kalidokit/dist/PoseSolver/calcArms.js

Blendshape and kinematics calculator for Mediapipe/Tensorflow.js Face, Eyes, Pose, and Finger tracking models.

import Vector from "../utils/vector";
import { clamp } from "../utils/helpers";
import { RIGHT, LEFT } from "./../constants";
import { PI } from "./../constants";
/**
 * Calculates arm rotation as euler angles
 * @param {Array} lm : array of 3D pose vectors from tfjs or mediapipe
 */
export const calcArms = (lm) => {
    //Pure Rotation Calculations
    const UpperArm = {
        r: Vector.findRotation(lm[11], lm[13]),
        l: Vector.findRotation(lm[12], lm[14]),
    };
    UpperArm.r.y = Vector.angleBetween3DCoords(lm[12], lm[11], lm[13]);
    UpperArm.l.y = Vector.angleBetween3DCoords(lm[11], lm[12], lm[14]);
    const LowerArm = {
        r: Vector.findRotation(lm[13], lm[15]),
        l: Vector.findRotation(lm[14], lm[16]),
    };
    LowerArm.r.y = Vector.angleBetween3DCoords(lm[11], lm[13], lm[15]);
    LowerArm.l.y = Vector.angleBetween3DCoords(lm[12], lm[14], lm[16]);
    LowerArm.r.z = clamp(LowerArm.r.z, -2.14, 0);
    LowerArm.l.z = clamp(LowerArm.l.z, -2.14, 0);
    const Hand = {
        r: Vector.findRotation(Vector.fromArray(lm[15]), Vector.lerp(Vector.fromArray(lm[17]), Vector.fromArray(lm[19]), 0.5)),
        l: Vector.findRotation(Vector.fromArray(lm[16]), Vector.lerp(Vector.fromArray(lm[18]), Vector.fromArray(lm[20]), 0.5)),
    };
    //Modify Rotations slightly for more natural movement
    const rightArmRig = rigArm(UpperArm.r, LowerArm.r, Hand.r, RIGHT);
    const leftArmRig = rigArm(UpperArm.l, LowerArm.l, Hand.l, LEFT);
    return {
        //Scaled
        UpperArm: {
            r: rightArmRig.UpperArm,
            l: leftArmRig.UpperArm,
        },
        LowerArm: {
            r: rightArmRig.LowerArm,
            l: leftArmRig.LowerArm,
        },
        Hand: {
            r: rightArmRig.Hand,
            l: leftArmRig.Hand,
        },
        //Unscaled
        Unscaled: {
            UpperArm: UpperArm,
            LowerArm: LowerArm,
            Hand: Hand,
        },
    };
};
/**
 * Converts normalized rotation values into radians clamped by human limits
 * @param {Object} UpperArm : normalized rotation values
 * @param {Object} LowerArm : normalized rotation values
 * @param {Object} Hand : normalized rotation values
 * @param {Side} side : left or right
 */
export const rigArm = (UpperArm, LowerArm, Hand, side = RIGHT) => {
    // Invert modifier based on left vs right side
    const invert = side === RIGHT ? 1 : -1;
    UpperArm.z *= -2.3 * invert;
    //Modify UpperArm rotationY  by LowerArm X and Z rotations
    UpperArm.y *= PI * invert;
    UpperArm.y -= Math.max(LowerArm.x);
    UpperArm.y -= -invert * Math.max(LowerArm.z, 0);
    UpperArm.x -= 0.3 * invert;
    LowerArm.z *= -2.14 * invert;
    LowerArm.y *= 2.14 * invert;
    LowerArm.x *= 2.14 * invert;
    //Clamp values to human limits
    UpperArm.x = clamp(UpperArm.x, -0.5, PI);
    LowerArm.x = clamp(LowerArm.x, -0.3, 0.3);
    Hand.y = clamp(Hand.z * 2, -0.6, 0.6); //side to side
    Hand.z = Hand.z * -2.3 * invert; //up down
    return {
        //Returns Values in Radians for direct 3D usage
        UpperArm: UpperArm,
        LowerArm: LowerArm,
        Hand: Hand,
    };
};