CustomDataTag Manual
A CustomDataTag is a BaseTag that stores custom point or polygon data. It is a generalized tag type to store mesh-based data like normals, UVs, vertex colors etc. It can replace dedicated tags like NormalTag , UVWTag or VertexColorTag .
A CustomDataTag gives access to data and functionality implemented with maxon::MeshAttribute , maxon::MeshAttributeClassInterface , maxon::CustomDataTagClassInterface and maxon::CustomDataTagDisplayInterface (见 Mesh Attributes Interfaces ).
A CustomDataTag object is created using the usual tools and the specific data type ID:
// create tag BaseTag * const tag = CustomDataTag::Alloc (ID_VERTEXSCALARTAG); if (tag == nullptr ) return maxon::OutOfMemoryError( MAXON_SOURCE_LOCATION );
// insert tag polygonObject-> InsertTag (tag);
// init tag CustomDataTag * const customDataTag = static_cast< CustomDataTag * > (tag); customDataTag-> InitData () iferr_return ; customDataTag-> SetMode ( CUSTOMDATATAG_MODE::VERTEX );
The data type stored in a given CustomDataTag is obtained with:
A CustomDataTag can stores either point data ( CUSTOMDATATAG_MODE::VERTEX ) or polygon point data ( CUSTOMDATATAG_MODE::POLYVERTEX ):
The number of stored elements is returned with:
The stored vertex data is accessed with these functions:
// get number of components const Int count = customDataTag-> GetComponentCount ();
// for each component, set a random value maxon::LinearCongruentialRandom<maxon::Float32> random; for ( Int32 i = 0; i < count; ++i) { Float value = random. Get01 (); customDataTag-> SetVertexData < Float >(i, std::move(value)); }
The stored polygon data is accessed with:
// get number for components const Int count = customDataTag-> GetComponentCount ();
// for each polygon set random values maxon::LinearCongruentialRandom<maxon::Float32> random; for ( Int32 i = 0; i < count; ++i) { // create polygon value maxon::Float value = random. Get01 ();
// set each point of the given polygon to that value for ( Int32 polyvertexIndex = 0; polyvertexIndex < 4; ++polyvertexIndex) { customDataTag-> SetPolyVertexData < maxon::Float >(i, polyvertexIndex, std::move(value)); } }
The maxon::PolyData template class stores data for either a triangle or quad:
// for each polygon of the object set the polygon vertex colors for ( Int32 polygonIndex = 0; polygonIndex < polyCount; ++polygonIndex) { // get polygon vertex data for the given polygon maxon::PolyData<Float> polygonData = customDataTag-> GetPolygonData < Float >(polygonIndex);
// set the color of each polygon vertex // the CustomDataTag always stores four point values for each polygon for ( Int32 pointIndex = 0; pointIndex < 4; ++pointIndex) { // get polygon vertex color // float value dispalyed in the red channel Color32 color { 0.0 }; color.r = maxon::Float32 (polygonData[pointIndex]);
// store polygon vertex color // "cds" is the ControlDisplayStruct argument const maxon::Int colorIndex = 4 * polygonIndex + pointIndex; cds.vertex_color[colorIndex] = static_cast< Color32 > (color); } }
// show polygon vertex color cds.perPolygonVertexColor = true ;
