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Monte Carlos
Registered: Jun 2004
Posts: 358 |
4x4 block effects, extensions
Is this the only release which extends 4x4 in the grey fli bug area?
Revision 2011 Invitation
Have other "extensions" besides more fli $d011 switches have been introduced to this mode?
I checked some demos i remember having 4x4 effects. Some Resource productions like Error23, Cauldron from Camelot, ...
but did not found another one with 80x50x16. |
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Oswald
Registered: Apr 2002
Posts: 5086 |
its rare indeed.
Smart Girls Hate Booze
Desert Dream
(the ugly filled circles part)
takes away a lot of rastertime for a small benefit. |
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chatGPZ
Registered: Dec 2001
Posts: 11352 |
a bunch of fpp scrollers use that kind of thing (stretching down the vram, giving you full 40 chars of fli). but indeed, eats too much rastertime to be terribly useful. |
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Six
Registered: Apr 2002
Posts: 289 |
Quote: a bunch of fpp scrollers use that kind of thing (stretching down the vram, giving you full 40 chars of fli). but indeed, eats too much rastertime to be terribly useful.
Can you elaborate on "stretching down the vram" for the less enlightened? |
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Oswald
Registered: Apr 2002
Posts: 5086 |
in our demos the routine was coded by Ninja, and it uses 1 sprite overlay on a "normal" 4x4 routine. the pixels are read from screen ram (so the speedcode can work transparently) and selfmodded into the specialized colorizer code,
you need to fill up 6 4x4 pixels with colors you can do this by:
- 1 pixel uses d021 color
- 1 pixel uses d800 magic opcode color
- 3 sprite colors
- okay maybe there's 2 sprites ? ask ninja :) |
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chatGPZ
Registered: Dec 2001
Posts: 11352 |
six: check this: http://codebase64.org/doku.php?id=base:fli-fpp-scroller |
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Monte Carlos
Registered: Jun 2004
Posts: 358 |
Yes, thank you very much for your replies. Seems, that many people avoid 4x4 these days or the trick with the opcode color, $d021 and 2 sprites is not known very widely. Looking at pasts demo with 4x4 effects very rare use even 74x50. Most use 68x50 or even smaller. Resources invitro seems to be an exception in this regard and i found this really looks bigtime! The FPP effect works differently as it leaves you 3 more cycles a line than fli. The drawback is, that the first screenram character line and the first bitmap line are replicated over all 25 character display lines. Therefore, to do 4x4 with FPP one needs to reserve memory for 50 screens which is appr. 50kB. Anyway, i already found out how to do 80 column 4x4. I was just curious of how widespread this effect is and if it is worth to make a release with it.
The overhead needed is as far as i calculated it right 21 rasterlines which is worth it i think (48 cycles to set the colors and 5 for the two sprites per character line). HCL uses 4 sprites, unnecessarily. On the other hand, he seems to be the first one who did it. (HCL 2005, Clarence 2007, Ninja 2011). What i don't understand is, that all those 40 chars wide fli pics use similar tricks and they were done much earlier. However, they are not moving like a plasma. |
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HCL
Registered: Feb 2003
Posts: 727 |
Why wasn't it used earlier? My guess is that the 4x4 "people" were not that much into detailed techniques.. but more into splattering effects. But i'm probably wrong as usual :P..
One way of doing it (don't know if you discussed it already) is of course to trigger an interrupt every 4:th line and update $d011+d018 and possibly $dd00/2 also. This doesn't need stable raster, but will use up alot of char banks of course. I fiddled a little with such a routine, and possibly you can reduce it to every 8:th line just like normal 4x4. Can't remember if i succeded, but i never used that code anyway :P. |
