Atari 7800 Graphics Modes & Max Sprites Tested
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- เผยแพร่เมื่อ 24 ก.ค. 2020
- I paused working on my homebrew Atari 7800 game "Into The Void" so I could discover more of the capabilities of the 7800 combined with Atari 7800 Basic. This video shows some Atari 7800 application I built using Atari Dev Studio, Atari 7800 Basic and the A7800 emulator to try to push the 7800 to it's limits. These are all emulated right now, but I hope to soon have a flash cart to run them on real hardware.
You can download the tool described here on this thread at AtariAge.com
atariage.com/forums/topic/309...
You can listen to our podcast about Generation Atari here:
www.intotheverticalblank.com - เกม
This is cool! I'm just scratching the surface of 6502 assembly, having written some VERY simple programs for the C64 and Atari 400/800. An end goal of mine is to learn the 7800, it's such a neat machine.
Hey I can help you learn the 7800 if you want!
Nicely done. Wikipedia said "100" sprites generically, which was a bottomless pit compared to most '80 systems of the day.
My impression is Atari set there design goal to be 100 generically (a very simple "impressive" nice big round #), then your tricks get it "higher, higher, higher", especially at 09:20! :)
I would love to see more about Atari 7800 game development. Or at least videos like this exploring the 7800
That is coming up this year.
Very well done. When i use to make games in Amos for the Amiga i would make small test programs to see the limits of what i was hoping to achieve, this would inform me on changes and limits i need to stay within in order for the program to 'somewhat' work the way i wanted. This would often times challenge me to rewrite code in a more efficient way to still be able to do what i want.
I am starting to write a game for the Atari 7800 using 7800Basic. Thank you for your post; it clears up a few things for me. I'm thinking of writing a platform game similar to Miner 49'er or ApplePanic. I could write it in 6502 assembler but would prefer Atari7800 Basic. Again, thank you for your video. I hope I have something to show you shortly.
The 7800 is lacking in all kinds of game genre's so Apple Panic or Miner would be good to play!
@@IntoTheVerticalBlank I'm having problems getting my keyboard to work as a joystick with my emulator (Altirra64). any ideas?
@@bjbell52 For Atari 8bit games? Let me check. ... I have it working fine in 3.10. I just when to input and selected Port 1 --> Keys
Which version are you using?
@@IntoTheVerticalBlank 3.10
You've got to get your "frames" and "sprites" straight! LOL! Great video and sample code that you did!
Sur of the moment discussion bring out fumbled explanations =)
Awesome job, Steve!
Hell, the Intro game looks sweet; great job all around
I've made a new generator and with modifications could produce 50-70 sprites!
There's also 320D but it is pretty useless outside of some artifacting uses.
Hmm...
I wonder what would have happened if Atari used a 65C02 clocked at 5.355 Mhz, put MARIA on its own bus, and put 24KB each of system and video RAM and a FREDDIE MMU (capable of addressing up to 4MB via bankswitching) exposed to the cartridge slot?
Nice!
I wish Atari 65 XE has got so many colors :/
heck, be nice if some of that capability had been carried over into the ST (or STe at least) even if not the 8-bits. If they could afford to put a colour sprite engine in the 7800 in what should have been 83-84 (vs its actual release), why not a much more expensive computer many years later?
@@tahrey Different companies (Atari Inc. contracting out to GCC vs Atari Corp, which was run by ex-Commodore folks) and different priorities (video games vs lowest cost 16/32-bit personal+business computer w/GUI).
@@RetroDawn I guess, but once they had the IP they could have used it elsewhere (but for the stupid management in-fighting of course), and the STe was rather a reaction to the Amiga to give the machine more game-focussed audiovisual capabilities... and there was the mythical Panther which was seemingly at least partly ST(e) based and had at least some minimal display list stuff in terms of having a separate palette for each scanline. So it could have gone together nicely, maybe with an extension of the 7800 tech. Extended to 16 bits and running at 8MHz it would have been amazingly powerful (if hard to program) seeing what was possible with 8 bits at less than 2MHz...
Very clever!
Thank you! Cheers!
NOTHING CAN STOP TORG!
This should be helpful! Cool youre making 7800 games. Any ideas to port to the Atari VCS?
If they could be packaged-up as VCS executables, sure.
@@IntoTheVerticalBlank it's been happening. You should!
What does dropped frame mean in this case? Does it occur when you write too much data to vmem?
Pushing too much data in the VBL, so it skips a frame.
Slightly disappointed that we don't get to see any of the 320 modes, will that be in a follow up maybe?
Anyway guess this sort of explains why so many 7800 games seem to be a pile of sprites against a black background... And what is the method of rendering, does the system actually have enough memory to build a bitmap framebuffer? The double buffering and the frame drops make me wonder. Even if it's only actually drawing 20 frames, or maybe less than 10, per second, the screen still has to be updated at 60fps (or 50) and that image data has to come from somewhere...
Oh yeah, the colors are weird in those modes, but we'll get to those in a demo. The best way to use them is to layer sprites on one another, but the screen also uses up a lot of memory.
@@IntoTheVerticalBlank I wonder if it can get close to the ST record for 2bpp BOBs with no framedrops... Probably not STe / ST+Blitter, but maybe the raw machine?
Source code please!
I am working on a 7800 asm game "It's Conner Time!" and managed 8 sprites..... You managed 200. Please give me your source code!
No ASM. I used 7800Basic. It used the extra 16K RAM for display lists and two frames to draw the screen instead of one (doublebuffering). Hopefully that helps.
@@IntoTheVerticalBlank oh, does the basic cart have extra memory onboard?
I thought the 7800 could do 52 hardware sprites to avoid flickering.
It can do an "unlimited number" but it comes out to about 50-100 depending on size that can be push in an single Vertical Blank. It's quite enough for most games.
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Isn't the Atari 7800 basically a slightly improved Atari 2600? I mean, it can play Atari 2600 games, and it has the same TIA sound chip that the Atari 2600 had (except for a couple games, which used the later POKEY chip)
In the 2600, the TIA was both the graphics & sound chip; the 7800 has another graphics chip, called MARIA, plus more RAM, a MOS 6502 CPU instead of the 2600's cut-down 6507 CPU, & a lock-out feature so only official Atari-licensed carts could access the extra resources.
I think it's vastly improved on the graphics and memory front, just a shame they didn't keep the POKEY from the 5200 to work in parallel with the compatibility-reasons TIA. Going with the NES style on-cartridge upgrade chips only really works if your default soundsystem is somewhat usable in the first place, so the extra silicon can be used to add pizazz to premium titles which can justify the cost, rather than being pretty much mandatory for even what would otherwise be considered base-level audio for all your competitors... jacking up the price of the games across the board. (And meaning homebrews are stuck with rubbish sound, unless you have a flashcart that has extra chips in...)
More memory, a completely different graphics architecture with the Maria being able to put 20+ multi colored sprites per horizontal zone, etc. The sound is TIA to keep compatibility with the VCS, but the ability to shove more dated into the stereo channels was used in Food Fight and other games to made some very decent music and sounds considering the lackluster chip. + pokey, other sounds chips and "mappers" can be added just like the NES.