Cafeman

I went to the Philly Classic this past spring. Click here to check out my little tour -- http://cafeman.www9.50megs.com/atari/phillyexpo2001/ You may see somebody you know or who is referred to here at AtariAge! Tempest, the DP guys, Tom Zjaba, Randy from Syzygy, even the Caféman is seen. And some home-brew guys. Maybe you've seen my documentation of the show already -- the Atari sections of my site, including the Philly stuff, still get the most hits! Anyway, it sure would be great if they'd get a bigger room for the next Philly -- it was crowded and hot! I plan on making it an annual pilgrimege.

Challenging, indeed. But perhaps someday... For now, I'm sticking with strictly 2D perspective, no 3/4 isometrics!!! Thanks for the comments. I am now officially scared off!

Post a link to his column.

I don't know how to look a rom's code. I only use the VSS and since i have sound probs, I don't even use that now. I have the 800Win, but even though I put some 5200 roms in the appropriate folder, it never does anything ... it's like it can't find them. How do yuo see a .rom's code? Besides, it probably doesn't have variable names when you unassemble it, right? It's got to be hard to read. Oh, and John who? John Hardie? Where'd he find it?

I was thinking about how I'd do Crystal Castles on 5200/8bit. (I've been playing it on Dreamcast Atari Anniversary). It seems to draw background 'layers' from back to front, which end up forming that 3D image. But I wonder how you keep the Bear and enemies on the 'track' in the background? Invisible mapping? Marble Madness seems to employ similar design, although I don't have a copy of this game myself.

Welcome aboard, ElvisDJ. Interesting suggestions there ... I'll keep them in mind once my sticks start to act up again.

I always thought it sucked. I mean, it was indeed a travesty to call that game Zaxxon. But I recently downloaded the ROM, and now I think its decent game on its own, especially given the system's weakness compared to Sega's arcade hardware. Heck, even the 5200 and 8bit Zaxxon versions were far from arcade perfect (although better than this particular version, snicker!)

Dan, are you reffering to using a Kernel, where the program sits inside a DLI to defeat Antic?

still can't get Player1 to display. Player0 display fine. Player 1 is another color and mapped to the same offset as Player 0, but those pixels are black (bg color) and don't display. I set my PRIOR register to $21 because I think bit 5 must be set to graft player 0 to player 1. Thus PRIOR is 0010 0001 where bit zero is a 1 to give priority over the playfield. See any prob with that?! I store the pointer for Player0 at $20,$21. I store the pointer for Player1 at $22,#23. My screen RAM starts at $1800. My pmbase is at $2000 ( edited -- I think). Player0 starts at $2400, Player1 starts at $2500. I'm in Antic E, so my player RAM is cutting into the screen RAM and I'll have to change that soon, but it shouldn't have an effect on Player1 not displaying when Player0 does, right? Any thoughts? [ 08-18-2001: Message edited by: Cafeman ]

Actually Tempest, I just read that recently. Did you just read that recently too? where?

I have yet to order stuff from Tom Zjaba online, but I've met him, and purchased stuff from him in person. I'd recommend him in a second. He's not out to screw you.

tillenterprises, Yes, thanks for pointing that out -- 5200 Pitfall 2 has mildly improved visuals, but it also has twice the game! Has anybody ever beaten that *extremely difficult* 2nd level? With the wild bats and manic jumps and scampering bugs/rats? I sure didn't, but typing this makes me feel sad because it reminds me that I ran over a defenseless racoon tonight.

The above code works. I assumed it is using Player0. I want to have a Player1 address which is 256 decimal bytes (#$100 bytes) beyond Player0's, correct? It seems Player0 is at $2430. Would that make Player1 at $2530? What would really help me is to see some example code setting up the addresses for Player0 and Player1. I tried to put stuff like this: Player0 equ $31 ; defining Player0 Player1 equ $32 ; defining Player1 ... The thing that confuses me is that I can't see where $2430 is #$1024 bytes past a PMBASE address?! It seems like $20,$21 holds not a base address but Player0's address.

