Streamed background for games

[Stefan jL]

As i don't know anything about coding so was i wondering if having streamed backgrounds is possible on a 4mb STE... now when most people have either Ultrasatan or HD for their Atari setups.
Something like the tunnel sequence in Stardust but more variation, or is the constant ultrasatan reading becoming a bottleneck and making no room for game physics?

I am meaning none compressed streamed graphics and maybe 10-15 fps.

Would something similar to Silpheed (Sega CD) be possble? http://www.youtube.com/watch?v=xpaXvvug5qc

[nativ]

hi,

midi stream?

mod player?

2channel sample sequence?

full audio? like summer delights?

Computer controlled cd player with audio wired in via mic / stereo master with an audio monitor!

or YM2149!

cheers

/nativ

[Stefan jL]

I mean animated graphics in the background that streams (movie) and maybe some parts taht are "interactive" (dangerous parts not to crash into or something) just like in the Silpheed movie i linked to.
Stardust don't have much variation in the tunnel sequences but i guess it is because it was distributed on 3.5 disks wich limited the amount of space the graphics was allowed to use.

So i was just wondering if having it streamed from ultrasatan (not compressed) would make it possible to make something like the Silpheed game.

And now when i think about it i presume 10fps or below is more reasonable for the STE... not 10-15 as i first thought.

[nativ]

Hi,

yes I know silpheed I have Mega CD and PS2 version.

mega is 68k so this is definatly possibly on Falcon.

D2D is possible on STe and SofiST released a player recently that will 'do' the audio as you wish.

I have played 1min of audio in GFA via DMA and doing so required little effort!

What you got planned?

/nativ

[darklight]

I suspect this is a step too far for the ST - I'd be happy to be proved wrong though

Reading / unpacking / displaying so much info would take a significant chunk of processor time, on top of (presumably) your own game display code, AI, etc, etc.

Megadrive would have had custom chips for that sort of thing?

[nativ]

megadrive had a z80 for audio although it wasn't used all the time.
megacd had faster cpu?

an 11khz 25khz replay ought to be possible on an STe via DMA.
Some compression could be used but probably not during replay! a 2 channel sample sequence very possible! really!! if I ever find this samseq 'wizard ' pd disk i had once! else I'll have to code it myself!

[Stefan jL]

I have no interest in knowing if streamed audio is possible... but i presume it is done easily.

and this question is only for STE with 4mb and Ultrasatan (or HD)... the actual reading speed should not be a problem.
If using uncompressed graphics that will save some CPU..right? or how much CPU time does the actual reading from Ultrasatan/HD take?
How much will be left for game physics?
I have no plans on coding (i cant code) but might come up with an game concept using streamed graphics if it is possible on STE... the Atari STE has no "FMV movie games"... yet

Silpheed on Mega CD does look like it actually is using realtime polygon backgrounds but it really is FMV movie that streames from the CD
the Mega CD is much better than the STE... it uses two CPU's.. the origanl Megadrive CPU (7 mhz 68000) and the CPU (12 mhz 68000) on the CD addon. and additional effects like rotating and zooming.
It unpacks movies using software and not special hardware... dont know how exactly but maybe the Megadrive processor is used for unpacking the streamed movies and the CD addon CPU for the rest of the game physics.

[Nyh]

and this question is only for STE with 4mb and Ultrasatan (or HD)... the actual reading speed should not be a problem.
If using uncompressed graphics that will save some CPU..right? or how much CPU time does the actual reading from Ultrasatan/HD take?
How much will be left for game physics?
I have no plans on coding (i cant code) but might come up with an game concept using streamed graphics if it is possible on STE... the Atari STE has no "FMV movie games"... yet

In theory you can get about 1.8 Mb/s over the DMA bus. The total band width of the Atari bus is about 2 Mb/s. So when you manage to use the full band width there is 10% left for the processor to do something useful.

Let us say that you want 25 frames per second, that is a total of about 0.8 Mb per second. Leaving you with 60% of processor time to do something else.

Oh, yes before I forget, the blitter has to share the bus too. Blitter, processor and DMA can not use the bus at the same time. I don't know what has most priority on the bus, blitter or ACSI DMA.

Hans Wessels

[nativ]

I have no interest in knowing if streamed audio is possible... but i presume it is done easily.

Sure! - Must have been thinking aloud! I looked at the hardware requirements for Silpheed a little while back...

