_prepareAxesAndDirs()

in packages/miew/src/gfx/geometries/IsoSurface.js [105:147]

• 32 lines of code
• 16 McCabe index (conditional complexity)

  _prepareAxesAndDirs() {
    const volData = this._volumetricData;

    const cellSize = volData.getCellSize();

    // calculate cell axes
    const xAxis = this._xAxis;
    const yAxis = this._yAxis;
    const zAxis = this._zAxis;
    const xDir = this._xDir;
    const yDir = this._yDir;
    const zDir = this._zDir;

    xAxis.set(cellSize.x, 0, 0);
    yAxis.set(0, cellSize.y, 0);
    zAxis.set(0, 0, cellSize.z);

    xDir.set(1, 0, 0);
    yDir.set(0, 1, 0);
    zDir.set(0, 0, 1);

    // flip normals if coordinate system is in the wrong handedness
    const tmp = new THREE.Vector3();
    tmp.crossVectors(xDir, yDir);
    if (tmp.dot(zDir) < 0) {
      xDir.negate();
      yDir.negate();
      zDir.negate();
    }

    // check that the grid is in the all-positive octant of the coordinate system
    if (xDir.x < 0 || xDir.y < 0 || xDir.z < 0
      || yDir.x < 0 || yDir.y < 0 || yDir.z < 0
      || zDir.x < 0 || zDir.y < 0 || zDir.z < 0) {
      return false;
    }

    // check that the grid is axis-aligned
    const notZero = (axe) => Math.abs(axe) > Number.EPSILON;
    return !(notZero(xAxis.y) || notZero(xAxis.z)
          || notZero(yAxis.x) || notZero(yAxis.z)
          || notZero(zAxis.x) || notZero(zAxis.y));
  }