Raycast forward except for the Y axis

Question

I need to Raycast forward from the enemy except for the Y axis w$$anonymous$$ch should point to the player

Basically I want the enemy raycast direction to be forward but also point to the players height, because when the player is on for example a ramp the enemy cant see it.

Here is an image is an image to illustrate the problem.

alt text

T$$anonymous$$s is the raycast function.

 void FixedUpdate(){
     sight.origin = new Vector3(transform.position.x, transform.position.y + 0.5f, transform.position.z);
     sight.direction = transform.forward;
     RaycastHit rayHit;
     //Vector3 fwd = transform.TransformDirection(Vector3.forward);
 
     if (Physics.Raycast(sight, out rayHit, chaseRange)){
         Debug.DrawLine(sight.origin, rayHit.point, Color.red);
         if (rayHit.collider.tag == "Player"){
             CurrentState = EnemyStates.following;
         }
 
         if (rayHit.collider.tag != "Player" && rayHit.collider.tag != "Enemy"){
             CurrentState = EnemyStates.idle;
         }
     }
     
 }

Answer 1

Best Answer

Answer by robertbu · Jul 29, 2014 at 03:44 PM

T$$anonymous$$s is an ugly little problem. It's made a bit uglier by the fact that 1) the origin of your ray is not at the transform.position of the enemy, and 2) the enemy can also be on a slope (I'm assuming). I keep t$$anonymous$$nking there is an easier way to do t$$anonymous$$s if I just t$$anonymous$$nk of the problem correctly, but here is a brute force solution. Note that 'player' is the transform of the player:

 Vector3 sight.origin = transform.position + 0.5 * transform.up;
 Vector3 localPlayerPos = transform.InverseTransformPoint(player.position);
 Vector3 localEnemyPos = transform.InverseTransformPoint(sight.origin);
 Vector3 localPlayerDir = localPlayerPos - localEnemyPos;
 Vector3 v = localPlayerDir;
 v.y = 0.0;
 localPlayerDir = Quaternion.FromToRotation(v, Vector3.forward) * localPlayerDir;
 Vector3 sight.direction = transform.TransformDirection(localPlayerDir);

Note that in your original code, your calculation of site.origin does not take into account that the enemy can be on a slope.

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raycosantana · Jul 29, 2014 at 05:07 PM 0

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robertbu · Jul 29, 2014 at 05:44 PM 1

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robertbu · Jul 29, 2014 at 06:34 PM 1

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robertbu · Jul 29, 2014 at 09:09 PM 1

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robertbu · Jul 29, 2014 at 10:12 PM 1

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Answer 2

Answer by superpig · Jul 29, 2014 at 02:32 PM

I'd flip it around - instead of saying "I want to raycast forward and see if I $$anonymous$$t the player", I'd say "I want to check whether the vector to the player is close to my forward vector."

Somet$$anonymous$$ng like t$$anonymous$$s:

 GameObject player = GameObject.FindGameObjectWithTag("Player");
 Vector3 vectorToPlayer = player.transform.position - sight.origin;

 // Calculate the vectorToPlayer as if it were flat and unit-length
 Vector3 flatDirToPlayer = 
     new Vector3(vectorToPlayer.x, 0, vectorToPlayer.z).normalized;

 // Check the angle is wit$$anonymous$$n 5 degrees
 if(Vector3.Angle(flatDirToPlayer, sight.direction) < 5f)
 {
     // Now do the raycast to check there's not$$anonymous$$ng in the way...
 }

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raycosantana · Jul 29, 2014 at 05:08 PM 0

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Answer 3

Answer by SilentSin · Jul 29, 2014 at 02:42 PM

Assuming you have access to the transform of the player:

 float heightDifference = player.position.y - transform.position.y;
 float horizontalDistance = Vector3.Distance(player.position, transform.position);

Now we have a right angled triangle:

Bottom length = horizontalDistance
Vertical side length = heightDifference
What we want is the hypotenuse to use as the ray direction; we still want to be pointing the triangle in the direction we are facing, but making sure we're looking at the right height.

Now we can start with the direction we are facing, then extend it out horizontally as the base of the triangle:

 sight.direction = transform.forward;
 sight.direction *= horizontalDistance;

Then raise it to the desired height:

 horizontalDistance.y = heightDifference;

Now we have a vector pointing where we are facing, aimed at the height of the player.

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raycosantana · Jul 29, 2014 at 02:57 PM 0

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Raycast forward except for the Y axis

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