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[gimymblert]

That's not pixelart.

No but there is some basis there to go where we want (crisp and solid line on a pixel level) TOO bad the screen are blurry

[jfroco]

Hi,

This is NOT pixel art.. but it is a simple way of pixelating a 3D scene...



This is a video that shows the scene in movement, please check the last example in the video for a retro pre-ZX Spectrum look





I made this a couple of weeks ago.. not using shaders as an exercize, but you can get the same effect using shaders easily. What I did was to resize the camera from the actual screen size to a smaller size and then resize it back again to the actual screen size.

****

On the other hand, you may want to check isometric projection of 3D scenes:

I made this simple real 3D scene using an isometric projection:





Does it look like a pixel scene? I think so 

This is the texture.




Hope this helps.

Best regards

JF

[Firepith]

Wow, love the video. Would love to see that effect combined with cel-shading.
Still wouldn't be the bona-fide pixel art look, but it'd be cool.

[gimymblert]

There is Two problem here (general problem not particular post): One is 3D to Pixel art, the other one is texture to pixel.
The first involve extracting silhouette, edge and volume.
The second involve scaling, warping and shape + details preservation.
The first one seems easy to me. SHADER
The second ask for more expertise and the knowledge of image frequency manipulation.

[Rob Lach]

Hmm...

I'll see if I could cook something up. I am currently working on something similar, dynamic shading/lighting on 2D Textures and if I add a step to the pipeline and I could probably push the 2D stuff as a post-process after rendering 3D with only ambient light.

[Firepith]

What about this, and other great stuff from that forum (Low Spec Art)?

In a way it's also pixel art, cause the creator really cared about how the colors on a pixel level finally hit the screen... Not as clean an perfect as 2d pixelart, but still very beautiful... those rotating 3d models look kinda perfect from all possible angles

Holy cow that is awesome.
So, pixel-art-ish textures on low poly models, with cel shading, displayed at low res.
I like it. Even if it's not 100% what I was going for, it could look nearly as good.
Haha. Now I need to actually learn how to make games. Or maybe I can just be a texture & modeling guy...

[Firepith]

Holy shit, here's another great example.

http://www.wayofthepixel.net/pixelation/index.php?topic=6977.0

I mean... that is pretty much it, man. Keep it low res at full screen, maybe add cel shading for lighting and outlines. Dude.

Games need to be made in this style.

[jfroco]

Hi,

Amazing low poly models and textures!!!

After reading this post I played with shaders a couple of hours... this is just a simple directx cartoon effect applied to a 3d object:

No effect:



Cartoon effect:



(I wrote no shader in the screen because I wasn't applying any fullscreen shader )

I know it is not the same as creating a "pixel-art-ish texture", but in some cases it could be a good alternative

Best regards

JF

[Ntero]

Yeah judging from the samples, texturing using small, flat , pixel-arty coloured textures (or using a Toon Shader), and the downscaling the the output (using a lower resolution than the actual screen) should get something close, and something tweakable.  using outlines would depend on the game itself.

[jpetrie]

You might also want to consider adapting one of the many painterly rendering techniques. These are generally all about reproducing an image with low fidelity and quantized color ranges -- very similar to what is done in pixel art. Also, some of the slightly older techniques (such as this one) are quite easy to implement, especially on modern hardware.

Their downside -- as with most non-photorealistic effects -- is that they tend to suffer from the 'shower door' problem: they don't have very good temporal coherence, so the strokes can seem to 'swim' a bit for anything that is in motion. You'd need to take steps to counteract this, but fortunately there are a fair number of options, mostly related to preprocessing the data or trying to forcing "pixel grid" alignment in shaders.

[gimymblert]

You might also want to consider adapting one of the many painterly rendering techniques. These are generally all about reproducing an image with low fidelity and quantized color ranges -- very similar to what is done in pixel art. Also, some of the slightly older techniques (such as this one) are quite easy to implement, especially on modern hardware.

Their downside -- as with most non-photorealistic effects -- is that they tend to suffer from the 'shower door' problem: they don't have very good temporal coherence, so the strokes can seem to 'swim' a bit for anything that is in motion. You'd need to take steps to counteract this, but fortunately there are a fair number of options, mostly related to preprocessing the data or trying to forcing "pixel grid" alignment in shaders.

