#include <skin_spl.hxx>
Public Member Functions | |
| int | accurate_derivs (SPApar_box const &area=*(SPApar_box *) NULL_REF) const |
| Calculates the derivatives within the given parameter box. | |
| void | add_path_data (int no_curves, curve **curves) |
| Adds the path data to the skin_spl_sur object. | |
| void | add_ref () |
| Uses count manipulation. | |
| void | clear_trans () |
| Clears any references to this object using transformation lists, before incompatible changes. | |
| logical | closed_u () const |
| Determines if the surface is closed, smoothly or not, in the u-parameter direction. | |
| logical | closed_v () const |
| Determines if the surface is closed, smoothly or not, in the v-parameter direction. | |
| virtual spl_sur * | deep_copy (pointer_map *pm=NULL) const |
| Creates a copy of an item that does not share any data with the original. | |
| double | estimate_min_rad_curv () |
| This function estimates the minimum radius of curvature of the skin surface for a given set of tangent factor values. | |
| void | estimate_tanfacs_scale (SPAinterval &tan_range) |
| Estimates the scaling factor range. | |
| virtual SPAposition | eval_position (SPApar_pos const ¶meter) const |
| Finds the point on the spline for a given parameter-space point. | |
| double | fitol () const |
Returns the fit tolerance for the approximating bs3_surface. | |
| void | get_curves (int &no_crv, curve ***curves) const |
| Returns the surface curves. | |
| void | get_laws (int &no_laws, law **&laws) const |
| Returns a list of laws used by the skin_spl_sur. | |
| subtrans_object * | get_next () const |
| Returns the next object in the list. | |
| virtual curve * | get_path () const |
Returns the sweep path curve for this spl_sur. | |
| virtual sweep_path_type | get_path_type () const |
Returns the sweep path type for this spl_sur. | |
| virtual curve * | get_profile (double param) const |
Returns the sweep profile curve for this spl_sur. | |
| virtual law * | get_rail () const |
Returns the sweep rail law for this spl_sur. | |
| void | get_surfaces (int &no_surfaces, surface **&surf_arr) const |
| Returns the surfaces. | |
| logical | get_tanfacs (double *tangents) const |
| Get the tangent factors to determine optimal values for them. | |
| void | get_v_knots (double u, int &out_no_knots, double **out_vknots) const |
| Returns the v_knot sequence for a given parameter value. | |
| void | invalidate_cache () |
| Method to be called by any user who modifies the surface in an external process, to ensure that stale evaluation results are discarded. | |
| logical | iterate_perp (SPAposition const &pos, SPAposition &surf, SPAunit_vector &normal, surf_princurv &curv, SPApar_pos const &guess, SPApar_pos &actual, logical pt) const |
Support function for point_perp (and bs3_surface_perp). | |
| subtrans_object * | make_trans (SPAtransf const &trans) |
Transforms the subtrans_object on an external level. | |
| logical | mult_ref () const |
Returns TRUE if there is more than one reference - else, it returns FALSE. | |
| logical | operator!= (subtype_object const &rhs) const |
TRUE if two subtype objects are not the same. | |
| double | param_period_u () const |
| Returns the u period of a periodic parametric surface, zero if the surface is not periodic in the u direction. | |
| double | param_period_v () const |
| Returns the v period of a periodic parametric surface, zero if the surface is not periodic in the v direction. | |
| SPApar_box | param_range (SPAbox const &box=*(SPAbox *) NULL_REF) const |
| Returns the principal parameter range of a parametric surface in both u and v-parameter directions. | |
| SPAinterval | param_range_u (SPAbox const &box=*(SPAbox *) NULL_REF) const |
| Returns the principal parameter range of a parametric surface in the u-parameter direction. | |
| SPAinterval | param_range_v (SPAbox const &box=*(SPAbox *) NULL_REF) const |
| Returns the principal parameter range of a parametric surface in the v-parameter direction. | |
| logical | periodic_u () const |
| Determines if a parametric surface is periodic in the u direction. | |
| logical | periodic_v () const |
| Determines if a parametric surface is periodic in the v direction. | |
| int | ref_count () |
| Returns the use count. | |
| void | remove_ref () |
| Removes a reference. | |
| virtual void | save () const |
| Saves the skin_spl_sur as an approximation if there is a need to approximate. | |
| virtual void | save_data () const |
| Saves the information for skin_spl_sur to the save file. | |
| void | set_next (subtrans_object *obj) |
| Sets the next object in the list. | |
| void | set_tanfacs (double *tangents, logical remake_approx=TRUE) |
| Set the tangent factors and get them for purposes of determining optimal values for them. | |
| logical | singular_u (double uparam) const |
| Reports whether the surface parameterization is singular at the specified u-parameter value. | |
| logical | singular_v (double vparam) const |
