custom material shader doesnt work in override....

V-Ray for Maya V-Ray for Maya :: SDK
1

i wrote a custom material shader for maya, all has gone very well until I put it in a override field of a basic surface shader( ex. Reflection Material. ), and in the final image, i got the object shaded in a basic shading. I looked in the vray_MtlOverride.cpp and I noticed that override’s shade() calls my overriding material’s shade(). I tried printing something when my own material’s shade() is called. But nothing was printed… So I supposed that override material has not called my material’s shade() at all??? How that could happen?? Am I missing something?

Best regards

thekraken

here is a simple pseudo code of my material shader:


using namespace VR;

// Plugin parameters
struct MyMaterialParams: VRayParameterListDesc {
	MyMaterialParams(void) {

	//////////////////
} ;

// The plugin itself
struct MyMaterialMyMaterial: VRayMaterial {
	MyMaterial(VRayPluginDesc *desc):VRayMaterial(desc) {
		/////////
	}

	// From VRayPlugin
	void renderBegin(VRayRenderer *vray) { brdf_pool.init(vray->getSequenceData().maxRenderThreads); }
	void renderEnd(VRayRenderer *vray) { brdf_pool.freeMem(); }
	void frameBegin(VR::VRayRenderer *vray);

	// From MaterialInterface
	void shade(VR::VRayContext &rc);

	// From BRDFInterface
	BSDFSampler *newBSDF(const VR::VRayContext &rc, BSDFFlags flags) {
		VR::smile:iffuseBRDF *bsdf=brdf_pool.newBRDF(rc);
		initBSDF(rc, *bsdf);
		return static_cast<BSDFSampler*>(bsdf);
	}
	void deleteBSDF(const VR::VRayContext &rc, BSDFSampler *bsdf) {
		if (bsdf) brdf_pool.deleteBRDF(rc, (VR::smile:iffuseBRDF*) bsdf);
	}
	void initBSDF(const VRayContext &rc, VR::smile:iffuseBRDF &brdf);

	PluginBase* getPlugin() { return static_cast<PluginBase*>(this); }

	virtual PluginInterface* newInterface(InterfaceID id)
	{
		if( id == EXT_RTMTL )
		{
			return static_cast<PluginInterface*>((RTMtlInterface*)this);
		}

		return VRayMaterial::newInterface(id);
	}

private:
	// Cached parameters
	//////////////////////

	BRDFPool<VR::smile:iffuseBRDF> brdf_pool;
};

// Define the plugin
#define MyMaterial_PluginID PluginID(LARGE_CONST(2012022011))
SIMPLE_PLUGIN_LIBRARY(MyMaterial_PluginID, EXT_MATERIAL, "MyMaterial", "MyMaterial for VRay", MyMaterial, MyMaterialParams);

void MyMaterial::frameBegin(VR::VRayRenderer *vray) {
	VRayMaterial::frameBegin(vray);

}

void MyMaterial::initBSDF(const VRayContext &rc, VR::smile:iffuseBRDF &bsdf) {
    std::cout<< "initBSDF is called"<<std::endl;
	Color diffuse=combineTex(rc, diffuse_tex, Color(0.0,0.0,0.0),1.0);
    bsdf.init(diffuse, Color(.0,.0,.0), rc);
}

void MyMaterial::shade(VR::VRayContext &rc) {

    std::cout<< "shade is called" <<std::endl;
	Color alpha=transparency.whiteComplement();

	if ((rc.rayparams.rayType & RT_SHADOW) || rc.rayresult.realBack) {

        rc.mtlresult.color.makeZero();
		rc.mtlresult.transp=transparency;
		rc.mtlresult.alpha=alpha;
		rc.mtlresult.alphaTransp=transparency;

		return;
	}

	/*

		computing		

	*/

	rc.mtlresult.color+=result;
	rc.mtlresult.transp=transparency;
	rc.mtlresult.alpha=alpha;
	rc.mtlresult.alphaTransp=transparency;

}
2

Is the newBSDF() method called for your material? It is possible that your material is wrapped in a MtlSingleBRDF material eventually, and that MtlSingleBRDF is attached to the node. In that case, it will call only the BSDF/BRDF functions of your material, and not its shade() method.

