1 /** 2 * The Render Engine 3 * Vector2D 4 * 5 * @fileoverview A Vector2D class 6 * 7 * @author: Brett Fattori (brettf@renderengine.com) 8 * @author: $Author: bfattori $ 9 * @version: $Revision: 1555 $ 10 * 11 * Copyright (c) 2011 Brett Fattori (brettf@renderengine.com) 12 * 13 * Permission is hereby granted, free of charge, to any person obtaining a copy 14 * of this software and associated documentation files (the "Software"), to deal 15 * in the Software without restriction, including without limitation the rights 16 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell 17 * copies of the Software, and to permit persons to whom the Software is 18 * furnished to do so, subject to the following conditions: 19 * 20 * The above copyright notice and this permission notice shall be included in 21 * all copies or substantial portions of the Software. 22 * 23 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 24 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 25 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE 26 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 27 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, 28 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN 29 * THE SOFTWARE. 30 * 31 */ 32 33 // The class this file defines and its required classes 34 R.Engine.define({ 35 "class":"R.math.Vector2D", 36 "requires":[ 37 "R.math.Math2D", 38 "R.math.Point2D" 39 ] 40 }); 41 42 /** 43 * @class A 2D vector class with helpful manipulation methods. 44 * 45 * @param x {R.math.Vector2D|Number} If this arg is a Vector2D, its values will be 46 * copied into the new vector. If a number, 47 * the X length of the vector. 48 * @param y {Number} The Y length of the vector. Only required if X 49 * was a number. 50 * @constructor 51 * @description Create a new 2D Vector 52 * @extends R.math.Point2D 53 */ 54 R.math.Vector2D = function () { 55 "use strict"; 56 return R.math.Point2D.extend(/** @scope R.math.Vector2D.prototype */{ 57 58 /** 59 * @private 60 */ 61 constructor:function (x, y) { 62 return this.base(x, y); 63 }, 64 65 /** 66 * A mutator method that normalizes this vector, returning a unit length vector. 67 * @return {R.math.Vector2D} This vector, normalized 68 * @see #len 69 */ 70 normalize:function () { 71 var ln = this.len(); 72 if (ln != 0) { 73 this.x /= ln; 74 this.y /= ln; 75 } 76 return this; 77 }, 78 79 /** 80 * Get the magnitude/length of this vector. 81 * 82 * @return {Number} A value representing the length (magnitude) of the vector. 83 */ 84 len:function () { 85 return Math.sqrt((this.x * this.x) + (this.y * this.y)); 86 }, 87 88 /** 89 * Set the magnitude/length of this vector without altering the angle 90 * @param len {Number} The length 91 */ 92 setLen:function (len) { 93 var angle = R.math.Math2D.degToRad(this.getAngle()); 94 this.x = Math.cos(angle) * len; 95 this.y = Math.sin(angle) * len; 96 if (Math.abs(this.x) < 0.00000001) this.x = 0; 97 if (Math.abs(this.y) < 0.00000001) this.y = 0; 98 }, 99 100 /** 101 * Get the angle, in degrees, of this vector. 102 * @return {Number} 103 */ 104 getAngle:function () { 105 return R.math.Math2D.radToDeg(Math.atan2(this.y, this.x)); 106 }, 107 108 /** 109 * Set the angle of this vector without altering the length 110 * @param angle {Number} The angle 111 */ 112 setAngle:function (angle) { 113 var len = this.len(); 114 this.x = Math.cos(R.math.Math2D.degToRad(angle)) * len; 115 this.y = Math.sin(R.math.Math2D.degToRad(angle)) * len; 116 }, 117 118 /** 119 * Is the vector to the right or left of this one? 120 * @param vector {R.math.Vector2D} The vectore to compare against 121 * @return {Number} -1 (left) 1 (right) 122 */ 123 getSign:function (vector) { 124 return this.rightNormal().dot(vector) < 0 ? -1 : 1; 125 }, 126 127 /** 128 * Get the dot product of this vector and another. 