How to change Voronoie OSL code to make it more linework

Artistic Support Materials and Textures
1

Any idea maybe what can be changed of the code so that instead of the voronoie effect we know with blurred filled cells we can get more a sharp crisp cell outline with rounded edges like this:

Please excuse my low level question, I hardly understand the code, and tried play with it but I mainly break the code ;(

http://datumdezign.com/itp/wp-content/uploads/2011/04/voronoi_marble_bookcase_decorative_shelving.jpg

#include “stdosl.h”
#include “node_texture.h”

/* Voronoi */

shader node_voronoi_texture(
int use_mapping = 0,
matrix mapping = matrix(0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0),
string Coloring = “Intensity”,
float Scale = 5.0,
point Vector = P,
output float Fac = 0.0,
output color Color = color(0.0, 0.0, 0.0))
{
point p = Vector;

if (use_mapping)
p = transform(mapping, p);

/* compute distance and point coordinate of 4 nearest neighbours */
float da[4];
point pa[4];

voronoi(p * Scale, “Distance Squared”, 1.0, da, pa);

/* Colored output */
if (Coloring == “Intensity”) {
Fac = fabs(da[0]);
Color = color(Fac);
}
else {
Color = cellnoise_color(pa[0]);
Fac = (Color[0] + Color[1] + Color[2]) * (1.0 / 3.0);

}
}

2

I dug a bit deeper and here is what I got:


#include "node_texture.h"

/* B&W Voronoi */

shader node_voronoi_texture(
    int use_mapping = 0,
    matrix mapping = matrix(0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0),
    float Scale = 5.0,
    float Limit = 0.0,
    point Vector = P,
    output float Fac = 0.0,
    output color Color = color(0.0, 0.0, 0.0))
{
    point p = Vector;

    if (use_mapping)
        p = transform(mapping, p);

    Fac = 1.0 - voronoi_F1F2(p* Scale); // Inverted
        
    if (Fac < Limit)
    {
        Fac = 0.0;
    }
    else
    {
        Fac = 1.0;
    }
    Color = color(Fac);
}

Set the “Limit” just a little above 0.9 and we’re getting some B&W line art. Some more work is needed to smooth out the cells border. Any way, you’re stuck here for now, waiting for Cycles to get volumetric materials.

snap51.png1920×1080 363 KB

3

This can also be achieved by running the voronoi through an rub curve. Even more control. No screenshot as I’m not on my pc.

4

A better function is than if then is …
float step(float a, float x)
{return x >= a;}
this function will be easier to antialias down the road.

5

or smoothstep(edge0,edge1,x)…e.g. smoothstep(0.8,0.9,x)