Write a working bullet hell

I just fucked up the enemy movement, but hopefully I won't ever need
that old code. The new one is going to look really cool and sweet.
Anything with just modifying acceleration must look very cool and
smooth.

4 files changed, 463 insertions, 0 deletions

diff --git a/src/constants.rs b/src/constants.rs
new file mode 100644
index 0000000..3868ce3
--- /dev/null
+++ b/src/constants.rs
@@ -0,0 +1,2 @@
+pub const X_DIM: u32 = 800;
+pub const Y_DIM: u32 = 600;
diff --git a/src/main.rs b/src/main.rs
new file mode 100644
index 0000000..76b7a5b
--- /dev/null
+++ b/src/main.rs
@@ -0,0 +1,124 @@
+extern crate sdl2;
+
+mod state;
+mod player;
+mod constants;
+
+use state::Positioned;
+use state::Drawable;
+
+enum Result {
+    Win,
+    Loss,
+    Nothing,
+}
+
+fn spawn(count: u64) -> Vec<state::Enemy> {
+    if count == 0 {
+        vec![state::Enemy::new()]
+    } else {
+        Vec::new()
+    }
+}
+
+fn frame(canvas: &mut sdl2::render::WindowCanvas, state: &mut state::State, events: &mut sdl2::event::EventPollIterator) -> Result {
+    let mut new_bullets = Vec::new();
+    let count = state.count;
+    for enemy in state.enemies.iter_mut() {
+        new_bullets.append(&mut enemy.act(count));
+    }
+    for bullet in state.bullets.iter_mut() {
+        bullet.act();
+    }
+    for bullet in state.player_bullets.iter_mut() {
+        bullet.act();
+    }
+    state.player.act(events);
+    if count % state.player.fire_rate as u64 == 0 {
+        state.player_bullets.push(state::PBullet::new(state.player.x, 0., state.player.y, -1.));
+    }
+    if state.bullets.iter().any(|bullet| state.player.overlaps(bullet)) || new_bullets.iter().any(|bullet| state.player.overlaps(bullet)) {
+        return Result::Loss;
+    }
+    for enemy in state.enemies.iter_mut() {
+        for bullet in state.player_bullets.iter_mut() {
+            if enemy.overlaps(bullet) {
+                bullet.delete();
+                enemy.health -= 1;
+            }
+        }
+    }
+    state.enemies.retain(|enemy| state::Enemy::health(enemy) > 0);
+    state.enemies.append(&mut spawn(count));
+    if state.enemies.len() == 0 {
+        return Result::Win;
+    }
+    state.bullets.retain(|bullet| !state::EBullet::outside(bullet));
+    state.bullets.append(&mut new_bullets);
+    state.player_bullets.retain(|bullet| !state::PBullet::outside(bullet));
+    for bullet in state.player_bullets.iter() {
+        bullet.draw(canvas);
+    }
+    for enemy in state.enemies.iter() {
+        enemy.draw(canvas);
+    }
+    for bullet in state.bullets.iter() {
+        bullet.draw(canvas);
+    }
+    state.player.draw(canvas);
+    state.count += 1;
+    Result::Nothing
+}
+
+fn main() {
+    let sdl_context = sdl2::init().unwrap();
+    let video_subsystem = sdl_context.video().unwrap();
+
+    let window = video_subsystem.window("rust-sdl2 demo", constants::X_DIM, constants::Y_DIM).position_centered().build().unwrap();
+    let mut canvas = window.into_canvas().build().unwrap();
+
+    canvas.set_draw_color(sdl2::pixels::Color::RGB(255, 255, 255));
+    canvas.clear();
+    canvas.present();
+    let mut event_pump = sdl_context.event_pump().unwrap();
+    let start = std::time::Instant::now();
+    let frame_duration = std::time::Duration::new(0, 1_000_000_000u32 / 60);
+    let mut frame_count = 0;
+    let mut state = state::State::new();
+    let mut won = false;
+    'running: loop {
+        if won {
+            for event in event_pump.poll_iter() {
+                match event {
