hdk: first steps with UT_PNoise::noise3D

[JoshJ]

Hi,

 

So I'm making my first steps into the HDK, having very minimal, casual c++ experience over the years.  I successfully compiled some of the examples, and I'm experimenting with changing the demoVolumeSphere into a custom VRAY volume procedural.

 

It's going well, except I can't figure out how to get any 3d noise working.  I'm currently adjusting the vray_VolumeSphere::evaluate function.  Here's my current code:

 

included at the top is:

 

#include <UT/UT_PNoise.h>

---------------------------------------------

 

void
vray_VolumeSphere::evaluate(const UT_Vector3 &pos,
              const UT_Filter &,
              float, float,
              int idx, float *data) const

{

data[0] = -pos[1]+1 + UT_PNoise::noise1D(pos[0]);

}

 

---------------------------------------------

Correctly results in a 1d noise along the x axis.

 

However, as soon as I attempt to use any of the 3d noise, I can't get the types, pointers, and references to cooperate.

 

for example, when I use UT_PNoise::noise3D , I've tried every combination of * , &, etc I can think of for the inputs, but I always get an error message like:

 

error: no matching function for call to ‘UT_PNoise::noise3D(UT_Vector3&, const UT_Vector3&, int)’
     UT_PNoise::noise3D(dest,pos,1);

 

I know I haven't mastered a lot of the c++ pointer concepts, but I'd like to learn by example and figuring it out, and I'll eventually get it.  I looked through most of the HDK documentation though, and didn't find any example which could apply to this case.

 

If someone could write out a simple example for UT_PNoise::noise3D with const UT_Vector3 &pos as an input, resulting in a 1d value, that would be awesome.

[edward]

float x[3] = { pos(0), pos(1), pos(2) };

data[0] = UT_PNoise::noise3D(x);

[JoshJ]

Awesome, Thanks edward, it worked.

 

Now I'm experimenting with UT_Noise::turbulence , which doesn't have the float x[3] input.  Instead it has , for example:

 

  fpreal turbulence(

const UT_Vector3 &pos,

unsigned fractalDepth,

fpreal rough = 0.5,

fpreal atten = 1.0) const;

 

I'm not sure what to put for the "const" entry after the end parenthesis.

 

I've attempted to call it like this:

    const a = 0;
    fpreal x = UT_Noise::turbulence(pos,5) a;
    data[0] = -pos[1]+0.5 + x;

 

which of course did not work,

and I've tried a few variations and google searches about "error: cannot call member function ... const’ without object"

So, what does it mean when "const" is after the function parenthesis, and how do I call this type of function correctly?

 

also, for the void style of the function:

 

void turbulence(

const UT_Vector3 &pos,

unsigned fractalDepth,

UT_Vector3 &noise,

fpreal rough = 0.5,

 fpreal atten = 1.0) const;

 

Would I just create a UT_Vector3 variable beforehand, and enter it in like:

 

UT_Vector3 dest;
UT_Noise::turbulence(pos,5,dest);

 

Then dest contains my noise as a UT_Vector3 object?

[ranxerox]

 the "const" after the member function name is just indicating that the function call won't affect the object it's a member of.  You can safely ignore it in your case (ie. you don't have to pass anything in place of the 'const' keyword).

 

 -G

 

 

 

Awesome, Thanks edward, it worked.

 

Now I'm experimenting with UT_Noise::turbulence , which doesn't have the float x[3] input.  Instead it has , for example:

 

  fpreal turbulence(

const UT_Vector3 &pos,

unsigned fractalDepth,

fpreal rough = 0.5,

fpreal atten = 1.0) const;

 

I'm not sure what to put for the "const" entry after the end parenthesis.

 

I've attempted to call it like this:

    const a = 0;
    fpreal x = UT_Noise::turbulence(pos,5) a;
    data[0] = -pos[1]+0.5 + x;

 

which of course did not work,

and I've tried a few variations and google searches about "error: cannot call member function ... const’ without object"

So, what does it mean when "const" is after the function parenthesis, and how do I call this type of function correctly?

 

also, for the void style of the function:

 

void turbulence(

const UT_Vector3 &pos,

unsigned fractalDepth,

UT_Vector3 &noise,

fpreal rough = 0.5,

 fpreal atten = 1.0) const;

 

Would I just create a UT_Vector3 variable beforehand, and enter it in like:

 

UT_Vector3 dest;
UT_Noise::turbulence(pos,5,dest);

 

Then dest contains my noise as a UT_Vector3 object?

 

[JoshJ]

thanks ranxerox, that helps.

I figured out that UT_Noise needs to be instanced as an object like this:

    UT_Noise anoise;
    data[0] = -pos[1]+0.5 + anoise.turbulence(pos,5,0.5,0.5);

 

Now it works.

[JoshJ]

How do I use the enum values for the noise?

 

    UT_Vector3 x = {pos(0),0,pos(2)};
    UT_Noise anoise;

// set the noise type here to alligator using an enum, like:

// anoise.setType(UT_Noise::UT_NoiseType(ALLIGATOR));  // which gives the error: ‘ALLIGATOR’ was not declared in this scope

    data[0] = -pos[1]+0.5+ anoise.turbulence(x,3,0.5,0.5)*0.1;

 

Edit:

Ok, I solved it,

anoise.setType(UT_Noise::UT_NoiseType::ALLIGATOR);

Edited February 11, 2015 by JoshJ