Struct App 

pub struct App<'w, 's> { /* private fields */ }

A Bevy SystemParam providing nannou’s application conveniences.

See the module documentation for an overview and example.

Implementations

impl<'w, 's> App<'w, 's>

pub fn time(&self) -> f32

The elapsed seconds since startup.

pub fn time_delta(&self) -> f32

The elapsed seconds since the last frame.

pub fn elapsed_frames(&self) -> u64

The number of update frames that have elapsed since the start of the program.

pub fn fps(&self) -> f64

The smoothed frames-per-second as reported by Bevy’s frame-time diagnostics.

Returns 0.0 if the FPS diagnostic is unavailable (e.g. if FrameTimeDiagnosticsPlugin was not registered).

pub fn keys(&self) -> ButtonInput<KeyCode>

The current input state for the keyboard.

pub fn mouse_buttons(&self) -> ButtonInput<MouseButton>

The current input state for the mouse buttons.

pub fn mouse(&self) -> Vec2

The current mouse position in points, relative to the centre of the focused window.

pub fn window_id(&self) -> Entity

The Entity of the “current” window: the focused window, else the primary window, else a window created this call (but not yet spawned), else any open window.

Panics if there are no windows open.

pub fn window_ids(&self) -> Vec<Entity>

The Entity for each currently open window.

pub fn window_count(&self) -> usize

The number of windows currently open (including any created this call but not yet spawned).

pub fn window_rect(&self) -> Rect<f32>

The geom::Rect of the currently focused window, in points.

Panics if there are no windows open.

pub fn available_monitors(&self) -> Vec<(Entity, Monitor)>

The list of all monitors available on the system.

pub fn primary_monitor(&self) -> Option<Entity>

The primary monitor of the system, if one can be detected.

pub fn draw(&self) -> Draw

The Draw API for the window whose view is currently running, or the focused window.

Panics if there are no windows open.

pub fn draw_for_window(&self, window: Entity) -> Draw

The Draw API for the given window.

Panics if the entity has no Draw component (e.g. it is not a nannou window).

pub fn asset_server(&self) -> &AssetServer

A reference to the AssetServer for loading assets.

pub fn image_assets(&self) -> &Assets<Image>

A reference to the Image assets, for reading texture data.

To add a new asset, use asset_server().add(..); for arbitrary asset types or mutable access, take the relevant Assets<T> parameter in your own Bevy system.

pub fn modify_image( &self, handle: &Handle<Image>, f: impl FnOnce(&mut Image) + Send + 'static, )

Queue a mutation of the Image behind handle, applied via the deferred command queue.

A convenience for editing a texture from a classic update/view - e.g. overwriting its pixel data or swapping its sampler - without dropping to a custom Bevy system. Bevy re-uploads the image to its GPU texture on the next extract. The mutation lands after the current update/view returns, and f is skipped if the handle no longer resolves.

// Overwrite a texture's pixels each frame.
app.modify_image(&model.texture, move |image| image.data = Some(pixels));

pub fn text_layout<'b>(&self, s: &'b str) -> Builder<'b>

Build a text layout for measurement or glyph extraction.

App-level equivalent of draw.text_layout().

pub fn command_scope<R>(&self, f: impl FnOnce(Commands<'_, '_>) -> R) -> R

Run a closure with deferred Commands access, returning its result.

A convenience around ParallelCommands::command_scope for spawning entities or queueing world mutations from a shared &App. For example, spawn a camera bound to a window:

app.command_scope(|mut commands| {
    commands.spawn(render::NannouCamera::for_window(window));
});

Do not call another mutating App method (quit, new_window().build(), window(..).set_title(..), …) from inside the closure - they re-enter command_scope, which panics on the already-borrowed thread-local command queue. Use commands directly.

pub fn quit(&self)

Quit the currently running application.

pub fn set_update_mode(&self, mode: UpdateMode)

Set the update mode used while the window is both focused and unfocused.

See UpdateModeExt for convenient wait/freeze modes.

pub fn set_unfocused_update_mode(&self, mode: UpdateMode)

Set the update mode used while the window is unfocused.

pub fn set_focused_update_mode(&self, mode: UpdateMode)

Set the update mode used while the window is focused.

pub fn set_update_rate(&self, hz: f64)

Drive updates at a fixed rate of hz ticks per second, while both focused and unfocused. Analogous to Processing’s frameRate(fps).

