lecture 3

Question 1

intersects(other) {
let d = dist(this.xPos, this.yPos, other.xPos, other.yPos);
if (d < this.radius + other.radius) {
return true;
} else {
return false;
}
}

what is the above code doing?

Answer 1

checking collision based on radius

Question 2

if (missile1.intersects(enemy1)) {
enemy1.colour = ‘black’;
}

what will occur when the above code is called?

Answer 2

if a missile intersects with an enemy the colour of the enemy will be black

Question 3

for (let i = 0; i < missiles.length; i++) {
for (let j = 0; j < numOfEnemies; j++) {
if (missiles[i].intersects(enemies[j]) || missiles[i].xPos > width) {
enemies[j].colour = ‘black’;
missiles.splice(i, 1);

What single piece of code would you add after splice to prevent accessing deleted missiles in a loop?

Answer 3

break;

Question 4

for an enemy is it better to A. delete and create a new enemy or B. make the enemy invisible and reuse it after its traversed the screen?

Answer 4

B

Question 5

for a missile is it better to reuse or recreate?

Answer 5

recreate as it is dynamic to the player and they are no longer required. e.g. after a collision or if they have traversed the screen (without a collision).

Question 6

what would happen if you didn’t delete the missile after it traverses your screen?

Answer 6

it will continue moving and increase memory usage in your application.