+                    sdl2::event::Event::Quit {..} | sdl2::event::Event::KeyDown { keycode: Some(sdl2::keyboard::Keycode::Escape), .. } => {
+                        std::process::exit(0);
+                    },
+                    _ => { },
+                }
+            }
+        } else {
+            canvas.set_draw_color(sdl2::pixels::Color::RGB(255, 255, 255));
+            canvas.clear();
+            match frame(&mut canvas, &mut state, &mut event_pump.poll_iter()) {
+                Result::Loss => {
+                    break;
+                }
+                Result::Win => {
+                    canvas.set_draw_color(sdl2::pixels::Color::RGB(255, 204, 102));
+                    canvas.clear();
+                    canvas.present();
+                    won = true;
+                }
+                _ => {
+                    canvas.present();
+                }
+            }
+        }
+        let calc_time = frame_duration * frame_count;
+        match calc_time.checked_sub(start.elapsed()) {
+            Some(t) => std::thread::sleep(t),
+            None => (),
+        }
+        frame_count += 1;
+    }
+}
diff --git a/src/player.rs b/src/player.rs
new file mode 100644
index 0000000..97c98f6
--- /dev/null
+++ b/src/player.rs
@@ -0,0 +1,100 @@
+extern crate sdl2;
+extern crate std;
+
+use super::state;
+
+pub struct Player {
+    pub x: i32,
+    pub y: i32,
+    left_p: bool,
+    right_p: bool,
+    up_p: bool,
+    down_p: bool,
+    y_d: i32,
+    x_d: i32,
+    pub fire_rate: u32,
+}
+
+impl Player {
+    pub fn new() -> Player {
+        Player { x: 400, y: 500, x_d: 0, y_d: 0, down_p: false, left_p: false, right_p: false, up_p: false, fire_rate: 30 }
+    }
+
+    pub fn act(&mut self, events: &mut sdl2::event::EventPollIterator){
+        for event in events {
+            match event {
+                sdl2::event::Event::Quit {..} |
+                    sdl2::event::Event::KeyDown { keycode: Some(sdl2::keyboard::Keycode::Escape), .. } => {
+                        std::process::exit(0);
+                    },
+                sdl2::event::Event::KeyDown { keycode: Some(sdl2::keyboard::Keycode::Down), .. } => {
+                    self.down_p = true;
+                    self.y_d = -1;
+                }
+                sdl2::event::Event::KeyUp { keycode: Some(sdl2::keyboard::Keycode::Down), .. } => {
+                    self.down_p = false;
+                }
+                sdl2::event::Event::KeyDown { keycode: Some(sdl2::keyboard::Keycode::Up), .. } => {
+                    self.up_p = true;
+                    self.y_d = 1;
+                }
+                sdl2::event::Event::KeyUp { keycode: Some(sdl2::keyboard::Keycode::Up), .. } => {
+                    self.up_p = false;
+                }
+                sdl2::event::Event::KeyDown { keycode: Some(sdl2::keyboard::Keycode::Left), .. } => {
+                    self.left_p = true;
+                    self.x_d = -1;
+                }
+                sdl2::event::Event::KeyUp { keycode: Some(sdl2::keyboard::Keycode::Left), .. } => {
+                    self.left_p = false;
+                }
+                sdl2::event::Event::KeyDown { keycode: Some(sdl2::keyboard::Keycode::Right), .. } => {
+                    self.right_p = true;
+                    self.x_d = 1;
+                }
+                sdl2::event::Event::KeyUp { keycode: Some(sdl2::keyboard::Keycode::Right), .. } => {
+                    self.right_p = false;
+                }
+                _ => { },
+            }
+        }
+        if self.left_p {
+            if !self.right_p {