Silpheed on Mega CD does look like it actually is using realtime polygon backgrounds but it really is FMV movie that streames from the CD

That's interesting! Does a good job of fooling!

the Mega CD is much better than the STE... it uses two CPU's.. the origanl Megadrive CPU (7 mhz 68000) and the CPU (12 mhz 68000) on the CD addon. and additional effects like rotating and zooming.

At least the Falcon is closer to this spec!

It unpacks movies using software and not special hardware... dont know how exactly but maybe the Megadrive processor is used for unpacking the streamed movies and the CD addon CPU for the rest of the game physics.

Sounds like an interesting project!

I cannot think of any FMV gameplay games on the STe? there's a few mixed intros Awesome? and Roadwars?

Good luck!

[bid]

The guy who knows most about streaming video on the Atari right at the moment is Guillaume Tello http://gtello.pagesperso-orange.fr/mplayere.htm

He is currently in active development of mplayer, and I would imagine that you can decide yourself if you can overlay sprites onto FMV on the 68000 or 030

I would certainly be interested in playing something like this, and running video from Solid State such as UltraSatan or CF Card. Would be very cool, even if just a simple shooter or demo type game for fun.

Can you look at what has been done with Mplayer, and see if sprites can be added?

[Zamuel_a]

The game Fast Striker on the SEGA Dreamcast is a good example on how to have a animated background that is very effectful, but still simple and don't take up so much memory
http://www.youtube.com/watch?v=YUU5WOdwK1w

If you look at the background you can see that it's just the same image that repeats itself so you need only something like 10,20,30.. images depending on how fast/smooth you want the animation to be, but it would fit in RAM on a 4Mb STE. Colors could be a problem since you don't have so much to play with if you need a good looking animation and still colors for sprites.

[bid]

The game Fast Striker on the SEGA Dreamcast ....

Yeah! I love that background and Raiden like gameplay shooters.

Seriously, if anyone wants a 3D background like that, I could render one up and dither it down to 16 colour 320x200 images, to see what it looks like. I do 3D CAD animation, and I am pretty familiar with 16 colour limitation as I used to do all my raytracing on Atari.

If anyone wants something like this, then give me an idea of the background and I'll render using SolidWorks, and then convert to Animated GIF, and finally use a bit of floyd steinberg on the Atari to get some nice dithering. I bet it would look ace in 16 colour. But would prob need to use lets say 10 colour or less, as needs sprites too!!! Fun fun fun.

I'll do you some Atari Fuji /|\ logo 3D towers if you like with flyover tesselated rendering like this. Nice bit of congruence! Reminds me of M C Escher.

An M C Escher blaster would be pretty neat come to think of it. Anyone remember that screensaver? What was it called, with the flying toasters?? After dark!

[Zamuel_a]

I tried to calculate how many frames they used in Fast Striker for one loop and I used a stopwatch and got that 10 loops took 20 seconds, so one loop every 2 second = 100 frames for 2 second animation in 320x200. 100 * 32000 = 3,2mb for the animation. Maybe some simple realtime compression could be used to reduce the amount of memory, but it looks like you need 4Mb anyway, which shouldn't be a problem anyway on a STE.

[EvilFranky]

That would be 50 fps though right? Surely not possible on an ST.

Thought the idea was for maybe 25 fps?

Would half the amount needed...

Sent from my HTC Desire using Tapatalk

[alexh]

Dunno about a streamed 2D pixel background data but the STNICCC2k demo from Leonard of Oxygene streams the vectors off the disk for a live 3D renderer.

http://leonard.oxg.free.fr/stniccc/stniccc.html

[bid]

I tried to calculate how many frames they used in Fast Striker for one loop and I used a stopwatch and got that 10 loops took 20 seconds, so one loop every 2 second = 100 frames for 2 second animation in 320x200. 100 * 32000 = 3,2mb for the animation. Maybe some simple realtime compression could be used to reduce the amount of memory, but it looks like you need 4Mb anyway, which shouldn't be a problem anyway on a STE.

I did the same, and it looked to me to repeat every 1 second. I am looking at the big round feature. This at 24 fps would be only 24 frames, at around 32kb making it less than 800kb. Its def one second loop, look again!!

[Zamuel_a]

No it's a 2 second loop:) I timed it again on a different computer:) I started the stopwatch when I had the big middle building at the bottom of the screen and then counted for 10 loops. That took 20 seconds.

