Amazing demo, and amazing emulation! Thank you for explaining the intricacies of this demo and taking the time to create such an accurate 5150 + CGA virtualization.
F*** arrrgh! I was planning on going, but had couldn't make it! Nice work on the emulator. Really fantastic job. Of courde, kudos to the demo team too. Wish I saw it live.
Not CGA, but in terms of shipping PC games that did raster effects, the game Masterblazer in VGA mode does per-scanline palette changes to get smooth a gradient background in 16-color 320x200 mode. It uses similar techniques of syncing to the VBLANK, programming the PIT to trigger around the start of the gradient, and then polling the HBLANK signal to count scanlines and tweak the DAC registers to create the effect.
There appears to be a small error in the Lockstep Math sheet at around 36:40. It says: 1 CPU Cycle = 4 Timer Ticks. It's actually the other way around. The CPU runs at 4.77 MHz, and the timer at 1.19 MHz. So 4 CPU Cycles = 1 Timer Tick (or 1 Timer Tick = 4 CPU Cycles). Then the next line also makes sense: 1 CPU Cycle = 3 Pixels on screen. 1 Timer Tick == 4 CPU Cycles, so 1 Timer Tick == (4*3) Pixels on screen.
Imagine how different personal computer history (and maybe even console gaming history) might have been if IBM game programmers figured this stuff out in 1983 to make better games.
The IBM PC can now rival the 1982 C64 in demos. Better in some ways, worse than others. Impressive deconstruction of the demo. Amazing how certain elegant ideas appear to start on one platform, then eventually find their way onto another some 40+ years later- if the hardware is capable. Everyone still laughing at the Apple ][e though.
And yet, the Apple II+/IIe has a small but competent demoscene community. Look up productions by "deater" and "French Touch". Lots of neat cycle-counting effects.
@@VCFMWwell aware of Deiter's work. Technically impressive but seem like masochistic effort for such little return. But l guess an Amiga user might think the same of 6502 or C64 or IIGS demos or Mac demos. I will check out that French democoder. Thanks.
it's the same palette as green, red, brown, but in high intensity. brown is actually low intensity yellow. it's a long story, and a conversion actually performed by the monitor itself
Now I want one of these explainer videos for every demo. Absolutely brilliant work. Well done.
great explanation of all the tricks! :)
Amazing demo, and amazing emulation! Thank you for explaining the intricacies of this demo and taking the time to create such an accurate 5150 + CGA virtualization.
Great presentation
A thing of beauty.
Awesome talk!
Great presentation!
Thank you and congrats on your video. This is the first one I found explaining how the demo was achieved!
F*** arrrgh! I was planning on going, but had couldn't make it!
Nice work on the emulator. Really fantastic job.
Of courde, kudos to the demo team too.
Wish I saw it live.
great talk! fascinating stuff
Not CGA, but in terms of shipping PC games that did raster effects, the game Masterblazer in VGA mode does per-scanline palette changes to get smooth a gradient background in 16-color 320x200 mode. It uses similar techniques of syncing to the VBLANK, programming the PIT to trigger around the start of the gradient, and then polling the HBLANK signal to count scanlines and tweak the DAC registers to create the effect.
Hero - Thank you!
Mind-blowing
sick talk - dope demo. pure awesomeness.
dam takes me back to my childhood playing with the atari st and amiga demos was a brilliant time
There appears to be a small error in the Lockstep Math sheet at around 36:40. It says: 1 CPU Cycle = 4 Timer Ticks. It's actually the other way around. The CPU runs at 4.77 MHz, and the timer at 1.19 MHz. So 4 CPU Cycles = 1 Timer Tick (or 1 Timer Tick = 4 CPU Cycles).
Then the next line also makes sense: 1 CPU Cycle = 3 Pixels on screen. 1 Timer Tick == 4 CPU Cycles, so 1 Timer Tick == (4*3) Pixels on screen.
Correct, good catch.
@@GloriousCow Only a very minor mistake in an otherwise excellent and very informative presentation. Nice job!
Imagine how different personal computer history (and maybe even console gaming history) might have been if IBM game programmers figured this stuff out in 1983 to make better games.
The IBM PC can now rival the 1982 C64 in demos. Better in some ways, worse than others. Impressive deconstruction of the demo. Amazing how certain elegant ideas appear to start on one platform, then eventually find their way onto another some 40+ years later- if the hardware is capable. Everyone still laughing at the Apple ][e though.
And yet, the Apple II+/IIe has a small but competent demoscene community. Look up productions by "deater" and "French Touch". Lots of neat cycle-counting effects.
@@VCFMWwell aware of Deiter's work. Technically impressive but seem like masochistic effort for such little return. But l guess an Amiga user might think the same of 6502 or C64 or IIGS demos or Mac demos. I will check out that French democoder. Thanks.
This is real wizardry.
...hopefully they will make something for the tandy 1000 after the upcoming pc-jr demo. hopefully....
Wasn't there a CGA palette: green, red, yellow(, black)?
it's the same palette as green, red, brown, but in high intensity. brown is actually low intensity yellow. it's a long story, and a conversion actually performed by the monitor itself
@@GloriousCow aah yes, indeed. Low and high intensity. 👍 I totally forgot about that.. after so many years
sweet
it would be very nice if the demo works on more cga machines like europc....
To do that, each group member would need a europc.
👏👏👏🤓
Wow (I mean it)
The PC bucket is missing so much hardware ($d012) that we always took for granted on the Commodore64 and the Amiga.
A scanline register, how luxurious! :D
My kingdom for a raster interrupt!
@@VCFMWhave you seen some of those PET demos? Crazy. Monochrome never looked so good.