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/* <copyright>
This file contains proprietary software owned by Motorola Mobility, Inc.<br/>
No rights, expressed or implied, whatsoever to this software are provided by Motorola Mobility, Inc. hereunder.<br/>
(c) Copyright 2011 Motorola Mobility, Inc. All Rights Reserved.
</copyright> */
/**
* quat = {}
* This library contains utility functions for operating on quaternions.
* --
* TODO:
* -need to add more helper functions for generating quaternions from
* other representations (i.e. - eulers, angle-axis).
*/
quat = {}
/**
* vec4.string
*/
quat.string = function(q) {
return "{ " + q[0] + ", " + q[1] + ", " + q[2] + ", " + q[3] + " }";
}
/**
* quat.verify
*/
quat.verify = function(q) {
if (q == undefined || q.length == undefined || q.length < 4) {
return false;
}
if (typeof (q[0]) != "number" || typeof (q[1]) != "number" || typeof (q[2]) != "number" || typeof (q[3]) != "number") {
return false;
}
return true;
}
/**
* quat.identity
*/
quat.identity = function() {
return [0.0, 0.0, 0.0, 1.0];
}
/**
* quat.add
*/
quat.add = function(a, b) {
return [ a[0] + b[0],
a[1] + b[1],
a[2] + b[2],
a[3] + b[3]];
}
/**
* quat.sub
*/
quat.sub = function(a, b) {
return [ a[0] - b[0],
a[1] - b[1],
a[2] - b[2],
a[3] - b[3]];
}
/**
* quat.mul
*/
quat.mul = function( a, b ) {
return [ a[3]*b[3] - a[0]*b[0] - a[1]*b[1] - a[2]*b[2],
a[3]*b[0] + a[0]*b[3] + a[1]*b[2] - a[2]*b[1],
a[3]*b[1] - a[0]*b[2] + a[1]*b[3] + a[2]*b[0],
a[3]*b[2] + a[0]*b[1] - a[1]*b[0] + a[2]*b[3] ];
}
/**
* quat.addMul
*/
quat.addMul = function(a, b, s) {
if (s.length != undefined && s.length >= 4) {
return [a[0] + b[0] * s[0], a[1] + b[1] * s[1], a[2] + b[2] * s[2], a[3] + b[3] * s[3]];
} else {
return [a[0] + b[0] * s, a[1] + b[1] * s, a[2] + b[2] * s, a[3] + b[3] * s];
}
}
/**
* quat.scale
*/
quat.scale = function(q, s) {
if (s.length != undefined && s.length >= 4) {
return [q[0] * s[0], q[1] * q[1], q[2] * s[2], q[3] * s[3]];
} else {
return [q[0] * s, q[1] * s, q[2] * s, q[3] * s];
}
}
/**
* quat.lengthSq
*/
quat.lengthSq = function(q) {
return q[0] * q[0] +
q[1] * q[1] +
q[2] * q[2] +
q[3] * q[3];
}
/**
* quat.length
*/
quat.length = function(q) {
return Math.sqrt( q[0] * q[0] +
q[1] * q[1] +
q[2] * q[2] +
q[3] * q[3]);
}
/**
* quat.normalize
*/
quat.normalize = function(q) {
var l = Math.sqrt(q[0] * q[0] + q[1] * q[1] + q[2] * q[2] + q[3] * q[3]);
if (Math.abs(1.0 - l) > 0.0001) {
var ool = 1.0 / l;
return [q[0] * ool, q[1] * ool, q[2] * ool, q[3] * ool];
}
return q;
}
/**
* quat.inverse
*/
quat.inverse = function(q) {
var n = vec4.lengthSq( q );
if( n > 0.00001 ) {
n = 1.0 / n;
return [ q[0] * -n, q[1] * -n, q[2] * -n, q[3] ];
} else {
// error condition
}
return q;
}
/**
* quat.dot
*/
quat.dot = function(a, b) {
return a[0] * b[0] + a[1] * b[1] + a[2] * b[2] + a[3] * b[3];
}
/**
* quat.applyRotation
*/
quat.applyRotation = function(q, v) {
return mat4.transformPoint(quat.toMatrix(q), v);
}
/**
* quat.lerp
*/
quat.lerp = function(q0, q1, t) {
return quat.normalize( [ q0[0] + (q1[0] - q0[0]) * t, q0[1] + (q1[1] - q0[1]) * t, q0[2] + (q1[2] - q0[2]) * t, q0[3] + (q1[3] - q0[3]) * t ] );
}
/**
* quat.slerp
*/
quat.slerp = function(q0, q1, t) {
var c = quat.dot(q0, q1); // cosine of the angle
// just lerp if the quats are "close" enough
if (c >= 0.9) {
return quat.lerp(q0, q1, t);
}
var s = Math.sqrt(Math.abs(1.0 - c * c)); // sine of the angle
if (s < 0.001)
return q0; // too close
var sign = c < 0.0 ? -1.0 : 1.0;
var angle = Math.asin(s);
var invs = 1.0 / s; // sine^-1
var coef0 = Math.sin((1.0 - t) * angle) * invs; // interp. coefficients
var coef1 = Math.sin(t * angle) * invs * sign;
quat.scale(q0, coef0);
quat.scale(q1, coef1);
return quat.normalize( quat.add(q0, q1) );
}
/**
* quat.toMatrix
*/
quat.toMatrix = function(q) {
var tx = 2.0 * q[0];
var ty = 2.0 * q[1];
var tz = 2.0 * q[2];
var twx = tx * q[3];
var twy = ty * q[3];
var twz = tz * q[3];
var txx = tx * q[0];
var txy = ty * q[0];
var txz = tz * q[0];
var tyy = ty * q[1];
var tyz = tz * q[1];
var tzz = tz * q[2];
return [ 1.0 - (tyy + tzz),
txy + twz,
txz - twy,
0,
txy - twz,
1.0 - (txx + tzz),
tyz + twx,
0,
txz + twy,
tyz - twx,
1.0 - (txx + tyy),
0, 0, 0, 0, 1];
}
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