Add a_tension_span

1 files changed, 59 insertions, 0 deletions

diff --git a/2026/games_submissions/asrael_io/source/src/starfield.rs b/2026/games_submissions/asrael_io/source/src/starfield.rs
new file mode 100644
index 0000000..ab7a199
--- /dev/null
+++ b/2026/games_submissions/asrael_io/source/src/starfield.rs
@@ -0,0 +1,59 @@
+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);
+        }
+    }
+}