function o (e, t, n) {
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return e > t - n && e < t + n
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}
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function a (e, t) {
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return o(e, 0, t)
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}
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export function Spring (e, t, n) {
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this._m = e
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this._k = t
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this._c = n
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this._solution = null
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this._endPosition = 0
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this._startTime = 0
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}
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Spring.prototype._solve = function (e, t) {
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var n = this._c
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var i = this._m
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var r = this._k
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var o = n * n - 4 * i * r
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if (o === 0) {
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const a = -n / (2 * i)
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const s = e
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const l = t / (a * e)
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return {
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x: function (e) {
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return (s + l * e) * Math.pow(Math.E, a * e)
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},
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dx: function (e) {
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var t = Math.pow(Math.E, a * e)
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return a * (s + l * e) * t + l * t
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}
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}
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}
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if (o > 0) {
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const c = (-n - Math.sqrt(o)) / (2 * i)
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const u = (-n + Math.sqrt(o)) / (2 * i)
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const l = (t - c * e) / (u - c)
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const s = e - l
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return {
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x: function (e) {
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let t
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let n
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if (e === this._t) {
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t = this._powER1T
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n = this._powER2T
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}
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this._t = e
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if (!t) {
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t = this._powER1T = Math.pow(Math.E, c * e)
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}
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if (!n) {
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n = this._powER2T = Math.pow(Math.E, u * e)
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}
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return s * t + l * n
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},
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dx: function (e) {
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let t
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let n
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if (e === this._t) {
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t = this._powER1T
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n = this._powER2T
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}
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this._t = e
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if (!t) {
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t = this._powER1T = Math.pow(Math.E, c * e)
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}
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if (!n) {
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n = this._powER2T = Math.pow(Math.E, u * e)
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}
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return s * c * t + l * u * n
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}
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}
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}
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var d = Math.sqrt(4 * i * r - n * n) / (2 * i)
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var a = -n / 2 * i
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var s = e
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var l = (t - a * e) / d
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return {
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x: function (e) {
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return Math.pow(Math.E, a * e) * (s * Math.cos(d * e) + l * Math.sin(d * e))
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},
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dx: function (e) {
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var t = Math.pow(Math.E, a * e)
|
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var n = Math.cos(d * e)
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var i = Math.sin(d * e)
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return t * (l * d * n - s * d * i) + a * t * (l * i + s * n)
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}
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}
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}
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Spring.prototype.x = function (e) {
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if (e === undefined) {
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e = ((new Date()).getTime() - this._startTime) / 1e3
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}
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return this._solution ? this._endPosition + this._solution.x(e) : 0
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}
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Spring.prototype.dx = function (e) {
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if (e === undefined) {
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e = ((new Date()).getTime() - this._startTime) / 1e3
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}
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return this._solution ? this._solution.dx(e) : 0
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}
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Spring.prototype.setEnd = function (e, t, n) {
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if (!n) {
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n = (new Date()).getTime()
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}
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if (e !== this._endPosition || !a(t, 0.4)) {
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t = t || 0
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var i = this._endPosition
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if (this._solution) {
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if (a(t, 0.4)) {
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t = this._solution.dx((n - this._startTime) / 1e3)
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}
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i = this._solution.x((n - this._startTime) / 1e3)
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if (a(t, 0.4)) {
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t = 0
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}
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if (a(i, 0.4)) {
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i = 0
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}
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i += this._endPosition
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}
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if (!(this._solution && a(i - e, 0.4) && a(t, 0.4))) {
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this._endPosition = e
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this._solution = this._solve(i - this._endPosition, t)
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this._startTime = n
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}
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}
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}
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Spring.prototype.snap = function (e) {
|
this._startTime = (new Date()).getTime()
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this._endPosition = e
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this._solution = {
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x: function () {
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return 0
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},
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dx: function () {
|
return 0
|
}
|
}
|
}
|
Spring.prototype.done = function (e) {
|
if (!e) {
|
e = (new Date()).getTime()
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}
|
return o(this.x(), this._endPosition, 0.4) && a(this.dx(), 0.4)
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}
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Spring.prototype.reconfigure = function (e, t, n) {
|
this._m = e
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this._k = t
|
this._c = n
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if (!this.done()) {
|
this._solution = this._solve(this.x() - this._endPosition, this.dx())
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this._startTime = (new Date()).getTime()
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}
|
}
|
Spring.prototype.springConstant = function () {
|
return this._k
|
}
|
Spring.prototype.damping = function () {
|
return this._c
|
}
|
Spring.prototype.configuration = function () {
|
function e (e, t) {
|
e.reconfigure(1, t, e.damping())
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}
|
|
function t (e, t) {
|
e.reconfigure(1, e.springConstant(), t)
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}
|
return [{
|
label: 'Spring Constant',
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read: this.springConstant.bind(this),
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write: e.bind(this, this),
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min: 100,
|
max: 1e3
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}, {
|
label: 'Damping',
|
read: this.damping.bind(this),
|
write: t.bind(this, this),
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min: 1,
|
max: 500
|
}]
|
}
|