| Reports whether the surface parameterization is singular at the specified v-parameter value. | |
| skin_spl_sur (const skin_spl_sur &surf) | |
| C++ copy constructor requests memory for this object and populates it with the data from the object supplied as an argument. | |
| bs3_surface | sur () const |
Returns the bs3_surface approximation. | |
| virtual int | type () const |
| Returns the type of skin_spl_sur. | |
| virtual char const * | type_name () const |
| Returns the string of the given spline surface type, which is "skinsur" for a skin_spl_surf. | |
| virtual logical | unknown_type () const |
Returns TRUE if this object type is unknown to the system - else, it returns FALSE. | |
Static Public Member Functions | |
| static int | id () |
| Returns the ID for the skin_spl_sur list. | |
| static spl_sur * | make_skin_spl_sur (logical arc, logical perp, int section, curve **cur, double *arrknot, double *left, double *right, surface **surf, double *fac, law **arrlaw, closed_forms flagu=OPEN, closed_forms flagv=OPEN) |
| Constructs a loft surface from the given section curves and the corresponding surfaces on which the sections lie and the optional tangent factors that should be applied to cross-boundary tangents. | |
| static spl_sur * | make_skin_spl_sur (logical length, int cur, curve **arrcur, double *arrknot, double *left, double *right, SPAvector *dir=(SPAvector *) NULL, closed_forms flagu=OPEN, closed_forms flagv=OPEN) |
| Constructs a skin surface from the given section curves and the optional matching tangents. | |
Protected Member Functions | |
| virtual subtrans_object * | copy () const |
Constructs a duplicate spl_sur in free storage of this object, with a zero use count. | |
| virtual void | debug (char const *, logical, FILE *) const |
Writes the subtype_object in readable form for debugging. | |
| virtual void | eval (SPApar_pos const &uv, SPAposition &pos, SPAvector *dpos, SPAvector *ddpos) const |
| Finds the position and the first and second derivatives of the surface at a specified parameter-space point. | |
| logical | operator== (subtype_object const &) const |
| Determines if two subtype objects are the same. | |
Role: Surface Parameterization
The surface parameterization is the u-direction corresponds to the parameterization of the curves to be skinned and the v-direction corresponds to the cubic Bezier between the skin-curves.
The input to this surface class are the curves to be skinned (all the curves are reparameterized to lie in [0.0 - 1.0] range), optional tangents (the magnitude of the curves' tangents have to match on the ends) in u-direction, and the optional surfaces on which the curves lie. If surfaces containing the curves are provided, these determine the tangent directions in v.
Evaluation Process
The evaluation process is a three-step process, as described below.
Step 1
If any matching tangent magnitudes are given, the section curves (curves to be skinned) are reparameterized as follows: parameter t is the parameter on the original curve. Parameter u on the skin surface is determined such that the u-partial at each end of the skin surface is equal to the matching tangent magnitude.
t = f(u) = ts*H0(u) + m0*H1(u) + m1*H2(u) + te*H3(u)
In the above expression, Hn are the cubic Hermite polynomials and ts and te are the start and end parameter values of the original curves to be skinned, which here are 0 and 1, respectively.
So, ds/du on the ends are:
dc/du = dc/dt * dt/du
where the dt/du values on the ends are m0 and m1. So by choosing the values m0 and m1 such that the dc/du on the left surface is equal to dc/du on the right surface (provided that the curves are G1), a C1 continuous surface is achieved even when skinning G1 continuous curves.
Step 2
The tangent directions for the v are determined by fitting a circle through the points corresponding to the same u-value on the adjacent section curves to the left and right. The scheme followed is similar to the way Bessel tangents are computed. If there are only two section curves, the circle radius is chosen to be infinity. If the surfaces are given for any section, the tangent direction in v when on that curve is obtained by the cross product of surface normal and the section curve tangent at that point. The direction also has an optional scalar value that can be applied. The surface is called a loft surface when such a surface is provided. Step 3
Now the skin/loft surface is defined using cubic Hermite interpolants between sections that join each other C1 continuously. To evaluate the surface s(u,v) at a particular v-parameter, the first step is to find the segment to which this parameter corresponds. Then a local parameter vi is computed, which ranges from 0 to 1. The section curves ci and ci+1, and the v-tangents ti and ti+1 are also obtained. The surface is defined as:
s(u,v) = ci(u)*H0(vi) + ti*H1(vi) + ti+1*H2(vi) + ci+1*H3(vi) The parametric derivatives of this surface are obtained by differentiating the above equation algebraically.
