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swapd0

Video init and vertical resolution

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How on the hell I can fill the whole vertical screen?

 

In my game I'm using a vertical resolution of 224 lines and it leaves a big bottom border (in PAL, not tested on NTSC), but if I launch checkered flag game it fills the whole vertical screen, and I doubt that it's using more than 200 lines...

 

By the way I'm using jaglib, maybe I need to write my own video init routine?

 

 

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For a given video standard (NTSC or PAL), the height/thickness of the lines are fixed. So it can be two things:

 

- Checkered Flag uses more lines in PAL mode (that's easy to check using Virtual Jaguar)

 

- overscan / centering problems. I've never used JagLib, but maybe it puts the active area at the top of the screen, instead of centering it? That would explain why you get a border at the bottom but not at the top.

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I thought that you can tweak the video registers to scale a bit the image (vertically), because the jaguar games that I've tried fill the whole screen but when I code something it leaves a lot of empty space.

 

I find it a bit strange if they are rendering more lines in PAL.

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I thought that you can tweak the video registers to scale a bit the image (vertically), because the jaguar games that I've tried fill the whole screen but when I code something it leaves a lot of empty space.

Wouldn't that give you really wonky artifacting if it were the case?

 

I find it a bit strange if they are rendering more lines in PAL.

There's more lines on an old PAL TV and more time to calculate each frame as NTSC updates 20% more frequently. Kinda evens out and seems right doesn't it?

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I thought that you can tweak the video registers to scale a bit the image (vertically)

You would have to tweak the video timing registers, and the result will no longer be standard PAL or NTSC.

That's not a good idea, because there's no guarantee TV sets would display the video correctly (or at all).

 

There's more lines on an old PAL TV and more time to calculate each frame as NTSC updates 20% more frequently. Kinda evens out and seems right doesn't it?

Indeed, and even not all Jaguar games use more lines in PAL. Some just have black border(s) in PAL mode.
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Evolution Dinodudes is not the standard 320x200 . Its noticeable if you compare the game to other platforms. For the first batch of games there was no standard code to set the screen to 320x200.

If I remember correctly I-War when its displays the title screen / credits in the attract mode is 640 wide to make it looks a lot smoother ( https://youtu.be/K6EAd7VoJl0?t=258 )

Edited by Seedy1812

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