut q_window: Query<&mut Window, With<PrimaryWindow>>,
) {if mousebtn.just_pressed(MouseButton::Left) {let mut window = q_window.single_mut();// toggle "IME mode"// 切换"IME模式"window.ime_enabled = !window.ime_enabled;// We need to tell the OS the on-screen coordinates where the text will// 我们需要告诉OS文本在屏幕上的坐标// be displayed; for this simple example, let's just use the mouse cursor.// 显示;在这个简单的例子中，我们只使用鼠标光标。// In a real app, this might be the position of a UI text field, etc.// 在实际应用中，这可能是UI文本框的位置等window.ime_position = window.cursor_position().unwrap();}
}fn ime_input(mut evr_ime: EventReader<Ime>,
) {for ev in evr_ime.iter() {match ev {Ime::Commit { value, .. } => {println!("IME confirmed text: {}", value);// println!("IME确认文本: {}", value);}Ime::Preedit { value, cursor, .. } => {println!("IME buffer: {:?}, cursor: {:?}", value, cursor);// println!("IME缓冲区: {:?}, 光标: {:?}", value, cursor);}Ime::Enabled { .. } => {println!("IME mode enabled!");// println!("输入法模式启用！");}Ime::Disabled { .. } => {println!("IME mode disabled!");// println!("输入法模式禁用！");}}}
}

为了简洁起见，此示例仅将事件打印到控制台。

在真实的应用程序中，您需要在屏幕上显示“预编辑”文本，并使用不同的格式来显示光标。在“提交”时，您可以将提供的文本附加到您通常接受文本输入的实际字符串中。

非官方 Bevy 作弊书

9.4 游戏手柄（控制器、操纵杆）

相关官方示例： gamepad_input、 gamepad_input_events。

Bevy 支持游戏手柄输入硬件：控制台控制器、操纵杆等。许多不同类型的硬件都应该可以工作，但如果您的设备不受支持，您应该向 gilrs项目提交问题。

游戏手柄 ID

Bevy为每个连接的游戏手柄分配一个唯一的 ID ( Gamepad)。这使您可以将设备与特定玩家关联起来，并区分您的输入来自哪一个。

您可以使用该Gamepads 资源列出当前连接的所有游戏手柄设备的 ID，或检查特定设备的状态。

要检测游戏手柄何时连接或断开连接，您可以使用 GamepadEvent events。

显示如何记住第一个连接的游戏手柄 ID 的示例：

/// Simple resource to store the ID of the connected gamepad.
/// 存储连接手柄ID的简单资源。
/// We need to know which gamepad to use for player input.
/// 我们需要知道使用哪个手柄进行玩家输入。
#[derive(Resource)]
struct MyGamepad(Gamepad);fn gamepad_connections(mut commands: Commands,my_gamepad: Option<Res<MyGamepad>>,mut gamepad_evr: EventReader<GamepadEvent>,
) {for ev in gamepad_evr.iter() {// the ID of the gamepad// 手柄的IDlet id = ev.gamepad;match &ev.event_type {GamepadEventType::Connected(info) => {println!("New gamepad connected with ID: {:?}, name: {}", id, info.name);// if we don't have any gamepad yet, use this one// 如果我们还没有任何手柄，请使用这个if my_gamepad.is_none() {commands.insert_resource(MyGamepad(id));}}GamepadEventType::Disconnected => {println!("Lost gamepad connection with ID: {:?}", id);// if it's the one we previously associated with the player,// 如果它是我们之前与玩家关联的那个元素，// disassociate it:// 解除关联:if let Some(MyGamepad(old_id)) = my_gamepad.as_deref() {if *old_id == id {commands.remove_resource::<MyGamepad>();}}}// other events are irrelevant// 其他事件不相关_ => {}}}
}

处理游戏手柄输入

 您可以使用Axis<GamepadAxis>(Axis, GamepadAxis).来处理模拟摇杆和触发器。按钮可以用 Input<GamepadButton> (Input, GamepadButton)，类似于鼠标按钮或键盘按键。

请注意， GamepadButton 中按钮的名称与供应商无关（例如South和 East，而不是 X/O 或 A/B）。

fn gamepad_input(axes: Res<Axis<GamepadAxis>>,buttons: Res<Input<GamepadButton>>,my_gamepad: Option<Res<MyGamepad>>,
) {let gamepad = if let Some(gp) = my_gamepad {// a gamepad is connected, we have the id// 手柄已连接，我们有idgp.0} else {// no gamepad is connected// 没有连接手柄return;};// The joysticks are represented using a separate axis for X and Y// 操纵杆使用单独的X轴和Y轴表示let axis_lx = GamepadAxis {gamepad, axis_type: GamepadAxisType::LeftStickX};let axis_ly = GamepadAxis {gamepad, axis_type: GamepadAxisType::LeftStickY};if let (Some(x), Some(y)) = (axes.get(axis_lx), axes.get(axis_ly)) {// combine X and Y into one vector// 将X和Y合并为一个向量let left_stick_pos = Vec2::new(x, y);// Example: check if the stick is pushed up// 例子:检查操纵杆是否向上推if left_stick_pos.length() > 0.9 && left_stick_pos.y > 0.5 {// do something}}// In a real game, the buttons would be configurable, but here we hardcode them// 在真实的游戏中，按钮是可配置的，但在这里我们对它们进行了硬编码let jump_button = GamepadButton {gamepad, button_type: GamepadButtonType::South};let heal_button = GamepadButton {gamepad, button_type: GamepadButtonType::East};if buttons.just_pressed(jump_button) {// button just pressed: make the player jump// 刚刚按下的按钮:让玩家跳跃}if buttons.pressed(heal_button) {// button being held down: heal the player// 按下按钮:治愈玩家}
}

