rj-action-library/Runtime/Procedural/Mesh/MeshExtractor.cs

using System.Collections;
using System.Collections.Generic;
using Godot;
using System;



namespace Rokojori
{
  public class MeshExtractor
  {
    public static bool CanExtract( Node3D n ) 
    {
      if ( n is MeshInstance3D mi )
      {
        return mi.Mesh != null;
      }

      if ( n is MultiMeshInstance3D mmi )
      {
        var mm = mmi.Multimesh;
        return mm.Mesh != null;
      }

      return false;
    }
    
    public static List<Transformable<SingleMaterialMesh>> ExtractMeshesInHierarchy( Node n, List<Transformable<SingleMaterialMesh>> list = null ) 
    {
      list = list == null ? new List<Transformable<SingleMaterialMesh>>() : list;

      Nodes.ForEach<Node3D>( n, 

        n => 
        {
          ExtractMeshes( n, list );
        }
      );

      return list;
    }

    public static List<Transformable<SingleMaterialMesh>> ExtractMeshes( Node n, List<Transformable<SingleMaterialMesh>> list = null ) 
    {
      list = list == null ? new List<Transformable<SingleMaterialMesh>>() : list;

      
      if ( n is MeshInstance3D mi )
      {       
        var mesh = mi.Mesh;

        var singleMaterialMesh = new SingleMaterialMesh( mesh );

        if ( mi.GetSurfaceOverrideMaterialCount() > 0 && mi.GetSurfaceOverrideMaterial( 0 ) != null )
        {
          singleMaterialMesh.material = mi.GetSurfaceOverrideMaterial( 0 );
        }
        
        if ( mi.MaterialOverride != null )
        {
          singleMaterialMesh.material = mi.MaterialOverride;
        }

        list.Add( new Transformable<SingleMaterialMesh>( singleMaterialMesh, mi.GlobalTransform ) );
      }

      if ( n is MultiMeshInstance3D mmi )
      {
        var mm = mmi.Multimesh;
        
        for ( var j = 0; j < mm.InstanceCount; j++ )
        {
          var mesh = mm.Mesh;
          var transform = mm.GetInstanceTransform( j );

          var singleMaterialMesh = new SingleMaterialMesh( mesh );

          if ( mmi.MaterialOverride != null )
          {
            singleMaterialMesh.material = mmi.MaterialOverride;
          }

          list.Add( new Transformable<SingleMaterialMesh>( singleMaterialMesh, transform ) );
        }
      }

      return list;
    }

    public static List<Transformable<MeshSurface>> ExtractSurfacesInHierarchy( Node n, List<Transformable<MeshSurface>> list = null ) 
    {
      list = list == null ? new List<Transformable<MeshSurface>>() : list;

      Nodes.ForEach<Node3D>( n, 

        n => 
        {
          ExtractSurfaces( n, list );
        }
      );

      return list;
    }

    public static List<Transformable<MeshSurface>> ExtractSurfaces( Node n, List<Transformable<MeshSurface>> list = null ) 
    {
      list = list == null ? new List<Transformable<MeshSurface>>() : list;

      
      if ( n is MeshInstance3D mi )
      {       
        var mesh = mi.Mesh;

        for ( int i = 0; i < mesh.GetSurfaceCount(); i++ )
        {
          var surface = new MeshSurface( mesh, mesh.SurfaceGetMaterial( i ), i );

          if ( i < mi.GetSurfaceOverrideMaterialCount() &&  mi.GetSurfaceOverrideMaterial( i ) != null )
          {
            surface.material = mi.GetSurfaceOverrideMaterial( i );
          }

          if ( mi.MaterialOverride != null )
          {
            surface.material = mi.MaterialOverride;
          }

          list.Add( new Transformable<MeshSurface>( surface, mi.GlobalTransform ) );
        }
      }

      if ( n is MultiMeshInstance3D mmi )
      {
        var mm = mmi.Multimesh;
        
        for ( var j = 0; j < mm.InstanceCount; j++ )
        {
          var mesh = mm.Mesh;
          var transform = mm.GetInstanceTransform( j );

          for ( int i = 0; i < mesh.GetSurfaceCount(); i++ )
          {
            var surface = new MeshSurface( mesh, mesh.SurfaceGetMaterial( i ), i );

            if ( mmi.MaterialOverride != null )
            {
              surface.material = mmi.MaterialOverride;
            }

            list.Add( new Transformable<MeshSurface>( surface, transform ) );
          }
        }
      }

      return list;
    }

  }

}