vertical games in groovymame

[stiegi]

Hello guys!

I have got a specific question about vertical games in groovymame. I want to keep it as simple as possible. Currently I play vertical games on a Sony pvm monitor which is mounted vertically in the cab. I use groovy mame. I am talking about games with the originial resolution of 256 x 224 such as Gun Smoke, Donkey Kong etc. Groovy mame switches to the exact resolution of 256 x 224 and the exact refresh rate.

Now here is the thing I donīt understand at all. Groovy mame draws every game with the resolution of 256x 224 in full screen. In some of the games there is a "test grid" where you can see that it is definitely stretched vertically in order to fill the whole screen.

As a matter of fact the Sony CRT TV has got the aspect ratio of 4:3 and I suppose that the monitor in the original arcade cabs (still talking about the games with the resolution of 256 x 224 for example star force) also had 4:3 format.

What confuses me is that Groovy mame obviously streches the games to full screen - but this does not seem right to me cause you can see in the game that the whole picture is streched. If groovy mame did not strech to fullscreen the test grid would be perfect (all perfect squares) but this would mean that there are black borders on the upper side and the lower side.

So how did they do it in the real arcade cab? Was the picture also streched to full screen meaning that the aspect ratio is not correct or did the games with the resolutio of 256 x 224 had black borders? I cannot imagine that the picture was streched so they would have to cover the border with the bezel?

Anyways does anyone know hot to set Groovy mame / vmmaker so that it does not stretch to fullscreen in order to give the original aspect ratio of the games

Regards,
Alex

[Calamity]

That doesn't happen here. Post a log.

[machyavel]

Well that's simple: 256/224 = 1.14, 4/3 = 1.33. The picture has to be stretched in order to fit a 4/3 screen, that's normal. The grid thing is that some were designed with "squares" only in terms of pixels (e.g. 16px by 16px).

[Calamity]

The picture has to be stretched in order to fit a 4/3 screen, that's normal.

No 

[machyavel]

Oh I was not clear, I meant pixels have to be "stretched", geometrically speaking, from square pixels to rectangular pixels.

It's not GM that stretches anything in this case.

[stiegi]

I still confused about it. All I can tell is that some games (256x224) which have a test grid donīt have regular squares but rectangles. When I load Galaga for example which has 288x224 the test grid shows regular squares this is logical to me since the value 288 is higher than 256 and it can fit to the screen without stretching.

In case of games with 256x224 resolution the only solution to this problem is to leave black borders in order to achieve regular squares in the test grid.

Of course I cannot tell if the test grid really refers to the original aspect ratio ratio of the games - if not the games with 256x224 would be like the original and are not streched. With streched I mean that for example I understand that apart from the whole picture sprites are displayed with the wrong height in relationship to there width.

On the other hand if the streched full screen picture does not have the correct aspect ratio the only possibilty would be to stretch the picture horizontally which means to cut left and right side of the picture since the physical size of the monitor is constant.

An other question is - is there a connection between aspect ratio (correct display of the picture of the games) and specific resolution or not.

The thing is the resolution is 256x224 does this express the exact dimension of the picture and the aspect ratio of 256/224? If so it would be impossible to fit into a 4:3 screen without changing the first value (256).

regards

[cools]

A CRT doesn't necessarily have to have square pixels like an LCD.

Height and width adjustments on the CRT change the shape of the pixels.

[Calamity]

An other question is - is there a connection between aspect ratio (correct display of the picture of the games) and specific resolution or not.

No. All these games are 4:3, regardless the resolution. At the time these games were made, all screens were 4:3. The "aspect ratio" thing was invented later.

You simply adjust the pots so the exterior bounding box of the grid matches the tube borders. Expect the grid squares to show different degrees of compression depending on their place in the screen.

[stiegi]

Hello!

Thanks Calamity and all in the forum.  :applaud:So everything is fine. The exterior bounding box of the grid matches the monitor nicely thanks to groovy mame. Good work.

regards,
Alex