def test_flip_error():
transform = CompositeTransform()
with pytest.raises(ValueError, match=r"Expected dim to be 0, 1, or 2"):
transform.flip(-1)
class Transform:
"""
Encapsulate a composite transform operation.
Invoke `.end()` to apply the transform operation and create a mesh with
transformed vertices and faces.
Args:
target (lacecore.Mesh): The mesh on which to operate.
See also:
https://polliwog.readthedocs.io/en/latest/#polliwog.CompositeTransform
"""
def __init__(self, target):
self.target = target
self._transform = CompositeTransform()
self._flip_faces = False
def append_transform(self, forward, reverse=None):
"""
Append an arbitrary transformation, defined by 4x4 forward and reverse
matrices.
Returns:
self
"""
self._transform.append_transform(forward=forward, reverse=reverse)
return self
def uniform_scale(self, factor):
"""
Scale by the given factor.
Args:
factor (float): The scale factor.
Returns:
self
"""
self._transform.uniform_scale(factor=factor)
return self
def non_uniform_scale(self, x_factor, y_factor, z_factor):
"""
Scale along each axis by the given factors.
Args:
x_factor (flot): The scale factor along the `x` axis.
y_factor (flot): The scale factor along the `y` axis.
z_factor (flot): The scale factor along the `z` axis.
Returns:
self
"""
self._transform.non_uniform_scale(x_factor, y_factor, z_factor)
return self
def convert_units(self, from_units, to_units):
"""
Convert the mesh from one set of units to another.
Supports the length units from Ounce:
https://github.com/lace/ounce/blob/master/ounce/core.py#L26
Returns:
self
"""
self._transform.convert_units(from_units=from_units, to_units=to_units)
return self
def translate(self, translation):
"""
Translate by the vector provided.
Args:
vector (np.arraylike): A 3x1 vector.
Returns:
self
"""
self._transform.translate(translation=translation)
return self
def reorient(self, up, look):
"""
Reorient using up and look.
Returns:
self
"""
self._transform.reorient(up=up, look=look)
return self
def rotate(self, rotation):
"""
Rotate by the given 3x3 rotation matrix or a Rodrigues vector.
Returns:
self
"""
self._transform.rotate(rotation=rotation)
return self
def flip_faces(self):
"""
Flip the orientation of the faces.
Returns:
self
"""
self._flip_faces = not self._flip_faces
return self
def flip(self, dim, preserve_vertex_centroid=False):
"""
Flip about the given axis.
Args:
dim (int): The axis to flip around: 0 for `x`, 1 for `y`, 2 for `z`.
preserve_vertex_centroid (bool): When `True`, translate after
flipping to preserve the original vertex centroid.
Returns:
self
"""
if dim not in (0, 1, 2):
raise ValueError("Expected dim to be 0, 1, or 2")
self._transform.flip(dim=dim)
self.flip_faces()
if preserve_vertex_centroid:
translation = np.zeros(3)
# `2 * vertex_centroid[dim]` takes it all the way back to the other
# side of the axis.
translation[dim] = 2 * self.target.vertex_centroid[dim]
self._transform.translate(translation=translation)
return self
def end(self, reverse=False):
"""
Apply the requested transformation and return a new mesh.
Args:
reverse (bool): When `True` applies the selected transformations
in reverse.
Returns:
lacecore.Mesh: The transformed mesh.
"""
from .._mesh import Mesh # Avoid circular import.
return Mesh(
v=self._transform(self.target.v),
f=flip_faces(self.target.f) if self._flip_faces else self.target.f,
face_groups=self.target.face_groups,
)