Javascript custom variable and custom array type

Question

im trying to create a vector3 array in JavaScript, im trying to create a Vertex, Edge, Face structure for an openGL cube, now it's pretty new for JavaScript, but as HTML5 supports it, I feel that JS should be the language I understand now: ),

Now I do not know how to declare a structure in JS, and then how to implement it as an array?

I have something like this, but I'm not sure if this is correct.

var vector3 = (x=0,y=0,z=0); 

but how can i use this for an array?

Cheers for help.

Answer 1

I would create an object:

 var vector3 = { x:0, y:0, z:0 }; 

You can access individual fields using code, for example:

 var tmp = vector3.x; 

To put dots in a vector

 var myPolygon = [ {x: 3, y: 8, z: -8}, {x: 3, y: 4, z: 10}, {x: 9, y: 8, z: -8}, ]; 

You can also write a vector type so you don't have to write x , y and z every time:

 var vec3 = {x:0,y:0,z:0}; var demoVec = vec3; var demo2Vec = vec3; demoVec.x+=demo2Vec.y; 

Answer 2

Use javascript object:

 var vector1 = {x:0,y:0,z:0}; var vector2 = {x:10,y:0,z:0}; //example function to find scalar distance between two points function distance(v1,v2){ return Math.sqrt(Math.pow((v1.x-v2.x),2) + Math.pow((v1.y-v2.y),2) + Math.pow((v1.z-v2.z),2)); } var d = distance(vector1,vector2); //returns 10 console.log(d); 

Answer 3

I like Tobias Springer's solution, but you can also create a vector object with utilities:

 Vector = function(x, y, z) { this._init(x, y, z); }; Vector.prototype = { /** * Fixed Constructor. */ constructor: Vector, x: null, y: null, z: null, /** * Add documentation! */ _init: function(x, y, z) { this.x = x; this.y = y; this.z = z; }, /** * Add documentation! */ add: function(otherVector) { return new Vector(this.x + otherVector.x, this.y + otherVector.y, this.z + otherVector.z); }, /** * Add documentation! */ scalarProduct: function(otherVector) { return this.x * otherVector.x + this.y * otherVector.y + this.z * otherVector.z; }, /** * From Asad answer. Returns the distance between this vector * and <code>otherVector</code>. * @param otherVector {Vector} * @returns {Number} */ distance: function(otherVector) { return Math.sqrt(Math.pow((this.x-otherVector.x),2) + Math.pow((this.y-otherVector.y),2) + Math.pow((this.z-otherVector.z),2)); } // and so on.... }; 

So you would use it like this:

 var vector1 = new Vector (1, 1, 1); var vector2 = new Vector (1, 0, 1); var addedVector = vector1.add(vector2); // --> = (2, 1, 2) var scalarProduct = vector1.scalarProduct(vector2); // --> = 2 

Answer 4

I would write a constructor

 function Vector(x,y,z){ this.dimension = 0; if( undefined !== x ) this.dimension = 1, this.x = x || 0; else this.x = 0; if( undefined !== y ) this.dimension = 2, this.y = y || 0; else this.y = 0; if( undefined !== z ) this.dimension = 3, this.z = z || 0; else this.z = 0; } Vector.prototype = Object.create(null, { length: { get: function(){ return Math.sqrt(this.x * this.x + this.y * this.y + this.z * this.z); } }, add : { value: function(v){ var d = Math.max(this.dimension, v.dimension), x, y, z; if( d > 0 ) x = (this.x || 0) + (vx || 0); if( d > 1 ) y = (this.y || 0) + (vy || 0); if( d > 2 ) z = (this.z || 0) + (vz || 0); return new Vector(x, y, z); } } }); var vector3 = new Vector(0,0,0);