Created
August 25, 2024 05:22
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generate random points outside the screen bevy
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| use bevy::prelude::*; | |
| use rand::{thread_rng, Rng}; | |
| fn main() { | |
| App::new() | |
| .insert_resource(ClearColor(Color::srgb(1.0, 0.0, 0.0))) | |
| .add_plugins(DefaultPlugins) | |
| .add_systems(Startup, setup) | |
| .add_systems(Update, point_out) | |
| .run(); | |
| } | |
| fn setup(mut commands: Commands) { | |
| commands.spawn(Camera2dBundle::default()); | |
| } | |
| fn rand_outside(rect: Rect) -> Vec2 { | |
| let r = rect.inflate(100.0); // we want to be solidly outside the screen, not just on the edge | |
| let Vec2 { | |
| x: width, | |
| y: height, | |
| } = r.size(); | |
| let perimeter = 2.0 * (width + height); | |
| let rnum = rand::thread_rng().gen_range(0.0..perimeter); | |
| if rnum < width { | |
| // Bottom edge | |
| Vec2 { | |
| x: r.min.x + rnum, | |
| y: r.min.y, | |
| } | |
| } else if rnum < width + height { | |
| // Right edge | |
| Vec2 { | |
| x: r.max.x, | |
| y: r.min.y + (rnum - width), | |
| } | |
| } else if rnum < 2.0 * width + height { | |
| // Top edge | |
| Vec2 { | |
| x: r.max.x - (rnum - width - height), | |
| y: r.max.y, | |
| } | |
| } else { | |
| // Left edge | |
| Vec2 { | |
| x: r.min.x, | |
| y: r.max.y - (rnum - 2.0 * width - height), | |
| } | |
| } | |
| } | |
| fn point_out( | |
| mut gizmos: Gizmos, | |
| q_window: Query<&Window>, | |
| q_camera: Query<(&Camera, &GlobalTransform)>, | |
| ) { | |
| let (camera, camera_transform) = q_camera.single(); | |
| let window = q_window.single(); | |
| let w = window.resolution.width(); | |
| let h = window.resolution.height(); | |
| let bottom_right = camera | |
| .viewport_to_world_2d(camera_transform, Vec2::new(w, h)) | |
| .unwrap(); | |
| let top_left = camera | |
| .viewport_to_world_2d(camera_transform, Vec2::new(0., 0.)) | |
| .unwrap(); | |
| let rect = Rect::from_corners(top_left, bottom_right); | |
| let outside = rand_outside(rect); | |
| gizmos.line_2d(Vec2::ZERO, outside, Color::WHITE); | |
| } |
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