10 replies to this topic

[Andrew Davie]

I expect there are approximately zero Atari 2600 SECAM users out there.
Nonetheless, Boulder Dash® not only works with PAL and NTSC machines, it is also optimised for good looks on SECAM consoles!
If anyone has a SECAM unit, please let me know.  This may be the ultimate in completely pointless programming effort... SECAM compatibility
Anyway, here's a few screen grabs from Stella running the game under SECAM.  Given the *incredibly* limited SECAM palette, I'm quite stoked at the outcome.
Even the amoeba is a decent green
Cheers
A

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[Rom Hunter]

LOL

Perfect.

What a service!

[Rastignac]

I do have two or three SECAM 2600, but they suck so much ! I don't even use them.
I bought real PAL machines (all 2600jr are PAL, all 7800 are PAL, other countries 2600 are PAL) and I can now enjoy games as they must be seen !
(Playing  the same game years later and seeing it now with its real colors is such a huge shock).

(PS: I didn't forget  to add SECAM support to F40...).

Edited by Rastignac, Fri Dec 23, 2011 12:04 PM.

[maiki]

Although SECAM is very limited, those few colours tend to be more vivid than the whole PAL range for instance, especially the yellow colour. That's why it is likely that secam games may look great in the end. Bright and shiny.

[Ben_Larson]

I love doing SECAM versions! It's like a bonus technical challenge at the very end to see if you can make it look presentable...

Yours is actually looking very good... better than my SECAM conversions for Incoming and Panky the Panda anyway.

[Phredreeke]

Something just struck my mind. On PAL systems it's possible to generate additional colors by displaying two colors on alternating lines. Could something similar be done with SECAM on the 2600?

[Andrew Davie]

Phredreeke, on Sat Dec 24, 2011 1:58 PM, said:

Something just struck my mind. On PAL systems it's possible to generate additional colors by displaying two colors on alternating lines. Could something similar be done with SECAM on the 2600?

That's exactly how Boulder Dash® works!  Only, not two colours on alternating lines, but three colours on 3 lines.
It works for all systems, not just PAL.
Cheers
A

[Andrew Davie]

Ben_Larson, on Sat Dec 24, 2011 1:27 PM, said:

I love doing SECAM versions! It's like a bonus technical challenge at the very end to see if you can make it look presentable...

Yours is actually looking very good... better than my SECAM conversions for Incoming and Panky the Panda anyway.

The added challenge here is that we don't have a SECAM switch.  It's just the PAL palette, which has been adjusted so that the screens look good both in PAL and SECAM with the same colour values (but different colours shown) being used. It was a fun challenge working it.  Basically, SECAM uses the intensity bits to choose a colour, so for the PAL palette I had to choose intensities which worked for PAL which displayed nice colours for SECAM.
Cheers
A

[Phredreeke]

Andrew Davie, on Sat Dec 24, 2011 3:52 PM, said:

Phredreeke, on Sat Dec 24, 2011 1:58 PM, said:

Something just struck my mind. On PAL systems it's possible to generate additional colors by displaying two colors on alternating lines. Could something similar be done with SECAM on the 2600?

That's exactly how Boulder Dash® works!  Only, not two colours on alternating lines, but three colours on 3 lines.
It works for all systems, not just PAL.
Cheers
A

With NTSC, if you alternate two colors the TV still shows those colors and you're relying on the eyes/brain of the viewer to interpret it as one color. With PAL the TV got a delay line that blends the color with the previous line, so if you alternate two colors of the same luminance they appear as a single color. SECAM got a delay line too but it works in a different way. I don't know what R-Y and B-Y values the 2600 SECAM chip use for its colors, but I'm thinking that if alternating colors it would use the R-Y value of one color and the B-Y value of the other, potentially yielding a new color (this would not work in an emulator, it would need a SECAM 2600 with a SECAM decoder to work)

[Eckhard Stolberg]

PhredreekePhredreekeI

Andrew Davie, on Fri Dec 23, 2011 8:52 AM, said:

If anyone has a SECAM unit, please let me know.  This may be the ultimate in completely pointless programming effort... SECAM compatibility

I don't know if anyone will ever really play Boulder Dash on a SECAM 2600, but since you took the effort to optimize the colours for this TV standard, I thought you might like to see how it turned out. So I took some pictures of the game playing on a SECAM VCS connected to my multi-standard TV.

Unfortunately  Phredreeke was right. SECAM VCSs don't like striped displays too much. When you use single line colour changes, the colour may even be different depending on which scanline you display it in (odd or even). This is most noticeable in Rockford's face, which has a different colour when he is displayed in an odd row then he has in an even row of tiles. But it also shows in the colour pattern of the dirt tiles or the boulders, where the red and blue lines differ depending on which row the tile gets displayed in.

Another thing to notice is that using PAL colours the look-around mode doesn't show the dirt tiles in some caves, while this works fine using NTSC colours. Nevertheless all tiles are still easily recognizable in both colour modes on a SECAM VCS, so the game is still just as playable as it is on NTSC or PAL colsoles.

PAL 50


PAL 60


NTSC

[Andrew Davie]

Eckhard Stolberg, on Sun Aug 19, 2012 5:36 AM, said:

I don't know if anyone will ever really play Boulder Dash on a SECAM 2600, but since you took the effort to optimize the colours for this TV standard, I thought you might like to see how it turned out. So I took some pictures of the game playing on a SECAM VCS connected to my multi-standard TV.

Thanks for doing that!
Actually, what I didn't tell the world is that SECAM support was quietly dropped basically because of the endless "fights" that Thomas and I had about the colour palettes. We never did agree on a palette which was SECAM compatible AND which both Thomas and I liked. Given there were precious few colours we could agree on at all, the SECAM compatibility was the first to go.  Nonetheless, it is really interesting to see the results of the existing (non-optimised) palettes. Thanks for this. Seems to me that it's not really going to work anyway.  Maybe.
Cheers
A