ants reflect back from map edges

src/ant.rs

@@ -24,6 +24,7 @@ impl Ant {
             .collect()
     }
     pub(crate) fn walk(&mut self, frame_time: f32, trail_map: &mut Image) {
+        self.sense(trail_map);
         let new_dir = PI / 8. * RandomRange::gen_range(-2, 2) as f32;
         self.dir += new_dir;
         if self.dir > 2. * PI {
@@ -32,16 +33,29 @@ impl Ant {
 
         let acceleration = Vec2::new(self.dir.sin(), -self.dir.cos());
         self.pos += acceleration * ANT_SPEED * frame_time;
+        // if we are out of the map, turn around 180 degrees (or pi in radian)
+        if self.pos.x < 0.0
+            || self.pos.x >= (MAP_WIDTH - 1) as f32
+            || self.pos.y < 0.0
+            || self.pos.y >= (MAP_HEIGHT - 1) as f32
+        {
+            self.dir += PI;
+        }
         self.pos.x = self.pos.x.clamp(0., (MAP_WIDTH - 1) as f32);
         self.pos.y = self.pos.y.clamp(0., (MAP_HEIGHT - 1) as f32);
 
         // TODO: change color over time
         trail_map.set_pixel(self.pos.x as u32, self.pos.y as u32, RED);
     }
+    fn sense(&self, trail_map: &mut Image) {
+        trail_map.set_pixel(self.dir.sin() as u32, -self.dir.cos() as u32, YELLOW);
+        trail_map.set_pixel(self.dir.sin() as u32, -self.dir.cos() as u32, YELLOW);
+        trail_map.set_pixel(self.dir.sin() as u32, -self.dir.cos() as u32, YELLOW);
+    }
 }
 
 impl Drawable for Ant {
     fn draw(&self) {
-        draw_circle(self.pos.x, self.pos.y, 1., WHITE);
+        //draw_circle(self.pos.x, self.pos.y, 1., WHITE);
     }
 }

src/constants.rs

@@ -1,3 +1,3 @@
-pub static ANT_SPEED: f32 = 20.;
+pub static ANT_SPEED: f32 = 200.;
 pub const MAP_WIDTH: u32 = 1280;
 pub const MAP_HEIGHT: u32 = 720;