High Fidelity script to procedurally manipulate the hands using IK

snoopDance.js

var handlerId = 0;
var phi = 0.0;
var phi2 = 0.0;
var forward = true;
var RX90 = Quat.angleAxis(90.0, {x: 1, y: 0, z: 0});

function init() {
    var t = 0;
    var propList = ["leftHandType", "leftHandPosition", "leftHandRotation", "rightHandType", "rightHandPosition", "rightHandPosition"];
    handlerId = MyAvatar.addAnimationStateHandler(function (props) {
        // a dt would be nice here!

        phi2 += 0.02;
        if (forward) {
            phi += 0.02;
        } else {
            phi -= 0.02;
        }

        if (phi > 1.0 || phi < 0.0) {
            forward = !forward;
        }

        var sphi = Math.sin((Math.PI / 2) * phi) * Math.sin((Math.PI / 2) * phi)

        var rightHandTheta = -(Math.PI / 3) + sphi * (2 * Math.PI + ((4 * Math.PI) / 6));
        var leftHandTheta = phi2 * (2 * Math.PI);

        var leftHandRotation = RX90;
        var rightHandRotation = {x: 0, y: 0, z: 0, w: 1};

        var z = 0.25;
        return {
            rightHandType: 0,
            rightHandPosition: {x: -0.2 + 0.2 * Math.sin(rightHandTheta), y: 0.2 + 0.2 * Math.cos(rightHandTheta), z: z},
            rightHandRotation: rightHandRotation,
            leftHandType: 0,
            leftHandPosition: {x: 0.25 + 0.05 * Math.sin(2 * leftHandTheta), y: -0.1 + 0.1 * Math.cos(leftHandTheta), z: z + 0.1},
            leftHandRotation: leftHandRotation
        };
    }, propList);
}

function shutdown() {
    MyAvatar.removeAnimationStateHandler(handlerId);
}

init();
Script.scriptEnding.connect(shutdown);