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85 lines
1.8 KiB
85 lines
1.8 KiB
/**
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* @prototype Point3d
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* @param {Number} [x]
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* @param {Number} [y]
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* @param {Number} [z]
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*/
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function Point3d(x, y, z) {
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this.x = x !== undefined ? x : 0;
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this.y = y !== undefined ? y : 0;
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this.z = z !== undefined ? z : 0;
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}
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/**
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* Subtract the two provided points, returns a-b
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* @param {Point3d} a
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* @param {Point3d} b
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* @return {Point3d} a-b
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*/
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Point3d.subtract = function(a, b) {
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var sub = new Point3d();
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sub.x = a.x - b.x;
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sub.y = a.y - b.y;
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sub.z = a.z - b.z;
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return sub;
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};
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/**
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* Add the two provided points, returns a+b
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* @param {Point3d} a
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* @param {Point3d} b
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* @return {Point3d} a+b
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*/
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Point3d.add = function(a, b) {
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var sum = new Point3d();
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sum.x = a.x + b.x;
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sum.y = a.y + b.y;
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sum.z = a.z + b.z;
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return sum;
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};
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/**
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* Calculate the average of two 3d points
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* @param {Point3d} a
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* @param {Point3d} b
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* @return {Point3d} The average, (a+b)/2
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*/
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Point3d.avg = function(a, b) {
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return new Point3d(
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(a.x + b.x) / 2,
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(a.y + b.y) / 2,
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(a.z + b.z) / 2
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);
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};
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/**
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* Calculate the cross product of the two provided points, returns axb
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* Documentation: http://en.wikipedia.org/wiki/Cross_product
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* @param {Point3d} a
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* @param {Point3d} b
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* @return {Point3d} cross product axb
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*/
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Point3d.crossProduct = function(a, b) {
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var crossproduct = new Point3d();
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crossproduct.x = a.y * b.z - a.z * b.y;
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crossproduct.y = a.z * b.x - a.x * b.z;
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crossproduct.z = a.x * b.y - a.y * b.x;
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return crossproduct;
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};
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/**
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* Rtrieve the length of the vector (or the distance from this point to the origin
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* @return {Number} length
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*/
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Point3d.prototype.length = function() {
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return Math.sqrt(
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this.x * this.x +
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this.y * this.y +
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this.z * this.z
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);
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};
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module.exports = Point3d;
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