| skin_spl_sur::skin_spl_sur | ( | const skin_spl_sur & | surf | ) |
C++ copy constructor requests memory for this object and populates it with the data from the object supplied as an argument.
| surf | surface to copy |
| int skin_spl_sur::accurate_derivs | ( | SPApar_box const & | area = *(SPApar_box *) NULL_REF |
) | const [virtual] |
Calculates the derivatives within the given parameter box.
| area | area for deriv |
Reimplemented from spl_sur.
| void skin_spl_sur::add_path_data | ( | int | no_curves, | |
| curve ** | curves | |||
| ) |
Adds the path data to the skin_spl_sur object.
| no_curves | number of curves in path | |
| curves | curve paths to add |
| void subtype_object::add_ref | ( | ) | [inherited] |
Uses count manipulation.
| void subtrans_object::clear_trans | ( | ) | [inherited] |
Clears any references to this object using transformation lists, before incompatible changes.
| logical spl_sur::closed_u | ( | ) | const [inline, inherited] |
Determines if the surface is closed, smoothly or not, in the u-parameter direction.
| logical spl_sur::closed_v | ( | ) | const [inline, inherited] |
Determines if the surface is closed, smoothly or not, in the v-parameter direction.
| virtual subtrans_object* skin_spl_sur::copy | ( | ) | const [protected, virtual] |
| virtual void skin_spl_sur::debug | ( | char const * | leader, | |
| logical | output, | |||
| FILE * | fp | |||
| ) | const [protected, virtual] |
Writes the subtype_object in readable form for debugging.
Role: If logical is TRUE, brief output is produced; if logical is FALSE, long output is produced.
| leader | leader for second and subsequent lines of output. | |
| output | TRUE for brief output, FALSE for full output. | |
| fp | file name. |
Implements spl_sur.
| virtual spl_sur* skin_spl_sur::deep_copy | ( | pointer_map * | pm = NULL |
) | const [virtual] |
Creates a copy of an item that does not share any data with the original.
Role: Allocates new storage for all member data and any pointers. Returns a pointer to the copied item.
In a deep copy, all the information about the copied item is self-contained in a new memory block. By comparison, a shallow copy stores only the first instance of the item in memory, and increments the reference count for each copy.
The pointer_map keeps a list of all pointers in the original object that have already been deep copied. For example, a deep_copy of a complex model results in self contained data, but identical sub-parts within the model are allowed to share a single set of data.
| mp | list of items within the entity that are already deep copied |
Implements spl_sur.
| double skin_spl_sur::estimate_min_rad_curv | ( | ) |
This function estimates the minimum radius of curvature of the skin surface for a given set of tangent factor values.
| void skin_spl_sur::estimate_tanfacs_scale | ( | SPAinterval & | tan_range | ) |
| virtual void skin_spl_sur::eval | ( | SPApar_pos const & | uv, | |
| SPAposition & | pos, | |||
| SPAvector * | dpos, | |||
| SPAvector * | ddpos | |||
| ) | const [protected, virtual] |
| virtual SPAposition spl_sur::eval_position | ( | SPApar_pos const & | parameter | ) | const [virtual, inherited] |
Finds the point on the spline for a given parameter-space point.
| parameter | given parameter-space point. |
| double spl_sur::fitol | ( | ) | const [inline, inherited] |
Returns the fit tolerance for the approximating bs3_surface.
| void skin_spl_sur::get_curves | ( | int & | no_crv, | |
| curve *** | curves | |||
| ) | const |
| void skin_spl_sur::get_laws | ( | int & | no_laws, | |
| law **& | laws | |||
| ) | const |
Returns a list of laws used by the skin_spl_sur.
Role: The use count of the laws is incremented by one.
| no_laws | number of laws | |
| laws | list of laws pointer |
| subtrans_object* subtrans_object::get_next | ( | ) | const [inline, inherited] |
Returns the next object in the list.
| virtual curve* spl_sur::get_path | ( | ) | const [inline, virtual, inherited] |
Returns the sweep path curve for this spl_sur.
Reimplemented in off_spl_sur, rot_spl_sur, sum_spl_sur, and sweep_spl_sur.
| virtual sweep_path_type spl_sur::get_path_type | ( | ) | const [inline, virtual, inherited] |
Returns the sweep path type for this spl_sur.
