update Boid class for new Monobehavior structure

Assets/Boid.cs

@@ -1,22 +1,13 @@
 using System.Collections.Generic;
 using UnityEngine;
 
-public class Boid {
-    private Vector2 _position;
-    private Vector2 _velocity;
-
-    public Boid(Vector2 position, Vector2 velocity) {
-        _position = position;
-        _velocity = velocity;
-    }
-
-    public void SetPosition(Vector2 position) {
-        _position = position;
-    }
-    
-    // Renders the Boid. If focused, the 
-    void Render(bool focused = false) {
+// Boids are represented by a moving, rotating triangle.
+// Boids should communicate with sibling Boids
+public class Boid : MonoBehaviour {
+    public Vector2 velocity = Vector2.zero;
 
+    void Start() {
+        velocity = Vector2.one;
     }
 
     // Returns the next position the Boid will be moving to
@@ -29,23 +20,23 @@ public class Boid {
         Vector2 r2 = Rule2(flock) * magnitudes[1];
         Vector2 r3 = Rule3(flock) * magnitudes[2];
 
-        return _position + r1 + r2 + r3;
+        return transform.position + (Vector3) (r1 + r2 + r3);
     }
 
     // Cohesion: Steer towards center of mass of flock
     Vector2 Rule1(List<Boid> flock) {
         Vector2 center = Vector2.zero;
         foreach (Boid boid in flock)
-            center += boid._position;
+            center += (Vector2) boid.transform.position;
         center /= flock.Count;
-        return (center - _position) / 100;
+        return (center - (Vector2) transform.position) / 100;
     }
 
     // Separation: Steer to avoid other Boids within flock
     Vector2 Rule2(List<Boid> flock) {
         Vector2 c = Vector2.zero;
         foreach (Boid boid in flock) {
-            Vector2 diff = boid._position - _position;
+            Vector2 diff = boid.transform.position - transform.position;
             if (diff.magnitude < 5)
                 c -= diff;
         }
@@ -56,15 +47,16 @@ public class Boid {
     Vector3 Rule3(List<Boid> flock) {
         Vector2 perceived = Vector2.zero;
         foreach (Boid boid in flock)
-            perceived += boid._velocity;
+            perceived += boid.velocity;
         perceived /= flock.Count;
-        return (perceived - _velocity) / 8;
+        return (perceived - velocity) / 8;
     }
 
+    // Returns a list of boids within a certain radius of the Boid, representing it's local 'flock'
     List<Boid> GetFlock(List<Boid> boids, float radius) {
         List<Boid> flock = new List<Boid>();
         foreach(Boid boid in boids)
-            if(boid != this && Vector2.Distance(_position, boid._position) <= radius)
+            if(boid != this && Vector2.Distance(transform.position, boid.transform.position) <= radius)
                 flock.Add(boid);
         return flock;
     }