Convenience for set_update_mode(UpdateMode::rate(hz)). See UpdateModeExt::rate for the exact semantics.

pub fn exe_name(&self) -> Result<String>

The name of the nannou executable that is currently running.

pub fn project_path(&self) -> Result<PathBuf, Error>

The path to the current project directory (the directory containing Cargo.toml).

pub fn assets_path(&self) -> PathBuf

The path to the assets directory.

pub fn new_window<M: 'static>(&self) -> Builder<'_, 'w, 's, M>

Begin building a new window.

The returned window::Builder spawns the window along with a NannouCamera targeting it (so its Draw is rendered), and returns the window Entity from build.

pub fn new_camera(&self) -> CameraBuilder<'_, 'w, 's>

Begin building a new NannouCamera.

Configure it with the SetCamera methods, then call build to spawn it and obtain its Entity.

pub fn new_light(&self) -> LightBuilder<'_, 'w, 's>

Begin building a new directional light.

Configure it with the SetLight methods, then call build to spawn it and obtain its Entity.

pub fn window(&self, entity: Entity) -> Window<'_, 'w, 's>

A handle for reading and updating the window with the given Entity.

pub fn main_window(&self) -> Window<'_, 'w, 's>

A handle for reading and updating the app’s main window.

This is the window explicitly marked primary (see Builder::primary) if there is one, including a primary window created this call but not yet spawned. Otherwise it falls back to the current window (see window_id), so a single window is treated as the main window without needing to be marked primary.

Panics if there are no windows open.

Trait Implementations

impl<'w, 's> ReadOnlySystemParam for App<'w, 's>

where ParallelCommands<'w, 's>: ReadOnlySystemParam, Res<'w, Time>: ReadOnlySystemParam, Res<'w, FrameCount>: ReadOnlySystemParam, Option<Res<'w, DiagnosticsStore>>: ReadOnlySystemParam, Res<'w, ButtonInput<KeyCode>>: ReadOnlySystemParam, Res<'w, ButtonInput<MouseButton>>: ReadOnlySystemParam, Query<'w, 's, (Entity, &'static Window)>: ReadOnlySystemParam, Query<'w, 's, Entity, With<PrimaryWindow>>: ReadOnlySystemParam, Query<'w, 's, &'static Draw>: ReadOnlySystemParam, Query<'w, 's, (Entity, &'static Monitor)>: ReadOnlySystemParam, Query<'w, 's, Entity, With<PrimaryMonitor>>: ReadOnlySystemParam, Query<'w, 's, (&'static RenderTarget, &'static Msaa), With<NannouCamera>>: ReadOnlySystemParam, Res<'w, AssetServer>: ReadOnlySystemParam, Res<'w, Assets<Image>>: ReadOnlySystemParam, Res<'w, SharedTextCx>: ReadOnlySystemParam, Option<Res<'w, RenderDevice>>: ReadOnlySystemParam, Option<Res<'w, RenderQueue>>: ReadOnlySystemParam, Local<'s, Cell<Option<Entity>>>: ReadOnlySystemParam, Local<'s, RefCell<Vec<(Entity, bool, Window)>>>: ReadOnlySystemParam,

impl SystemParam for App<'_, '_>

type State = FetchState

Used to store data which persists across invocations of a system.

type Item<'w, 's> = App<'w, 's>

The item type returned when constructing this system param. The value of this associated type should be Self, instantiated with new lifetimes.

fn init_state(world: &mut World) -> Self::State

Creates a new instance of this param’s State.

fn init_access( state: &Self::State, system_meta: &mut SystemMeta, component_access_set: &mut FilteredAccessSet, world: &mut World, )

Registers any World access used by this SystemParam.

fn apply(state: &mut Self::State, system_meta: &SystemMeta, world: &mut World)

Applies any deferred mutations stored in this SystemParam’s state. This is used to apply Commands during ApplyDeferred.

fn queue( state: &mut Self::State, system_meta: &SystemMeta, world: DeferredWorld<'_>, )

Queues any deferred mutations to be applied at the next ApplyDeferred.

unsafe fn get_param<'w, 's>( state: &'s mut Self::State, system_meta: &SystemMeta, world: UnsafeWorldCell<'w>, change_tick: Tick, ) -> Result<Self::Item<'w, 's>, SystemParamValidationError>

Creates a parameter to be passed into a SystemParamFunction.