It depends on the design brief/use case. Things like lighting, cooling,etc. The big one is driver sight-lines. A flat windshield at 90 degrees to sight-line is best, sloped and curved windshields are subject to refraction and glare.
The example uses flat faceted panes, while the rest of the body can be compound curved. The two forward facing hexagons could be flattened, enabling a Luigi Colani spinning windshield wiper. The front wheels are held back where leading and trailing spats are possible. The overall form is your nominal solar racer inflated for interior volume.