Best regards,
Vlado

3

1. Is the newBSDF() method called for your material?

Yes, override shader called newBSDF() for sure, and it called only newBSDF() :frowning: :frowning:

2. It is possible that your material is wrapped in a MtlSingleBRDF material eventually, and that MtlSingleBRDF is attached to the node.

nope, my material is not wrapped in a MtlBRDF(If I have understood CORRECTLY what you talked about)… it was just in a lambert’s override material field…

could you PLEASE detail a little… i’ve been looking for the solution for 4 hours… it’s driving me crazy… :frowning:

best regards

4

Ok then; can you show me a .vrscene file with the material exported in this way? In any case, the solution would probably be to do what you need in the traceForward() method of your BRDF - i.e. derive your own BRDF class from VUtils::smile:iffuseBRDF and reimplement its traceForward() method to do what you need (you’ll still need to call DiffuseBRDF::traceForward() to do the regular shading stuff before that).

Best regards,
Vlado

5

that’s very kind of you.

here is the exported material


BRDFMirror VRayMtl1@mirror {
  transparency_tex=AColor(0, 0, 0, 1);
  cutoff=0.01;
  back_side=0;
  trace_reflections=1;
  trace_depth=5;
  reflect_exit_color=AColor(0, 0, 0, 1);
  reflect_dim_distance=100;
  reflect_dim_distance_on=0;
  reflect_dim_distance_falloff=0;
}

BRDFDiffuse VRayMtl1@diffuse {
  color=Color(0, 0, 0);
  color_tex=AColor(0, 0, 0, 1);
  transparency_tex=AColor(0, 0, 0, 1);
  roughness=0;
  use_irradiance_map=1;
}

BRDFLayered VRayMtl1@brdflayered {
  brdfs=List(
    VRayMtl1@mirror,
    VRayMtl1@diffuse
  );
  transparency=Color(0, 0, 0);
  channels=List(
  );
}

MtlSingleBRDF VRayMtl1@material {
  brdf=VRayMtl1@brdflayered;
  double_sided=1;
}

BRDFDiffuse lambert2@diffuse_brdf {
  color=Color(0, 0, 0);
  color_tex=lambert2@diffuse_brdf_color_tex@tex_with_amount;
  transparency=Color(0, 0, 0);
}

MtlOverride lambert2@diffuse_brdf_lambert2@override {
  base_mtl=lambert2@diffuse_brdf;
  reflect_mtl=VrayMyMaterial1;
}

VrayMyMaterialMayaPlugIn VrayMyMaterial1 {
  plgDiffuse_tex=AColor(0.1, 0.5, 0.2, 1);
  plgDiffuse_tex_mult=1;
  plgThresholdHigh=0.9;
  plgThresholdLow=0.3;
  plgHighColor=Color(1, 1, 1);
  plgMedColor=Color(0.8, 0.8, 0.8);
  plgLowColor=Color(0.2, 0.2, 0.2);
  plgTransparency=Color(0, 0, 0);
}

MtlSingleBRDF lambert2@material {
  brdf=lambert2@diffuse_brdf_lambert2@override;
}

I will derive my own BRDF from DiffuseBRDF… so there is no way that override would call my material shade() methode then?

Thank you

Best regards

kraken

6

Well, you could attach the MtlOverride material directly to the node, instead of passing it through a MtlSingleBRDF material. You can do this for example with the post-translate Python callback.

Best regards,
Vlado

7

Thanks vlado,

I wrote a new class derived from BRDF to do the things finally and that works well. Thank you for all your replies. :slight_smile: I will try the post-translate python callback later.

best regards

thekraken