NurbsSurfaceEvaluator

from panda3d.core import NurbsSurfaceEvaluator

class NurbsSurfaceEvaluator

Bases:

Bases: ReferenceCount

This class is an abstraction for evaluating NURBS surfaces. It accepts an array of vertices, each of which may be in a different coordinate space (as defined by a NodePath), as well as an optional knot vector.

Inheritance diagram

__init__()

__init__(param0: NurbsSurfaceEvaluator)

evaluate(rel_to: NodePath) → NurbsSurfaceResult: Returns a NurbsSurfaceResult object that represents the result of applying the knots to all of the current values of the vertices, transformed into the indicated coordinate space.

get_extended_vertex(ui: int, vi: int, d: int) → float: Returns an n-dimensional vertex value. See set_extended_vertex(). This returns the value set for the indicated dimension, or 0.0 if nothing has been set.

get_num_u_knots() → int: Returns the number of knot values in the surface in the U direction. This is based on the number of vertices and the order.

get_num_u_segments() → int: Returns the number of piecewise continuous segments in the surface in the U direction. This is based on the knot vector.

get_num_u_vertices() → int: Returns the number of control vertices in the U direction on the surface. This is the number passed to the last call to reset().

get_num_v_knots() → int: Returns the number of knot values in the surface in the V direction. This is based on the number of vertices and the order.

get_num_v_segments() → int: Returns the number of piecewise continuous segments in the surface in the V direction. This is based on the knot vector.

get_num_v_vertices() → int: Returns the number of control vertices in the V direction on the surface. This is the number passed to the last call to reset().

get_u_knot(i: int) → float: Returns the value of the nth knot.

get_u_knots() → list

get_u_order() → int: Returns the order of the surface in the U direction as set by a previous call to set_u_order().

get_v_knot(i: int) → float: Returns the value of the nth knot.

get_v_knots() → list

get_v_order() → int: Returns the order of the surface in the V direction as set by a previous call to set_v_order().

get_vertex(ui: int, vi: int) → LVecBase4: Returns the nth control vertex of the surface, relative to its indicated coordinate space.

get_vertex(ui: int, vi: int, rel_to: NodePath) → LVecBase4: Returns the nth control vertex of the surface, relative to the given coordinate space.

get_vertex_space(ui: int, vi: int, rel_to: NodePath) → NodePath: Returns the coordinate space of the nth control vertex of the surface, expressed as a NodePath.

normalize_u_knots(): Normalizes the knot sequence so that the parametric range of the surface in the U direction is 0 .. 1.

normalize_v_knots(): Normalizes the knot sequence so that the parametric range of the surface in the U direction is 0 .. 1.

output(out: ostream)

reset(num_u_vertices: int, num_v_vertices: int): Resets all the vertices and knots to their default values, and sets the surface up with the indicated number of vertices. You must then call set_vertex() repeatedly to fill in all of the vertex values appropriately.

set_extended_vertex(ui: int, vi: int, d: int, value: float)

Sets an n-dimensional vertex value. This allows definition of a NURBS surface or surface in a sparse n-dimensional space, typically used for associating additional properties (like color or joint membership) with each vertex of a surface.

The value d is an arbitrary integer value and specifies the dimension of question for this particular vertex. Any number of dimensions may be specified, and they need not be consecutive. If a value for a given dimension is not specified, is it implicitly 0.0.

The value is implicitly scaled by the homogenous weight value–that is, the fourth component of the value passed to set_vertex(). This means the ordinary vertex must be set first, before the extended vertices can be set.

set_extended_vertices(ui: int, vi: int, d: int, values: PN_stdfloat_const_[], num_values: int): Simultaneously sets several extended values in the slots d through (d + num_values - 1) from the num_values elements of the indicated array. This is equivalent to calling set_extended_vertex() num_values times. See set_extended_vertex().

set_u_knot(i: int, knot: float): Sets the value of the nth knot. Each knot value should be greater than or equal to the preceding value. If no knot values are set, a default knot vector is supplied.

set_u_order(u_order: int)

Sets the order of the surface in the U direction. This resets the knot vector to the default knot vector for the number of vertices.

The order must be 1, 2, 3, or 4, and the value is one more than the degree of the surface.

set_v_knot(i: int, knot: float): Sets the value of the nth knot. Each knot value should be greater than or equal to the preceding value. If no knot values are set, a default knot vector is supplied.

set_v_order(v_order: int)

Sets the order of the surface in the V direction. This resets the knot vector to the default knot vector for the number of vertices.

The order must be 1, 2, 3, or 4, and the value is one more than the degree of the surface.

set_vertex(ui: int, vi: int, vertex: LVecBase3, weight: float): Sets the nth control vertex of the surface. This flavor sets the vertex as a 3-d coordinate and a weight; the 3-d coordinate values are implicitly scaled up by the weight factor.

set_vertex(ui: int, vi: int, vertex: LVecBase4): Sets the nth control vertex of the surface, as a vertex in 4-d homogeneous space. In this form, the first three components of the vertex should already have been scaled by the fourth component, which is the homogeneous weight.

set_vertex_space(ui: int, vi: int, space: NodePath)

Sets the coordinate space of the nth control vertex. If this is not specified, or is set to an empty NodePath, the nth control vertex is deemed to be in the coordinate space passed to evaluate().

This specifies the space as a fixed NodePath, which is always the same NodePath. Also see setting the space as a path string, which can specify a different NodePath for different instances of the surface.

set_vertex_space(ui: int, vi: int, space: str)

Sets the coordinate space of the nth control vertex. If this is not specified, or is set to an empty string, the nth control vertex is deemed to be in the coordinate space passed to evaluate().

This specifies the space as a string, which describes the path to find the node relative to the rel_to NodePath when the surface is evaluated.

property u_knots → Sequence[float]

Getter: Returns the value of the nth knot.
Setter: Sets the value of the nth knot. Each knot value should be greater than or equal to the preceding value. If no knot values are set, a default knot vector is supplied.

property u_order → int

Getter

Returns the order of the surface in the U direction as set by a previous call to set_u_order().

Setter

Sets the order of the surface in the U direction. This resets the knot vector to the default knot vector for the number of vertices.

The order must be 1, 2, 3, or 4, and the value is one more than the degree of the surface.

property v_knots → Sequence[float]

Getter: Returns the value of the nth knot.
Setter: Sets the value of the nth knot. Each knot value should be greater than or equal to the preceding value. If no knot values are set, a default knot vector is supplied.

property v_order → int

Getter

Returns the order of the surface in the V direction as set by a previous call to set_v_order().

Setter

Sets the order of the surface in the V direction. This resets the knot vector to the default knot vector for the number of vertices.

The order must be 1, 2, 3, or 4, and the value is one more than the degree of the surface.