Added boid generation and borders physics

src/main.rs

@@ -0,0 +1,122 @@
+use sdl2::pixels::Color;
+use sdl2::event::Event;
+use sdl2::keyboard::Keycode;
+use sdl2::keyboard::Scancode;
+use std::collections::HashSet;
+use std::time::Duration;
+use sdl2::rect::Point;
+use sdl2::rect::Rect;
+use rand::Rng;
+
+const WINDOW_HEIGHT:i32 = 600;
+const WINDOW_WIDTH:i32 = 800;
+const BIRD_SPEED:i32 = 2;
+const MAX_BIRD_SPEED:i32 = 10;
+const BIRDS_COUNT:i32 = 50;
+const MIN_BIRD_SIZE:i32 = 20;
+const MAX_BIRD_SIZE:i32 = 50;
+
+pub struct Bird{
+    shape:Rect,
+    velocity:Point,
+}
+
+pub struct Simulation{
+    birds:Vec<Bird>,
+}
+impl Simulation{
+    pub fn render(&mut self,ctx:&mut sdl2::render::Canvas<sdl2::video::Window>){
+        ctx.set_draw_color(Color::RGB(0x6D, 0x6D, 0x64));
+        ctx.clear();
+        ctx.set_draw_color(Color::RGB(0x33, 0x33, 0x33));
+        for bird in self.birds.iter(){
+            ctx.fill_rect(bird.shape).expect("Rusty Boids");
+        }
+    }
+    pub fn update(&mut self){
+        for bird in &mut self.birds{
+            let mut posx = bird.shape.x;
+            let mut posy = bird.shape.y;
+            let width:i32 = bird.shape.width() as i32;
+            let height:i32 = bird.shape.height() as i32;
+            let left_wall = WINDOW_WIDTH - width;
+            let bottom_wall = WINDOW_HEIGHT- height;
+
+            if posx + bird.velocity.x > WINDOW_WIDTH - width{
+                let offset = left_wall - (posx + bird.velocity.x);
+                posx = left_wall - offset;
+                bird.velocity.x = -bird.velocity.x;
+            }
+            if posx + bird.velocity.x < 0{
+                let offset = posx + bird.velocity.x;
+                posx = 0 + offset;
+                bird.velocity.x = -bird.velocity.x;
+            }
+
+            if posy + bird.velocity.y > WINDOW_HEIGHT - height{
+                let offset = bottom_wall - (posy + bird.velocity.y);
+                posy = bottom_wall - offset;
+                bird.velocity.y = -bird.velocity.y;
+            }
+            if posy + bird.velocity.y < 0{
+                let offset = posy + bird.velocity.y;
+                posy = 0 + offset;
+                bird.velocity.y = -bird.velocity.y;
+            }
+
+            posx += bird.velocity.x;
+            posy += bird.velocity.y;
+            bird.shape.set_x(posx);
+            bird.shape.set_y(posy);
+        }
+    }
+}
+
+pub fn main_loop(canvas: &mut sdl2::render::Canvas<sdl2::video::Window>,event_pump:&mut sdl2::EventPump,game:&mut Simulation){
+    'running: loop {
+        for event in event_pump.poll_iter() {
+            match event {
+                Event::Quit {..} |
+                Event::KeyDown { keycode: Some(Keycode::Escape), .. } => {
+                    break 'running
+                },
+                _ => {}
+            }
+        }
+        
+        // MAIN LOOP
+        game.update();
+        game.render(canvas);
+        // MAIN LOOP
+
+        canvas.present();
+        ::std::thread::sleep(Duration::new(0, 1_000_000_000u32 / 60));
+    }
+}
+pub fn generate_birds() -> Vec<Bird>{
+    let mut rng = rand::thread_rng();
+    let mut birds = Vec::with_capacity(BIRDS_COUNT as usize);
+    for bird in  0..BIRDS_COUNT{
+        let size = rng.gen_range(MIN_BIRD_SIZE as u32..MAX_BIRD_SIZE as u32);
+        let rectangle = Rect::new(rng.gen_range(0..WINDOW_WIDTH - MAX_BIRD_SIZE),rng.gen_range(0..WINDOW_HEIGHT - MAX_BIRD_SIZE),size, size);
+        let velocity = Point::new(rng.gen_range(0..MAX_BIRD_SPEED), rng.gen_range(0..MAX_BIRD_SPEED));
+        birds.push(Bird{shape:rectangle,velocity:velocity});
+    }
+    return birds;
+}
+pub fn main() {
+    let sdl_context = sdl2::init().unwrap();
+    let video_subsystem = sdl_context.video().unwrap();
+
+    let window = video_subsystem.window("Test SDL Rust", WINDOW_WIDTH as u32, WINDOW_HEIGHT as u32)
+        .position_centered()
+        .build()
+        .unwrap();
+
+    let mut canvas = window.into_canvas().build().unwrap();
+    let mut event_pump = sdl_context.event_pump().unwrap();
+
+    let mut simulation = Simulation{birds:generate_birds()};
+
+    main_loop(&mut canvas,&mut event_pump,&mut simulation);
+}