About

The maxon::MeshAttributeClassInterface allows to implement a new mesh attribute. Such a mesh attribute describes any kind of data assigned to the points of a mesh or the polygon points of a mesh. Such data could be normal data, UV coordinates, vertex colors etc.

The data is stored in a CustomDataTag that also gives access to the data assigned to a specific polygon object. See CustomDataTag Manual.

The behaviour of this CustomDataTag is defined by implementing maxon::CustomDataTagClassInterface and maxon::CustomDataTagDisplayInterface.

MeshAttribute

A maxon::MeshAttribute represents the data assigned to a point or polygon point. It can be accessed from the CustomDataTag:

CustomDataTag::GetVertexAttribute(): Returns the maxon::MeshAttribute at the given index.
CustomDataTag::SetVertexAttribute(): Sets the maxon::MeshAttribute at the given index.
CustomDataTag::GetPolyVertexAttribute(): Returns the maxon::MeshAttribute for the given polygon and point index.
CustomDataTag::SetPolyVertexAttribute(): Sets the maxon::MeshAttribute for the given polygon and point index.

See CustomDataTag Manual.

Macros

A new mesh attribute is introduced by using the macro MAXON_MESHATTRIBUTE: The created data type name is the given name plus "_MESHATTRIBUTE"

// This example declares a new mesh attribute based on a Float value.
 
// declare mesh attribute
MAXON_MESHATTRIBUTE(maxon::Float, VERTEXSCALAR);
// declare corresponding data type
MAXON_DATATYPE(VERTEXSCALAR_MESHATTRIBUTE, "net.maxonexample.meshattribute.scalar");

Note: The data type must be registered as usual. See MAXON Data Type.

MeshAttributeClassInterface

An implementation of maxon::MeshAttributeClassInterface defines how the custom mesh data should be interpolated. This allows to automatically calculate correct values for new points or polygons that are created in various modeling operations.

An implementation must be registered at CustomDataTagDisplayClasses.

The data type handled by this attribute is accessed with:

maxon::MeshAttributeClassInterface::GetDataType(): Returns the maxon::DataType.
maxon::MeshAttributeClassInterface::GetDefaultValue(): Returns the default value for this attribute.

The interpolation of attribute values is defined with:

maxon::MeshAttributeClassInterface::InterpolateLinear(): Performs a linear interpolation between the given values.
maxon::MeshAttributeClassInterface::InterpolateInOutline(): Performs an interpolation in the outline using the given weights.

Further mathematical operations on the attribute values are defined with:

maxon::MeshAttributeClassInterface::AtrLessThen(): Returns true if a value is less then the other value.
maxon::MeshAttributeClassInterface::AtrIsEqual(): Returns true if the given values are equal.
maxon::MeshAttributeClassInterface::AtrAdd(): Adds the two given values.
maxon::MeshAttributeClassInterface::AtrSubstract(): Subtracts a value from the other.
maxon::MeshAttributeClassInterface::AtrMultiply(): Multiplies the given values.
maxon::MeshAttributeClassInterface::AtrDivide(): Divides a value by the other value.
maxon::MeshAttributeClassInterface::AtrToString(): Returns a maxon::String representation of the given value.

Note: Multiplication and division has to be implemented for both the operation on the data type itself and on a maxon::Float value.

CustomDataTagClassInterface

An implementation of maxon::CustomDataTagClassInterface defines how the CustomDataTag that stores the custom data should behave. Such an implementation can also be easily be written with the MAXON_CUSTOMDATATAG macro. maxon::CustomDataTagClassInterface is based on maxon::MeshAttributeClassInterface.

maxon::CustomDataTagClassInterface::GetTagPluginId(): Returns the ID of the tag plugin.
maxon::CustomDataTagClassInterface::GetTagPluginName(): Returns the name of the tag plugin.
maxon::CustomDataTagClassInterface::GetResourceId(): Returns the resource ID.
maxon::CustomDataTagClassInterface::GetTagPluginLevel(): Returns the version of the plugin.
maxon::CustomDataTagClassInterface::GetDisplayClassId(): Returns the display class. See maxon::CustomDataTagDisplayInterface below.
maxon::CustomDataTagClassInterface::IsSdsCompatible(): Returns true if the data is compatible with the SDS object.
maxon::CustomDataTagClassInterface::Read(): Reads the data from the given HyperFile.
maxon::CustomDataTagClassInterface::Write(): Writes the data to the given HyperFile.
maxon::CustomDataTagClassInterface::GetIcon(): Returns the icon ID for the tag and the given mode.
maxon::CustomDataTagClassInterface::GetDefaultResourceId(): Returns the standard resource ID if no custom UI is provided.
maxon::CustomDataTagClassInterface::GetTagPluginFlags(): Returns the tag flags.

CustomDataTagDisplayInterface

An implementation of maxon::CustomDataTagDisplayInterface is optional. It defines how an internal scene hook should draw the attribute data in the viewport. An implementation must be registered at maxon::CustomDataTagDisplayClasses.

maxon::CustomDataTagDisplayInterface::Init(): Initializes the class after creation.
maxon::CustomDataTagDisplayInterface::Draw(): Draws the data of the given CustomDataTag in the viewport. Corresponds to SceneHookData::Draw().
maxon::CustomDataTagDisplayInterface::InitDisplayControl(): Corresponds to SceneHookData::InitDisplayControl().
maxon::CustomDataTagDisplayInterface::DisplayControl(): Corresponds to SceneHookData::DisplayControl().
maxon::CustomDataTagDisplayInterface::FreeDisplayControl(): Corresponds to SceneHookData::FreeDisplayControl().
maxon::CustomDataTagDisplayInterface::Reset(): Resets any local data before destroying the instance.

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