USD Write Sample

//start_of_mainusdmeshwritemain
 
//! \brief Sample 1: writes a cube and a cylinder mesh in a two-node hierarchy into a USD file
Dtk_ErrorStatus UsdwThreeMeshes( const Dtk_string& inOutputFileName )
{ // SAMPLE 1
     Dtk_MeshPtr cubeMesh, cylinderMesh, wireMesh;
     Dtk_bool unusedIsNew; // not needed for this sample
 
     // Create geometry
     cubeMesh = sampleWriter::CreateMeshCube();
     cylinderMesh = sampleWriter::CreateMeshCylinder( 30 );
     wireMesh = sampleWriter::CreateMeshWire();
 
     DtkErrorStatus err = dtkNoError;
     // Initialise the writer; binary file with .usd extension
     WriterOptions options;
     Dtk_UsdWriter usdWriter( inOutputFileName, err, options );
     if( err != dtkNoError )
          return err;
 
     // Create the root Xform prim
     usdWriter.OpenInstance( "RootNode", -1, unusedIsNew );
 
     // Add a child prim for the cube.
     usdWriter.OpenInstance( "Cube", -1, unusedIsNew );
     usdWriter.WriteMesh( cubeMesh );
     usdWriter.CloseLastInstance();
 
     // Add a child prim for the cylinder
     usdWriter.OpenInstance( "Cylinder", -1, unusedIsNew );
     usdWriter.WriteMesh( cylinderMesh );
     usdWriter.CloseLastInstance();
 
     // Add a child prim for the wire
     usdWriter.OpenInstance( "Wire", -1, unusedIsNew );
     usdWriter.WriteMesh( wireMesh );
     usdWriter.CloseLastInstance();
 
     // Close the root prim — triggers the actual file write
     usdWriter.CloseLastInstance();
 
     return dtkNoError;
}
 
 
//! \brief Sample 2: writes 10 re-instanced cubes into a USD file, demonstrating USD referencing.
//!
//! The first OpenInstance() call with prototype ID 1 creates the real Xform+Mesh prim
//! All subsequent calls with the same prototype ID emit a USD reference to that prim,
//! each with its own transform, avoiding geometry duplication.
Dtk_ErrorStatus UsdwInstances( const Dtk_string& inOutputFileName )
{ // SAMPLE 2
     Dtk_MeshPtr cubeMesh = sampleWriter::CreateMeshCube();
     Dtk_transfo cubeTransfo;
     Dtk_bool isNewNode; // true only for the first occurrence of a given protoID
 
     DtkErrorStatus err = dtkNoError;
     // Initialise the writer
     WriterOptions options;
     Dtk_UsdWriter usdWriter( inOutputFileName, err, options );
     if( err != dtkNoError )
          return err;
 
     Dtk_bool unusedIsNew;
     usdWriter.OpenInstance( "RootNode", -1, unusedIsNew );
 
     for( int instanceIdx = 0; instanceIdx < 10; ++instanceIdx )
     {
          // All calls share prototype ID 1 so they reference the same prim
          usdWriter.OpenInstance( "Cube", 1, isNewNode, cubeTransfo );
          if( isNewNode )
          {
               usdWriter.WriteMesh( cubeMesh );
          }
          usdWriter.CloseLastInstance();
 
          // Shift the transform for the next instance along the X axis.
          cubeTransfo.addTranslate( Dtk_dir( 10, 0, 0 ) );
     }
 
     usdWriter.CloseLastInstance();
     return dtkNoError;
}
 
 
DtkErrorStatus UsdWriteSample( const Dtk_string& inResultDirectory )
{
     Dtk_string outputDirectory, fileName;
     std::cout << std::endl << "----------------------------------------------" << std::endl;
 
     // Choose the output directory and create it if necessary
     outputDirectory = inResultDirectory + L"Usd/";
     outputDirectory.FixPathSeparator();
     outputDirectory.mkdir();
 
     std::cout << "Usd Write start" << std::endl;
 
     std::cout << "sample 1" << std::endl;
     // Sample 1: simple three-mesh hierarchy.
     fileName = outputDirectory + L"threemeshes.usd";
     Dtk_ErrorStatus errorStatus = UsdwThreeMeshes( fileName );
     if( errorStatus == dtkNoError )
          std::cout << "=> " << fileName.c_str() << std::endl;
     else
          std::cout << "error : " << dtkTypeError( errorStatus ).c_str() << std::endl;
 
     std::cout << "sample 2" << std::endl;
     // Sample 2: geometry instancing with USD references
     fileName = outputDirectory + L"instances.usd";
     errorStatus = UsdwInstances( fileName );
     if( errorStatus == dtkNoError )
          std::cout << "=> " << fileName.c_str() << std::endl;
     else
          std::cout << "error : " << dtkTypeError( errorStatus ).c_str() << std::endl;
 
     std::cout << "Usd Write end" << std::endl;
 
     return errorStatus;
}
 
//end_of_mainusdmeshwritemain