Shader Idea

[Amon26]

So here it comes from the guy who knows nothing about programming/modifying quake engines, telling you what you should do. get your bats with nails in em ready.

Ive seen a lot of really cool hi-detail, bumpmapped, refracted and cellshaded mods for quake over the years, and I'd enjoy them all fair enough. but I always liked how scratchy and sketchy the raw pixels looked. The imagination had to do a lot to fill in the gaps and that made the world feel scarier in a way to me.

so here's the pitch. what could be done with post-processing shaders to simulate a thick, greasy gesture-painting like appearance? Here's some image references of the style im thinking of if anyone thinks this is at all feasible or are just crazy enough to try.

[FC Zvyozdochka]

Try this - NPRQuake.
It is not exactly what you're asking for, but it still got sketchy look =)

[Amon26]

Yeah something sort of like that, but whats the feasibility of taking the actual textural data and running a shader over it that smudges and blurs it out in organic brushtrokey looking ways? This might really be more than what's possible technically speaking though, but just curious.

[LambentHammerBurst]

I don't think shaders would be enough to properly do this. This seems like it's be more of a rendering edit on the engine over texture shaders. Darkplaces only put some of the Q3 shader options - not all

[Spiney]

This seems like one of those feature requests that won't gather any following, but I like the idea quite a lot.

One way we might think about it is to divide between 3D rendering and 2D painting.

In 3D rendering, we generally rasterize triangles to pixels and do per pixel shaders.

In 2D rendering, you can do layers on top of each other and blend them together. You could use different sizes of framebuffers overlayed on top of eachother. Ofcourse you can smell that it's going to get a bit tricky.

Anyway, I think when doing a 2D effect, you need to think of it as a 2D compositing process, rather than using 3D to make it look 2D. So I like the concept of layering.

Example... render outlines, but don't have them be clean CG outlines. There's a demo + sourcecode that does this quite nicely, and plenty fast.
Humus - 3D

You could copy the lines buffer, blur it by some pixels, and multiply it back onto itself...
You could render lighting seperatly and apply a high pass filter to it, compose it back in for a more gritty look.

You could fade lighting based on depth, so thing up close could be shaded, things in the distance would have flat albedo.

Instead of applying texture mapping, you could have materials render to something of a stencil buffer, and use that to apply 2D cutout style textures. So it becomes something of a collage.

Perhaps for something like this pic, you could do such a thing, and blend something of an ambient occlusion map on top for adding back in features.
http://www.intoxicated-demons.com/an...gs/16_bes1.jpg

Anyway, just throwing ideas. Easier said then done ofcourse, but I can't say no to experimentation
Essentially it's somewhat of a deferred rendering approach, but not with photo realism in mind.

[Amon26]

Yeah very much on the same page with me, Spiney. In fact, when I first read about deferred rendering that's what i thought it could potentially be used for. I'll agree its a tall order, and a rather obtuse one. Maybe somewhere soon I should learn more about the graphical end of IdTech1 and mess with it on my own.