Reimplemented in off_spl_sur, rot_spl_sur, sum_spl_sur, and sweep_spl_sur.
| virtual curve* spl_sur::get_profile | ( | double | param | ) | const [inline, virtual, inherited] |
Returns the sweep profile curve for this spl_sur.
| param | parameter |
Reimplemented in rot_spl_sur, sum_spl_sur, and sweep_spl_sur.
| virtual law* spl_sur::get_rail | ( | ) | const [inline, virtual, inherited] |
Returns the sweep rail law for this spl_sur.
Reimplemented in off_spl_sur, rot_spl_sur, sum_spl_sur, and sweep_spl_sur.
| void skin_spl_sur::get_surfaces | ( | int & | no_surfaces, | |
| surface **& | surf_arr | |||
| ) | const |
Returns the surfaces.
Role: The array of surfaces need to be deleted by the calling routine.
| no_surfaces | number of surfaces | |
| surf_arr | surface array pointer |
| logical skin_spl_sur::get_tanfacs | ( | double * | tangents | ) | const |
Get the tangent factors to determine optimal values for them.
| tangents | tangent factors, returns FALSE if there are none |
| void skin_spl_sur::get_v_knots | ( | double | u, | |
| int & | out_no_knots, | |||
| double ** | out_vknots | |||
| ) | const |
Returns the v_knot sequence for a given parameter value.
| u | u parameter | |
| out_no_knots | number of knots | |
| out_vknots | output array pointer |
| static int skin_spl_sur::id | ( | ) | [static] |
Returns the ID for the skin_spl_sur list.
| void spl_sur::invalidate_cache | ( | ) | [inherited] |
Method to be called by any user who modifies the surface in an external process, to ensure that stale evaluation results are discarded.
| logical spl_sur::iterate_perp | ( | SPAposition const & | pos, | |
| SPAposition & | surf, | |||
| SPAunit_vector & | normal, | |||
| surf_princurv & | curv, | |||
| SPApar_pos const & | guess, | |||
| SPApar_pos & | actual, | |||
| logical | pt | |||
| ) | const [inherited] |
Support function for point_perp (and bs3_surface_perp).
Role: This method finds a true perpendicular given an initial parameter guess, and avoiding oscillations. It may be set to iterate to the nearest perpendicular of any sort (minimum or maximum distance, or inflexion), or to find only minima (which is sometimes more reliable when there are inflexions), and it returns a success or failure indication.
| static spl_sur* skin_spl_sur::make_skin_spl_sur | ( | logical | arc, | |
| logical | perp, | |||
| int | section, | |||
| curve ** | cur, | |||
| double * | arrknot, | |||
| double * | left, | |||
| double * | right, | |||
| surface ** | surf, | |||
| double * | fac, | |||
| law ** | arrlaw, | |||
| closed_forms | flagu = OPEN, |
|||
| closed_forms | flagv = OPEN | |||
| ) | [static] |
Constructs a loft surface from the given section curves and the corresponding surfaces on which the sections lie and the optional tangent factors that should be applied to cross-boundary tangents.
Role: The surfaces are passed in are owned by the skin_surface, so the user should pass in a copy. All arrays are the size of int, the number of sections.
| arc | arc-length flag | |
| perp | perpendicular flag | |
| section | number of section curves | |
| cur | array of curves | |
| arrknot | array of knot values | |
| left | array of left tangents | |
| right | array of right tangents | |
| surf | array of surfaces | |
| fac | crossboundary tangents array | |
| arrlaw | array of laws | |
| flagu | flag for periodicity of surface in u | |
| flagv | flag for periodicity of surface in v |
| static spl_sur* skin_spl_sur::make_skin_spl_sur | ( | logical | length, | |
| int | cur, | |||
| curve ** | arrcur, | |||
| double * | arrknot, | |||
| double * | left, | |||
| double * | right, | |||
| SPAvector * | dir = (SPAvector *) NULL, |
|||
| closed_forms | flagu = OPEN, |
|||
| closed_forms | flagv = OPEN | |||
| ) | [static] |
Constructs a skin surface from the given section curves and the optional matching tangents.
| subtrans_object* subtrans_object::make_trans | ( | SPAtransf const & | trans | ) | [inherited] |
Transforms the subtrans_object on an external level.
Role: This method searches the transform list to find a match. It returns the corresponding transformed object if it is found; otherwise, it constructs a new transformed object, enters it into the transformation list for future reference, and returns the new object. If this object is only singly-referenced and has no transformed counterpart, then it transforms directly without copying, and "this" returns.
| trans | transformation. |
| logical subtype_object::mult_ref | ( | ) | const [inline, inherited] |
Returns TRUE if there is more than one reference - else, it returns FALSE.
| logical subtype_object::operator!= | ( | subtype_object const & | rhs | ) | const [inline, inherited] |
TRUE if two subtype objects are not the same.
