Curve and geometry shader

[thecouze]

I would like to attach a geoshader to a curve in Maya. I have been trying few things but it did not work. I just need to get the curve into my shader and collect the CVs coordinates.
Any help will be appreciated! Cheers
Gerome.

[bart]

Pass the curve as an input argument of type geometry to the geoshader.

In an mi file this would appear as the name of the object (shape node).

[thecouze]

I tried the following and it does not pick up my curve.

Below it is my simple code for getting the curve.

#include <shader.h>
#include <geoshader.h>

typedef struct {
miTag object;
} curveParm;


DLLEXPORT int curveToPlane_version(void) {return(1);}

DLLEXPORT miBoolean curveToPlane(
miTag *result,
miState *state,
curveParm *param )
{
miTag src_obj_tag = *mi_eval_tag( &param->object );
miObject *curveOBJ;

curveOBJ = (miObject*)mi_db_access( src_obj_tag );

if ( curveOBJ->type == miOBJECT_SPACECURVES )
{
mi_warning( " We have a curve " );
}
else if ( curveOBJ->type == miOBJECT_POLYGONS )
{
mi_warning( " We have a poly " );
}
else
{
mi_warning( " It is something else " );
}

return ( miTRUE );
}

and my .mi file

declare shader
geometry "curveToPlane" (
geometry "object"
)
version 1
apply geometry
#: nodeid 1093867
end declare



Nothing is happening. I feed the "curve"|geometry shader with this shader the following connection is done:
Connected curveToPlane1.outValue to nurbsSphere1.mentalRayControls.miGeoShader
then as my argument in the geo shader I feed it with the curveShape node and the following is connected:

connectAttr -f nurbsSphere1.message curveToPlane1.object;

However it seems to work with Poly, so I believe I am doing something wrong regarding NURBS inputs.
Any ideas? Cheers

[ctrl_studio]

'geometry' keyword in mi declaration files does not work in maya.
and I'm not even sure you can pick up a curve anyway.
try in the first soomething like this ..

miTag src_obj_tag = *mi_eval_tag( &param->object );
if( !src_obj_tag) mi_info("oops.. I got a null tag !! ");
[....]


max

[stefanminning]

Sorry to revive an old thread like this.

I'm also trying to access a curve in a geometry shader in Maya. The problem is, I'm not even sure whether Maya actually translates the curves at all so I don't know if what I'm doing is simply wrong or if Maya is just preventing me from seeing the data.

Has there been any progress in this area? How would I go about accessing a curve's CVs in my shader?