[Effect] lookupfilter

lookupfilter effect.

requested by ruskul.

Based on code from: https://github.com/BradLarson/GPUImage

How To Use:

1) Use your photo editing application to apply a filter to the 'lookup.png' original thats included.

// For this to work properly each pixel color must not depend on other pixels (e.g. blur will not work).

See the example project to better understand it. (not 100% finished)

Fx files and demo-

https://dl.dropboxusercontent.com/u/22173473/lookupfilter.rar

Hey chrisbrobs, thanks for all the efx you're doing,

unfortunatly this one doesn't work for me ... or at least it doesn't look like your preview picture

here is how it looks to me

http://i.imgur.com/yfcjhlF.jpg

(tested in chrome,firefox and NW.js all with the same results)

im using win 8.1 64bit

nvidia GTX 760 with the latest drivers

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Does the 'lut6 Chrome2' render correctly?

chrisbrobs

No, they basicaly look all the same as in the image i posted previously.

I did a little test because i wanted to know if the blue parts in the image is transparent and just showing the background... Its not transparent.

It looks like it gets the color from somewhere on the screen, have a look at this image

http://i.imgur.com/33x5XDV.jpg

I added a red sprite object to the project that toggles visible and invisible and you see it somehow effects the filter

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Not sure why your getting the problem, I would expect to see other post's reporting the same problem if it was happening on other machines.

1, You might have the 'pic' sprite and the 'lookup' sprite miss-aligned or not both scaled to the same size...worth checking?

2, What is the red square behind the buttons in your sample image.

chrisbrobs

1. the problem occurs with unchanged ver. of the included lookuptest1.capx

2. the red square is just a sprite.

chrisbrobs

I have the same issue with all of your latest effects. None render correctly on my GTX 970.

It was the same with a lot of effects from Gigatron until he found out what the problem was and fixed it.

chrisbrobs I have the same artifacts.

GTX970

zenox98

evgy

I'm not sure why this works for some systems, and not others?

I will post solutions when I find them.

Hey, thanks for throwing this up on the forums. I got a chance to dl it and test. I'm having the same problem as others that have mentioned it.

As I mentioned on another post, I have at this point created my own effect that does this, I'll have a look at the two and see if I can spot the differences that may give you a clue what it doesn't work on some machines.

Okay, so as I mentioned, I know nothing of shaders lol, but it looks like we are basically doing the same thing mathematically speaking... but In mine I flip y at the end for the 2 texture coordinates that you then mix together. Also in mine, I apply the fx to a sprite that is the lookup table - that then has to be scaled to fit the screen exactly. Anything you don't want affected has to go above the layer containing the table. I added a few other properties like collums and rows for the table so you can use multiple sizes and a version that has no color mixing at the end for crispy pixels in a retro game , but other than that...

Again, I checked the math and I think it is basically the same (pretty sure) except for what I noted. As I said, I'm bad with shaders so the nuances escape me, but maybe you know?