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use crate::color::Palette;
use crate::color::db32::{BLUE, CYAN, GRAY, LIGHT_RED, LIME, PALE_BLUE, WHITE, YELLOW};
use crate::rng::Rng;
use crate::{GAME_H, GAME_W};
const STAR_COLORS: [u8; 8] = [WHITE, GRAY, PALE_BLUE, CYAN, BLUE, YELLOW, LIGHT_RED, LIME];
struct Star {
color: u8,
speed: f32,
x: i32,
y: f32,
}
#[derive(Default)]
pub struct Starfield {
stars: Vec<Star>,
}
impl Starfield {
pub fn new(count: usize, rng: &mut Rng) -> Self {
let stars = (0..count)
.map(|i| {
let speed = match i % 3 {
0 => 0.5,
1 => 1.0,
_ => 1.5,
};
Star {
color: STAR_COLORS[rng.range(STAR_COLORS.len() as u32) as usize],
speed,
x: rng.range(GAME_W) as i32,
y: rng.range(GAME_H) as f32,
}
})
.collect();
Self { stars }
}
pub fn update(&mut self) {
for star in &mut self.stars {
star.y += star.speed;
if star.y >= GAME_H as f32 {
star.y -= GAME_H as f32;
}
}
}
pub fn draw(&self, frame: &mut [u32], palette: &Palette, a: f32) {
for star in &self.stars {
let y = star.y - star.speed * (1.0 - a);
let y = (y as i32).rem_euclid(GAME_H as i32);
frame[(y * GAME_W as i32 + star.x) as usize] = palette.at(star.color);
}
}
}
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