VEX function - colormap

[sadhu]

Hello friends,

I am learning vex functions. I came across colormap function. I want to apply color to the grid based on the colormap. Can I use this expression for that? I tried it but it didn't work.

1)I created a custom vex node in material shader builder with outcol output para of color type.

2)In inner code, $outcol = colormap("/obj/cop2net1/Mandril.pic",P,u,v,20)

3) Output of this custom vex node is connected to surface color. But it didn't work.

vector colormap(string filename, vector uv, vector du, vector dv, int samples) , I want to use this function. I am not sure what can I input for vector uv, vector du, vector dv.

Can someone please help me out with this.

Thanks a lot for your time.

[sadhu]

It is working. With following changes.

1)I applied uv texture to the grid.

2)Created 3 new inputs, two float para u and v and a vector para uv on custom vex node.

3)Used uvcoords operator and connected its output to u, v and uv of custom vex operator.

4)set ,$outcol = colormap("c:\Program Files\Side Effects Software\Houdini 12.0.575\houdini\pic\Mandril.pic",$uv,$u,$v,100);

It is working.

Even if I set, $outcol = colormap("c:\Program Files\Side Effects Software\Houdini 12.0.575\houdini\pic\Mandril.pic",$u,$v);

It is working.

The question is how to use pixel sample input in colormap function in step 4, even if I set it to 0, it is working.

Edited April 20, 2012 by sorry