void _faceIjkToVerts()

in src/h3lib/lib/faceijk.c [783:837]
34 lines of code
4 McCabe index (conditional complexity)

void _faceIjkToVerts(FaceIJK* fijk, int* res, FaceIJK* fijkVerts) {
    // the vertexes of an origin-centered cell in a Class II resolution on a
    // substrate grid with aperture sequence 33r. The aperture 3 gets us the
    // vertices, and the 3r gets us back to Class II.
    // vertices listed ccw from the i-axes
    CoordIJK vertsCII[NUM_HEX_VERTS] = {
        {2, 1, 0},  // 0
        {1, 2, 0},  // 1
        {0, 2, 1},  // 2
        {0, 1, 2},  // 3
        {1, 0, 2},  // 4
        {2, 0, 1}   // 5
    };

    // the vertexes of an origin-centered cell in a Class III resolution on a
    // substrate grid with aperture sequence 33r7r. The aperture 3 gets us the
    // vertices, and the 3r7r gets us to Class II.
    // vertices listed ccw from the i-axes
    CoordIJK vertsCIII[NUM_HEX_VERTS] = {
        {5, 4, 0},  // 0
        {1, 5, 0},  // 1
        {0, 5, 4},  // 2
        {0, 1, 5},  // 3
        {4, 0, 5},  // 4
        {5, 0, 1}   // 5
    };

    // get the correct set of substrate vertices for this resolution
    CoordIJK* verts;
    if (isResClassIII(*res))
        verts = vertsCIII;
    else
        verts = vertsCII;

    // adjust the center point to be in an aperture 33r substrate grid
    // these should be composed for speed
    _downAp3(&fijk->coord);
    _downAp3r(&fijk->coord);

    // if res is Class III we need to add a cw aperture 7 to get to
    // icosahedral Class II
    if (isResClassIII(*res)) {
        _downAp7r(&fijk->coord);
        *res += 1;
    }

    // The center point is now in the same substrate grid as the origin
    // cell vertices. Add the center point substate coordinates
    // to each vertex to translate the vertices to that cell.
    for (int v = 0; v < NUM_HEX_VERTS; v++) {
        fijkVerts[v].face = fijk->face;
        _ijkAdd(&fijk->coord, &verts[v], &fijkVerts[v].coord);
        _ijkNormalize(&fijkVerts[v].coord);
    }
}