25 replies to this topic

[Albert]

/images/news/RedVsBlue.gifMatt Reichert of AtariProtos.com has released the binary to the a technology demo 2600 prototype called Red vs. Blue. This early demo was put together by Tod Frye to see how many sprites he could get onscreen at once, and eventually formed the basis for Realsports Football. You can download the binary here, and read more about it over at AtariProtos.com.

[oesii]

Hey, this looks just like a scene from the Bucs-Indy game this last Monday night. The 2 Bucs are out of position and everyone is leaping

Thanks for the release though

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[Inky]

Albert said:

/images/news/RedVsBlue.gifMatt Reichert of AtariProtos.com has released the binary to the a technology demo 2600 prototype called Red vs. Blue.  This early demo was put together by Tod Frye to see how many sprites he could get onscreen at once, and eventually formed the bases for Realsports Football. You can download the binary here, and read more about it over at AtariProtos.com.

Formed the BASES?

You mean BASIS, right?

Zylon jr.

[Albert]

Inky said:

Formed the BASES?

You mean BASIS, right?

Yes, thanks. /me slaps forehead.

..Al

[NovaXpress]

Will this cause a decline in the amount of Tod Frye bashing that goes on? Probably not, but it should.

[Tempest]

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Hey, this looks just like a scene from the Bucs-Indy game this last Monday night. The 2 Bucs are out of position and everyone is leaping

Haha... Keep in mind that those two extra men are the result of emualtion problems. On a real 2600 the two guys aren't there and everyone is lined up appropriately (they're a little off center in that screenshot).


Tempest

[Lost Monkey]

ALL YOUR BASIS..

nevermind..

I really don't think this kernel could accomodate vertical movement of the player sprites. It actually looks like 9 separate small kernels with a blank space between each for horizontal repositioning.

Freeway and Frogger used a display kernel similar to this (in theory) too.

Nice to see demo's like this surface though!

[Tempest]

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Nice to see demo's like this surface though!

I've had this thing for about two years now (I actually bought it as a "non-playable football game"). I would have released it sooner, but I honestly didn't think it would be of interest to anyone (afterall it's not a playable game or anything). It never occured to me that it could contain useful coding techniques.

Oh well, better late than never I suppose.

Tempest

[DEBRO]

Thanks for the ROM Matt

I for one stop doubting Tod after I saw Stella @ 20.

I see what he's doing for this effect. He's changing the NUSIZx of the players so he gets 2 copies close or 2 copies medium. Since the players are positioned in the center of the screen this allows plenty of time to color them.

BTW, the 2 players could be out of sync because an HMCLR was done on cycle 19 which is 16 cycles after HMOVE...naughty, naughty.

Still I think this is neat.

[Godzilla]

Thanks! thats awesome! all your roms that are the basis for other games are belong to us now!

[Eckhard Stolberg]

Tempest said:

Haha...  Keep in mind that those two extra men are the result of emualtion problems.  On a real 2600 the two guys aren't there and everyone is lined up appropriately (they're a little off center in that screenshot).

Could you explain what you mean with "lined up appropriately" for those of us who usually only get the other kind of football on TV. On my PAL VCS all the red players are positioned about 8 pixels to the left, which also pushes the two red players in the top left corner behind the HMOVE bars so that they aren't visible. But the blue players seem to be positioned just like on z26.

Looking at the code I think I know what the problem is. Tod changes the NUSIZ registers too soon after an HMOVE command. When we experimented with the "changing positioning registers after HMOVE" problem for z26, it never occured to us to check NUSIZ too. But Kool Aid Man does this as well for the score positioning, and I think there was a similar problem with one of Thomas' Robot City demos. I guess I'll have to expand the testing program and spend the weekend counting pixels on the TV.


Ciao, Eckhard Stolberg

[Inky]

Godzilla said:

Thanks! thats awesome! all your roms that are the basis for other games are belong to us now!

Move all proto for great justice!

[Tempest]

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Could you explain what you mean with "lined up appropriately" for those of us who usually only get the other kind of football on TV.  On my PAL VCS all the red players are positioned about 8 pixels to the left, which also pushes the two red players in the top left corner behind the HMOVE bars so that they aren't visible. But the blue players seem to be positioned just like on z26.  