129 * @param vector {R.math.Vector2D} The Point to perform the operation against. 130 * @return {Number} The dot product 131 */ 132 dot:function (vector) { 133 Assert(vector != null, "Dot product to undefined vector"); 134 return (this.x * vector.x) + (this.y * vector.y); 135 }, 136 137 /** 138 * A mutator method that gets the cross product of this vector and another. 139 * @param vector {R.math.Vector2D} The vector to perform the operation against. 140 * @return {R.math.Vector2D} This vector 141 */ 142 cross:function (vector) { 143 Assert(vector != null, "Cross multiply with undefined vector"); 144 this.x = this.y - vector.y; 145 this.y = vector.x - this.x; 146 // this.z = (this.x * vector.y) - (this.y * vector.x); 147 return this; 148 }, 149 150 truncate:function (max) { 151 if (this.len() > max) { 152 this.setLen(max); 153 } 154 return this; 155 }, 156 157 /** 158 * Returns the angle (in degrees) between two vectors. This assumes that the 159 * point is being used to represent a vector, and that the supplied point 160 * is also a vector. 161 * 162 * @param vector {R.math.Vector2D} The vector to perform the angular determination against 163 * @return {Number} The angle between two vectors, in degrees 164 */ 165 angleBetween:function (vector) { 166 Assert(vector != null, "Angle between undefined vector"); 167 var t = R.clone(this).normalize(), v = R.clone(vector).normalize(), 168 a = Math.acos(t.dot(v)); 169 170 t.destroy(); 171 v.destroy(); 172 return R.math.Math2D.radToDeg(a); 173 174 //var v1 = $V([this.x,this.y,1]), v2 = $V([vector.x,vector.y,1]); 175 //return R.math.Math2D.radToDeg(v1.angleFrom(v2)); 176 }, 177 178 /** 179 * Returns the signed angle (in degrees) between two vectors. This assumes that the 180 * point is being used to represent a vector, and that the supplied point 181 * is also a vector. 182 * 183 * @param vector {R.math.Vector2D} The vector to perform the angular determination against 184 * @return {Number} The angle between two vectors, in degrees 185 */ 186 signedAngleBetween:function (vector) { 187 Assert(vector != null, "Angle between undefined vector"); 188 var t = R.clone(this).normalize(), v = R.clone(vector).normalize(), 189 a = Math.atan2(v.y, v.x) - Math.atan2(t.y, t.x); 190 191 t.destroy(); 192 v.destroy(); 193 return R.math.Math2D.radToDeg(a); 194 }, 195 196 /** 197 * Returns <tt>true</tt> if this vector is parallel to <tt>vector</tt>. 198 * @param vector {R.math.Vector2D} The vector to compare against 199 * @return {Boolean} 200 */ 201 isParallelTo:function (vector) { 202 Assert(vector != null, "Parallel to undefined vector"); 203 var v1 = $V([this.x, this.y, 1]), v2 = $V([vector.x, vector.y, 1]); 204 return v1.isParallelTo(v2); 205 }, 206 207 /** 208 * Returns <tt>true</tt> if this vector is anti-parallel to <tt>vector</tt>. 209 * @param vector {R.math.Vector2D} The vector to compare against 210 * @return {Boolean} 211 */ 212 isAntiparallelTo:function (vector) { 213 Assert(vector != null, "Anti-parallel to undefined vector"); 214 var v1 = $V([this.x, this.y, 1]), v2 = $V([vector.x, vector.y, 1]); 215 return v1.isAntiparallelTo(v2); 216 }, 217 218 /** 219 * Returns <tt>true</tt> if this vector is perpendicular to <tt>vector</tt>. 