[Unity3D] Basic player movement

#pragma strict

private var rotacao : float;
private var distancia : float;
private var xpos : float;
private var zpos : float;
public var player : GameObject;
public var xcam : Camera;
public var terreno : GameObject;
private var grounded : boolean = false;

@script RequireComponent(Rigidbody, CapsuleCollider)

function Start() {
    distancia = 0.1;
    player.rigidbody.freezeRotation = true;
    player.rigidbody.useGravity = true;
}
function Update() {
    if(Input.GetKey(KeyCode.W)) {
        rotacao = xcam.transform.eulerAngles.y;
        xpos = (distancia * Mathf.Sin(rotacao*(Mathf.PI/180))) / 2.0;
        zpos = (distancia * Mathf.Cos(rotacao*(Mathf.PI/180))) / 2.0;
        player.transform.Translate(xpos,0,zpos);
    }
    else if(Input.GetKey(KeyCode.S)) {
        rotacao = xcam.transform.eulerAngles.y + 180.0;
        xpos = (distancia * Mathf.Sin(rotacao*(Mathf.PI/180))) / 2.0;
        zpos = (distancia * Mathf.Cos(rotacao*(Mathf.PI/180))) / 2.0;
        player.transform.Translate(xpos,0,zpos);
    }
    else if(Input.GetKey(KeyCode.A)) {
        rotacao = xcam.transform.eulerAngles.y - 90.0;
        xpos = (distancia * Mathf.Sin(rotacao*(Mathf.PI/180))) / 2.0;
        zpos = (distancia * Mathf.Cos(rotacao*(Mathf.PI/180))) / 2.0;
        player.transform.Translate(xpos,0,zpos);
    }
    else if(Input.GetKey(KeyCode.D)) {
        rotacao = xcam.transform.eulerAngles.y + 90.0;
        xpos = (distancia * Mathf.Sin(rotacao*(Mathf.PI/180))) / 2.0;
        zpos = (distancia * Mathf.Cos(rotacao*(Mathf.PI/180))) / 2.0;
        player.transform.Translate(xpos,0,zpos);
    }
    else if(Input.GetKey(KeyCode.Space)) {
        if(grounded == true) {
            player.transform.Translate(0.0,1.0,0.0);
            grounded = false;
        }
    }
}
function OnCollisionEnter (hit : Collision) {
    if(hit.gameObject.name == terreno.name) {
        grounded = true;
    }
}