Yes this is what I meant. On my 2600 IIRC (it's been about a year since I last played around with the demo) the red guys are a bit to the left and not on the white line (which is why I noticed they were in the wrong spot on the emulator).

Can you explain the HMOVE bar thing to someone who isn't a 2600 programming wiz? Are those two guys always there and just not visible? Are they supposed to be there?

Since you've obviously looked into the code, is there any hidden functionality that I missed or is it WYSIWYG?

Tempest

[Thomas Jentzsch]

Eckhard Stolberg said:

I guess I'll have to expand the testing program and spend the weekend counting pixels on the TV.

Yes please, do that!

Maybe I can finally make my 11 invaders in a row work on real hardware then.

[Eckhard Stolberg]

On the 2600 you can shift objects horizontally by writing the offset into the objects shifting register and then trigger the HMOVE register which will then reposition all objects at once. This positioning process takes some time in the TIA, so if you change the positioning registers for an object while the TIA is still processing the shifting for it, the object might be positioned differently than one would expect.

One other side effect of triggering HMOVE is that the TIA is turned off for 8 pixels into the screen. So in a line where you do this there is this little black bar. You might know it as the "referee" from Pele's Soccer. Some programmers didn't like to have the little black bar every time they were positioning an object, so they put a black bar into every line, reducing the available screen space by 8 pixels. Activision did that in almost all their games.

In this demo the constant black bar is generated by triggering HMOVE in every scanline. Since the TIA's output is turned off during these 8 pixels, you can't see any object that is positioned there. The two red players in the top left corner are probably only a side effect of the setup for the players in the center of the screen in that line. I suppose one purpose for having a black bar in every scanline might have been to hide these two players.

I have only had a short look at the code so far, but it seems to be pretty straight forward. Except for the fact that the emulators are all handling early changes to NUSIZ incorrectly there doesn't seem to be any new information about graphical tricks in this demo.


Ciao, Eckhard Stolberg

[Eckhard Stolberg]

Thomas Jentzsch said:

Maybe I can finally make my 11 invaders in a row work on real hardware then.

IIRC the problem in your invaders demo was caused by an inacuracy in z26 that requires some bigger changes in the TIA core. But I guess we'll have enough time to take care of that while you finish your Robot Tank game after we fixed the NUSIZ problem.


Ciao, Eckhard Stolberg

[NE146]

Hey comes out looking pretty good on the ol' tv

REDBLUE.JPG

[ZylonBane]

Hey, this ROM even has its own website!

http://www.redvsblue.com/

[Thomas Jentzsch]

NE146 said:

Hey comes out looking pretty good on the ol' tv

Hm, looks like the left white line is further to the right!

[Curt Vendel]

This is such a cool demo, thanks for releasing it Matt.



Curt

[mos6507]

Now when are we going to dig up Tod's 2600 Ballblazer kernel demo?

[Scooterb23]

Cool demo...

Now somebody, get these bastards to RIVERDANCE!!!

[StanJr]

Eckhard Stolberg said:

 
Could you explain what you mean with "lined up appropriately" for those of us who usually only get the other kind of football on TV.  

Sure, although beyond the Offensive and Defensive lines there isn't much about the RvB screenshot that looks remotely like football.

There are 11 players to a side in football, those two extra cats in the upper left hand corner are going to get a "Too many men on the field" penalty and move the offense back about 10 yards. To put it bluntly, they should not be there. You'll note the Blue team appears to have the correct number of players.

[bjk7382]

Why do the two guys on the far left have black hair on the actual hardware not on the emulator. And the guy on the bottom has flashing black hair?

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[Nathan Strum]

Eckhard Stolberg said:

On the 2600 you can shift objects horizontally by writing the offset into the objects shifting register and then trigger the HMOVE register which will then reposition all objects at once.

Oww!!

I think I just fried a synapse.

I keep thinking, "I'll have to sit down and go through Andrew's 2600 Programming for Newbies and try to learn some of this stuff", then I read something like that, and my brain starts hurting.

Is there any hope for a complete programming novice like myself to learn this stuff? (One class of BASIC on an Apple II, 23 years ago.)