New To Arcade Games And Emulation

[AutumnGhost]

For Arcade games what is meant by vertical and horizontal games? Can someone give me examples of each? and in the mame support forum some members have said to play vetical games on the gp2x Just rotate 90 degrees and use the volume button as fire, Why do you need to do this to play "vertical games"


In emulation what does frameskip mean? and terms like auto frameskip, frameskip 1, frameskip 2 etc.


I feel a bit thick asking these questions, as I am new to arcade games and emulation, thanks for any replies,
there may be other newbies who do not know this, I hope the replies are helpful to them as well.

 

[^RaZ]

u can rotate the screen in mame 2x, 'verticle' games, i believe this is for two player games like pong and therefore allows two player by sharing the unit end to end with another person but still making sense in the way its displayed to the players???

frame skip is abit like frames per second, although a certain number of frames can be skipped ie not all need to be drawn thus saving on performance, and sometimes has the effect of making the game look as if it is doing more fps than it is, too much frame skip can make the game look juddery... probably wrong on this look up a good wiki to get a better definitiion -- its a performance thingy =D

 

[Morpheus384]

For Arcade games what is meant by vertical and horizontal games? Can someone give me examples of each? and in the mame support forum some members have said to play vetical games on the gp2x Just rotate 90 degrees and use the volume button as fire, Why do you need to do this to play "vertical games"


In emulation what does frameskip mean? and terms like auto frameskip, frameskip 1, frameskip 2 etc.


I feel a bit thick asking these questions, as I am new to arcade games and emulation, thanks for any replies,
there may be other newbies who do not know this, I hope the replies are helpful to them as well.

In the good old Arcade days some machines had their monitors mounted on their side (Like a TV Screen on its side facing you-e.g less width and more height) This gave a longer verticle view for fast paced shooters/breakout games like 1942,Galaga,Time pilot 84,Centipede,Arkanoid etc etc. Some games like Pacman and Donkey Kong were mounted in this way as well.

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By default, Mame outputs them as a horizontal screen to match your monitors orientation e. g. like your GP2X/telivision screen-more width / less height.


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This causes the verticle game itself to be "squished" to fit in height of the screen with black bars on each side. it may also cause some of the game (bottom or top)to be cut and not viewable.

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This makes some of the older fast paced shooters much harder to play because you have less lead time as baddies travel from the top of the screen to your ships position. At the very least it is not the way the game was classically made to be viewed/played; and emulation strives for authenticity in display/sound/gameplay.

One of the brilliant things worked into mame gp2x is the ability to rotate the image 90 degrees to a vertical one (L+R Shoulder buttons), and use the joystick and (which is automatically rotated 90 degrees to match the screen) volume buttons (which are automatically remapped to A/X buttons) to play these games the way they were originally meant to be played.

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Horizontal or "Raster" Games were oriented the same as your GP2X/Computer monitor/TV screen and display just fine. Examples: Rastan,Rygar,Street Fighter, King of Fighters,Strider etc.

Frame skip is an option used when the emulator in question is unable to play a given game in full speed and frame rate.
Most games run natively at 60 frames per second to give the illusion of motion like a cartoon image drawn many times in sequence. If the emulator cannot match this speed due to lack of processor power ect. etc. the game will appear slow during game play.

Applying frameskip will lessen the amount of frames displayed each cycle.

FS-1=Skip one frame every cycle to speed up display.
FS-5 =skip 5 frames every cycle etc. etc
Auto Frameskip will automatically compensate the frame skip to the game play.

This gives the illusion that the game is playing at full speed since the human eye can only detect 30 frames per second..i think. And since the unit does not have to process so many frames, games run smoother. However if you skip too many frames the play will appear jagged/jittery and hence be unplayable.

 

[slaanesh]

My two cents worth on Frameskip (and Frames Per Second):

All computers with a display refresh the screen a number of times per second. This is known as Frames Per Second or FPS.
For example, a television will usually refresh at either 50 or 60 FPS. This means the image is redrawn that many times per second.

