private EyeViewport initViewportForEye(final FieldOfView fov, final float xOffset) {
final float left = (float) Math.tan(Math.toRadians(fov.getLeft()));
final float right = (float) Math.tan(Math.toRadians(fov.getRight()));
final float bottom = (float) Math.tan(Math.toRadians(fov.getBottom()));
final float top = (float) Math.tan(Math.toRadians(fov.getTop()));
final EyeViewport vp = new EyeViewport();
vp.x = xOffset;
vp.y = 0.0f;
vp.width = left + right;
vp.height = bottom + top;
vp.eyeX = left + xOffset;
vp.eyeY = bottom;
return vp;
}