220 * @param vector {R.math.Vector2D} The vector to compare against 221 * @return {Boolean} 222 */ 223 isPerpendicularTo:function (vector) { 224 Assert(vector != null, "Perpendicular to undefined vector"); 225 var v1 = $V([this.x, this.y, 1]), v2 = $V([vector.x, vector.y, 1]); 226 return v1.isPependicularTo(v2); 227 }, 228 229 /** 230 * Mutator method that modifies the vector rotated <tt>angle</tt> degrees about 231 * the vector defined by <tt>axis</tt>. 232 * 233 * @param angle {Number} The rotation angle in degrees 234 * @param axis {R.math.Vector2D} The axis to rotate about 235 * @return {R.math.Vector2D} This vector 236 */ 237 rotate:function (angle, axis) { 238 var v1 = $V([this.x, this.y, 1]); 239 var v3 = v1.rotate(R.math.Math2D.degToRad(angle), axis); 240 this.x = v3.elements[0]; 241 this.y = v3.elements[1]; 242 return this; 243 }, 244 245 /** 246 * Project this vector onto <tt>vector</tt>. 247 * 248 * @param vector {R.math.Vector2D} The vector to project onto 249 * @return {R.math.Vector2D} 250 */ 251 projectOnto:function (vector) { 252 Assert(vector != null, "Project onto undefined vector"); 253 var proj = R.math.Vector2D.create(0, 0), v = vector, dp = this.dot(vector); 254 proj.set((dp / (v.x * v.x + v.y * v.y)) * v.x, (dp / (v.x * v.x + v.y * v.y)) * v.y); 255 return proj; 256 }, 257 258 /** 259 * Get the right-hand normal of this vector. The left-hand 260 * normal would simply be <tt>this.rightNormal().neg()</tt>. 261 * @return {R.math.Vector2D} 262 */ 263 rightNormal:function () { 264 return R.math.Vector2D.create(-this.y, this.x).normalize(); 265 }, 266 267 /** 268 * Get the perproduct (sign) of this vector and <tt>vector</tt>. Returns 269 * -1 if <tt>vector</tt> is to the left, or 1 if it is to the right 270 * of this vector. 271 * @param vector {R.math.Vector2D} The other vector 272 * @return {Number} 273 */ 274 perProduct:function (vector) { 275 Assert(vector != null, "Per-product with undefined vector"); 276 return this.dot(vector.rightNormal()); 277 } 278 279 }, /** @scope R.math.Vector2D.prototype */{ 280 /** 281 * Return the classname of the this object 282 * @return {String} "R.math.Vector2D" 283 */ 284 getClassName:function () { 285 return "R.math.Vector2D"; 286 }, 287 288 /** @private */ 289 resolved:function () { 290 R.math.Vector2D.ZERO = R.math.Vector2D.create(0, 0); 291 R.math.Vector2D.UP = R.math.Vector2D.create(0, -1); 292 R.math.Vector2D.LEFT = R.math.Vector2D.create(-1, 0); 293 R.math.Vector2D.DOWN = R.math.Vector2D.create(0, 1); 294 R.math.Vector2D.RIGHT = R.math.Vector2D.create(1, 0); 295 if (Object.freeze) { 296 Object.freeze(R.math.Vector2D.ZERO); 297 Object.freeze(R.math.Vector2D.UP); 298 Object.freeze(R.math.Vector2D.LEFT); 299 Object.freeze(R.math.Vector2D.DOWN); 300 Object.freeze(R.math.Vector2D.RIGHT); 301 } 302 303 }, 304 305 /** 306 * The "zero" vector. This vector should not be modified. 307 * @type {R.math.Vector2D} 308 * @memberOf R.math.Vector2D 309 */ 310 ZERO:null, 311 312 /** 313 * The normalized "up" vector. This vector should not be modified. 314 * @type {R.math.Vector2D} 315 * @memberOf R.math.Vector2D 316 */ 317 UP:null, 318 319 /** 320 * The normalized "left" vector. This vector should not be modified. 321 * @type {R.math.Vector2D} 322 * @memberOf R.math.Vector2D 323 */ 324 LEFT:null, 325 326 /** 327 * The normalized "down" vector. This vector should not be modified. 328 * @type {R.math.Vector2D} 329 * @memberOf R.math.Vector2D 330 */ 331 DOWN:null, 332 333 /** 334 * The normalized "right" vector. This vector should not be modified. 335 * @type {R.math.Vector2D} 336 * @memberOf R.math.Vector2D 337 */ 338 RIGHT:null 339 }); 340 341 };