MeshAttributeData class
Mesh attribute data
Associates a typed data view with a name, vertex format and other mesh attribute properties, which can be subsequently put into a MeshData instance, for example with meshtools.interleave(). The data view can be either one-dimensional, for example a NumPy array:
data = np.array([(-0.5, 0.0), (+0.5, 0.0), ( 0.0, 0.5)], dtype='2f') positions = trade.MeshAttributeData( trade.MeshAttribute.POSITION, VertexFormat.VECTOR2, data)
Or it can be two-dimensional, for example by expanding a flat array into a list of two-component vectors:
data = array.array('f', [-0.5, 0.0, +0.5, 0.0, 0.0, 0.5]) positions = trade.MeshAttributeData( trade.MeshAttribute.POSITION, VertexFormat.VECTOR2, containers.StridedArrayView1D(data).expanded(0, (3, 2)))
Memory ownership and reference counting
On initialization, the instance inherits the
containers.StridedArrayView1D.owner
object, storing it in the owner field, meaning that calling
del on the original data will not invalidate the instance.
Data access
Similarly to MeshData, the class makes use of Python’s dynamic
nature and provides direct access to attribute data in their concrete type
via data. However, the MeshAttributeData is considered a low
level API and thus a containers.StridedArrayView2D
is returned always, even for non-array attributes. The returned view
inherits the owner and element access coverts to a type
corresponding to a particular VertexFormat. For example, extracting
the data from the positions attribute created above:
>>> view = positions.data >>> view.owner is data True >>> view[1][0] Vector(0.5, 0)
Special methods
- def __init__(self, name: MeshAttribute, format: VertexFormat, data: corrade.containers.StridedArrayView1D, *, array_size: int = 0, morph_target_id: int = -1) -> None
- Construct from a 1D view
- def __init__(self, name: MeshAttribute, format: VertexFormat, data: corrade.containers.StridedArrayView2D, *, array_size: int = 0, morph_target_id: int = -1) -> None
- Construct from a 2D view
Properties
- array_size: int get
- Attribute array size
- data: corrade.containers.StridedArrayView2D get
- Attribute data
- format: VertexFormat get
- Attribute format
- morph_target_id: int get
- Morph target ID
- name: MeshAttribute get
- Attribute name
- owner: object get
- Memory owner
Method documentation
def magnum.
Construct from a 1D view
| Exceptions | |
|---|---|
| AssertionError | If format is not valid for name |
| AssertionError | If data size doesn’t fit into 32 bits |
| AssertionError | If data stride doesn’t fit into 16 bits |
| AssertionError | If data format size is smaller than size of
format at given array_size |
| AssertionError | If morph_target_id is less than -1 or
greater than 127 |
| AssertionError | If morph_target_id is not allowed for name |
| AssertionError | If array_size is zero and name is an array
attribute |
| AssertionError | If array_size is non-zero and name can’t
be an array attribute |
def magnum.
Construct from a 2D view
| Exceptions | |
|---|---|
| AssertionError | If format is not valid for name |
| AssertionError | If data first dimension size doesn’t fit into
32 bits |
| AssertionError | If data first dimension stride doesn’t fit into
16 bits |
| AssertionError | If data second dimension isn’t contiguous |
| AssertionError | If data format size times second dimension size
is smaller than size of format at given array_size |
| AssertionError | If morph_target_id is less than -1 or
greater than 127 |
| AssertionError | If morph_target_id is not allowed for name |
| AssertionError | If array_size is zero and name is an array
attribute |
| AssertionError | If array_size is non-zero and name can’t
be an array attribute |
Property documentation
magnum.
Attribute data
| Exceptions | |
|---|---|
| NotImplementedError | If format is a half-float or matrix type |
A 2D view is returned always, non-array attributes have the second
dimension size 1.