Is there a way to make switch/case using Vector3?

Question

What i want to do is to detect each side when my character(ThirdPerSonController) touch a cube. In fact my main goal is to detect when my player is standing on the cube surface on top. This is my script:

using UnityEngine; using System.Collections; public class Test : MonoBehaviour { void OnCollisionEnter(Collision collision) { ContactPoint contact = collision.contacts[0]; Vector3 normal = contact.normal; Vector3 inverseNormal = transform.InverseTransformDirection(normal); Vector3 roundNormal = RoundVector3(inverseNormal); ReturnSide(roundNormal); } Vector3 RoundVector3(Vector3 convertThis) { int x = (int)Mathf.Round(convertThis.x); int y = (int)Mathf.Round(convertThis.y); int z = (int)Mathf.Round(convertThis.z); Vector3 returnVector = new Vector3(x, y, z); return returnVector; } void ReturnSide(Vector3 side) { string output = null; switch (side) { case Vector3.down: output = "Down"; break; case Vector3.up: output = "Up"; break; case Vector3.back: output = "Back"; break; case Vector3.forward: output = "Front"; break; case Vector3.left: output = "Left"; break; case Vector3.right: output = "Right"; break; } Debug.Log(output + " was hit."); } // Use this for initialization void Start () { } // Update is called once per frame void Update () { } }

I'm getting error on the line:

switch (side)

Severity Code Description Project File Line Suppression State Error CS0151 A switch expression or case label must be a bool, char, string, integral, enum, or corresponding nullable type test.cs 33 Active

The simple answer is no, forget about this. The way you do this is very simply have a trigger or collider, ON EACH FACE. It's an absolute basic of making video games. Enjoy. — Fattie
– Fattie, Commented Nov 9, 2016 at 1:37

Lucas · Accepted Answer · 2020-07-01 05:10:20Z

With C# 7, you can do this. You case use the when statement:

https://learn.microsoft.com/en-us/dotnet/csharp/language-reference/keywords/switch#the-case-statement-and-the-when-clause

So, for example, if you wanted to know which side of a cube is clicked, you can use something like this:

void OnMouseDown() { RaycastHit hit; Ray ray = Camera.main.ScreenPointToRay(Input.mousePosition); if (Physics.Raycast(ray, out hit, Mathf.Infinity)) { switch (hit.normal) { case Vector3 v when v.Equals(Vector3.up): Debug.Log("Up"); break; case Vector3 v when v.Equals(Vector3.left): Debug.Log("Left"); break; case Vector3 v when v.Equals(Vector3.back): Debug.Log("Back"); break; } } }

I'm not sure about the efficiency of this method. YMMV.

Kieran · Accepted Answer · 2024-04-26 12:25:30Z

For people looking for an answer now:

You can't create a switch statement using Vector3 like the others have mentioned because there's no way to represent a Vector3 as a constant

However, you can convert the Vector3 into a type which can be constant and match against that. An easy way to do that is with a tuple:

public void MatchVector3(Vector3 vec) { switch ((vec.x, vec.y, vec.z)) { case (0,1,0): { Debug.Log("up"); break; } case (0,-1,0): { Debug.Log("down"); break; } case (-1,0,0): { Debug.Log("left"); break; } case (1,0,0): { Debug.Log("right"); break; } case (0,0,1): { Debug.Log("forward"); break; } case (0,0,-1): { Debug.Log("back"); break; } } }

Though for this specific usecase of finding out if the player is standing on top of a box, you're definitely better off just using a separate collider, it's far easier to tweak

Alox · Accepted Answer · 2016-11-09 14:35:53Z

No, there is no way to make a switch/case using Vector3.

"A switch expression or case label must be a bool, char, string, integral, enum or corresponding nullable type."

Demon · Accepted Answer · 2016-11-09 07:51:59Z

No you cant use switch/case on vector3, but what you can do (what is not the best solution, but will do the job) is convert vector3d.x ,z and y and run them over switch case. Tho I dont think it will look good.

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