Aspect Ratio, VGA, and Scaling

[cosmicr]

I know the native resolution is 640x480. Most will probably use an LCD with VGA input. When the VERA scales the screen for different resolutions, how does it do the scaling?

If I want say, 320x200 (Classic MS-DOS game res) it will stay 4:3 but scaled. That's what I want, but will the pixels look evenly scaled, or a bit janky/uneven? Is the scaling done digitally or analog?

As an example, if you scale an image using a paint program with those dimensions and nearest neighbour it doesn't look great. The emulators have bilinear filtering etc, but that's probably not an indication of how it will look on real hardware.

Can anyone offer any insight?

[DragWx]

The VERA performs the screen scaling by itself, but it uses nearest neighbor scaling, so resolutions which are not integer divisions of 640x480 will look wiggly and uneven.

The pixel aspect ratio of the VERA is 1:1 (square) in VGA mode, and 54:55 in NTSC mode (close enough to square that you shouldn't need to worry about the difference). In other words, images that rely on a non-square-pixel screen resolution are not going to work well on the VERA.

[BruceRMcF]

I know the native resolution is 640x480. Most will probably use an LCD with VGA input. When the VERA scales the screen for different resolutions, how does it do the scaling?

If I want say, 320x200 (Classic MS-DOS game res) it will stay 4:3 but scaled. That's what I want, but will the pixels look evenly scaled, or a bit janky/uneven? Is the scaling done digitally or analog?

As an example, if you scale an image using a paint program with those dimensions and nearest neighbour it doesn't look great. The emulators have bilinear filtering etc, but that's probably not an indication of how it will look on real hardware.

Can anyone offer any insight?

A 320x200 active area on a 320x240 display would not have the scaling artifacts, since it would be integral 2x doubling of the pixels, though if assets are designed for 1.6 pixel aspect ratio, they would look squashed.

[cosmicr]

I talking about scaling the display to 320x200 though, not 320x240. So the HSCALE is 64 and the VSCALE is (approx.) 54.

The VERA performs the screen scaling by itself, but it uses nearest neighbor scaling, so resolutions which are not integer divisions of 640x480 will look wiggly and uneven.

Yeah that's how it looks on the emulator. hmmm... Thanks for the reply.

[kelli217]

Have you considered letterboxing? Set VSTART and VSTOP to give a 20-pixel bar at the top and the bottom.

[cosmicr]

Have you considered letterboxing? Set VSTART and VSTOP to give a 20-pixel bar at the top and the bottom.

Yeah definitely, but it ruins the aspect ratio then, making everything squished. Best option is to program for both and let the user choose I reckon