public Vector3D getCentroid()

in commons-geometry-euclidean/src/main/java/org/apache/commons/geometry/euclidean/threed/AbstractConvexPolygon3D.java [98:150]

• 38 lines of code
• 3 McCabe index (conditional complexity)

    public Vector3D getCentroid() {
        final List<Vector3D> vertices = getVertices();

        double areaSum = 0.0;
        double scaledCentroidSumX = 0.0;
        double scaledCentroidSumY = 0.0;
        double scaledCentroidSumZ = 0.0;

        final Iterator<Vector3D> it = vertices.iterator();

        final Vector3D startPt = it.next();

        Vector3D prevPt = it.next();
        Vector3D curPt;

        Vector3D prevVec = startPt.vectorTo(prevPt);
        Vector3D curVec;

        double triArea;
        Vector3D triCentroid;
        while (it.hasNext()) {
            curPt = it.next();
            curVec = startPt.vectorTo(curPt);

            triArea = 0.5 * prevVec.cross(curVec).norm();
            triCentroid = Vector3D.centroid(startPt, prevPt, curPt);

            areaSum += triArea;

            scaledCentroidSumX += triArea * triCentroid.getX();
            scaledCentroidSumY += triArea * triCentroid.getY();
            scaledCentroidSumZ += triArea * triCentroid.getZ();

            prevPt = curPt;
            prevVec = curVec;
        }

        if (areaSum > 0) {
            final double scale = 1 / areaSum;
            return Vector3D.of(
                        scale * scaledCentroidSumX,
                        scale * scaledCentroidSumY,
                        scale * scaledCentroidSumZ
                    );
        }

        // zero area, which means that the points are all linear; return the point midway between the
        // min and max points
        final Vector3D min = Vector3D.min(vertices);
        final Vector3D max = Vector3D.max(vertices);

        return min.lerp(max, 0.5);
    }