+                self.x_d = -1;
+            }
+        } else if self.right_p {
+            self.x_d = 1;
+        } else {
+            self.x_d = 0;
+        }
+        if self.up_p {
+            if !self.down_p {
+                self.y_d = -1;
+            }
+        } else if self.down_p {
+            self.y_d = 1;
+        } else {
+            self.y_d = 0;
+        }
+        self.x += self.x_d;
+        self.y += self.y_d;
+    }
+}
+
+impl state::Positioned for Player {
+    fn x(&self) -> i32 {
+        self.x
+    }
+    fn y(&self) -> i32 {
+        self.y
+    }
+    fn radius(&self) -> u32 {
+        5
+    }
+}
+
+impl state::Drawable for Player {
+    fn color(&self) -> sdl2::pixels::Color {
+        sdl2::pixels::Color::RGB(0, 0, 0)
+    }
+}
diff --git a/src/state.rs b/src/state.rs
new file mode 100644
index 0000000..74ac73b
--- /dev/null
+++ b/src/state.rs
@@ -0,0 +1,237 @@
+extern crate sdl2;
+extern crate std;
+extern crate rand;
+
+use super::player;
+use super::constants;
+
+pub struct EBullet {
+    x: i32,
+    y: i32,
+    radius: u32,
+    real_x: f64,
+    real_y: f64,
+    d_x: f64,
+    d_y: f64,
+}
+
+pub struct Enemy {
+    pub x: i32,
+    pub y: i32,
+    action_count: u64,
+    v_x: f64,
+    v_y: f64,
+    a_x: f64,
+    a_y: f64,
+    target_x: f64,
+    target_y: f64,
+    radius: u32,
+    pub health: i64,
+}
+
+const STARTING_HEALTH: i64 = 100;
+
+impl EBullet {
+    pub fn new(x: i32, d_x: f64, y: i32, d_y: f64) -> EBullet {
+        EBullet { x: x, real_x: x as f64, y: y, real_y: y as f64, radius: 10, d_x: d_x, d_y: d_y }
+    }
+
+    pub fn act(&mut self) {
+        self.real_x += self.d_x;
+        self.real_y += self.d_y;
+        self.x = self.real_x.round() as i32;
+        self.y = self.real_y.round() as i32;
+    }
+}
+
+pub struct PBullet {
+    b: EBullet,
+}
+
+impl PBullet {
+    pub fn new(x: i32, d_x: f64, y: i32, d_y: f64) -> PBullet {
+        PBullet { b: EBullet::new(x, d_x, y, d_y) }
+    }
+    pub fn act(&mut self) {
+        self.b.act()
+    }
+    pub fn delete(&mut self) {
+        self.b.x = -10;
+    }
+}
+
+fn random_bullet(enemy: &Enemy) -> EBullet {
+    let multiplier = 2. + (STARTING_HEALTH as i64 - enemy.health) as f64 / STARTING_HEALTH as f64 * 2.;
+    let theta: f64 = rand::random::<f64>()*2.*std::f64::consts::PI/3. + std::f64::consts::PI/6.;
+    let dx = f64::cos(theta) * multiplier;
+    let dy = f64::sin(theta) * multiplier;
+    EBullet::new(enemy.x, dx, enemy.y, dy)
+}
+
+fn random_position() -> (f64, f64) {
+    (rand::random() * (constants::X_DIM - 200) as f64 + 100., rand::random() * 200)
+}
+
+impl Enemy {
+    pub fn new() -> Enemy {
+        Enemy { x: 200, y: 40, action_count: 1, v_x: 0., v_y: 0., a_x: 0., a_y: 0., radius: 30, health: STARTING_HEALTH, target_x: 200, target_y: 400 }
+    }
+    pub fn act(&mut self, count: u64) -> Vec<EBullet> {
+        let dx = self.target_x - self.x;
+        let dy = self.target_y - self.y;
+        /* Made it; pick a new destination */
+        if f64::sqrt(dx*dx + dy*dy) < 10 {
+            let (self.target_x, self.target_y) = random_position();
+        }
+        let vec_x = self.target_x - self.real_x;
+        let vec_y = self.target_y - self.real_y;
+        let len = f64::sqrt(vec_x*vec_x + vec_y*vec_y);
+        self.a_x = vec_x / len / 2.;
+        self.a_y = vec_y / len / 2.;
+
+        self.v_x += self.a_x;
+        self.x = (self.x as f64 + self.v_x).round() as i32;
+        self.v_y += self.a_y;
+        self.y = (self.y as f64 + self.v_y).round() as i32;
+        if count % 20 == 0 {
+            let num_bullets;
