bevy/examples/2d/2d_viewport_to_world.rs
jiang heng dfac3b9bfd
Fix window close in example cause panic (#17533)
# Objective

Fixes #17532 

## Solution

- check window valide
2025-01-28 05:37:23 +00:00

50 lines
1.2 KiB
Rust

//! This example demonstrates how to use the `Camera::viewport_to_world_2d` method.
use bevy::{color::palettes::basic::WHITE, prelude::*};
fn main() {
App::new()
.add_plugins(DefaultPlugins)
.add_systems(Startup, setup)
.add_systems(Update, draw_cursor)
.run();
}
fn draw_cursor(
camera_query: Single<(&Camera, &GlobalTransform)>,
window: Query<&Window>,
mut gizmos: Gizmos,
) {
let Ok(window) = window.get_single() else {
return;
};
let (camera, camera_transform) = *camera_query;
let Some(cursor_position) = window.cursor_position() else {
return;
};
// Calculate a world position based on the cursor's position.
let Ok(point) = camera.viewport_to_world_2d(camera_transform, cursor_position) else {
return;
};
gizmos.circle_2d(point, 10., WHITE);
}
fn setup(mut commands: Commands) {
commands.spawn(Camera2d);
// Create a minimal UI explaining how to interact with the example
commands.spawn((
Text::new("Move the mouse to see the circle follow your cursor."),
Node {
position_type: PositionType::Absolute,
top: Val::Px(12.0),
left: Val::Px(12.0),
..default()
},
));
}