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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 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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Mr SQL
Registered: Feb 2023
Posts: 114 |
Quote: "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"?
Yes the PETSCII is an extra feature, I think it looks really cool. You can select solid blocks to get rid of the textures with this kit if you don't like PETSCII.
Yes the Atari 2600 TIA and RIOT chips are really emulated using a shadow register bus in the zero page so the program code could run on a real Atari 2600.
Other than the difference in colors/lack of colors there are also different sounds and sound Fx, TIA to SID audio translation sounds very different on the C64.
Try this example with the Arkanoid and Fluid City demos above:
Play a few rounds on the Atari and the C64 and you will see that while the visuals match fluidly beyond the PETSCII the soundscapes are very different.
You'll need to use the real Commodore hardware or VICE set to 6581 (resid) to hear the analog filter effects.
I'm not sure I should try to correct this feature to match the TIA audio more precisely for being so intriguing. |
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chatGPZ
Registered: Dec 2001
Posts: 11135 |
Quote:Yes the Atari 2600 TIA and RIOT chips are really emulated using a shadow register bus in the zero page so the program code could run on a real Atari 2600.
But "cycle precise and pixel perfect"? I have my doubts, sorry. |
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TheRyk
Registered: Mar 2009
Posts: 2076 |
Quoting Mr SQL...
cycle precise ...
Really, I don't get what this is all about. As a proof-of-concept porting Atari->C64 it might be fun but the outcome is far from stunning or revolutionary. |
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Mr SQL
Registered: Feb 2023
Posts: 114 |
Quote: Quote:Yes the Atari 2600 TIA and RIOT chips are really emulated using a shadow register bus in the zero page so the program code could run on a real Atari 2600.
But "cycle precise and pixel perfect"? I have my doubts, sorry.
Can you elaborate?
I gave a timing example with screen tearing and explained the same code was being run / same cycles.
You cited an example of the color not matching, could you share a similar example of the timing not matching or the pixels on the sprites and playfield not matching in the demos? |
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tlr
Registered: Sep 2003
Posts: 1720 |
Quote: Can you elaborate?
I gave a timing example with screen tearing and explained the same code was being run / same cycles.
You cited an example of the color not matching, could you share a similar example of the timing not matching or the pixels on the sprites and playfield not matching in the demos?
I think this just a confusion of terms. Cycle exactness is a term commonly used to describe an emulators ability to emulate events cycle for cycle, matching what would happen in those cycles on the hardware. |
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Mr SQL
Registered: Feb 2023
Posts: 114 |
Quote: Quoting Mr SQL...
cycle precise ...
Really, I don't get what this is all about. As a proof-of-concept porting Atari->C64 it might be fun but the outcome is far from stunning or revolutionary.
The New Space Invaders is a lot of fun see if you like it :)
http://relationalframework.com/c64.html?file=newspaceinvaders.p..
prg:
http://relationalframework.com/newspaceinvaders.prg |
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Mr SQL
Registered: Feb 2023
Posts: 114 |
Quote: I think this just a confusion of terms. Cycle exactness is a term commonly used to describe an emulators ability to emulate events cycle for cycle, matching what would happen in those cycles on the hardware.
Yes I agree. Fluid City is a good example of cycle exactness for being able to update the whole screen every frame 60x per second when the throttle is on.
That is where we see more tearing in Tiny8Bit emulation not being cycle exact. |
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tlr
Registered: Sep 2003
Posts: 1720 |
Quote: Yes I agree. Fluid City is a good example of cycle exactness for being able to update the whole screen every frame 60x per second when the throttle is on.
That is where we see more tearing in Tiny8Bit emulation not being cycle exact.
That's not what I ment. Reproducing the code execution cycle for cycle would require running the exact same binary. Is this what is happening here?
I'm not trying to value the work done here, just trying to understand what it does. |
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chatGPZ
Registered: Dec 2001
Posts: 11135 |
Quote:being able to update the whole screen every frame 60x per second when the throttle is on
I don't think that is what tlr was trying to explain. |
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