WebService / ben-test · Files

import { Vector3 } from 'three';

const signedVolumeOfTriangle = (p1, p2, p3) => {
    return p1.dot(p2.cross(p3)) / 6.0;
};

export const getGeometryVolume = (geometry) => {
    const { position } = geometry.attributes;

    let sum = 0;
    const p1 = new Vector3();
    const p2 = new Vector3();
    const p3 = new Vector3();

    const indices = geometry.getIndex();

    let a = 0;
    let b = 0;
    let c = 0;

    for (let i = 0; i < indices.count / 3; i += 1) {
        a = indices.array[i * 3 + 0];
        b = indices.array[i * 3 + 1];
        c = indices.array[i * 3 + 2];

        p1.set(position.getX(a), position.getY(a), position.getZ(a));
        p2.set(position.getX(b), position.getY(b), position.getZ(b));
        p3.set(position.getX(c), position.getY(c), position.getZ(c));

        sum += signedVolumeOfTriangle(p1, p2, p3);
    }
    return Math.round(sum, 2);
};