Role: Use this method for sharing on restoration of old save files.
| rhs | subtype-object. |
| logical skin_spl_sur::operator== | ( | subtype_object const & | obj | ) | const [protected, virtual] |
Determines if two subtype objects are the same.
Role: Use this method for sharing on restoration of old save files.
| obj | subtype-object. |
Reimplemented from spl_sur.
| double spl_sur::param_period_u | ( | ) | const [inline, inherited] |
| double spl_sur::param_period_v | ( | ) | const [inline, inherited] |
| SPApar_box spl_sur::param_range | ( | SPAbox const & | box = *(SPAbox *)NULL_REF |
) | const [inline, inherited] |
Returns the principal parameter range of a parametric surface in both u and v-parameter directions.
Role: A periodic surface is defined for all parameter values in the periodic direction, by reducing the given parameter modulo the period into this principal range. For a surface open or nonperiodic in the chosen direction the surface evaluation functions are defined only for parameter values in the returned range.
If a box is specified, the parameter range returned may be restricted to a portion of the surface which is guaranteed to contain all portions of the surface that lie within the region of interest. If none is specified and the parameter range in some direction is unbounded, then an interval unbounded in that direction is returned.
| box | object space box. |
| SPAinterval spl_sur::param_range_u | ( | SPAbox const & | box = *(SPAbox *)NULL_REF |
) | const [inline, inherited] |
Returns the principal parameter range of a parametric surface in the u-parameter direction.
Role: A periodic surface is defined for all parameter values in the periodic direction, by reducing the given parameter modulo the period into this principal range. For a surface open or nonperiodic in the chosen direction the surface evaluation functions are defined only for parameter values in the returned range.
| box | object space box. |
| SPAinterval spl_sur::param_range_v | ( | SPAbox const & | box = *(SPAbox *)NULL_REF |
) | const [inline, inherited] |
Returns the principal parameter range of a parametric surface in the v-parameter direction.
Role: A periodic surface is defined for all parameter values in the periodic direction, by reducing the given parameter modulo the period into this principal range. For a surface open or nonperiodic in the chosen direction the surface evaluation functions are defined only for parameter values in the returned range.
| box | object space box. |
| logical spl_sur::periodic_u | ( | ) | const [inline, inherited] |
| logical spl_sur::periodic_v | ( | ) | const [inline, inherited] |
| int subtype_object::ref_count | ( | ) | [inline, inherited] |
Returns the use count.
| void subtype_object::remove_ref | ( | ) | [inherited] |
Removes a reference.
| virtual void skin_spl_sur::save | ( | ) | const [virtual] |
Saves the skin_spl_sur as an approximation if there is a need to approximate.
Reimplemented from subtype_object.
| virtual void skin_spl_sur::save_data | ( | ) | const [virtual] |
| void subtrans_object::set_next | ( | subtrans_object * | obj | ) | [inherited] |
Sets the next object in the list.
| obj | object. |
| void skin_spl_sur::set_tanfacs | ( | double * | tangents, | |
| logical | remake_approx = TRUE | |||
| ) |
Set the tangent factors and get them for purposes of determining optimal values for them.
| tangents | tangent factors | |
| remake_approx | remake enabled or not |
| logical spl_sur::singular_u | ( | double | uparam | ) | const [inherited] |
Reports whether the surface parameterization is singular at the specified u-parameter value.
Role: The only singularity recognized is where every value of the v parameter generates the same object-space point, and these can only occur at the ends of the parameter range as returned by param_range_u.
| uparam | specified u parameter value. |
| logical spl_sur::singular_v | ( | double | vparam | ) | const [inherited] |
Reports whether the surface parameterization is singular at the specified v-parameter value.
Role: The only singularity recognized is where every value of the u parameter generates the same object-space point, and these can only occur at the ends of the parameter range as returned by param_range_v.
| vparam | specified v parameter value. |
| bs3_surface spl_sur::sur | ( | ) | const [inline, inherited] |
Returns the bs3_surface approximation.
| virtual int skin_spl_sur::type | ( | ) | const [virtual] |
| virtual char const* skin_spl_sur::type_name | ( | ) | const [virtual] |
| virtual logical subtype_object::unknown_type | ( | ) | const [virtual, inherited] |
Returns TRUE if this object type is unknown to the system - else, it returns FALSE.
Role: This method returns FALSE as the default, so except for the system unknown subtype, the method should be omitted from derived class definitions.