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Golara Account closed
Registered: Jan 2018 Posts: 212 |
Sine sprites in the sideborder. VSP garbage and more
Hello everyone. I'm working on my first C64 demo / intro. I managed to open the sideborder at the top and obviously I immediately put some X-sinus sprites there (I'm still trying to figure out how a DYSP works, right know i have opened lines with 0 and 8 sprites). I noticed that the positioning of the sprites on the X axis is a bit weird. Position 0 is slighty on the left border, but if you want to go all the way to the left you have to use X 500 or there about. My question is, is there some sinus maker or converter that would take care of this ? (so it goes from 0 to ~500 looking like smooth movement to the left). Another question, what is the good way of handling the 9th bit of X position ? What I do is generate a 256 words sinus with values 0 to 500 and use c++ program to split that into 2 256 bytes tables like
sin_1:
1,2,3,4,5,6,7,55,33,....
sin_2:
1,0,0,0,0,1,0,0,1.... where 1 means to set the bit and 0 to not do that.
My sprite 0 is bugging out in the right most border while other sprites display just fine. Why is that ? I've read somewhere that sprite 0 is evil, but could not find any details on why.
I also do VSP by turning on the screen at the right moment together with XSCROLL for smooth scrolling. I see few pixel lines of garbage just above the image, I cover that with the illegal screen mode, disable it at line 56. Is that a good idea ? Another thing about VSP is that it seems to move the whole screen down by one char on the scrolled side (makes sence I guess, as the part of the chars that are outside of the image are displayed on the next text line). So should I copy the 25 lines of graphics in each column when scrolling for seamless scroll or do people not do that ?
Here's a picture of what it looks right know. A big mess !
(PETSCII picture by Archmage as a placeholder. I can't find any pics in binary and that was the easiest to take out of a compiled prg) Hope you have the patience to help a lamer out.
https://i.imgur.com/byWFRsH.jpg[/url]
HughJass from Poland |
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Golara Account closed
Registered: Jan 2018 Posts: 212 |
Quote: btw how do you create these nice gifs?
It's this program. https://github.com/NickeManarin/ScreenToGif/releases/download/2..
Works like a normal screen recording software, but saves the video as gif or other animated formats. I actually posted .apng here because their size is much smaller than the old .gif
After recording you can view all the frames, so the last few animations i posted i actually took care to remove the excess frames to make it wrap seamless. It has a nice editor for that. It's a great program and it's less than 1MB |
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Golara Account closed
Registered: Jan 2018 Posts: 212 |
<IGNORE> |
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Golara Account closed
Registered: Jan 2018 Posts: 212 |
What do you guys think ?
https://i.imgur.com/NQ8Bkgk.mp4[/url]
I still have about 180 lines of raster time (with bad lines) free, so i'll put something nice on the screen yet. The graphic will be replaced with some nice bitmap, since it's VSP movement, overkill for just PETSCII. I also decided to do some design, not just an intro, so this is a screen you'll see after some time, it has to build up somehow... I have couple of ideas already. |
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Oswald
Registered: Apr 2002 Posts: 5094 |
nice stuff, I'd double/triple the sine frequency to make it look more pleasing, and a nice multicolor logo wouldnt hurt either :) |
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Golara Account closed
Registered: Jan 2018 Posts: 212 |
Quote: nice stuff, I'd double/triple the sine frequency to make it look more pleasing, and a nice multicolor logo wouldnt hurt either :)
Yep, definitely a multi color logo would look better, but it's harder to get one, this is just some PC font converted to sprites.. Right now I have 4 sinus tables, but maybe i'll add more, we'll see how good i'm on memory. Right know i'm almost at 16kb |
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Oswald
Registered: Apr 2002 Posts: 5094 |
doublesin would be even better ( add up some sines) |
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Digger
Registered: Mar 2005 Posts: 437 |
how many sprites are you squeezing into the bottom border? 6? :) |
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Compyx
Registered: Jan 2005 Posts: 631 |
I'd say no more than five. $d017 stretch takes at least 8* cycles and opening the border takes at least another 8*. That leaves 47 cycles of which quite a few are consumed by the VICII. So to move 5 sprites we need 5 x LDA#/STA$ (6 cycles), another 30 cycles:
8+8+30 == 46 which according to victimer might work.
* = this assumes having registers preset (for example X=0 and Y=8) for quick $d016/$d017 writes, and unrolled code.
I could very well be wrong though. Haven't done any sprite tech-tech stuff for a long while. |
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Golara Account closed
Registered: Jan 2018 Posts: 212 |
Quote: I'd say no more than five. $d017 stretch takes at least 8* cycles and opening the border takes at least another 8*. That leaves 47 cycles of which quite a few are consumed by the VICII. So to move 5 sprites we need 5 x LDA#/STA$ (6 cycles), another 30 cycles:
8+8+30 == 46 which according to victimer might work.
* = this assumes having registers preset (for example X=0 and Y=8) for quick $d016/$d017 writes, and unrolled code.
I could very well be wrong though. Haven't done any sprite tech-tech stuff for a long while.
I'm doing 6 sprites. I have 4 cycles left too (after opening the second line of border). I don't update all the sprite registers on the same line, but it works fine as you can see, although I had to fiddle around with the order of instructions until I got rid of the bugs. The SS is not supposed to flash, I just don't update the colors for it yet, althought I have plenty of time for that, I just forgot. In this screen you see couple of posts above I have free raster time from about line 56 to line 250, so I can do some other cool stuff too. I don't know what to do next right know though. I'm also thinking if I should make it a tiny demo in this intro like format (where only the middle of the screen changes with some new pictures or some other effect), or to do a multi prg press-space-to-continue kind of demo. I definitely don't know how to do stuff like one-der or dawnfall in onefile yet. |
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Golara Account closed
Registered: Jan 2018 Posts: 212 |
Can you do VSP and FLD at the same time ? Both effects work for me individually, but I can't do both at the same time. I have a big square on the left going left and right. Am I accidentally doing FLI or something ? Can't be, as i'm doing the FLD the slow but sure way of reading the current line and setting Yscroll to something different.
same code moves the whole screen without vsp. I do vsp at line 47 and fld at 56
EDIT. I've fixed that, the code for enabling illegal screen mode to cover VSP garbage was causing the problem. |
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