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Since I don't really have a better way of getting hold of Jezze, I figure this is probably my best bet.

The NYC Museum of Modern Art (MoMA) is interested in seeing if MAME's shader tech can be used to reproduce the pattern of pixels use by this one specific projector that the use in an exhibit. The general use case is that it's used to project a composite video stream supplied by a Laserdisc player, which is necessary as the exhibit uses a computer attached to the LD player for certain control purposes.

I have a close-up video of what the pixels actually look like, and I'd like to get your input on how feasible it would be to do something like MAME's shader system as a standalone application. I think it should be pretty easy to do via a small form-factor PC equipped with a decent GPU, I'd just like to get your opinion.

Also, pay is potentially involved. smile

Please send me a private message or reply here with your e-mail address so I can get ahold of you easier.

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It's quite easy to simulate any pattern of pixels with the current implementation of the MAME shader, at least if you have an authentic image of the pattern.

However I've never tested how good the simulation would be if you want to see a detailed close-up of the pattern. For instance the glow is currently calculated based on the raw image; which is good enough for a distant simulation. But for a detailed close-up it would have to be calculated based on the actual pattern.

Maybe I can give some better impressions/suggestions when I see what exactly should be simulated.

p.s. I added some public contact information to my profile.

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For what it's worth, here's a close-up photo of an image displayed by the projector:



I don't know about you, but the weird hexagonal configuration of the pixels seems a bit weird.

Here are also the specs for it:

SHARP XV P300
Number Of Pixels: Single Panel 181,470 pixels (RGB)
Resolution: 340 TV Lines
Luminance: 60 ANSI Lumens

Just some info that was provided by the museum dude. smile

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Looks like a shadow mask to me.



With the current shader implementation you can achieve the following. The images were made with a 16x zoom.

Shadow Mask (Shader)


Shadow Mask + Raw Image Glow (Shader)


But as I said before, for a close-up simulation the glow should be calculated on the mask instead of the raw image, which would look similar to this.

Shadow Mask + Mask Glow (Photoshop)


Another problem of the current implementation is, that some mask-pixel sharing more than one raw-pixel, so that these mask-pixel look chopped at the junction between raw-pixel.


This is the used raw image, which was pre-scaled by ~4.


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The trouble with that output for this application is that it's simulating a directly-viewed CRT where beam defocus happens before shadow mask. On an LCD projector, defocus happens after the pixel matrix (CRT projector is more complex, but let's ignore that. The pixel matrix is:
Code:
RBGG
GGRB

So you have to apply that like a shadow mask, then apply defocus afterwards.

edit: just to clarify, the pixel matrix applies at the LCD's native resolution, so you need to convert the video to the native resolution of the projector's LCD, then blow up each pixel into four pixels, alternating between ((RB)(GG)) and ((GG)(RB)) on each pixel, and offsetting by one on each line, to produce the characteristic pattern of the LCD. Then defocussing it will make adjacent colour areas bleed into each other to get the secondary and tertiary colours you see in the photo.

Last edited by Vas Crabb; 03/06/16 04:06 AM. Reason: clarification

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