This example shows how to use Simplygon shading network with a custom shading node.

// Copyright (c) Microsoft Corporation. 
// Licensed under the MIT license. 

#include <string>
#include <stdlib.h>
#include <filesystem>
#include <future>
#include "SimplygonLoader.h"

class CustomObserver : public Simplygon::Observer
{
	public:
	Simplygon::ShadingColor OnShadingCustomNodeEvaluate(Simplygon::spObject subject) override
	{
		Simplygon::ShadingColor outputValue( 0.0f, 0.0f, 0.0f, 1.0f );
		if (!subject.IsNull())
		{
			Simplygon::spShadingCustomNode customNode = Simplygon::spShadingCustomNode::SafeCast(subject);
			if (!customNode.IsNull())
			{
				Simplygon::ShadingColor inputValue = customNode->GetInputValue(0);
				outputValue.r = inputValue.r * 0.393f + inputValue.g * 0.769f + inputValue.b * 0.189f;
				outputValue.g = inputValue.r * 0.349f + inputValue.g * 0.686f + inputValue.b * 0.168f;
				outputValue.b = inputValue.r * 0.272f + inputValue.g * 0.534f + inputValue.b * 0.131f;
			}
		}
		return outputValue;
	}
	bool OnShadingCustomNodeGenerateShaderCode(Simplygon::spObject subject, Simplygon::EShaderLanguage shaderLanguage) override
	{
		if (!subject.IsNull())
		{
			Simplygon::spShadingCustomNode customNode = Simplygon::spShadingCustomNode::SafeCast(subject);
			if (!customNode.IsNull())
			{
				customNode->SetCustomShaderCode( "result = float4(dot(rgba_custom_input_0, float3(0.393f, 0.769f, 0.189f)), dot(rgba_custom_input_0, float3(0.349f, 0.686f, 0.168f)), dot(rgba_custom_input_0, float3(0.272f, 0.534f, 0.131f)), 1.0f);");
				return true;
			}
		}
		return false;
	}
} customObserver;


void RunReductionWithShadingNetworks(Simplygon::ISimplygon* sg)
{
	Simplygon::spSceneImporter sgSceneImporter = sg->CreateSceneImporter();
	sgSceneImporter->SetImportFilePath( "../Assets/SimplygonMan/SimplygonMan.obj" );
	if(!sgSceneImporter->RunImport())
		throw std::exception("Failed to load SimplygonMan/SimplygonMan.obj.");
	Simplygon::spScene sgScene = sgSceneImporter->GetScene();

	Simplygon::spReductionProcessor sgReductionProcessor = sg->CreateReductionProcessor();

	sgReductionProcessor->SetScene( sgScene );

	Simplygon::spReductionSettings sgReductionSettings = sgReductionProcessor->GetReductionSettings();
	Simplygon::spMappingImageSettings sgMappingImageSettings = sgReductionProcessor->GetMappingImageSettings();

	// Generates a mapping image which is used after the reduction to cast new materials to the new 
	// reduced object. 
	sgMappingImageSettings->SetGenerateMappingImage( true );
	sgMappingImageSettings->SetApplyNewMaterialIds( true );
	sgMappingImageSettings->SetGenerateTangents( true );
	sgMappingImageSettings->SetUseFullRetexturing( true );

	// Inject a sepia filter as a custom shading node into the shading network for the diffuse channel 
	// for each material in the scene. 
	int materialCount = (int)sgScene->GetMaterialTable()->GetMaterialsCount();
	for (int i = 0; i < materialCount; ++i)
	{
		Simplygon::spMaterial sgMaterial = sgScene->GetMaterialTable()->GetMaterial(i);

		Simplygon::spShadingNode sgMaterialShadingNode = sgMaterial->GetShadingNetwork("Diffuse");
		Simplygon::spShadingCustomNode sgSepiaNode = sg->CreateShadingCustomNode();

		// Add the custom observer to our custom shading node.
		sgSepiaNode->AddObserver(&customObserver);
		
		// Set the number of input slots to the custom node. In this case we only use the diffuse color from the loaded material as input.
		sgSepiaNode->SetInputCount(1);


		sgSepiaNode->SetInput(0, sgMaterialShadingNode);

		sgMaterial->SetShadingNetwork("Diffuse", sgSepiaNode);

