snake/src/game.rs

use bevy::prelude::*;

use crate::components as c;

pub fn setup(mut commands: Commands, mut materials: ResMut<Assets<ColorMaterial>>) {
    commands.spawn_bundle(OrthographicCameraBundle::new_2d());
    commands.insert_resource(c::Materials {
        head_material: materials.add(Color::rgb(0.7, 0.7, 0.7).into()),
        segment_material: materials.add(Color::rgb(0.3, 0.3, 0.3).into()),
        food_material: materials.add(Color::rgb(1.0, 0.0, 1.0).into()),
    });
}

pub fn size_scaling(windows: Res<Windows>, mut q: Query<(&c::GridSize, &mut Sprite)>) {
    let window = windows.get_primary().unwrap();
    for (size, mut sprite) in q.iter_mut() {
        sprite.size = Vec2::new(
            size.width / c::ARENA_WIDTH as f32 * window.width() as f32,
            size.height / c::ARENA_HEIGHT as f32 * window.height() as f32,
        );
    }
}

pub fn position_translation(windows: Res<Windows>, mut q: Query<(&c::Position, &mut Transform)>) {
    fn convert(pos: f32, bound_window: f32, bound_game: f32) -> f32 {
        let tile_size = bound_window / bound_game;
        pos / bound_game * bound_window - (bound_window / 2.0) + (tile_size / 2.0)
    }

    let window = windows.get_primary().unwrap();
    for (pos, mut tf) in q.iter_mut() {
        tf.translation = Vec3::new(
            convert(pos.x as f32, window.width() as f32, c::ARENA_WIDTH as f32),
            convert(pos.y as f32, window.height() as f32, c::ARENA_HEIGHT as f32),
            0.0,
        )
    }
}