Here's some snippets of my code. This is from a prior version of it, but it's pretty much the same. ; ************ Hardware Adresses *************************** DMACTL equ $D400 ;DMA Control sDMACTL equ $07 ;DMA Control Shadow PMBASE equ $D407 ;PM base address CHBASE equ $D409 ;Character set base GRACTL equ $C01D ;Graphics control PRIOR equ $C01B ;PM priorities ... ;************* Setup Player/Missile registers *************** lda #$3A ;Enable DMA (single line resolution/ sta sDMACTL ;normal background) lda #$20 ;Set PM base address $20 sta PMBASE lda #$03 ;Enable players and missiles sta GRACTL lda #$16 ;Color of player 0 sta sCOLPM0 ldy #$00 lda #$00 ;Size of player 0 (pick from 0,1,3 vals) sta SIZEP0 ; I'm trying to store #$30 at location $20 and ; to store #$24 at location $21: lda #$30 ;start player's memory at $2430 sta $20 ;lo byte lda #$24 sta $21 ;hi byte ; lda #$01 ;Give players priority over playfield sta PRIOR ... ;************ Copy player data to RAM ******************************** pmloop1 lda pm1,y ;Get data ; The following is Indirect Indexed Addressing. ; It stores the value of the accumulator into the address found ; $20 (lo byte) and $21 (hi byte), which by is incremented from the ; original value of $2430. sta ($20),y ;Write it into RAM (RWL -- it was $2430 in Dan's example) iny cpy #$08 ;Copy 8 bytes (Compare reg Y to Hex bne pmloop1 [ 08-17-2001: Message edited by: Cafeman ]

I am unable to get Player1 to work, let alone graft it to Player0. Following Dan's PM example as I have been, I believe PMBASE is set to point to $20 (low byte) and $21 (high byte). I've been using this. The value stored here is initially $2430. I assume this is Player0 that I've been using. Anyway, could one of you guys show me a bit of code showing how to define the Players at the top, and simple loops or code showing how to refer to them? How do you specify the xxx+256 kind of statements? Or do you use pmbase+1024 for player0, PMbase+1536 for player1? Is that 1024 a decimal or hex number? Huh? Huh? Huh?!

Interesting! You changed the color and position of the smiley thing, and it is really just one player. I noticed that both use the same background/foregroudn priority setting, which leads me to another question. Can the priority register PRIOR be set in such a way that some players are in the background while some are in the foreground at the same time?

River Raid. Spy Hunter on the PSx classics disk is too hard to control & has a choppy frame rate for some reason, btw.

I missed CGE2k1 (and I may always miss it), but one thing about Philly -- I think it needs more room.

http://www.atarihq.com/5200/5200faq/05_02_01.html Nope. Check out the 5200 FAQ section on this subject. I did it, as have many -- using a pencil eraser will usually fix up the contacts fine!

http://cafeman.www9.50megs.com/classics.html Nateo, click on this link and read the 4 articles there on Zaxxon, Outrun, River Raid, and Joust. I wrote that while keeping in mind the 'magic' that the 80's classic era had, back when I was a teen. I am also 32 now, and I agree with what's been said already.

Bump. Still thinking about this. If you use a DLI to switch the memory pointer for a player, then you probably need to display the highest-on-screen player first, then at the DLI switch to the lower one. Game code draws Player0A and Player0B in different memory locations. Other variables store each split-player's horizontal and vertical locations. All the collisions and animation is handled in the normal game code, but during the DLI you decide which of the 2 is on top and switch pointers at that line. I imagine it would take some kind of counters set up in the game code that the DLI would check. After all, you don't have much time during DLI. During DLI you blindly switch to draw the 'lower' player. During normal game code you handle everything else, but during DLI you switch pointers. Hence, if Player0A and Player0B get on the same horizontal lines, you'll miss at least 1 frame and flicker will occur. I think?! Question: where do you put the DLI, since a DLI is invoked by setting a bit on a certain modeline? Perhaps you have the DLI bit enabled on every modeline in the display list?

5200 defender.bin -limit try the -limit option -- you need it on computers these days. Read the info .txt file that came with it. There are other options you can use (and must use at times, such as -Pengo which allows you to control Pengo.)

AHA! I knew I saw a picture of SNES River Raid years ago in a magazine! I've asked all kinds of people if they had access to a picture of it, and nobody could dig one up -- I asked some recent mag editors, I asked Bill Kunkle, nobody had one. So ... what are you going to do with those prototypes? How about posting a picture of River Raid SNES, or better yet, a few pictures? Or email them to me and I'll put 'em up at my own River Raid Homage Page!!

Dan, in many games the flickering only starts when sprites get on the same horizontal lines. Do you think the coder implemented both methods in that case? In other words, when he detects Player0's 2 uses getting close to one another horizontally, he branches to the every-other-frame routine instead? Otherwise, wouldn't the birds flicker all the time regardless of their position?

How can you tell if you put too much processing inside a Display List Interrupt? If you take too many cycles (remembering that you basically only have the time from the end of one horizontal electron beam until it gets to the beginning of the next horizontal scanline & turns on again). What is the impact and/or effect of not being out of the DLI in time?