	}

	// Start the reduction process. 
	sgReductionProcessor->RunProcessing();

	// Setup and run the diffuse material casting. 
	Simplygon::spColorCaster sgDiffuseCaster = sg->CreateColorCaster();
	sgDiffuseCaster->SetMappingImage( sgReductionProcessor->GetMappingImage() );
	sgDiffuseCaster->SetSourceMaterials( sgScene->GetMaterialTable() );
	sgDiffuseCaster->SetSourceTextures( sgScene->GetTextureTable() );
	sgDiffuseCaster->SetOutputFilePath( "DiffuseTexture" );

	Simplygon::spColorCasterSettings sgDiffuseCasterSettings = sgDiffuseCaster->GetColorCasterSettings();
	sgDiffuseCasterSettings->SetMaterialChannel( "Diffuse" );
	sgDiffuseCasterSettings->SetOutputImageFileFormat( Simplygon::EImageOutputFormat::PNG );

	sgDiffuseCaster->RunProcessing();
	std::string diffuseTextureFilePath = sgDiffuseCaster->GetOutputFilePath();

	// Update scene with new casted texture. 
	Simplygon::spMaterialTable sgMaterialTable = sg->CreateMaterialTable();
	Simplygon::spTextureTable sgTextureTable = sg->CreateTextureTable();
	Simplygon::spMaterial sgMaterial = sg->CreateMaterial();
	Simplygon::spTexture sgDiffuseTexture = sg->CreateTexture();
	sgDiffuseTexture->SetName( "Diffuse" );
	sgDiffuseTexture->SetFilePath( diffuseTextureFilePath.c_str() );
	sgTextureTable->AddTexture( sgDiffuseTexture );

	Simplygon::spShadingTextureNode sgDiffuseTextureShadingNode = sg->CreateShadingTextureNode();
	sgDiffuseTextureShadingNode->SetTexCoordLevel( 0 );
	sgDiffuseTextureShadingNode->SetTextureName( "Diffuse" );

	sgMaterial->AddMaterialChannel( "Diffuse" );
	sgMaterial->SetShadingNetwork( "Diffuse", sgDiffuseTextureShadingNode );

	sgMaterialTable->AddMaterial( sgMaterial );

	sgScene->GetTextureTable()->Clear();
	sgScene->GetMaterialTable()->Clear();
	sgScene->GetTextureTable()->Copy(sgTextureTable);
	sgScene->GetMaterialTable()->Copy(sgMaterialTable);

	Simplygon::spSceneExporter  sgSceneExporter = sg->CreateSceneExporter();
	sgSceneExporter->SetScene(sgScene);
	sgSceneExporter->SetExportFilePath( "ReductionOutput.fbx" );
	if(!sgSceneExporter->RunExport())
		throw std::exception("Failed to save ReductionOutput.fbx.");

}

void main()
{
	Simplygon::ISimplygon* sg = NULL;
	Simplygon::EErrorCodes initval = Simplygon::Initialize( &sg );
	if( initval != Simplygon::EErrorCodes::NoError )
	{
		return;
	}

	RunReductionWithShadingNetworks(sg);

	Simplygon::Deinitialize(sg);
}

// Copyright (c) Microsoft Corporation. 
// Licensed under the MIT license. 

using System;
using System.IO;
using System.Threading.Tasks;

public class CustomObserver : Simplygon.Observer
{
    public override Simplygon.ShadingColor OnShadingCustomNodeEvaluate(Simplygon.spObject subject)
    {
        Simplygon.ShadingColor outputValue = new Simplygon.ShadingColor( 0.0f, 0.0f, 0.0f, 1.0f );
        if (!subject.IsNull())
        {
            Simplygon.spShadingCustomNode customNode = Simplygon.spShadingCustomNode.SafeCast(subject);
            if (!customNode.IsNull())
            {
                Simplygon.ShadingColor inputValue = customNode.GetInputValue(0);
                outputValue.r = inputValue.r * 0.393f + inputValue.g * 0.769f + inputValue.b * 0.189f;
                outputValue.g = inputValue.r * 0.349f + inputValue.g * 0.686f + inputValue.b * 0.168f;
                outputValue.b = inputValue.r * 0.272f + inputValue.g * 0.534f + inputValue.b * 0.131f;
            }
        }
        return outputValue;
    }
    public override bool OnShadingCustomNodeGenerateShaderCode(Simplygon.spObject subject, Simplygon.EShaderLanguage shaderLanguage)
    {
        if (!subject.IsNull())
        {
            Simplygon.spShadingCustomNode customNode = Simplygon.spShadingCustomNode.SafeCast(subject);
            if (!customNode.IsNull())
            {
                customNode.SetCustomShaderCode( "result = float4(dot(rgba_custom_input_0, float3(0.393f, 0.769f, 0.189f)), dot(rgba_custom_input_0, float3(0.349f, 0.686f, 0.168f)), dot(rgba_custom_input_0, float3(0.272f, 0.534f, 0.131f)), 1.0f);");
                return true;
            }
        }
        return false;
    }
}

