Ray Casting Tutorial?

Questions & Answers
1

Ive looked everywhere for a simple tutorial on ray casting but all I have found is the script reference page which dosent really help with what I need. But I don’t know anything about ray casting. Instead of having a bullet prefab coming out of my gun I have heard a ray cast would be better, can anyone help me with this?

4

This is the best raycasting post I’ve come across link text

2

Slow projectiles like rockets or cannon balls may be instantiated. For fast projectiles like bullets, it’s better to use a Raycast instead (in the First Person Tutorial, the rockets are instantiated, while the machine gun uses raycast). The script below shows how to use raycast to shoot: when the Shoot function is called, a Raycast is done in the weapon forward direction; if nothing hit, nothing happens; if it’s an enemy, you can instantiate blood at the hit point and send a message to make the enemy reduce its health; if another thing is hit, you can emit sparks at the hit point.

var shotSound: AudioClip; // drag a shot sound here, if any
var bloodPrefab: GameObject; // drag the blood prefab here, if any
var sparksPrefab: GameObject; // drag the sparks prefab here, if any

function Shoot(){
    if (shotSound) audio.PlayOneShot(shotSound); // play the shot sound
    var hit: RaycastHit;
    if (Physics.Raycast(transform.position, transform.forward, hit)){
        // prepare rotation to instantiate blood or sparks
        var rot = Quaternion.FromToRotation(Vector3.up, hit.normal);
        if (hit.transform.tag == "Enemy"){ // if enemy hit...
            if (bloodPrefab) Instantiate(bloodPrefab, hit.point, rot); // make it bleed...
            hit.transform.SendMessage("ApplyDamage", 5, SendMessageOptions.DontRequireReceiver); // and consume its health
        } else { // otherwise emit sparks at the hit point
            if (sparksPrefab) Instantiate(sparksPrefab, hit.point, rot);
        }
    }
}

This script shoots in the forward direction of the object to which it’s attached. If the weapon model has a different orientation, child to it an empty object and align it to the shooting direction, then attach the script to this object.

NOTE: You must add a ApplyDamage function to the enemy, like this:

var health = 100;

function ApplyDamage(damage: int){
    health -= damage;
    if (health <= 0){
        // enemy dies
    }
}
3

This ai uses raycast