FAQ:Games

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How can I play Cruis'n USA when it frameskips so badly?

Short Answer: It isn't as bad as you think. Turn off autoframeskipping. Set your frameskip value to 0.

Long Answer: Many games use bitmaps and blitters to draw their graphics, much like modern computer hardware. With these games, they talk to a blitter chip, and give it commands to draw certain graphics into memory. This memory is also accessible to the main CPU directly, so it is free to manually hand-draw pixels just by writing to graphics memory. Furthermore, the CPU can also read graphics memory, thus allowing it to, for example, read back the data that was written there by the graphics chip. Because of this tight relationship between the CPU and graphics memory, it is important that all drawing commands sent to the blitter actually get executed, regardless of whether they will be displayed on the screen this frame.

Thus, when it comes time to draw the bitmap to the screen, all MAME has to do is copy the contents of graphics memory to the screen. Compared to other arcade hardware that uses tilemaps and sprites, this is a relatively quick and easy process. The problem comes when your computer is not fast enough to run the emulation of the game, the blitter, and the graphics. When this happens, MAME kicks in with "autoframeskipping", where it will gradually increase the frameskip count in order to hopefully save enough time to get the game running 100%. In order to save time, MAME skips the video rendering portion of the emulation periodically.

Now, for games which have fairly complex video rendering with tilemaps and sprites, this can save a lot of time, which is why autoframeskipping is generally a good thing. But in the case of games that use blitters and bitmaps, the only thing MAME can skip is the copying of the graphics memory to the screen. All the blitter commands still must be executed, and so increasing the frameskip value will make very little impact on the overall emulation speed. What's worse is that if your computer is too slow to run these games at frameskip 0, it is also likely too slow to run them at frameskip 11, and so the autoframeskip will shoot right to 11 and display only 1 out of every 12 frames. This is called a "slideshow".

The solution is to identify these kinds of games, and forget all about using autoframeskipping. In this case, you want to always run with a fixed frameskip of 0, because the amount of frameskipping doesn't matter much for performance, and a frameskip of 11 (which is what you'll get with the autoframeskipping) looks really, really bad.

Games that are affected by this pattern: All Williams games, the Cruis'n series of games, the Incredible Technologies games, Police Trainer, and several others.

How do I set up D&D - Shadow over Mystara or other games for 4 player use?

Usually the default number of players for most games is two — even if they support more. The most common way to set them for four players is to access the dipswitches, but sometimes the setting is not there. In these cases, try using the service mode (by default F2 key) and investigate the service mode options. Follow the screen instructions on how to move between the menus and save the options (usually by exiting the service mode properly).

How do I calibrate the guns in Terminator 2? Can I use a light gun?

Terminator 2 will automatically ask you to calibrate the guns when you start the game for the first time. Simply put, use your mouse or keyboard to "target" the top left corner when the game asks so. There aren't any visual cues to help this, so you'll have to go by the numerical coordinates that are visible on the screen. The numbers you see are in a simple 8-bit scale going from 0 to 255. To "target" the top left corner, keep moving your mouse until you get P1 X and P1 Y as near to 0 as possible. The middle is located at about 127, 127, and the bottom right corner is 255, 255. Repeat the process for the second player.

As for the light gun, the short answer is no. A longer answer is that Terminator 2 didn't actually have a light gun — it had two analog joysticks mounted as guns, and emulating them with a proper light gun is not viable. Try to use mouse control with this game.

Revolution X can be calibrated much the same way. Follow the instructions above.

How do I calibrate the guns in Namco games? (Golly! Ghost, Lucky & Wild etc.)

While holding the service coin (9) key, press the service mode button (F2). Shoot at the targets it shows using the crosshair. The target briefly lights up red while you shoot. After you've shot the target, press the service coin key (9) again to move onto the next one and it will also ask you to calibrate the second player's gun. Once the whole thing repeats, press the service mode button (F2) to exit.

Why doesn't 720 Degrees use a spinner?

The original controller for 720 Degrees was a joystick that was hardware-limited to only travel along the outermost edges in a circle. The internal mechanism for reading this control was similar to a spinner except that it had the additional benefit of knowing which direction the joystick was pointing. Because this knowledge is an important aspect of the game, the current emulation of the controller maps an analog joystick to the underlying controls instead of a spinner.

I am trying to play a Williams game (Joust, Defender, Bubbles, etc.) and I can't get into the game itself.

The first time you run these games, they will say "Factory settings restored". Press F2 to proceed. This works for most Williams games. Otherwise, try F3, or F1 and F2 together.

When I run Zookeeper, I get stuck on a THIS LOCATION screen.

The first time you run the game, it will ask the location. You can change the name using F5 / F6 and F2, then F1 to proceed through the configuration screens. Or just reset (F3).

What's wrong with the NVRAM in Food Fight?

The first time you run the game, it re-initializes the NVRAM (Non-volatile RAM) memory. To get past the initialization screen, hit the primary fire button (Left Control key, or the first joystick button).

When I try to play MACH 3 or Us vs. Them, I just get a "Disc" message.

These are laserdisc games. In the '80s, several "hybrid" video/laserdisc games appeared. Unlike Space Ace and Dragon's Lair — which were essentially interactive cartoons — these games mixed graphics and video for a more intense gaming experience. The MAME team decided to emulate the normal graphics portions of the games, and worry later about how to emulate the laserdisc video. Hence, you cannot play these games at this time in MAME. However, a lot of the laserdisc games are emulated in Daphne.

How do I play Water Match?

The instructions are on the game's bezel. The game involves waggling the two joysticks around like an idiot. Here's what you have to do:

For freestyle and backstroke swimming, move the two joysticks up and down in opposition to each other (when one is up, the other must be down).

For butterfly, turn the joysticks "outward" — left clockwise, right counterclockwise. For breaststroke, turn them "inward" (left counterclockwise, right clockwise).

(You need to use the start button to dive into the pool and the turn button to turn around.)

For rowing the rowboat, move the joysticks up and down in sync (both up, both down, both up, etc.).

For rowing the canoe, move the joysticks up and down independently: the left one if the canoe is veering to the left or the right one if the canoe is veering to the right. (One of the buttons is involved as well, but it's too hard to make out in the photo.) You have to press one of the buttons (not sure which one) to right your canoe when it capsizes.

How do I start a PlayChoice-10 game?

The Playchoice-10 system was a multigame arcade machine. MAME emulates a Playchoice-10 with one game in it. However, the "channel select" menus and timer still are there in MAME. PC-10 games are timer-based, which means coins buy playing time, instead of a certain number of lives. Game ends when time is up, although you can reset, start and continue unlimited times, as long as you have time left).

To start the game, do the following:

1. Run MAME with the PC-10 game you want to play (ex. "MAME PC_SMB3" would run Super Mario Bros 3, or "MAME PC_RCPAM" would run RC Pro-AM).
2. Insert a coin by pressing 5 to put some time on the timer (300 Units Per coin).
3. Press 0 to select channel one.
4. Press - to "Enter" the game.
5. Press 1 to select Options.
6. Press 2 to Start Game.