public class Program
{
    static private CustomObserver customObserver;

    static void RunReductionWithShadingNetworks(Simplygon.ISimplygon sg)
    {
        using (Simplygon.spSceneImporter sgSceneImporter = sg.CreateSceneImporter())
        {
            sgSceneImporter.SetImportFilePath( "../Assets/SimplygonMan/SimplygonMan.obj" );
            if(!sgSceneImporter.RunImport())
                throw new System.Exception("Failed to load SimplygonMan/SimplygonMan.obj.");
            Simplygon.spScene sgScene = sgSceneImporter.GetScene();

            using (Simplygon.spReductionProcessor sgReductionProcessor = sg.CreateReductionProcessor())
            {
                sgReductionProcessor.SetScene( sgScene );

                using (Simplygon.spReductionSettings sgReductionSettings = sgReductionProcessor.GetReductionSettings())
                using (Simplygon.spMappingImageSettings sgMappingImageSettings = sgReductionProcessor.GetMappingImageSettings())
                {
                    // Generates a mapping image which is used after the reduction to cast new materials to the new 
                    // reduced object. 
                    sgMappingImageSettings.SetGenerateMappingImage( true );
                    sgMappingImageSettings.SetApplyNewMaterialIds( true );
                    sgMappingImageSettings.SetGenerateTangents( true );
                    sgMappingImageSettings.SetUseFullRetexturing( true );

                }
                // Inject a sepia filter as a custom shading node into the shading network for the diffuse channel 
                // for each material in the scene. 
                int materialCount = (int)sgScene.GetMaterialTable().GetMaterialsCount();
                for (int i = 0; i < materialCount; ++i)
                {
                    Simplygon.spMaterial sgMaterial = sgScene.GetMaterialTable().GetMaterial(i);

                    using (Simplygon.spShadingNode sgMaterialShadingNode = sgMaterial.GetShadingNetwork("Diffuse"))
                    using (Simplygon.spShadingCustomNode sgSepiaNode = sg.CreateShadingCustomNode())
                    {
                        // Add the custom observer to our custom shading node.
                        sgSepiaNode.AddObserver(customObserver);
                        
                        // Set the number of input slots to the custom node. In this case we only use the diffuse color from the loaded material as input.
                        sgSepiaNode.SetInputCount(1);


                        sgSepiaNode.SetInput(0, sgMaterialShadingNode);

                        sgMaterial.SetShadingNetwork("Diffuse", sgSepiaNode);
                    }

                }

                // Start the reduction process. 
                sgReductionProcessor.RunProcessing();

                // Setup and run the diffuse material casting. 
                string diffuseTextureFilePath;
                using (Simplygon.spColorCaster sgDiffuseCaster = sg.CreateColorCaster())
                {
                    sgDiffuseCaster.SetMappingImage( sgReductionProcessor.GetMappingImage() );
                    sgDiffuseCaster.SetSourceMaterials( sgScene.GetMaterialTable() );
                    sgDiffuseCaster.SetSourceTextures( sgScene.GetTextureTable() );
                    sgDiffuseCaster.SetOutputFilePath( "DiffuseTexture" );

                    using (Simplygon.spColorCasterSettings sgDiffuseCasterSettings = sgDiffuseCaster.GetColorCasterSettings())
                    {
                        sgDiffuseCasterSettings.SetMaterialChannel( "Diffuse" );
                        sgDiffuseCasterSettings.SetOutputImageFileFormat( Simplygon.EImageOutputFormat.PNG );
                    }

                    sgDiffuseCaster.RunProcessing();
                    diffuseTextureFilePath = sgDiffuseCaster.GetOutputFilePath();
                }

