AudioSource error - unity3d

Question

I am following directions out of a book to put together a simple FPS. However, I am not getting the same results as the book says I should.
The last thing I have been trying to do is add a sound to my "gun", so that this sound clip "pop.wav" plays when you fire.
Here is the working code before I took the steps to add the sound.
var projectile : Rigidbody;
var speed = 50;
function Update () {
if(Input.GetButtonDown("Fire1"))
{
var instantiatedProjectile : Rigidbody = Instantiate(projectile, transform.position +
Vector3(0,-1,0), transform.rotation);
instantiatedProjectile.velocity = transform.TransformDirection(Vector3(0,0,speed));
Physics.IgnoreCollision(instantiatedProjectile.collider, transform.root.collider);
}
}
So I did what the book said, and imported Pop.wav. Then it said to add two simple lines of code to the script.
var projectile : Rigidbody;
var speed = 50;
var pop : AudioClip;
function Update () {
if(Input.GetButtonDown("Fire1"))
{
var instantiatedProjectile : Rigidbody = Instantiate(projectile, transform.position +
Vector3(0,-1,0), transform.rotation);
instantiatedProjectile.velocity = transform.TransformDirection(Vector3(0,0,speed));
Physics.IgnoreCollision(instantiatedProjectile.collider, transform.root.collider);
audio.Play(pop);
}
}
Assets/FireProjectile.js(12,27): BCE0023: No appropriate version of 'UnityEngine.AudioSource.Play' for the argument list '(UnityEngine.AudioClip)' was found.
I would really appreciate some help on this.

Answer 1

I don't see you assigning the file to be played to the audio clip... something like
pop.clip = ...
A brief search on unity 3d mentions assigning the clip, and checking that it's ready to play.

Answer 2

Actually, you have overlooked something outside the script. You do in fact need to add an audio listener and an audio source in the scene. Then, you'll be able to hear the sound.
The reason for this is that unity allows for 3D sound, i.e. sound which has a location in 3D space, and will increase in volume if you go near it. The Audio Source is obviously where the sound is comming from, and Audio Listener is where your ears are, so to speak. Usually the audio listener is on your character. But you can rig it so that it is on any object, but then that object would have to get near the audio source, and not the character, which doesn't make any sense at all.
However, remember to only have ONE audio LISTENER at a time. Infinite audio SOURCES are allowed. :)

Answer 3

You need to assign your variable. It would be something like
pop.clip = (anything here)

Answer 4

You must use audio.PlayOneShot(pop) instead of audio.Play().
But if you want to use audio.Play(); you should know that it doesn't take AudioClip as argument.
Use following code and make sure you assign pop to Audio Clip property of Audio Source component by dragging pop sound from Project to inspector. audio.Play() uses default assigned Audio Clip in AudioSource.
var projectile : Rigidbody;
var speed = 50;
function Update () {
if(Input.GetButtonDown("Fire1"))
{
var instantiatedProjectile : Rigidbody = Instantiate(projectile, transform.position +
Vector3(0,-1,0), transform.rotation);
instantiatedProjectile.velocity = transform.TransformDirection(Vector3(0,0,speed));
Physics.IgnoreCollision(instantiatedProjectile.collider, transform.root.collider);
audio.Play();
}
}
#script RequireComponent(AudioSource)

Answer 5

Based on the Unity documentation (I've never used Unity so I can't be sure this is correct) I find that you probably want to do something like this.
var projectile : Rigidbody;
var speed = 50;
var pop : AudioClip;
...
if(Input.GetButtonDown("Fire1"))
{
var instantiatedProjectile : Rigidbody = Instantiate(projectile, transform.position +
Vector3(0,-1,0), transform.rotation);
instantiatedProjectile.velocity = transform.TransformDirection(Vector3(0,0,speed));
Physics.IgnoreCollision(instantiatedProjectile.collider, transform.root.collider);
audio.PlayOneShot(pop);
}
This is actually all you have to do. Assign a variable, and then tell it to play in the update function, whenever Fire1 is pressed, which is LMB by default.
PlayOneShot means the sound won't loop or anything, which I assume you want for gunshots or similar. Within the parentheses you simply name the sound you want to play.