Access 2 of the 3 components of Vector3 (Vector3.xy?)

Questions & Answers
1

Hey guys,

I need to do something like the following

function Main()
{
    Vector3 vector = arrayOfVerts[0];

    calculationFunc(vector.xy);
}
function calculationFunc(Vector2 theVector2)
{
    //Use only those components to calculate something
}

The problem is at the vector.xy. Unlike in GLSL, you can’t access components like that (apparently). What would be the most performance-wise way of doing this?

3

I just want to sum up some ways:

// our vector3
var vec = new Vector3(1,2,3);

// #1 The usual way
var tmp = new Vector2(vec.x, vec.z);

// #2 Your way
var tmp = getAxis(vec, Axis.x, Axis.z);

// #3 My way ;)
var tmp = vec.xz();

My way requires you to add this extension class to your Standard Assets folder:

// Vector3Extensions.cs
// C#
using UnityEngine;

public static class Vector3Extensions
{
	public static Vector2 xy(this Vector3 aVector)
	{
		return new Vector2(aVector.x,aVector.y);
	}
	public static Vector2 xz(this Vector3 aVector)
	{
		return new Vector2(aVector.x,aVector.z);
	}
	public static Vector2 yz(this Vector3 aVector)
	{
		return new Vector2(aVector.y,aVector.z);
	}
	public static Vector2 yx(this Vector3 aVector)
	{
		return new Vector2(aVector.y,aVector.x);
	}
	public static Vector2 zx(this Vector3 aVector)
	{
		return new Vector2(aVector.z,aVector.x);
	}
	public static Vector2 zy(this Vector3 aVector)
	{
		return new Vector2(aVector.z,aVector.y);
	}
}

It will also work from UnityScript, but Monodevelop doesn’t seem to provide intellisens for the extension methods, however it works :wink:

edit

Just to have it complete:

  • 1 is the fastest and most efficient way
  • 2 is the most inefficient way of the 3 because it uses the indexer of vector3 two times and involves a function call
  • 3 in the middle since it also requires an additional function call but it has the shortest syntax.
2

EDIT: See accepted answer and explanations that go with it, much better than mine.

Future reference for anyone coming across this in the future. This is what I did. Vector3s’ components can be accessed like an array.

Vector3 bobTheVector = new Vector3(1, 2, 3);

float oneAxis = bobTheVector[0];

Here’s the way I implemented it.

enum Axis : int {x = 0, y = 1, z = 2}

function getAxis(Vector3 theVector, int a, int b)
{
     return Vector2(theVector[a], theVector**);**

}
The enum is just incase you want to do something like Axis.x instead of remembering that 0 is the x axis.
getAxis(new Vector3(1, 2, 3), Axis.x, Axis.z);