                // Update scene with new casted texture. 
                using (Simplygon.spMaterialTable sgMaterialTable = sg.CreateMaterialTable())
                using (Simplygon.spTextureTable sgTextureTable = sg.CreateTextureTable())
                using (Simplygon.spMaterial sgMaterial = sg.CreateMaterial())
                {
                    using(Simplygon.spTexture sgDiffuseTexture = sg.CreateTexture())
                    {
                        sgDiffuseTexture.SetName( "Diffuse" );
                        sgDiffuseTexture.SetFilePath( diffuseTextureFilePath );
                        sgTextureTable.AddTexture( sgDiffuseTexture );
                    }

                    using(Simplygon.spShadingTextureNode sgDiffuseTextureShadingNode = sg.CreateShadingTextureNode())
                    {
                        sgDiffuseTextureShadingNode.SetTexCoordLevel( 0 );
                        sgDiffuseTextureShadingNode.SetTextureName( "Diffuse" );

                        sgMaterial.AddMaterialChannel( "Diffuse" );
                        sgMaterial.SetShadingNetwork( "Diffuse", sgDiffuseTextureShadingNode );
                    }

                    sgMaterialTable.AddMaterial( sgMaterial );

                    sgScene.GetTextureTable().Clear();
                    sgScene.GetMaterialTable().Clear();
                    sgScene.GetTextureTable().Copy(sgTextureTable);
                    sgScene.GetMaterialTable().Copy(sgMaterialTable);
                }

            }
            using (Simplygon.spSceneExporter sgSceneExporter = sg.CreateSceneExporter())
            {
                sgSceneExporter.SetScene(sgScene);
                sgSceneExporter.SetExportFilePath( "ReductionOutput.fbx" );
                if(!sgSceneExporter.RunExport())
                    throw new System.Exception("Failed to save ReductionOutput.fbx.");

            }
        }
    }
    static void Main(string[] args)
    {
        using (var sg = Simplygon.Loader.InitSimplygon(out var errorCode, out var errorMessage))
        {
            if (errorCode != Simplygon.EErrorCodes.NoError)
                return;
            customObserver = new CustomObserver();
            RunReductionWithShadingNetworks(sg);
        }
    }
}

# Copyright (c) Microsoft Corporation. 
# Licensed under the MIT license. 

import math
import os
import sys
import glob
import gc
import threading

from pathlib import Path
from simplygon import simplygon_loader
from simplygon import Simplygon

class CustomObserver(Simplygon.Observer):
    def OnShadingCustomNodeEvaluate(self, subject: Simplygon.spObject):
        outputValue = Simplygon.ShadingColor( 0.0, 0.0, 0.0, 1.0 )
        if not subject.IsNull():
            customNode = Simplygon.spShadingCustomNode.SafeCast(subject)
            if not customNode.IsNull():
                inputValue = customNode.GetInputValue(0)
                outputValue.r = inputValue.r * 0.393 + inputValue.g * 0.769 + inputValue.b * 0.189
                outputValue.g = inputValue.r * 0.349 + inputValue.g * 0.686 + inputValue.b * 0.168
                outputValue.b = inputValue.r * 0.272 + inputValue.g * 0.534 + inputValue.b * 0.131
        return outputValue
    def OnShadingCustomNodeGenerateShaderCode(self, subject: Simplygon.spObject, shaderLanguage):
        if not subject.IsNull():
            customNode = Simplygon.spShadingCustomNode.SafeCast(subject)
            if not customNode.IsNull():
                customNode.SetCustomShaderCode( 'result = float4(dot(rgba_custom_input_0, float3(0.393f, 0.769f, 0.189f)), dot(rgba_custom_input_0, float3(0.349f, 0.686f, 0.168f)), dot(rgba_custom_input_0, float3(0.272f, 0.534f, 0.131f)), 1.0f);')
                return True
        return False

customObserver = CustomObserver()

def RunReductionWithShadingNetworks(sg: Simplygon.ISimplygon):
    sgSceneImporter = sg.CreateSceneImporter()
    sgSceneImporter.SetImportFilePath( '../Assets/SimplygonMan/SimplygonMan.obj' )
    if not sgSceneImporter.RunImport():
        raise Exception('Failed to load SimplygonMan/SimplygonMan.obj.')
    sgScene = sgSceneImporter.GetScene()

    sgReductionProcessor = sg.CreateReductionProcessor()

    sgReductionProcessor.SetScene( sgScene )

    sgReductionSettings = sgReductionProcessor.GetReductionSettings()
    sgMappingImageSettings = sgReductionProcessor.GetMappingImageSettings()

