Zach

You've been PM'ed.

After getting a stable 272, adjusting to 262 was easy. What I did is similar but a little different from your code. I also ended up with 259 and padded it with 3 WSYNCs. Check4InARow lda INTIM; poll timer bmi CheckVertical jsr Sync Sync lda INTIM cmp #126 bne Sync ; frame ends up at 259 lines here sta WSYNC sta WSYNC sta WSYNC lda #2 sta VSYNC sta WSYNC sta WSYNC sta WSYNC lda #0 sta VSYNC lda #146 sta T1024T rts

I think I understand now. This is what Fred just described, isn't it? Cool. I just got a stable 272 lines per frame. Now that I understand what to do, it's simple.

I think I understand now. This is what Fred just described, isn't it?

Answered in the Sync'ing while thinking thread. BTW, Maze Craze 2 is looking good.

The problem is that the frame size is not constant. I think what's happening is that it is difficult to read INTIM on a regular basis. The minimax search is sometimes busy checking for four in a row, sometimes adding marbles, and sometimes removing them. It is difficult to predict what the program is doing at a given point.

That's a nice view where you live. Do you have to move for your new job?

Thanks for the suggestion. Originally I had to compare colors in a graphics program to convince myself, but now I can see it with my own eyes. It was tough at first, but it's getting easier. You can stop regarding A as a square and think of a parallelogram. Then sharply focus on A and ignore the overall picutre. Then shapes with the same color as A will stand out. Thanks Chris, there a lot of cool illusions out there, more advanced than the ones from our childhood. "Best ever" was a bit of hyperbole. Another favorite I found just today is this dragon. It reminds me of a detail from Eternal Darkness.

At first I wondered why the day after taxes are due, but I get it now. I think it'll be most fun if someone finds it on their own. I advocate waiting until the cart has been out for a year before givcing any hints.

That looks great, Nathan. It'll take some creativity to shift the shadow by 1 pixel. It's not as trivial as moving a 48 pixel sprite. As long as we are considering alternatives to the first 2, the Pacman logo is a good candidate for 56 pixels using a method conceived by supercat. The restriction is that you can not have the following patterns in the leftmost and rightmost 4 pixels: X-X- -XX- -X-X -X-- --X- Nor can you have the following in the leftmost and rightmost 5: X---X Of course, someone would have to code it.

Thanks for the suggestions. I did take a look at Activision checkers, and it does maintain sync during the thinking state, but the frame size is not constant. The frames range from 260 to 263 lines. I figure if Activision couldn't stabilize the frame size, that's good enough for Four-Play too. I changed the code to read INTIM+1, (thanks, Eric) and now the frame size ranges from about 258 to 266*. Unfortunately there is a side-effect that does not show in z26. On the TV, there is a horizontal black line in the middle of the screen that bobs up and down. If I didn't know better, I'd say that VSYNC is happening in the middle of the screen. Is this an inevitable effect of the frame size changing? Does anyone have any idea what's going on, and how to eliminate the line? Latest source and binary are attached to the top of this thread. Here is the part of the code that handles sync: Check4InARow lda INTIM+1; poll timer beq CheckVertical jsr Sync ; the polling is repeated in other places as well CheckVertical lda gamestate . . . Sync lda #2 sta VSYNC sta WSYNC sta WSYNC sta WSYNC lda #0 sta VSYNC lda #19 sta T1024T rts * Except in the transition between thinking and game states, but that shouldn't be hard to fix.

Nope

Just tested on my Krok Cart and got similar results. It's not a flicker like the ghosts in Pacman. It's a momentary vertical shift of the entire screen as if the scanline count goes to 300 for a single frame. (Although z26 indicates the count is stable at 262)

Hmm, there were eight 1K games for the 2600 last year, and AFAIK no one has announced any plans for one this year. (I mentioned a possible project on my blog, but I'm pretty sure it's too much for 1K)

I would assume that Dennis can center the text in A and vote accordingly. Then you're really just voting on the Pac-Man text. Now thanks to supercat there is a third logo to consider.

That was quick, for a shipment to Canada.

I just played a little more Ico, starting from the beginning. It turns out that Yorda can eliminate enemies instantly while she opens one of the magic gates. So if there is a gate nearby, get her to it ASAP, and don't bother fighting. Wish I'd known that earlier.

I remember that game. I've also pondered how it could be ported to the 2600.

I believe the flying tank bug comes from the way Combat handles player-playfield collisions. When a tank is hit it travels more than one pixel per frame and may end up on top of the PF. In that case it keeps moving until it escapes the PF. The tank flies when it moves in a direction that keeps it on top of the PF. Also, there is some mechanism to keep the tank from flying forever. My hypothesis comes from working on the Combat code for many years, on and off.

John is right that Atari really got it right with Combat. That's the main reason I only wanted to do Tank AI as a combat update for so long, but the fact that old Atari games can still be profitable (e.g FB2) means that we may have to look elsewhere. Then again, Atari Inc. is going through a lot of changes, and maybe they will be able to work better with homebrewers in the future. For starters, some subtle momentum like Combat has is important. Look carefully, and you'll see that the tank takes some time to get to full speed and to stop. Also guided missiles make it easier if a computer is up against a human opponent. Although not realistic, I think the way the tanks wrap adds to some of Combat's charm.

Well, for starters, some subtle momentum like Combat has is important. Look carefully, and you'll see that the tank takes some time to get to full speed and to stop. Also guided missiles are important if a computer is going to have any chance against a human opponent.

I believe the source code in Paul's minidig has the typo fixed. Anyway, Maunel, if you are looking for new variants of Combat, remember that I've done a version with a high-resolution asymmetrical playfield. You could build on that. So far it only has tanks, but it won't be hard to do a plane version. I'm becoming increasingly open to the idea of a homebrew tank game from scratch. It could be to Combat what Gunfight was to Outlaw. I don't know when I would get around to working on it though. If anyone else wants to do it, I'll be happy to share my techniques and if it helps, AI code.

It's a good idea, but I've got a homebrew to finish. I going to stick with 52 pixels for the Four-Play title screen becuase Nathan's artwork doesn't work in 56. So far, you've only seen the text, but there is more. I think Nathan's work will provide a better example of the advantages of 52 pixels.

It's still impressive how quickly you finished Reindeer Rescue.

Thanks for sending me the screen shot, Dennis. I added it to the top of the thread.