source: Dev/trunk/src/client/dojox/gfx3d/vector.js

define(["dojo/_base/lang", "dojo/_base/array", "./_base"],function(lang, arrayUtil, gfx3d) {

gfx3d.vector =  {
        
        sum: function(){
                // summary:
                //              sum of the vectors
                var v = {x: 0, y: 0, z:0};
                arrayUtil.forEach(arguments, function(item){ v.x += item.x; v.y += item.y; v.z += item.z; });
                return v;
        },

        center: function(){
                // summary:
                //              center of the vectors
                var l = arguments.length;
                if(l == 0){
                        return {x: 0, y: 0, z: 0};
                }
                var v = gfx3d.vector.sum(arguments);
                return {x: v.x/l, y: v.y/l, z: v.z/l};
        },

        substract: function(/* Pointer */a, /* Pointer */b){
                return  {x: a.x - b.x, y: a.y - b.y, z: a.z - b.z};
        },

        _crossProduct: function(x, y, z, u, v, w){
                // summary:
                //              applies a cross product of two vectors, (x, y, z) and (u, v, w)
                // x: Number
                //              x coordinate of first vector
                // y: Number
                //              y coordinate of first vector
                // z: Number
                //              z coordinate of first vector
                // u: Number
                //              x coordinate of second vector
                // v: Number
                //              y coordinate of second vector
                // w: Number
                //              z coordinate of second vector
                return {x: y * w - z * v, y: z * u - x * w, z: x * v - y * u}; // Object
        },

        crossProduct: function(/* Number||Point */ a, /* Number||Point */ b, /* Number, optional */ c, /* Number, optional */ d, /* Number, optional */ e, /* Number, optional */ f){
                // summary:
                //              applies a matrix to a point
                // matrix: dojox.gfx3d.matrix.Matrix3D
                //              a 3D matrix object to be applied
                // a: Number|Point
                //              x coordinate of first point, or the whole first point
                // b: Number|Point
                //              y coordinate of first point, or the whole second point
                // c: Number
                //              z coordinate of first point
                // d: Number
                //              x coordinate of second point
                // e: Number
                //              y coordinate of second point
                // f: Number
                //              z coordinate of second point
                if(arguments.length == 6 && arrayUtil.every(arguments, function(item){ return typeof item == "number"; })){
                        return gfx3d.vector._crossProduct(a, b, c, d, e, f); // Object
                }

                return gfx3d.vector._crossProduct(a.x, a.y, a.z, b.x, b.y, b.z); // Object
        },

        _dotProduct: function(x, y, z, u, v, w){
                // summary:
                //              applies a cross product of two vectors, (x, y, z) and (u, v, w)
                // x: Number
                //              x coordinate of first point
                // y: Number
                //              y coordinate of first point
                // z: Number
                //              z coordinate of first point
                // u: Number
                //              x coordinate of second point
                // v: Number
                //              y coordinate of second point
                // w: Number
                //              z coordinate of second point
                return x * u + y * v + z * w; // Number
        },
        dotProduct: function(a, b, c, d, e, f){
                // summary:
                //              applies a matrix to a point
                // matrix: dojox.gfx3d.matrix.Matrix3D
                //              a 3D matrix object to be applied
                // a: Number|Point
                //              x coordinate of first point, or the whole first Point
                // b: Number|Point
                //              y coordinate of first Point, or the whole second Point
                // c: Number?
                //              z coordinate of first point
                // d: Number?
                //              x coordinate of second point
                // e: Number?
                //              y coordinate of second point
                // f: Number?
                //              z coordinate of second point
                if(arguments.length == 6 && arrayUtil.every(arguments, function(item){ return typeof item == "number"; })){
                        return gfx3d.vector._dotProduct(a, b, c, d, e, f); // Object
                }
                return gfx3d.vector._dotProduct(a.x, a.y, a.z, b.x, b.y, b.z); // Object
        },

        normalize: function(/* Point||Array*/ a, /* Point */ b, /* Point */ c){
                // summary:
                //              find the normal of the implicit surface
                // a: Object
                //              a point
                // b: Object
                //              a point
                // c: Object
                //              a point
                var l, m, n;
                if(a instanceof Array){
                        l = a[0]; m = a[1]; n = a[2];
                }else{
                        l = a; m = b; n = c;
                }

                var u = gfx3d.vector.substract(m, l);
                var v = gfx3d.vector.substract(n, l);
                return gfx3d.vector.crossProduct(u, v);
        }
};
        return gfx3d.vector;
});