return the brain rather than full bird object

Author: shiffman

examples/NeuroEvolution-flappy-bird/bird.js

@@ -1,9 +1,9 @@
 class Bird {
   constructor(brain) {
-    // A bird's brain receives 5 inputs and classifies them into one of two labels
     if (brain) {
       this.brain = brain;
     } else {
+      // A bird's brain receives 4 inputs and classifies them into one of two labels
       this.brain = ml5.neuralNetwork({
         inputs: 4,
         outputs: ["flap", "no flap"],

examples/NeuroEvolution-flappy-bird/sketch.js

@@ -7,7 +7,6 @@ function setup() {
     birds[i] = new Bird();
   }
   pipes.push(new Pipe());
-
   ml5.tf.setBackend("cpu");
 }
 
@@ -59,7 +58,7 @@ function reproduction() {
   for (let i = 0; i < birds.length; i++) {
     let parentA = weightedSelection();
     let parentB = weightedSelection();
-    let child = parentA.brain.crossover(parentB.brain);
+    let child = parentA.crossover(parentB);
     child.mutate(0.01);
     nextBirds[i] = new Bird(child);
   }
@@ -91,5 +90,6 @@ function weightedSelection() {
   }
   // Undo moving to the next element since the finish has been reached
   index--;
-  return birds[index];
+  // Instead of returning the entire Bird object, just the brain is returned
+  return birds[index].brain;
 }