bevy/examples/2d/2d_viewport_to_world.rs
ZoOL 17e504812b
simplify example, replace get_single to Single Query (#16187)
# Objective

clean up example get_single method, make code clean;

## Solution

- replace `Query`  with `Single` Query
- remove `get_single` or `get_single_mut` condition block
2024-11-01 18:25:42 +00:00

34 lines
863 B
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: Single<&Window>,
mut gizmos: Gizmos,
) {
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);
}