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Mr SQL
Registered: Feb 2023
Posts: 114 |
PETSCII demos and BASIC kit
Hello Everyone! :)
Try these new PETSCII demo's and download the BASIC for creating them here:
http://relationalframework.com/GameLoader_C64_Atari_emulator_wi..
This kit allows the C64 to run Advanced Atari 2600 demo programs using a soft ANTIC blitter, soft TIA and soft RIOT chip inside the prg. The code for the soft TIA and soft RIOT chips could be removed from the demo binaries and the programs would still run on a real Atari 2600 using just soft ANTIC.
The demos can be (re)compiled cross platform for the C64 and Atari 2600, and on the C64 the demos have texture mapped PETSCII and dynamic PETSCII.
Here is a fun dynamic petscii example of a Super Arkanoid demo in user mode (as a playabe game):
http://relationalframework.com/c64.html?file=arkanoidairheadb.p..
Download prg for the C64 and VICE:
http://relationalframework.com/arkanoidairheadb.prg
The kit is also great for creating Cracks of demos to change text and music like with fluid city and fluid city b side:
http://relationalframework.com/c64.html?file=fluidcitybside.prg
http://relationalframework.com/c64.html?file=fluidcity.prg
Download prgs for the C64 and VICE:
http://relationalframework.com/fluidcitybside.prg
http://relationalframework.com/fluidcity.prg
Fluid City took first place at Silly Venture on the Atari 2600 but I have not entered it in a Commodore contest yet, the prg is a C64 demo and also a demo of cycle precise pixel perfect emulation of an advanced Atari 2600 demo.
Coding demos and games with this kit will be easy and fascinating for C64 programmers using new hardware features like 4 levels of sprite scaling and hardware reversible sprites, and a large tile mapped virtual world and playfield cam.
Advanced programmers can explore the soft ANTIC, TIA and RIOT chip implementations.
Please share your thoughts! |
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chatGPZ
Registered: Dec 2001
Posts: 11135 |
cycle precise pixel perfect emulation of an advanced Atari 2600 demo
please elaborate. (Can you point to a video of the program running on VCS?) |
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Mr SQL
Registered: Feb 2023
Posts: 114 |
Quote: cycle precise pixel perfect emulation of an advanced Atari 2600 demo
please elaborate. (Can you point to a video of the program running on VCS?)
Here are links for both of those two demos running in Javatari the online Atari 2600 emulator:
https://javatari.org/?ROM=http://relationalframework.com/ARKANO..
https://javatari.org/?ROM=http://relationalframework.com/SillyV..
Atari 2600 ROM's:
http://relationalframework.com/ARKANOID_AIRHEAD_FINDS_AIRHEAD.b..
http://relationalframework.com/SillyVenture2019_Fluid_City_B_Si..
The tiny8bit emu for the C64 is not cycle precise so to compare them precisely side by side you will need to download the prg's for VICE or the real C64 hardware to match against the Javatari emulator which is cycle precise, or a real Atari 2600.
If you play Fluid City on an NTSC C64 you will see 60 FPS of full screen animation when you hit the throttle matching the Atari 2600 cycle timing precisely.
It is cycle perfect because the same program code is running on the 6502 with the C64 as on the Atari 2600, but on the 64 it is interacting with a shadow register bus on the zero page to talk to the soft TIA and RIOT chips.
If you play them on a PAL C64 the demos will run slower at 50 FPS. |
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chatGPZ
Registered: Dec 2001
Posts: 11135 |
Mmmh we may have different definitions of "cycle exact emulation"... Is it supposed to show what looks like mostly random petscii garbage instead of the colored blocks, like on VCS? *shrug* |
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Mr SQL
Registered: Feb 2023
Posts: 114 |
Quote: Mmmh we may have different definitions of "cycle exact emulation"... Is it supposed to show what looks like mostly random petscii garbage instead of the colored blocks, like on VCS? *shrug*
You can select four PETSCII characters for the foreground tiles and four PETSCII characters for the background tiles.
PETSCII textures can also be changed programmatically.
Multicolor playfields haven't been implemented yet but you can color in the color RAM to simulate them. |
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chatGPZ
Registered: Dec 2001
Posts: 11135 |
*shrug* But how is that "cycle precise pixel perfect emulation" then? I don't get it. The VCS doesn't even have a framebuffer iirc? |
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Oswald
Registered: Apr 2002
Posts: 5022 |
*shrug*
"the tiny8bit emu for the C64 is not cycle precise" |
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chatGPZ
Registered: Dec 2001
Posts: 11135 |
i think he refers to https://github.com/floooh/tiny8bit - not that anyone would use that :) |
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Mr SQL
Registered: Feb 2023
Posts: 114 |
Quoting Groepaz*shrug* But how is that "cycle precise pixel perfect emulation" then? I don't get it. The VCS doesn't even have a framebuffer iirc?
Yes the VCS has no framebuffer, but these advanced Atari demos have a soft ANTIC blitter with multiple frame buffers.
Here is a display list demo showing three separate frame buffers running on the Atari 2600 and the C64.
http://relationalframework.com/c64.html?file=displaylistdemo.prg
https://javatari.org/?ROM=http://relationalframework.com/Flashb..
You can see the three differently timed display zones render cycle precise and pixel perfect, with PETSCII textures added. |
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Mr SQL
Registered: Feb 2023
Posts: 114 |
Quoting Oswald*shrug*
"the tiny8bit emu for the C64 is not cycle precise"
Yes tiny8bit is the emu I am using in the links, is there a better online C64 emulator?
VICE is cycle precise by comparison and matches the real hardware. A good example of not being cycle precise is where you can see the screen start to tear in Fluid City using tiny8bit, particularly when using the throttle. |
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chatGPZ
Registered: Dec 2001
Posts: 11135 |
"cycle precise and pixel perfect" vs "with PETSCII textures added"? I don't get it. Is this even emulating anything? Let alone "cycle precise and pixel perfect"? |
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