How to sum vertex colors into one solid color of primitive

[Iskander]

Hi guys!

I want to make 'lowpoly stilyzed' image.

I know it is easy to make that by vex expression(for example),but i don't know vex syntax right now-just starting to learn it.

Please help me on my Houdini way.

 

Left what i have,right what i need.

Example in random colors,but i am reading colors from image,don't be afraid. 

All i want is to sum up 3 values of 3 vertex colors to 1 primitive color,and then i'll have 3 same vertex colors in primitive.
By this way: Pr[*].Cd = (Pr[*].Vtx[x].Cd+Pr[*].Vtx[y].Cd+Pr[*].Vtx[z].Cd)/3

Edited March 27, 2016 by umpaumpa

[Skybar]

Not vex, but you could try the Attribute Promote SOP. It has a few different operations including sum.

[f1480187]

For vertex color:

// Primitive Wrangle.
@Cd = 0;
int vtxs[] = primvertices(0, @primnum);
foreach (int vtx; vtxs)
    @Cd += vector(vertex(0, "Cd", vtx)) / len(vtxs);

For point color:

// Primitive Wrangle.
@Cd = 0;
int pts[] = primpoints(0, @primnum);
foreach (int pt; pts)
    @Cd += vector(point(0, "Cd", pt)) / len(pts);

Then delete point or vertex color with Attribute Delete node, since primitive color has low priority.
 
Use Attribute Promote node. It has different methods, not only averaging.

primitive_color.hipnc

Edited March 27, 2016 by f1480187

[Iskander]

Thank you guys.Perfect!
Promote node is amazing node.  
 

Edited March 28, 2016 by umpaumpa