bevy_adventure 0.4.0

use bevy::prelude::*;

pub struct CursorPlugin;

#[rustfmt::skip]
impl Plugin for CursorPlugin {
    fn build(&self, app: &mut App) {
        app
            .init_resource::<Cursor>()
            .add_system_to_stage(CoreStage::First, update_cursor);
    }
}

/// A resource that stores the current position of the Cursor.
///
/// Updated with the current mouse position whenever it is moved.
/// This resource can be used to render a cursor icon or move the cursor from gamepad inputs.
/// The position of this Cursor resource is used when interacting with objects in the scene.
#[derive(Resource, Default)]
pub struct Cursor {
    position: Vec2,
    last_position: Vec2,
}

impl Cursor {
    /// Set the current cursor position.
    pub fn set(&mut self, position: Vec2) {
        self.last_position = self.position;
        self.position = position;
    }

    /// Change the current cursor position by the given offset.
    pub fn offset(&mut self, offset: Vec2) {
        self.set(self.position + offset);
    }

    /// Returns the current cursor position.
    pub fn position(&self) -> Vec2 {
        self.position
    }
}

#[allow(clippy::needless_pass_by_value)]
fn update_cursor(window: Res<Windows>, mut cursor: ResMut<Cursor>) {
    if let Some(mouse) = window.primary().cursor_position() {
        if mouse != cursor.last_position {
            cursor.set(mouse);
        }
    }
}