Ilda laser projector load balancing? anyone?

[JohnYayas]

Color matching is an issue, too. Probably not a big deal if you have a set of identical projectors. But, in a LEM setting, it will end up looking like those old big screens with a bunch of TVs set in a wall with one of the TVs on the fritz.

But regardless, even with mismatched laser colors and galvo positioning, it would still be a cool thing to goof around with and you could create some really huge displays. How cool would it be if someone could create a 360 degree laser projected BattleZone game? You would be able to look around and see tanks coming up behind you. That would be so rad.

[masterpj]

Color matching is an issue, too. Probably not a big deal if you have a set of identical projectors. But, in a LEM setting, it will end up looking like those old big screens with a bunch of TVs set in a wall with one of the TVs on the fritz.

But regardless, even with mismatched laser colors and galvo positioning, it would still be a cool thing to goof around with and you could create some really huge displays. How cool would it be if someone could create a 360 degree laser projected BattleZone game? You would be able to look around and see tanks coming up behind you. That would be so rad.

Yes indeed.
and woa that is awsome ;3

Well indeed mismatched colors... good calibration does reduce that effect.
even when it still occurs.... i don't mind a bit off colour mismatch for a gain in scanning speed *or at least more KPPS*

[mpolak]

The load-balancing idea can work extremely well in practice, and below are some examples of a dual 6215H 60K scan-set projector that we used for SIGGRAPH 2007's Electronic Theatre. The laser output beam and color matches between both scanners identically due to having used a Chroma 5 mixed-gas laser and dual PCAOMs as the light source. This makes it nearly impossible to pick apart the separate scan-fields and gave us exceedingly sharp images at the screen over considerable distance.

Unfortunately the photo repository of still images from the event was removed recently, but I do have one of the shots handy as an example:



This is load-balanced between both projectors and the beam characteristics are identical, making it nearly impossible to tell which scanner any part of the image is coming from.

Unfortunately I don't have a copy handy of the video we shot on the event so I'm at the mercy of YouTube videos from audience members. Obviously the laser didn't flicker nearly as badly as it shows up on the video. I was specifically asked to do everything possible in order to allow Star Wars to run at near-full-frame-rate without having to eliminate detail as it was our "hero" game.

Star Wars -- http://www.youtube.com/watch?v=5iodpYzTgYE
Tempest -- http://www.youtube.com/watch?v=hvF3JZcGvBQ

The algorithm I employed was pretty simple in that the vector frame data (from the MAME state machine) was taken and then a search was performed forwards and backwards from the center of the display list to find the nearest blanking jump. The split was then done at that location between the scanners and the other frame was padded as necessary to keep both of the scan-list lengths identical for timing reasons. The result was an "equivalent" 120K scan-rate at the screen and an amazing level of detail with surprisingly little flicker. The 'text' screens are the worst for obvious reasons, but gameplay was buttery-smooth!

(And yes, if you were wondering, the legal rights for public exhibition of these games for this event were specifically cleared with both Atari and LucasArt's legal departments specifically for SIGGRAPH!)

[drlava]

Looks beautiful! That's pretty much exactly the way I was envisioning it could be done as well. Nice job!

[mikkojay]

Hey Matt,
I agree with Andrew, that is a great example of doing it right! I saved off a stream from some War of the Worlds so people can see that even with simple games the point count gets up there. I know what you mean about the text screens On this one, the text frames have point counts > 2500, no way is a Chinese 30k scanner going to swallow that in one bite. BTW, I have ogled that SIGGRAPH photo many times- true classic laser porn!

-Mike

[mpolak]

Thanks much, guys! We may have to try to set this up again at some point for SELEM or similar, as several of my projectors here have 6215's in them. The dual-scanner approach certainly makes the more complex LaserMAME games much more playable. I found another picture in my archives, this time of Ken Perlin (of the noise function name) playing Tempest.



Come to think of it, all of the laser content for SIGGRAPH ran through a pair of Transcoders, so we actually have most of the content recorded onto a Fostex deck somewhere in the archives. (We had a delightful "Instant Laser Teapot" button because of this, too!) So I guess there's something of geek-posterity, being able to play back the laser games played by some of the effects wizards from ILM and such.

Hey Matt,
I agree with Andrew, that is a great example of doing it right! I saved off a stream from some War of the Worlds so people can see that even with simple games the point count gets up there. I know what you mean about the text screens On this one, the text frames have point counts > 2500, no way is a Chinese 30k scanner going to swallow that in one bite. BTW, I have ogled that SIGGRAPH photo many times- true classic laser porn!

-Mike

[mikkojay]

So I guess there's something of geek-posterity, being able to play back the laser games played by some of the effects wizards from ILM and such.

Heee Haw- how's this for geeksmanship- I was actually considering throwing on a tune, playin' some MAME while making the "guy" swerve back and fro to the beat, then recording his actions in a stream, pasting a clip on the timeline in a show in sync with the tune, and seeing what percentage of the crowd connected to the groove! I love playing to that nth percent! You are the man Matt- eccentric laser fire at its best. Good on ya
-Mike

[mpolak]

Dude! Nice one! And thanks much for the compliment, too - 'Eccentric' is a word I've noticed people tend to associate with me, but I always take it as a compliment. As I see it life is too short not to get excited about all of the neat stuff we have to play with in the world these days, and being able to share it with other people of similar interests. It's never been a better time to be a techy person with a passion for whatever floats your boat!

Referencing your earlier post regarding dumping out a series of frames from MAME, the original LaserMame that got hacked out in October of 2000 with Rob Mudryk (has it been 10 years now? Yikes!) did similarly to what you describe in storing a rotating set of a few thousand frames or so, which made it easy to pull a stream of recorded frames out from a game sequence. This actually got put to great use in a large show as a sequence.

In 2002 Star Wars was coming out (again), and as part of the Darien Lake Amusement Park (New York) laser show there was planned to be a cool homage section. The producer of the show is a friend of ours, and asked for a few sections of gameplay frames from Asteroids and Star Wars to try to work in, and the composition worked brilliantly. I can say there's nothing like seeing 2400 square feet of laser Asteroids and Star Wars on a screen with a boatload of pyro going up behind it! The Star Wars section was later reprized (without the Asteroids graphics) in the 2005 show when Attack Of The Clones came out.

Heh... So now it's scary how much of stuff has made it up on to YouTube, as it took me only a few moments to find: http://www.youtube.com/watch?v=PUAct9bLrLA

The video quality is kind of crappy, but jog to 0:44 and put on your extrapolation cap and you can get the gist of the show sequence. The Star Wars trench sequences come up at 1:30. It's projected from a single-set of 6215Hs, but I had optimized away a few of the (redundant) gunning turret graphics along the edges to improve the scan-rate on the frame sets. (The copious quantities of beer that were usually consumed by the audience quite likely helped to reduce the precieved flicker as well, but someone should do more serious research in this area! )

Anyhow, this post is getting a bit off thread-topic (if anyone cares) so I'll park it here for now!

Heee Haw- how's this for geeksmanship- I was actually considering throwing on a tune, playin' some MAME while making the "guy" swerve back and fro to the beat, then recording his actions in a stream, pasting a clip on the timeline in a show in sync with the tune, and seeing what percentage of the crowd connected to the groove! I love playing to that nth percent! You are the man Matt- eccentric laser fire at its best. Good on ya
-Mike