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import { Matrix4, Quaternion, Vector3, Object3D } from 'three'
// tslint:disable-next-line:interface-name
export interface IKS {
effector: Object3D
iteration: number
links: Array<{
enabled: boolean
index: Object3D
limitation?: Vector3
rotationMin?: Vector3
rotationMax?: Vector3
}>
minAngle: number
maxAngle: number
target: Object3D
}
const _q = new Quaternion()
const _targetPos = new Vector3()
const _targetVec = new Vector3()
const _effectorPos = new Vector3()
const _effectorVec = new Vector3()
const _linkPos = new Vector3()
const _invLinkQ = new Quaternion()
const _linkScale = new Vector3()
const _axis = new Vector3()
const _vector = new Vector3()
const _matrix = new Matrix4()
/**
* CCD Algorithm
* - https://sites.google.com/site/auraliusproject/ccd-algorithm
*
* // ik parameter example
* //
* // target, effector, index in links are bone index in skeleton.bones.
* // the bones relation should be
* // <-- parent child -->
* // links[ n ], links[ n - 1 ], ..., links[ 0 ], effector
* iks = [ {
* target: 1,
* effector: 2,
* links: [ { index: 5, limitation: new Vector3( 1, 0, 0 ) }, { index: 4, enabled: false }, { index : 3 } ],
* iteration: 10,
* minAngle: 0.0,
* maxAngle: 1.0,
* } ];
*/
export class CCDIKSolver {
iks: IKS[]
constructor(iks: IKS[] = []) {
this.iks = iks
this._valid()
}
update() {
const iks = this.iks
for (let i = 0, il = iks.length; i < il; i++) {
this.updateOne(iks[i])
}
return this
}
updateOne(ik: IKS) {
const bones = ik.links.map((i) => i.index)
// for reference overhead reduction in loop
const math = Math
const effector = ik.effector
const target = ik.target
// don't use getWorldPosition() here for the performance
// because it calls updateMatrixWorld( true ) inside.
_targetPos.setFromMatrixPosition(target.matrixWorld)
const links = ik.links
const iteration = ik.iteration !== undefined ? ik.iteration : 1
for (let i = 0; i < iteration; i++) {
let rotated = false
for (let j = 0, jl = links.length; j < jl; j++) {
const link = bones[j]
// skip this link and following links.
// this skip is used for MMD performance optimization.
if (links[j].enabled === false) break
const limitation = links[j].limitation
const rotationMin = links[j].rotationMin
const rotationMax = links[j].rotationMax
// don't use getWorldPosition/Quaternion() here for the performance
// because they call updateMatrixWorld( true ) inside.
link.matrixWorld.decompose(_linkPos, _invLinkQ, _linkScale)
_invLinkQ.invert()
_effectorPos.setFromMatrixPosition(effector.matrixWorld)
// work in link world
_effectorVec.subVectors(_effectorPos, _linkPos)
_effectorVec.applyQuaternion(_invLinkQ)
_effectorVec.normalize()
_targetVec.subVectors(_targetPos, _linkPos)
_targetVec.applyQuaternion(_invLinkQ)
_targetVec.normalize()
let angle = _targetVec.dot(_effectorVec)
if (angle > 1.0) {
angle = 1.0
} else if (angle < -1.0) {
angle = -1.0
}
angle = math.acos(angle)
// skip if changing angle is too small to prevent vibration of bone
if (angle < 1e-5) continue
if (ik.minAngle !== undefined && angle < ik.minAngle) {
angle = ik.minAngle
}
if (ik.maxAngle !== undefined && angle > ik.maxAngle) {
angle = ik.maxAngle
}
_axis.crossVectors(_effectorVec, _targetVec)
_axis.normalize()
_q.setFromAxisAngle(_axis, angle)
link.quaternion.multiply(_q)
// TODO: re-consider the limitation specification
if (limitation !== undefined) {
let c = link.quaternion.w
if (c > 1.0) c = 1.0
const c2 = math.sqrt(1 - c * c)
link.quaternion.set(
limitation.x * c2,
limitation.y * c2,
limitation.z * c2,
c
)
}
if (rotationMin !== undefined) {
link.rotation.setFromVector3(
_vector.setFromEuler(link.rotation).max(rotationMin)
)
}
if (rotationMax !== undefined) {
link.rotation.setFromVector3(
_vector.setFromEuler(link.rotation).min(rotationMax)
)
}
link.updateMatrixWorld(true)
rotated = true
}
if (!rotated) break
}
return this
}
// private methods
_valid() {
const iks = this.iks
for (let i = 0, il = iks.length; i < il; i++) {
const ik = iks[i]
const effector = ik.effector
const links = ik.links
let link0, link1
link0 = effector
for (let j = 0, jl = links.length; j < jl; j++) {
link1 = links[j].index
if (link0.parent !== link1) {
console.warn(
'THREE.CCDIKSolver: bone ' +
link0.name +
' is not the child of bone ' +
link1.name
)
}
link0 = link1
}
}
}
}
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