I think this wouldn't look so good if it was only in 25fps. You would see how smooth it was if you had it running in 50fps, so 25 wouldn't look cool at all (I think)

[nativ]

Hi,

Just thinking? can the STe video genlock capabilities be used to pump video onscreen with the ST. doing the overlay?

cheers

[Zamuel_a]

I have never tested the genlock function but maybe it's possible. You need someway of sync it together so maybe you need another Atari generating the background or something else that could be controlled. Actually it sounds like it should be easy to do a game there you have two or more STEs connected together to generate one output For example have one computer generate the background and/or sprites and then send that out and connect to the other STE genlock input and then add more sprites and do game logic on this machine. Sounds like a cool idea

Is there some way to connect a CD to an Atari? Since it's possible to use SCSI or IDE harddrives, there shouldn't be a problem with CD ROM either and since the SEGA MEGADRIVE and DREAMCAST used CD to stream graphic from, then maybe the Atari could do the same. Even if you have a large HD and use ultrasatan or something, you still need to transfer the game onto the HD and that sounds like not so easy. A CD ROM solution had been better.

[nativ]

Concept! Dual Processor!

I was thinking about oneday doing a JAG Falcon link via DSP

What would you use for a high speed data link ST>ST? DMA | EtherNEC | MODEM ? MIDI?

[Zamuel_a]

I don't think you need a high speed link because the programs on each computer should be independant. You only need to sync them together and for example if the game logic is on the first computer and you draw sprites on the second, then you need to send a signal "I shoot down ship nr 1, don't draw it in next frame". So only a few bytes every VBL.

I have never used the genlock function, but from what I understand you need some external device for it, so you take the video signal from the atari to the genlock device and then a signal from example a video player what also goes to that device and then you mix them there. Best had been if there were a video IN signal on the Atari side that just would bypass the signal, but with the Atari image as a overlay, but from what I understod, you need a external device to.

[nativ]

- 'phase lock' of the video output to an external video source permitting direct linking to genlocking device.

so an STe video merge facility.

yes, considering options?

also have Music output on one STe and SFX on another! : ( running two copies of Hextracker sound driver? ) lol

Genlock and the STE

The ST (and STE) chip set have the ability to accept external sync. This is controlled by bit 0 at FF820A, as documented in the ST Hardware Specification. This was done to allow the synchronization of the ST video with an external source (a process usually known as GENLOCK). However, in order to do this reliably the system clock must also be phase-locked (or synchronized in some other way) to the input sync signals. No way to do this was provided in the ST, as a result the only GENLOCKs available are internal modifications (usually for the MEG A).

The STE allows this to be done without opening the case. To inject a system clock ground pin three (GPO) on the monitor connector and then inject the clock into pin 4 (mono detect). The internal frequency of this clock is 32.215905 MHz (NTSC) and 31.922046 MHz (PAL). Note: DO NOT SWITCH CLOCK SOURCE WHILE THE SYSTEM IS ACTIVE.

As a result of this GPO is no longer available.

couple of info bursts there...

[Zamuel_a]

You you can sync to an external genlock device, but what does such devices look like?

High quality music and SFX could be done on one STE and then you can use up ALL computer power on that one for just the sounds. You only need simple signal transfer for telling what sample to play next, turn on/off music and so.

[nativ]

You you can sync to an external genlock device, but what does such devices look like?

High quality music and SFX could be done on one STE and then you can use up ALL computer power on that one for just the sounds. You only need simple signal transfer for telling what sample to play next, turn on/off music and so.

Sound option : MIDI / MV16 / Twin STe

http://www.ebay.co.uk/itm/Amiga-Hardwar ... 1c1c5fd0e7

amiga genlock

[Stefan jL]

I was more thinking of a game that uses the streaming graphics as part of the gameplay and not as background decoration (like Fast Striker)... i think Silpheeed is a good example of that and also "Novastorm" http://www.youtube.com/watch?v=xZst7lzgNZM

I have no idea how dangerous objects in the scenery would be done in streamed animation, maybe it is too much for the STE?

Another thing is the read speed of Ultrasatan, judging by the benchmarks so should the limit probably be set at 800kb/s for maximum compatibility http://joo.kie.sk/ultrasatan/benchmarks.html

Anyway... making this kind of game is most likely to require too much effort in the graphics department (and the design) to actually become reality