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Flavioweb
Registered: Nov 2011
Posts: 463 |
FLD/FPP question.
I know how to delay char line visualization using FLD. I'm trying to do the same for every raster line. I tought to use something like FPP playing with D011 on cycle 58 and before 14 but i can't figure out if is possible to show gfx/char data during delay.
Can someone help me?
There is a way to stop vic updating internal gfx pointers at X rasterline, then delay the visualization to Y line and testart painting even if RC <> 7? |
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Flavioweb
Registered: Nov 2011
Posts: 463 |
About Crest's demo... i'm surprised to see that the fli-fpp routine was coded without stable raster at all...
just cycle-calculated code triggered by normal raster irq.
Fashinated... |
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Krill
Registered: Apr 2002
Posts: 2980 |
IIRC, FLI auto-stabilizes pretty much after the first line. This may be blacked out in the demo. Add a jmp * in the main loop, and you only have 3 cycles variance for the IRQ entry. Put a few sprites there, and it might get stabler.
There are many dirty ways and a bit of luck to get a stable raster, but the clean method is always superior and keeps you from stumbling over unpleasant surprises or weird bugs. :) |
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Flavioweb
Registered: Nov 2011
Posts: 463 |
I tought to code my versio of this fx over my stable raster routine because, my final goal, is to make it both pal/ntsc compliant and maybe works also on drean and others...
But first of all i need to exactly know how things works here, because a lot of things need to collime to make fx works. How and why ECM bit is used? Only to "blank" initial side effects or for more?
I know how to use the dma-delay to stabilize things... but here seems this is a very margnal question. A lot of D011 and bank switching trickery involved...
I think ECM is needed to compensate jitter side-fx on the standard irq call...
Let me study...
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HCL
Registered: Feb 2003
Posts: 728 |
Quoting Flaviowebi'm surprised to see that the fli-fpp routine was coded without stable raster at all I'm sorry are we still talking about the bitmap-fpd? There is no FLI in there and also no FPP, so lets be clear for once ;). |
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Danzig
Registered: Jun 2002
Posts: 440 |
Quote: IIRC, FLI auto-stabilizes pretty much after the first line. This may be blacked out in the demo. Add a jmp * in the main loop, and you only have 3 cycles variance for the IRQ entry. Put a few sprites there, and it might get stabler.
There are many dirty ways and a bit of luck to get a stable raster, but the clean method is always superior and keeps you from stumbling over unpleasant surprises or weird bugs. :)
Not to forget jsr * :D
check out One Year Crest f.e. the intro. |
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Flavioweb
Registered: Nov 2011
Posts: 463 |
Quoting HCLso lets be clear for once ;).
Ok, quoting demo scrolltext:
Quote:
so here you can take a look at the ultimate version of a single pixle fld, flexibel pixel distance, diffrent y pixel possition or multi-expaned-unidentified-black-area-in/decrasing-between-various-numbers-of-pi xel-lines (or however you wanna name it) routine !!!
This is what we are talking about.
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HCL
Registered: Feb 2003
Posts: 728 |
Yeah, that's the reason.. If this stuff were not invented by teenagers, perhaps we would have less confusion today. We just gotta live with it :P. But still you are a grownup today, and should of course be able to tell the difference between bitmap and fli, fpp and fpd, right? :) |
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Flavioweb
Registered: Nov 2011
Posts: 463 |
Ok. I want to avoid confusion, but this kind of code is an hybrid between fli, fpp and fpd to achieve a single pixel line FDL... and is a FLI used to show a "normal bitmap" reorganized ad-hoc.
Same people who invented this don't know exactly how to call it...
That's the problem, but now we know what is it...
And still have no name... |
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HCL
Registered: Feb 2003
Posts: 728 |
Well, he is using stretch-fli (22 cycles loop) to increase the char-size from 8 lines to whatever, then there is no fli while letting the last 8 lines draw. Changing d018/dd00 does not make an fpp, since only 8 lines are available within each char. In fact only 7 lines are available here.. one bank is used for empty (black) lines and another bank is used for two(!) of the lines where one of them only work during the stretch-fli. So there we have it :) |
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chatGPZ
Registered: Dec 2001
Posts: 11386 |
"this kind of code is an hybrid between fli, fpp and fpd to achieve a single pixel line FDL"
even after reading the thread again - i have no idea what that means =D |
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