    # Generates a mapping image which is used after the reduction to cast new materials to the new 
    # reduced object. 
    sgMappingImageSettings.SetGenerateMappingImage( True )
    sgMappingImageSettings.SetApplyNewMaterialIds( True )
    sgMappingImageSettings.SetGenerateTangents( True )
    sgMappingImageSettings.SetUseFullRetexturing( True )

    # Inject a sepia filter as a custom shading node into the shading network for the diffuse channel 
    # for each material in the scene. 
    materialCount = sgScene.GetMaterialTable().GetMaterialsCount()
    for i in range(0, materialCount):
        sgMaterial = sgScene.GetMaterialTable().GetMaterial(i)

        sgMaterialShadingNode = sgMaterial.GetShadingNetwork("Diffuse")
        sgSepiaNode = sg.CreateShadingCustomNode()

        # Add the custom observer to our custom shading node.
        sgSepiaNode.AddObserver(customObserver)
        
        # Set the number of input slots to the custom node. In this case we only use the diffuse color from the loaded material as input.
        sgSepiaNode.SetInputCount(1)


        sgSepiaNode.SetInput(0, sgMaterialShadingNode)

        sgMaterial.SetShadingNetwork('Diffuse', sgSepiaNode)


    # Start the reduction process. 
    sgReductionProcessor.RunProcessing()

    # Setup and run the diffuse material casting. 
    sgDiffuseCaster = sg.CreateColorCaster()
    sgDiffuseCaster.SetMappingImage( sgReductionProcessor.GetMappingImage() )
    sgDiffuseCaster.SetSourceMaterials( sgScene.GetMaterialTable() )
    sgDiffuseCaster.SetSourceTextures( sgScene.GetTextureTable() )
    sgDiffuseCaster.SetOutputFilePath( 'DiffuseTexture' )

    sgDiffuseCasterSettings = sgDiffuseCaster.GetColorCasterSettings()
    sgDiffuseCasterSettings.SetMaterialChannel( 'Diffuse' )
    sgDiffuseCasterSettings.SetOutputImageFileFormat( Simplygon.EImageOutputFormat_PNG )

    sgDiffuseCaster.RunProcessing()
    diffuseTextureFilePath = sgDiffuseCaster.GetOutputFilePath()

    # Update scene with new casted texture. 
    sgMaterialTable = sg.CreateMaterialTable()
    sgTextureTable = sg.CreateTextureTable()
    sgMaterial = sg.CreateMaterial()
    sgDiffuseTexture = sg.CreateTexture()
    sgDiffuseTexture.SetName( 'Diffuse' )
    sgDiffuseTexture.SetFilePath( diffuseTextureFilePath )
    sgTextureTable.AddTexture( sgDiffuseTexture )

    sgDiffuseTextureShadingNode = sg.CreateShadingTextureNode()
    sgDiffuseTextureShadingNode.SetTexCoordLevel( 0 )
    sgDiffuseTextureShadingNode.SetTextureName( 'Diffuse' )

    sgMaterial.AddMaterialChannel( 'Diffuse' )
    sgMaterial.SetShadingNetwork( 'Diffuse', sgDiffuseTextureShadingNode )

    sgMaterialTable.AddMaterial( sgMaterial )

    sgScene.GetTextureTable().Clear()
    sgScene.GetMaterialTable().Clear()
    sgScene.GetTextureTable().Copy(sgTextureTable)
    sgScene.GetMaterialTable().Copy(sgMaterialTable)

    sgSceneExporter = sg.CreateSceneExporter()
    sgSceneExporter.SetScene(sgScene)
    sgSceneExporter.SetExportFilePath( 'ReductionOutput.fbx' )
    if not sgSceneExporter.RunExport():
        raise Exception('Failed to save ReductionOutput.fbx.')


if __name__ == '__main__':
    sg = simplygon_loader.init_simplygon()
    if sg is not None:

        RunReductionWithShadingNetworks(sg)

    sg = None
    gc.collect()