# ParametricCurveCollection¶

class ParametricCurveCollection

Bases: ReferenceCount

This is a set of zero or more ParametricCurves, which may or may not be related. If they are related, the set should contain no more than one XYZ curve, no more than one HPR curve, and zero or more Timewarp curves, which can then be evaluated as a unit to return a single transformation matrix for a given unit of time.

Inheritance diagram

ParametricCurveCollection(void)
ParametricCurveCollection(ParametricCurveCollection const&) = default
void add_curve(ParametricCurve *curve)
void add_curve(ParametricCurve *curve, int index)

Adds a new ParametricCurve to the collection at the indicated index.

Adds a new ParametricCurve to the collection.

int add_curves(PandaNode *node)

Adds all the curves found in the scene graph rooted at the given node. Returns the number of curves found.

bool adjust_hpr(PN_stdfloat t, PN_stdfloat h, PN_stdfloat p, PN_stdfloat r)
bool adjust_hpr(PN_stdfloat t, LVecBase3 const &xyz)

Adjust the HPR curve at the indicated time to the new value. The curve shape will change correspondingly. Returns true if successful, false if unable to make the adjustment for some reason.

bool adjust_xyz(PN_stdfloat t, PN_stdfloat x, PN_stdfloat y, PN_stdfloat z)
bool adjust_xyz(PN_stdfloat t, LVecBase3 const &xyz)

Adjust the XYZ curve at the indicated time to the new value. The curve shape will change correspondingly. Returns true if successful, false if unable to make the adjustment for some reason.

void clear(void)

Removes all ParametricCurves from the collection.

void clear_timewarps(void)

Removes all the timewarp curves from the collection.

bool evaluate(PN_stdfloat t, LVecBase3 &xyz, LVecBase3 &hpr) const
bool evaluate(PN_stdfloat t, LMatrix4 &result, CoordinateSystem cs = ::CS_default) const

Computes the position and rotation represented by the first XYZ and HPR curves in the collection at the given point t, after t has been modified by all the timewarp curves in the collection applied in sequence, from back to front.

Returns true if the point is valid (i.e. t is within the bounds indicated by all the timewarp curves and within the bounds of the curves themselves), or false otherwise.

Computes the transform matrix representing translation to the position indicated by the first XYZ curve in the collection and the rotation indicated by the first HPR curve in the collection, after t has been modified by all the timewarp curves in the collection applied in sequence, from back to front.

Returns true if the point is valid (i.e. t is within the bounds indicated by all the timewarp curves and within the bounds of the curves themselves), or false otherwise.

bool evaluate_hpr(PN_stdfloat t, LVecBase3 &hpr) const

Computes only the HPR part of the curves. See evaluate().

PN_stdfloat evaluate_t(PN_stdfloat t) const

Determines the value of t that should be passed to the XYZ and HPR curves, after applying the given value of t to all the timewarps. Return -1.0f if the value of t exceeds one of the timewarps’ ranges.

bool evaluate_xyz(PN_stdfloat t, LVecBase3 &xyz) const

Computes only the XYZ part of the curves. See evaluate().

void face_forward(PN_stdfloat segments_per_unit)

Discards the existing HPR curve and generates a new one that looks in the direction of travel along the XYZ curve, based on the XYZ curve’s tangent at each point.

ParametricCurve *get_curve(int index) const

Returns the nth ParametricCurve in the collection.

ParametricCurve *get_default_curve(void) const

If there is an XYZ curve in the collection, returns it; otherwise, returns the first curve whose type is unspecified. Returns NULL if no curve meets the criteria.

ParametricCurve *get_hpr_curve(void) const

Returns the first HPR curve in the collection, if any, or NULL if there are none.

PN_stdfloat get_max_t(void) const

Returns the maximum T value associated with the last curve in the collection. Normally, this will be either the XYZ or HPR curve, or a timewarp curve.

int get_num_curves(void) const

Returns the number of ParametricCurves in the collection.

int get_num_timewarps(void) const

Returns the number of timewarp curves in the collection.

ParametricCurve *get_timewarp_curve(int n) const

Returns the nth timewarp curve in the collection.

ParametricCurve *get_xyz_curve(void) const

Returns the first XYZ curve in the collection, if any, or NULL if there are none.

bool has_curve(ParametricCurve *curve) const

Returns true if the indicated ParametricCurve appears in this collection, false otherwise.

void insert_curve(std::size_t index, ParametricCurve *curve)

Adds a new ParametricCurve to the collection at the indicated index.

void make_even(PN_stdfloat max_t, PN_stdfloat segments_per_unit)

Discards all existing timewarp curves and recomputes a new timewarp curve that maps distance along the curve to parametric time, so that the distance between any two points in parametric time is proportional to the approximate distance of those same two points along the XYZ curve.

segments_per_unit represents the number of segments to take per each unit of parametric time of the original XYZ curve.

The new timewarp curve (and thus, the apparent range of the collection) will range from 0 to max_t.

void output(std::ostream &out) const

Writes a brief one-line description of the ParametricCurveCollection to the indicated output stream.

bool recompute(void)

Ensures all the curves are freshly computed and up-to-date. Returns true if everything is valid, false if at least one curve is incorrect.

bool remove_curve(ParametricCurve *curve)
void remove_curve(std::size_t index)

Removes the indicated ParametricCurve from the collection. Returns true if the curve was removed, false if it was not a member of the collection.

Removes the indicated ParametricCurve from the collection, by its index number.

void reset_max_t(PN_stdfloat max_t)

Adjusts the apparent length of the curve by applying a new timewarp that maps the range [0..max_t] to the range [0..get_max_t()]. After this call, the curve collection will contain one more timewarp curve, and get_max_t() will return the given max_t value.

void set_curve(std::size_t index, ParametricCurve *curve)

Replaces the indicated ParametricCurve from the collection, by its index number.

bool stitch(ParametricCurveCollection const *a, ParametricCurveCollection const *b)

Regenerates this curve as one long curve: the first curve connected end-to- end with the second one. Either a or b may be the same as ‘this’. This will lose any timewarps on the input curves.

Returns true if successful, false on failure.

void write(std::ostream &out, int indent_level = 0) const

Writes a complete multi-line description of the ParametricCurveCollection to the indicated output stream.

bool write_egg(Filename filename, CoordinateSystem cs = ::CS_default)
bool write_egg(std::ostream &out, Filename const &filename, CoordinateSystem cs)

Writes an egg description of all the nurbs curves in the collection to the specified output file. Returns true if the file is successfully written.

Writes an egg description of all the nurbs curves in the collection to the specified output stream. Returns true if the file is successfully written.