User Interface Design
The biggest challenge in designing the user interface of a vehicle simulator is in mapping the vehicle's real controls to those available on the target machine. For serious simulations, analog controls are essential; the binary D-pads of older handheld controllers don't allow the kind of precision the player needs to steer accurately. At one time, console machines simply couldn't support serious simulations, but now that most console machines offer analog joysticks, mapping the controls of a race car to those of a home console machine presents less of a problem.
Vehicle simulations benefit from motion-sensing controllers almost as much as sports games do. Use their tilt sensors to serve as a steering wheel, and their buttons for acceleration and braking. Don't require the player to turn them by more than about 90 degrees in either direction from the central, neutral position, though. As drivers we can turn a real steering wheel hand-over-hand because it's circular and fixed in place by the steering column, but the iPhone and Wii controllers are rectangular and not attached to anything. It would be awkward for the player to reposition his hands on them during play.
DON’T RELY ON EXTRA-COST CONTROLLERS_________________
Force-feedback joysticks, throttles, control yokes, steering wheels, and pedals (rudder for planes, and gas and brake for cars) all help immensely, and serious players will have them. You can greatly improve the quality of the simulation experience for such players by supporting them. However, don't design—and, more important, don't tune—your game with a presumption that your players will have this kind of hardware. Your game should be an enjoyable experience even with only a standard console controller or a mouse and keyboard. If it's not, you've severely limited your audience, and reviewers are bound to slam it. You may ignore this advice if you ship the special controller with the game, as Guitar Hero does, but such an approach will raise the price of your game substantially.
Military flight simulators always require some simplification from the real thing; you will have to decide how much. Real military pilots require months or years of training, much of it spent sitting in classrooms. Because you want your players to be able to fly the planes within a few minutes of installing the software, you have to make considerable compromises in the realism of the games. You will almost certainly want to reduce the number of instruments in the cockpit and the number of functions that some of them perform.
Flight simulators commonly simplify navigation as well. Modern planes have global positioning systems, but World War I and II pilots still needed celestial navigation skills; they plotted their courses by the stars at night and by landmarks or dead reckoning during the daytime. Because this isn't the most exciting thing about flying, it's acceptable to just give the player a map.
control the direction it is facing, this can happen even more easily in the air. However, most players have only one control mechanism, the joystick. To simplify flight, the left-right motion of the joystick controls both the rudder and the ailerons simultaneously, producing automatically coordinated flight.
In a flight simulation, simply going fast is rarely the point. Most players either try to fly accurately and aerobatically or are engaging in aerial combat. Although speed is an important factor in the game, conveying that sense to the player isn't critical to the experience.
In driving simulations, however, the sense of speed is all-important. Here are some ways to create it:
■ Give the player a speedometer. This is the most obvious way to inform a player of his speed, but it creates a purely logical awareness, not a visceral one. It might also help to give him a tachometer so he can see that the engine is near its maximum potential.
■ Vary the driving surface. Don't present a smooth ribbon of black, but make the road a series of continuously changing dark grays. (Look back at Figure 17.7,
GTLegends, to see this done well.) The rate at which these color gradations move toward the car helps create the feeling of speed. Don't just use a set of random dots, though, or at high speed the player will just see a static, flickering surface. It's better to implement these cues as a series of narrow strips parallel to the road's edges. Also, on roads (as opposed to racetracks), be sure to implement the dotted white line down the center. The sight of the lines flicking by provides a continuous visual cue to the speed, as well as a good way to tell when the vehicle is speeding up or slowing down. (In a flight simulator, the equivalent is to be sure the ground is as detailed as possible.)
■ Include roadside objects. A continuous fence, guardrail, or strip of grass doesn't do much to give the player a feeling of motion. Make sure there are lots of trees, road signs, and bridges. Anything that rises vertically beside the road or that passes over or under the car helps create the impression of motion.
■ Use sounds. The sound of the engine is the most obvious auditory cue, but you can also include road noise (the sound the tires make on the pavement), wind noise, and tires squealing as the vehicle rounds corners. Another excellent cue is a Doppler shift as the car passes, or is passed by, some noise-making object.
The driver of any vehicle feels a variety of forces affecting her body: acceleration, deceleration, and centrifugal force. The forces give a lot of valuable feedback about the behavior of the vehicle. Unfortunately, in a home-based simulator, you can't
provide any of those physical feelings, so you have to substitute other indicators. With driving simulators, it isn't as important because automobiles seldom generate significant G-forces, and the player receives plenty of other visual cues, as the previous section describes.
Military aircraft can generate powerful G-forces, and the engines of modern fighter planes are powerful enough to tear the plane apart if it is mishandled. If you're doing a realistic simulation, you might want to include this deadly little detail. If so, or if you just want to give the pilot an indication of the G-forces involved, you should include a G-force meter showing the amount of stress being applied to the plane (and pilot). In addition, pilots undergoing strong downward G-forces can black out momentarily as all the blood drains out of their heads. They can also suffer an experience called redout if they encounter a strong upward G-force, because too much blood flows into their heads. Many games simulate these conditions by fading the screen to black or to red, which, in addition to preventing the player from seeing anything, gives a clear indication that something is wrong.
Vehicle simulations require a designer to knowledgeably represent a known physical world in a realistic manner to the player. You should spend time learning about the characteristics of the vehicles you wish to simulate within the game, work to adapt the core mechanics to the limitations of the user interface, and devise and create compelling opponents and courses for the player to use.
You should determine whether the audience of your game will be purists or casual players and design core game mechanics to satisfy that market. For the purist, the simulation needs to be the most accurate representation of the vehicle possible, whereas for the casual player, the simulation can more easily trade play mechanisms for realism.
The most critical things for you to consider after you choose your audience are the vehicle characteristics, the opponent behaviors, and finally the design of the courses or tracks within the game.
Vehicle simulations can be highly technical and challenging, and a dedicated designer must be prepared to undertake a lot of research.