init(data:semantic:vectorCount:usesFloatComponents:componentsPerVector:bytesPerComponent:dataOffset:dataStride:)
Creates a geometry source from the specified data and options.
Declaration
convenience init(data: Data, semantic: SCNGeometrySource.Semantic, vectorCount: Int, usesFloatComponents floatComponents: Bool, componentsPerVector: Int, bytesPerComponent: Int, dataOffset offset: Int, dataStride stride: Int)Parameters
- data:
The data for the geometry source.
- semantic:
The semantic value (or attribute) that the geometry source describes for each vertex. See Geometry Semantic Identifiers for available values.
- vectorCount:
The number of geometry source vectors.
- floatComponents:
A Boolean value that indicates whether vector components are floating-point values. Specify True for floating-point values, or False for integer values.
- componentsPerVector:
The number of scalar components in each vector.
- bytesPerComponent:
The size, in bytes, of each vector component.
- offset:
The offset, in bytes, from the beginning of the data to the first vector component to be used in the geometry source.
- stride:
The number of bytes from each vector to the next in the data.
Return Value
A new geometry source object.
Discussion
A geometry source’s data is an array of vectors, each of which represents a particular attribute (or semantic) of a vertex in the geometry. The other parameters determine how SceneKit interprets this data. For example, an array of vertex positions may have three 32-bit floating-point components per vector, but an array of texture coordinates may have two 8-bit integer coponents per vector. You can use the offset and stride parameters together to interleave data for multiple geometry sources in the same array, improving rendering performance. See SCNGeometrySource for details.
To create a custom SCNGeometry object from the geometry source, use the init(sources:elements:) method.