Example using 3DdataMaster

In the following example (located in $OIVHOME/src/MeshViz/Mentor), we will use a 2D Cartesian mesh, do a solid contouring on it, and add a legend to it. Notice the following steps:

• Mesh initialization from a file
• Definition of the color mapping
• Definition of an isovalue list
• Creation of the legend node (in a default view, the SoCamera node is after it in the scene graph, so the legend will not be affected by camera manipulations you can do through the plane viewer).
• Creation of contouring node, setting the valuesIndex field and the zValuesIndex field to achieve a “3D” visualization.

Example : A 2D Cartesian mesh and its legend

// tutorialMesh03.cxx
... 
void
read_mesh( int* nx, float*& x, int* ny, float*& y )
{
  FILE* f;
  int i, j, n;
  float c;
 
  f = fopen( "mesh2D.geo", "r" );
  if ( f == NULL )
    exit( -1 );
  fscanf( f, "%d%d", nx, ny );
  x = ( float* )malloc( nx * ny * sizeof( float ) );
  y = ( float* )malloc( nx * ny * sizeof( float ) );
  for ( i = 0, n = 0; i < *nx; i++ )
  {
    fscanf( f, "%f", &c );
    for ( j = 0; j < *ny; j++, n++ )
      x[n] = c;
  }
  for ( j = 0; j < *ny; j++ )
  {
    n = j;
    fscanf( f, "%f", &c );
    for ( i = 0; i < *nx; i++, n += *ny )
      y[n] = c;
  }
}
 
void
read_val( int nv, float*\* val, float* vmin, float* vmax )
{
  FILE* f;
  float c;
 
  f = fopen( "mesh2D.dat", "r" );
  if ( f == NULL )
    exit( -1 );
 
  *vmin = 1E30;
  *vmax = -1E30;
  float* v = ( float* )malloc( nv * sizeof( float ) );
  for ( int i = 0; i < nv; i++ )
  {
    fscanf( f, "%f", &c );
    v[i] = c;
    if (\* vmin > c )
      *vmin = c;
    if (\* vmax < c )
      *vmax = c;
  }
 
  *val = v;
}
 
int
main( int, char*\* argv )
{
  // Initialize Inventor and Xt
  Widget myWindow = SoXt::init( argv[0] );
  if ( myWindow == NULL )
    exit( 1 );
 
  // Initialize the new nodes class
  PoMeshViz::init();
 
  // Read back from file mesh data and geometry
  int numX, numY;
  float *xm,\*ym,\*vm, vmin, vmax;
  read_mesh( &numX, xm, &numY, ym );
  read_val( numX\* numY, &vm, &vmin, &vmax );
 
  // Define data mapping
  SbColor colors[5] = { SbColor( 0, 0, 1 ), SbColor( 0, 1, 1 ), SbColor( 0, 1, 0 ), SbColor( 1, 1, 0 ), SbColor( 1, 0, 0 ) };
  float val[5];
  val[0] = vmin;
  for ( int i = 1; i < 5; i++ )
    val[i] = val[i - 1] + ( vmax - vmin ) / 4.;
  PoNonLinearDataMapping2* myDataMapping = New PoNonLinearDataMapping2;
  myDataMapping->type = PoNonLinearDataMapping2::LINEAR_PER_LEVEL;
  myDataMapping->value.setValues( 0, 5, val );
  myDataMapping->color.setValues( 0, 5, colors );
 
  // Define the list of isovalues
  PoIsovaluesList* myIsovaluesList = new PoIsovaluesList;
 
  // Initialize the mesh
  myIsovaluesList->setRegularIsoList( vmin, vmax, 16 );
  PoCartesianGrid2D* mesh = new PoCartesianGrid2D;
  mesh->setGeometry( numX, numY, xm, ym );
  mesh->addvalueSet( 0, vm );
 
  // Create legend node
  PoNonLinearValueLegend1* myLegend = new PoNonLinearValueLegend1( SbVec2f( -1, 1 ), SbVec2f( -.5, -.5 ) );
  myLegend->set( "backgroundApp.material", "diffuseColor .4 .4 .4" );
  SoAnnotation* legendAnnot = new SoAnnotation;
  legendAnnot->addChild( myLegend );
  // Create the solid contour visualization node.
  PoMeshFilled* myfill = new PoMeshFilled;
  myFill->valuesIndex.setValue( 0 );
  myFill->zValuesIndex.setValue( 0 );
  myFill->coloringType = PoMesh::COLOR_CONTOURING;
 
  SoPerspectiveCamera* myCamera = new SoPerspectiveCamera;
 
  // Create the root of our scene graph
  SoSeparator* root = new SoSeparator;
  root->ref();
  root->addChild( mesh );
  root->addChild( myIsovaluesList );
  root->addChild( myDataMapping );
  root->addChild( legendAnnot );
  root->addChild( myCamera );
  root->addChild( myFill );
 
  SoXtExaminerViewer* viewer = new SoXtExaminerViewer( myWindow );
  viewer->setSceneGraph( root );
  viewer->setBackgroundColor( SbColor( 1., 1., 1. ) );
  viewer->show();
 
  SoXt::show( myWindow );
  SoXt::mainLoop();
  return 0;
}