How to return a struct from my shader?

[waltherg]

Hi again gmrf

I'd like to be able to write a shader which returns a struct rather than just a single colour - along the lines of misss_fast_skin_x / mia_material_x etc.

My aim here is to then write a phenomenon for my shader which passes these various outputs into max_mrStoreElements, where I can save them with mrLabelledElement render elements in 3dsmax.

Is this possible? Is it a case of using a different signature to :

DLLEXPORT miBoolean SlideTest(miColor *result, miState *state, slideTestParas *paras)
{ ... }

Any pointers or examples would be fantastic

Many thanks from Slide.

Rob

[haggi]

Returning a struct is quite easy.

First you will have to write your mi - interface file in a way it returns a struct.
For example you can have a look in the mayabase shaders oder if you use max, in the standard shaders include files:

Code: Select all

declare shader
   struct {
      scalar    "density",
      vector   "direction"
   }
   "myBeautyfulShader" (
      scalar  "steps",
      boolean "doitOrNot"
   )
   version 1
   apply material
    }
end declare


Then you build your data struct exactly like the params struct:

Code: Select all


typedef struct{
      miScalar steps;
      miBoolean doitOrNot;
} shaderParas;

typedef struct{
   miScalar    density;
   miVector   direction;
} returnStruct;

DLLEXPORT miBoolean myBeautyfulShader(returnStruct*result, miState *state, shaderParas*paras)
{
   result->density = 1.0;
   result->direction.x = 123.4;
   result->direction.y = 567.8;
   
  return miTRUE;
}



[waltherg]

Thank you Haggi, that's very helpful - I was hoping it would be that simple.

I will give it a go and post back with my results...

[waltherg]

Fantastic - that worked perfectly!

I now have a build of Pavel's p_HairTK which saves all it's various outputs to mrLabelledElement render elements in max. That will find it's way into the next official drop of SlideShaders.

Thanks again

[jb_alvarado]

Hi waltherg,
that's really cool! I think I need more time, then I can make a Softimage addon from your nice shaders .

[banned]

hi wahltherg,

you are great, i can´t wait of the new SlideShaders.

cheers
hot chip

[waltherg]

Thank you guys! I'm glad this is useful for everyone.

Most of the hard work has been done by Pavel though - we just add some 'klebstoff'

By the way : if you have any suggestions to make SlideShaders better, please tell us - contact@slidelondon.com will get through to me.