+            if self.health >= 80 {
+                num_bullets = 4;
+            } else if self.health >= 50 {
+                num_bullets = 5;
+            } else if self.health >= 30 {
+                num_bullets = 6;
+            } else if self.health >= 20 {
+                num_bullets = 7;
+            } else {
+                num_bullets = 8;
+            }
+            let mut result = Vec::new();
+            for _ in 0..num_bullets {
+                result.push(random_bullet(&*self));
+            }
+            result
+        } else {
+            Vec::new()
+        }
+    }
+    pub fn health(&self) -> i64 {
+        self.health
+    }
+}
+
+pub struct State {
+    pub player: player::Player,
+    pub enemies: Vec<Enemy>,
+    pub bullets: Vec<EBullet>,
+    pub player_bullets: Vec<PBullet>,
+    pub count: u64,
+}
+
+impl State {
+    pub fn new() -> State {
+        State { player: player::Player::new(), enemies: Vec::new(), bullets: Vec::new(), count: 0, player_bullets: Vec::new() }
+    }
+}
+
+fn dist(x1: i32, y1: i32, x2: i32, y2: i32) -> f64 {
+    let xdist = x1 - x2;
+    let ydist = y1 - y2;
+    f64::sqrt((xdist*xdist + ydist*ydist) as f64)
+}
+
+pub trait Positioned {
+    fn x(&self) -> i32;
+    fn y(&self) -> i32;
+    fn radius(&self) -> u32;
+    fn contains(&self, x: i32, y: i32) -> bool {
+        let d = dist(self.x(), self.y(), x, y);
+        d <= self.radius() as f64
+    }
+    fn overlaps<T: Positioned>(&self, other: &T) -> bool {
+        let dist = dist(self.x(), self.y(), other.x(), other.y());
+        dist < (self.radius() + other.radius()) as f64
+    }
+    fn outside(&self) -> bool {
+        let x = self.x();
+        let y = self.y();
+        x < 0 || x as u32 > constants::X_DIM || y < 0 || y as u32 > constants::Y_DIM
+    }
+}
+
+impl Positioned for EBullet {
+    fn x(&self) -> i32 {
+        self.x
+    }
+    fn y(&self) -> i32 {
+        self.y
+    }
+    fn radius(&self) -> u32 {
+        self.radius
+    }
+}
+
+impl Positioned for PBullet {
+    fn x(&self) -> i32 {
+        self.b.x()
+    }
+    fn y(&self) -> i32 {
+        self.b.y()
+    }
+    fn radius(&self) -> u32 {
+        self.b.radius()
+    }
+}
+
+impl Positioned for Enemy {
+    fn x(&self) -> i32 {
+        self.x
+    }
+    fn y(&self) -> i32 {
+        self.y
+    }
+    fn radius(&self) -> u32 {
+        self.radius
+    }
+}
+
+pub trait Drawable : Positioned {
+    fn color(&self) -> sdl2::pixels::Color;
+    fn draw(&self, canvas: &mut sdl2::render::WindowCanvas) {
+        let x = self.x();
+        let y = self.y();
+        let r = self.radius();
+        let r = r as i32;
+        let x_min = x - r;
+        let x_max = x + r;
+        let y_min = y - r;
+        let y_max = y + r;
+        canvas.set_draw_color(self.color());
+        for x in x_min..x_max + 1 {
+            for y in y_min..y_max + 1 {
+                if self.contains(x, y) {
+                    canvas.fill_rect(sdl2::rect::Rect::new(x, y, 1, 1)).unwrap();
+                }
+            }
+        }
+    }
+}
+
+impl Drawable for Enemy {
+    fn color(&self) -> sdl2::pixels::Color {
+        let red_scale = self.health as f64 / STARTING_HEALTH as f64 * 255.;
+        sdl2::pixels::Color::RGB(red_scale as u8, 255 - red_scale as u8, 0)
+    }
+}
+
+impl Drawable for EBullet {
+    fn color(&self) -> sdl2::pixels::Color {
+        sdl2::pixels::Color::RGB(0, 0, 255)
+    }
+}
+
+impl Drawable for PBullet {
+    fn color(&self) -> sdl2::pixels::Color {
+        sdl2::pixels::Color::RGB(230, 255, 230)
+    }
+}