SpiceWare's Blog

Works great, D.

Tested on 32" w/Heavy Sixer RF connection,

And on 14" w/Heavy Sixer RF connection (about 1/4 inch at top blank & 1/8 inch at bottom blank). This 14" is unadjusted with overscan the way it was bought in 2004.

With the colored lines going across the bottom you can see where you are not using the "comb" area on the left, the ship & rocks wrap before the left edge, but go all the way to the right edge.

7 digits make me say, "huh, how?" 14 digits make me say, "WOW!"

Thanks!

 

Yeah, I noticed that about the colored lines as well. I've added a new build that shortens the colored lines by 1 PF pixel. The HMOVE bars are equivalent to 2 PF pixels, but the score lines would be unbalanced if I turned off 2 PF pixels.

 

I've received Nathan's tests for the large asteroids. We might end up dropping the left/right shifting of the large asteroids based on this test. If we do, that means the HMOVE bars will go away and I'll restore the lines to the full width.

Works for me on a modded 4-switch over composite to a 10-year old 20" Magnavox CRT. I expect digital TVs to be where problems occur, but I don't have one handy.

I think it'll be less of an issue for digital TVs. The reason Atari games only used 192 scanlines back in the day was due to overscan.

Overscan is extra image area around the four edges of a video image that may not be seen reliably by the viewer. It exists because television sets in the 1930s through 1970s were highly variable in how the video image was framed within the cathode ray tube (CRT).

 

Newer digital TVs don't have this problem, so they show more of the picture than the old TVs did. Specifically they're designed to show 480 scanlines, or 240 from a progressive source like the Atari. The image I'm generating is around 203 scanlines.

Looks fine in my tv, 29". Even shows the blank space below the score as seen on emulator screenshot.

192 is a conservative figure. The original IBM PC CGA mode (which was based on TV timing) was 320x200.

 

IMVHO I'd skip the asteroid shifts if it allows the full width.

Nathan's sent me most of the asteroid graphics and we've decided to drop the shifting. The non-shifted asteroids look better than I was expecting, and it'll save 2K of ROM by not having all the shift data.

 

I'll probably be adding line-by-line color changes to the kernel when I rewrite it to remove the HMOVEs.

 

The new ship with 32 rotation positions is quite nice too!

I think it'll be less of an issue for digital TVs. The reason Atari games only used 192 scanlines back in the day was due to overscan.

Quote

 

Overscan is extra image area around the four edges of a video image that may not be seen reliably by the viewer. It exists because television sets in the 1930s through 1970s were highly variable in how the video image was framed within the cathode ray tube (CRT).

 

Newer digital TVs don't have this problem, so they show more of the picture than the old TVs did. Specifically they're designed to show 480 scanlines, or 240 from a progressive source like the Atari. The image I'm generating is around 203 scanlines.

 

Thanks for the correction! That statement started to smell wrong as soon as I posted it.