92 lines
2.6 KiB
JavaScript
92 lines
2.6 KiB
JavaScript
// Copyright (c) 2011 The Native Client Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file.
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/**
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* @fileoverview A 3D vector class. Proviudes some utility functions on
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* 3-dimentional vectors.
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*/
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// Requires tumbler
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/**
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* Constructor for the Vector3 object. This class contains a 3-tuple that
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* represents a vector in 3D space.
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* @param {?number} opt_x The x-coordinate for this vector. If null or
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* undefined, the x-coordinate value is set to 0.
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* @param {?number} opt_y The y-coordinate for this vector. If null or
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* undefined, the y-coordinate value is set to 0.
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* @param {?number} opt_z The z-coordinate for this vector. If null or
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* undefined, the z-coordinate value is set to 0.
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* @constructor
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*/
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tumbler.Vector3 = function(opt_x, opt_y, opt_z) {
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/**
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* The vector's 3-tuple.
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* @type {number}
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*/
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this.x = opt_x || 0;
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this.y = opt_y || 0;
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this.z = opt_z || 0;
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}
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/**
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* Method to return the magnitude of a Vector3.
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* @return {number} the magnitude of the vector.
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*/
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tumbler.Vector3.prototype.magnitude = function() {
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return Math.sqrt(this.dot(this));
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}
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/**
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* Normalize the vector in-place.
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* @return {number} the magnitude of the vector.
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*/
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tumbler.Vector3.prototype.normalize = function() {
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var mag = this.magnitude();
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if (mag < tumbler.Vector3.DOUBLE_EPSILON)
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return 0.0; // |this| is equivalent to the 0-vector, don't normalize.
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this.scale(1.0 / mag);
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return mag;
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}
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/**
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* Scale the vector in-place by |s|.
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* @param {!number} s The scale factor.
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*/
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tumbler.Vector3.prototype.scale = function(s) {
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this.x *= s;
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this.y *= s;
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this.z *= s;
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}
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/**
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* Compute the dot product: |this| . v.
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* @param {!tumbler.Vector3} v The vector to dot.
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* @return {number} the result of |this| . v.
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*/
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tumbler.Vector3.prototype.dot = function(v) {
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return this.x * v.x + this.y * v.y + this.z * v.z;
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}
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/**
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* Compute the cross product: |this| X v.
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* @param {!tumbler.Vector3} v The vector to cross with.
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* @return {tumbler.Vector3} the result of |this| X v.
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*/
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tumbler.Vector3.prototype.cross = function(v) {
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var vCross = new tumbler.Vector3(this.y * v.z - this.z * v.y,
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this.z * v.x - this.x * v.z,
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this.x * v.y - this.y * v.x);
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return vCross;
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}
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/**
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* Real numbers that are less than this distance apart are considered
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* equivalent.
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* TODO(dspringer): It seems as though there should be a const like this
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* in generally available somewhere.
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* @type {number}
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*/
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tumbler.Vector3.DOUBLE_EPSILON = 1.0e-16;
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