Emulating video games means that the emulator (like MAME) needs to redraw the screen at the same FPS rate that the original game ran at. This is usually 60 FPS but can be less - down to 30 FPS for some games.

Frameskip means that you are skipping some frames to keep the speed up as demanding games may take longer to draw each frame than the amount of time available to do so. ie. At 60FPS each frame *must* be drawn in 1/60th of a second otherwise the game will appear to start slowing down. ie. If it's taking 1/30th of a second to draw, the game will appear to run at half speed.

So, if we can skip drawing some frames, the game will appear to run at the originally intended speed - at the loss of some smoothness of animation.

Frameskip = 0 means that no frames are skipped. All frames are drawn.
Frameskip = 1 means that it skips every other frame. Only 1/2 frames are drawn.
Frameskip = 2 means that it skips two of every three frames. Only 1/3 frames are drawn.
Frameskip = 3 means that it skips three of every four frames. Only 1/4 frames are drawn.
etc

The highest you really want to go is Frameskip 2; at Frameskip 3 or higher it gets really noticeable.

 

[Morpheus384]

My two cents worth on Frameskip (and Frames Per Second):

All computers with a display refresh the screen a number of times per second. This is known as Frames Per Second or FPS.
For example, a television will usually refresh at either 50 or 60 FPS. This means the image is redrawn that many times per second.

Emulating video games means that the emulator (like MAME) needs to redraw the screen at the same FPS rate that the original game ran at. This is usually 60 FPS but can be less - down to 30 FPS for some games.

Frameskip means that you are skipping some frames to keep the speed up as demanding games may take longer to draw each frame than the amount of time available to do so. ie. At 60FPS each frame *must* be drawn in 1/60th of a second otherwise the game will appear to start slowing down. ie. If it's taking 1/30th of a second to draw, the game will appear to run at half speed.

So, if we can skip drawing some frames, the game will appear to run at the originally intended speed - at the loss of some smoothness of animation.

Frameskip = 0 means that no frames are skipped. All frames are drawn.
Frameskip = 1 means that it skips every other frame. Only 1/2 frames are drawn.
Frameskip = 2 means that it skips two of every three frames. Only 1/3 frames are drawn.
Frameskip = 3 means that it skips three of every four frames. Only 1/4 frames are drawn.
etc

The highest you really want to go is Frameskip 2; at Frameskip 3 or higher it gets really noticeable.

Thanx Slaannesh! Thats the best description of the frameskip function I've ever seen. I was just making a blind stab at it. Like most, I knew how to use it, but not fully how it works. Its amazing that I've been into emulation since '98 or so and still didnt understand it completely. :huh:

Many thanx for your great work on MAME with Franxis getting sound sample support to the GP2X! You guys Rock!

 

[Robotube]

I thought NTSC TV refreshed at 24 FPS?

 

[krosfyah]

If I remember correctly 24 is movies, PAL=25 and NTSC=30. The 50 and 60 are to do with interlacing.. I think.

 

[AutumnGhost]

I'm impressed with the replies, this has been very helpful and useful. Thank you for the in depth information, slaanesh and Morpheus 384.

 

[slaanesh]

If I remember correctly 24 is movies, PAL=25 and NTSC=30. The 50 and 60 are to do with interlacing.. I think.

Ah yes, interlacing.

A single image on a TV is interlaced to get the full picture resolution. What this means is that each image is made of two frames; the even lines are displayed in the first frame and the odd lines are displayed in the next frame. The TV shifts the second frame half a scan line down so that the 2nd frame is in between the first ("interlacing"). The persistence (the amount of time the image remains) of the TV's phoshor is usually enough to make the two frames look like one, higher resolution image.

(Though, if anyone remembers the Amiga and it's "interlace" mode screens, you'll know about the awful flicker.)

So that's why PAL is 25 FPS and NTSC is 30, though the TV actually has twice as many FPS.

 

[krosfyah]

I remember my first pc monitor could only manage 1024x768 with interlacing. It was impossible to use it for more than 30 minutes without getting a headache.