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; }