IO, a new MSX1 demo by Logon System

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Por Overflow

Resident (57)

Imagen del Overflow

03-05-2017, 08:44

Manuel wrote:

delta compression to update the lines on the raster in real time

I believe you were good at summarizing. Smile

I would give a few more details (about the Bat-Logo):
> animation is packed - each frame is packed
> from a HW point-of-view: one single line from VRAM is repeated on all raster-/scan-lines from head to bottom of screen
> using delta-compression to update that single line - following the raster, in real time, precise timing is required
This kind of trick comes likely from the Amiga demo-scene.

Por Manuel

Ascended (19053)

Imagen del Manuel

03-05-2017, 09:43

I wonder if this trick could directly be used on MSX or MSX2, which do not have direct VRAM access.

Por ren

Paragon (1930)

Imagen del ren

03-05-2017, 12:17

@Overflow I believe MSX(2) has good coders, but there seems to be some division in the community, and some don't like this site (history or something).
(Skilled) people that used to communicate do not longer communicate (am I right?), and seem to remain in their own silos.

Cool stuff does happen (all the time) (though a lot for 'just' MSX(1) as well). I guess the last 'big' (cross-community recognized) thing was the Street Fighter II conversion (but IMO they somewhat shot themselves in the foot by using that idiotic logo screen & title.. (I for one can't really take it seriously just because of that.. Tongue))
(And of course there's the SMW conversion in the making..)

Other skilled people seem to have left MSX behind (perhaps some couldn't take the b.s. (that was going on) anymore, or just chose to move on, and/or spend their energy more wisely, on stuff that actually matters, like 'real life' Wink)

There's quite an active community in Spain, some skilled people, but they seem to be MSX(1) oriented for a large part.

sd_snatcher was talking about MSX2+ btw, for which there's very little stuff available (mostly because MSX(2) penetration is widest, and the 2+ never officially was released outside of Japan, and most peeps over here already had an MSX2 and saw no need to upgrade (I figure))

Quote:

@Ren: I will ask Factor6 if he agrees to share the PT3 tune here.

And, did you ask him? Still like the tune a lot, having disposal over the .pt3 would be awesome, but otherwise a full version in mp3 form or something (or in the form of an extended demo? Tongue) would be cool as well! Smile

Por NYYRIKKI

Enlighted (5970)

Imagen del NYYRIKKI

03-05-2017, 14:39

Overflow wrote:

Thanks to all for your nice words.
About same kind of fx: watch again demos from Bandwagon on MSX1 - similar trick.
That said, same quality of fx (and possibly better one) could be done on MSX2: watch the tricks explained in the making-of and get inspired to code them on your beloved computer!

OMG. Not only that you make 1st class demos, but that you give out 1st class explanations together with really easy to understand graphical animations and all. Really good stuff, absolutely great to read this kind of stuff. I enjoy it a lot.

I've also experimented with similar pattern tricks. (See here the challenge was to make a demo in to single BASIC file without additional files) but indeed I think that much, much better could be done with prerendered graphics on more simple screen modes... Just think how many SCREEN 2 tile sets could be put in to 128KB of VRAM... When you add MSX2+ scroll registers to the mix, there are quite endless possibilities even before you need to touch the name tables.

The Gameboy animation how ever is out of reach as there is simply no time to get the data trough the I/O ports fast enough... I anyway used a bit similar tough much easier delta 2-line trick in the making of my first demo to make a flag to float on the screen... All the vertical stuff is done by adjusting palette... Today I would make the effect better, but hey, it was my first demo after all :) (link)

Congratulations once more!

Por Maggoo

Paragon (1216)

Imagen del Maggoo

03-05-2017, 15:35

I'm thinking the delta compression 2 lines at a time might work actually. We just need to experiment to see how many pixels could be done within the time available.

In this old demo (https://www.youtube.com/watch?v=iCaU7ivU1js) for the effect at 3:20, I used something similar where the same 2 lines are re-used and updated over and over. In this case I use the blitter to copy a the block over so it's consuming a lot of out. If the differences between each lines in the 3d GFX is limited to a 8-10 pixels it may actually work.

It would be worth experimenting.

Por Overflow

Resident (57)

Imagen del Overflow

03-05-2017, 22:14

ren wrote:

(...) some division in the community

Same goes in CPC community. Smile
.

@ren: Here is the pt3 tune! As usual: no commercial use, and state the author.

@NYYRIKKI: you're welcome! I would be very happy if someone uses my tips to code similar fx on MSX(2)!
I do remember the work you linked: such kind of big fx in Basic only!? then you wrote it: think bigger and asm.

About Gameboy or Bat-Logo: you're right! OUTing bytes to vram would be slow - let's compare with CPC:
main code relies on POP BC:LD L,B:LD (HL),C which is enough to poke C within VRAM at (H*#100 +B as index/row).

@Maggoo: nice kefrens bars!
This year at Revision party a 4K intro on CPC uses same trick - a bit more colorful - but definitely not enough to impress people nowadays.

@Maggoo: If you wish to compare with CPC: repeated line is (overscan) 96 bytes width. Bat-logo updates up to 9 bytes by scanline - while Gameboy updates up to 14 bytes on a single scanline.

Por Grauw

Ascended (10633)

Imagen del Grauw

03-05-2017, 23:54

Maggoo wrote:

I'm thinking the delta compression 2 lines at a time might work actually. We just need to experiment to see how many pixels could be done within the time available.

228 cycles per line. Assuming the address needs to be changed for every byte, mmh, OUTI, OUT (99H),A, DEC C, OUTI, INC C (58 cycles per byte), plus two OUTIs every other line for the vertical offset adjust (18 cycles per line); 3,6 bytes per scanline. Hard to get above 4… Crazy

Por sd_snatcher

Prophet (3592)

Imagen del sd_snatcher

04-05-2017, 00:39

Another problem is with the background bars. You can't play "racing the beam" on the MSX, as the VDP access speed varies from one machine to another. The effect would be ruined in the majority of the Sanyo and Panasonic MSX2+ machines, just to mention some of them.

Por sd_snatcher

Prophet (3592)

Imagen del sd_snatcher

04-05-2017, 00:51

Grauw wrote:

228 cycles per line. Assuming the address needs to be changed for every byte, mmh, OUTI, OUT (99H),A, DEC C, OUTI, INC C (58 cycles per byte), plus two OUTIs every other line for the vertical offset adjust (18 cycles per line); 3,6 bytes per scanline. Hard to get above 4… Crazy

Humm. But most of the changes occurs blocks of pixels, and not on totally random addresses. Each sequence of pixels could use OTIR to write them, at a cost of 22 cycles/byte, against 24 on the CPC.

Por Overflow

Resident (57)

Imagen del Overflow

04-05-2017, 06:57

My 2 cents:stop argueing and make a demo* about it. Smile
* even a small one, or a POC - turn your "it could " into action.

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