您还可以使用 GamepadEvent 事件处理游戏手柄输入：

fn gamepad_input_events(my_gamepad: Option<Res<MyGamepad>>,mut gamepad_evr: EventReader<GamepadEvent>,
) {let gamepad = if let Some(gp) = my_gamepad {// a gamepad is connected, we have the id// 手柄已连接，我们有idgp.0} else {// no gamepad is connected// 没有连接手柄return;};for ev in gamepad_evr.iter() {if ev.gamepad != gamepad {// event not from our gamepad// 事件不是来自我们的手柄continue;}use GamepadEventType::{AxisChanged, ButtonChanged};match ev.event_type {AxisChanged(GamepadAxisType::RightStickX, x) => {// Right Stick moved (X)// 右摇杆移动(X)}AxisChanged(GamepadAxisType::RightStickY, y) => {// Right Stick moved (Y)// 右摇杆被移动(Y)}ButtonChanged(GamepadButtonType::DPadDown, val) => {// buttons are also reported as analog, so use a threshold// 按钮也是模拟按钮，所以请使用阈值if val > 0.5 {// button pressed// 按下按钮}}_ => {} // don't care about other inputs// 不用关心其他输入}}
}

游戏手柄设置

您可以使用 GamepadSettings  资源 来配置各个轴和按钮的死区和其他参数。您可以设置全局默认值，也可以单独设置每个轴/按钮。

下面是一个示例，展示了如何使用自定义设置来配置游戏手柄（不一定是好的设置，请不要盲目复制这些）：

// this should be run once, when the game is starting
// 这应该在游戏开始时运行一次
// (transition entering your in-game state might be a good place to put it)
// (过渡状态可能是放置它的好地方)
fn configure_gamepads(my_gamepad: Option<Res<MyGamepad>>,mut settings: ResMut<GamepadSettings>,
) {let gamepad = if let Some(gp) = my_gamepad {// a gamepad is connected, we have the id// 手柄已连接，我们有idgp.0} else {// no gamepad is connected// 没有连接手柄return;};// add a larger default dead-zone to all axes (ignore small inputs, round to zero)// 为所有轴添加一个更大的默认死区(忽略小的输入，四舍五入为零)settings.default_axis_settings.set_deadzone_lowerbound(-0.1);settings.default_axis_settings.set_deadzone_upperbound(0.1);// make the right stick "binary", squash higher values to 1.0 and lower values to 0.0// 将右边的值设置为二进制，将较大的值压缩为1.0，较小的值压缩为0.0let mut right_stick_settings = AxisSettings::default();right_stick_settings.set_deadzone_lowerbound(-0.5);right_stick_settings.set_deadzone_upperbound(0.5);right_stick_settings.set_livezone_lowerbound(-0.5);right_stick_settings.set_livezone_upperbound(0.5);// the raw value should change by at least this much,// 原始值至少应该改变这么多，// for Bevy to register an input event:// 让Bevy注册输入事件:right_stick_settings.set_threshold(0.01);// make the triggers work in big/coarse steps, to get fewer events// 让触发器按大/粗的步骤工作，以获得更少的事件// reduces noise and precision// 降低噪声和精度let mut trigger_settings = AxisSettings::default();trigger_settings.set_threshold(0.25);// set these settings for the gamepad we use for our player// 为我们用于玩家的手柄设置这些设置settings.axis_settings.insert(GamepadAxis { gamepad, axis_type: GamepadAxisType::RightStickX },right_stick_settings.clone());settings.axis_settings.insert(GamepadAxis { gamepad, axis_type: GamepadAxisType::RightStickY },right_stick_settings.clone());settings.axis_settings.insert(GamepadAxis { gamepad, axis_type: GamepadAxisType::LeftZ },trigger_settings.clone());settings.axis_settings.insert(GamepadAxis { gamepad, axis_type: GamepadAxisType::RightZ },trigger_settings.clone());// for buttons (or axes treated as buttons):// 对于按钮(或者作为按钮的轴):let mut button_settings = ButtonSettings::default();// require them to be pressed almost all the way, to count// 几乎在整个过程中都需要按下它们来计数button_settings.set_press_threshold(0.9);// require them to be released almost all the way, to count// 几乎所有的过程中都需要释放它们button_settings.set_release_threshold(0.1);settings.default_button_settings = button_settings;
}