A problem i face with poor toon shading implementation

Was thinking about that and not making texture as pixel, but as "structured hierarchic shape"

EDIT: http://www.kennethfejer.com/lowpoly.html i was seeking that also

[Nektonico]

Yeah, this has crossed my mind as well.

The thing is, it is possible to render stuff in a cartoonish non photorealistic style already (in specialized 3D apps, that is).
For instance
http://freestyleintegration.files.wordpress.com/2009/12/2009_08_illustration_re.jpg
http://freestyleintegration.files.wordpress.com/2010/02/rylan_mech.jpg
http://blendman.free.fr/bd/vaisseaucolo3.jpg
To get something that looks like retro pixel art you would just need to (i guess) limit the color pallete and perhaps use simple stylized textures; and of course, use a low resolution.

The thing is, if you pre render the 3D models to use them as low res sprites, things tend to get "garbled", and inevitably one ends up having to do some pixel pushing.
It would be great to have some sort of automated system to do the cleaning up, the pixel pushing that is.

What is pixel art?
You can get the basics from any tutorial.
http://www.pixel.schlet.net/
http://www.derekyu.com/?page_id=218
Maybe code it into a shader. One that does NPR (non photorealistic rendering) and then uses pixelling rules. It wont be pixel art, but it may end up looking similar to it.

Then again, this hasnt been done for non realtime rendering, and you guys are asking to see if it can be done within the constraints of a realtime game engine.
Worse yet, i suspect the lower the resolution, the harder it would be. Emulating NES style graphics from 3D would be no small feat indeed. The greater the abstraction, the more it would have to rely on algorithms to keep everything from looking like a disjointed pixel soup.

I think its doable, but it would take reverse engineering what looks good and what doesnt at really low res.
But i see no technical limitation to it, i mean, much more sophisticated NPR stuff exists, emulating really complex art styles effectively.

[raigan]

I'm not sure if anyone has pointed this out, but Fez/Trixels are sort of a similar idea -- in this case not using rendering to achieve a pixel-art look, but instead building the 3D models out of Trixels (3D cubes, analogous to 2D pixels) to evoke the same aesthetic.

[Robotacon]

The reason tennis aka kenneth fejer low poly looks so much like pixel art is that all parts of his textures are as straight and rectangular as possible. Textures with anti-aliased diagonals and curves breaks the illusion.

[Core Xii]

building the 3D models out of Trixels (3D cubes, analogous to 2D pixels)

3D cubes analogous to 2D pixels are called voxels (volumetric pixels). This "trixel" thing is probably a misnomer; Sounds more like having something to do with triangles.

And it's a very old method. Command & Conquer: Tiberian Sun modeled its units in voxels, and they looked pretty pixel-art-y to me. But it does have its limitations.

[raigan]

I think they're distinct from each other; conceptually voxels may be cubes, but they're not explicitly cubes made of triangles. (This is sort of OT..)

AFAIK what makes voxels voxels is that they're not rendered using polygon rasterization -- you use some sort of alternate approach like raymarching or some other volumetric rendering to draw them. So they truly are "volumetric", not just a surface representation like meshes. Also they're a lot older than Tiberian Sun, Commanche and later Outcast both had voxel-based terrain.

Trixels on the other hand seem to be based on polygons, at least I would assume so given the target hardware, so I'm claiming they're distinct from voxels. But Renaud is on these forums so maybe he can clear this up

[Zaknafein]

Déjà vu...

http://forums.tigsource.com/index.php?topic=1600.0
http://theinstructionlimit.com/?p=30
http://theinstructionlimit.com/?p=200

Trixels is the "brand name" of the graphics tech we've created for Fez, it uses voxels for data storage and polygons for rendering. Voxels can be represented as cubes or smooth surfaces depending if you use interpolation, etc etc.

[Core Xii]

AFAIK what makes voxels voxels is that they're not rendered using polygon rasterization -- you use some sort of alternate approach like raymarching or some other volumetric rendering to draw them.

A 3D cube analogous to a 2D pixel is a voxel by definition, regardless of how one renders it. If your cube is not a solid-color cube then it is no more analogous to a 2D pixel than it is a voxel.

I also did not claim Tiberian Sun did it first, just an example of doing it right.

[Alex May]

Still, this all misses the point as neither voxels nor trixels end up looking like pixel art however prettily they are drawn.

[raigan]

Trixels DO look like pixel-art, at least when you're looking at them head-on/along an axis without perspective. That's sort of the whole point AFAICT, it's an extension of pixel art to 3D