DERP 2014 Invitation

Photon · 14 September 2013, 21:06

I never made one of those bob records back in the day so I made one a while back and added... some stuff.

I would say mention that it's NSFW, but then again if your boss lets you play Amiga demos at work you're safe already I'd say.

It became this 64K intro with a nice tune by Magnar, perfectly ruined by ... some immature unknown Scoopex member.

Apollo · 15 September 2013, 13:05

I like it. Nice, funky, chiptune and bobs.

How many bobs have you established?

Photon · 15 September 2013, 15:04

Well, the .NFO tells all, but in general the number directly follows from the screen size. Yep, it's that boring.

The time you have left after DMA displaying that screen and the blitter clearing it directly decides how many bobs you can have. I picked a screen size from a specific intro to have something to compare to.

I did have a look at some contenders to that intro, but none of them blitted 15 x 15px bobs with the proper cookie-cut method, they used an OR blit or had shrunk the screen or doubled the number by reflecting the bitplane vertically and things like that. Or didn't have 2 sine wave adds per coord.

208 with that screen size (and no music etc.) was easy, just a straight-forward blit loop. To get more, I used a trick too, but one which allowed all of the above. And changing the wave. A bit boring otherwise

Cos I mean if you REALLY want a record, just precalc a huge block of blitter register load instructions with finished frameloops to execute, one for each "animation-frame", but what's the point of that? Each loop would take like 3K, so the animation would only last a couple of seconds... and probably take longer to generate.

So bob records are pretty pointless really, and they've been done before. But a boob record - wah - that's totally different now isn't it? Hoho. :P

Apollo · 15 September 2013, 20:01

*laughs*

I was lazy and watched it at youtube, so I didn't read the nfo

You pretty much told what I think of a 'proper' bob record, no mirroring, 'cookie-cut' blitter term and proper sine calculations.

The time of the 'bob race' is long gone, of course. It was much more interesting back in the day, when coders pushed the limits of the amiga. One shouldn't ask for the use, anyway. From this point of view any Demo-coding is senseless, imho. But I hope you had fun doing it and I enjoyed watching it.

Yes, pre-calc'ing is a bit pointless and like you wrote: it would be more an animation than a realtime effect. Going ahead this road leads to the famous "unlimited bobs"

14 September 2013, 21:06	#1
Photon Moderator Join Date: Nov 2004 Location: Eksjö / Sweden Posts: 5,602	DERP 2014 Invitation I never made one of those bob records back in the day so I made one a while back and added... some stuff. I would say mention that it's NSFW, but then again if your boss lets you play Amiga demos at work you're safe already I'd say. It became this 64K intro with a nice tune by Magnar, perfectly ruined by ... some immature unknown Scoopex member.

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15 September 2013, 13:05	#2
Apollo Registered User Join Date: Sep 2008 Location: Germany Age: 49 Posts: 137	I like it. Nice, funky, chiptune and bobs. How many bobs have you established?

15 September 2013, 15:04	#3
Photon Moderator Join Date: Nov 2004 Location: Eksjö / Sweden Posts: 5,602	Well, the .NFO tells all, but in general the number directly follows from the screen size. Yep, it's that boring. The time you have left after DMA displaying that screen and the blitter clearing it directly decides how many bobs you can have. I picked a screen size from a specific intro to have something to compare to. I did have a look at some contenders to that intro, but none of them blitted 15 x 15px bobs with the proper cookie-cut method, they used an OR blit or had shrunk the screen or doubled the number by reflecting the bitplane vertically and things like that. Or didn't have 2 sine wave adds per coord. 208 with that screen size (and no music etc.) was easy, just a straight-forward blit loop. To get more, I used a trick too, but one which allowed all of the above. And changing the wave. A bit boring otherwise Cos I mean if you REALLY want a record, just precalc a huge block of blitter register load instructions with finished frameloops to execute, one for each "animation-frame", but what's the point of that? Each loop would take like 3K, so the animation would only last a couple of seconds... and probably take longer to generate. So bob records are pretty pointless really, and they've been done before. But a boob record - wah - that's totally different now isn't it? Hoho. :P

15 September 2013, 20:01	#4
Apollo Registered User Join Date: Sep 2008 Location: Germany Age: 49 Posts: 137	laughs I was lazy and watched it at youtube, so I didn't read the nfo You pretty much told what I think of a 'proper' bob record, no mirroring, 'cookie-cut' blitter term and proper sine calculations. The time of the 'bob race' is long gone, of course. It was much more interesting back in the day, when coders pushed the limits of the amiga. One shouldn't ask for the use, anyway. From this point of view any Demo-coding is senseless, imho. But I hope you had fun doing it and I enjoyed watching it. Yes, pre-calc'ing is a bit pointless and like you wrote: it would be more an animation than a realtime effect. Going ahead this road leads to the famous "unlimited bobs"

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