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EggMesherStrip Class Reference

Represents a triangle strip or quad strip in progress, as assembled by the mesher. More...

#include "eggMesherStrip.h"

Public Types

typedef plist< EggMesherEdge * > Edges
 
enum  MesherOrigin {
  MO_unknown, MO_user, MO_firstquad, MO_fanpoly,
  MO_mate
}
 
enum  MesherStatus { MS_alive, MS_dead, MS_done, MS_paired }
 
typedef plist< CPT(EggPrimitive) > Prims
 
enum  PrimType {
  PT_poly, PT_point, PT_line, PT_tri,
  PT_tristrip, PT_trifan, PT_quad, PT_quadstrip,
  PT_linestrip
}
 
typedef plist< int > Verts
 

Public Member Functions

 EggMesherStrip (PrimType prim_type, MesherOrigin origin)
 
 EggMesherStrip (const EggPrimitive *prim, int index, const EggVertexPool *vertex_pool, bool flat_shaded)
 
 EggMesherStrip (const EggMesherStrip &copy)
 
bool can_invert () const
 Returns true if the strip can be inverted (reverse its facing direction). More...
 
void combine_edges (EggMesherStrip &other, int remove_sides)
 Removes the edges from the given strip and appends them to our own. More...
 
void convert_to_type (PrimType want_type)
 Converts the EggMesherStrip from whatever form it is–triangle, quad, or quadstrip–into a tristrip or quadstrip. More...
 
PN_stdfloat coplanarity (const EggMesherStrip &other) const
 Returns the degree to which the two strips are coplanar. More...
 
int count_neighbors () const
 Returns the number of neighbors the strip shares. More...
 
void cut_sheet (int first_row_id, int do_mate, const EggVertexPool *vertex_pool)
 
const EggMesherEdgefind_adjacent_edge (const EggMesherEdge *edge) const
 Returns the first edge found that shares exactly one vertex with the given edge. More...
 
bool find_ideal_mate (EggMesherStrip *&mate, EggMesherEdge *&common_edge, const EggVertexPool *vertex_pool)
 Searches our neighbors for the most suitable mate. More...
 
const EggMesherEdgefind_opposite_edge (int vi) const
 Returns the first edge found that does not contain the given vertex. More...
 
const EggMesherEdgefind_opposite_edge (const EggMesherEdge *edge) const
 Returns the first edge found that shares no vertices with the given edge. More...
 
int find_uncommon_vertex (const EggMesherEdge *edge) const
 Returns the first vertex found that is not shared by the given edge. More...
 
EggMesherEdge get_head_edge () const
 Returns an EggMesherEdge which represents the leading edge in the quadstrip or tristrip. More...
 
EggMesherEdge get_tail_edge () const
 Returns an EggMesherEdge which represents the trailing edge in the quadstrip or tristrip. More...
 
bool invert ()
 Reverses the facing of a quadstrip by reversing pairs of vertices. More...
 
bool is_coplanar_with (const EggMesherStrip &other, PN_stdfloat threshold) const
 Returns true if the strip and the other strip are coplanar, within the indicated threshold. More...
 
bool is_odd () const
 Returns true if the tristrip or quadstrip contains an odd number of pieces. More...
 
bool mate (const EggVertexPool *vertex_pool)
 Finds a neighboring strip and joins up with it to make a larger strip. More...
 
void measure_sheet (const EggMesherEdge *edge, int new_row, int &num_prims, int &num_rows, int first_row_id, int this_row_id, int this_row_distance)
 Determines the extents of the quadsheet that can be derived by starting with this strip, and searching in the direction indicated by the given edge. More...
 
bool operator!= (const EggMesherStrip &other) const
 
bool operator== (const EggMesherStrip &other) const
 Defines equality for strips. More...
 
void output (ostream &out) const
 Formats the vertex for output in some sensible way. More...
 
void output_neighbors (ostream &out) const
 Writes all the neighbor indexes to the ostream. More...
 
bool pick_mate (const EggMesherStrip &a_strip, const EggMesherStrip &b_strip, const EggMesherEdge &a_edge, const EggMesherEdge &b_edge, const EggVertexPool *vertex_pool) const
 Defines an ordering to select neighbors to mate with. More...
 
bool pick_sheet_mate (const EggMesherStrip &a_strip, const EggMesherStrip &b_strip) const
 Defines an ordering to select neighbors to follow when measuring out a quadsheet. More...
 
 PT (EggPrimitive) make_prim(const EggVertexPool *vertex_pool)
 
void remove_all_edges ()
 Removes all active edges from the strip. More...
 
void rotate_back ()
 Rotates a triangle or quad by bringing its last vertex to the front. More...
 
void rotate_forward ()
 Rotates a triangle or quad by bringing its first vertex to the back. More...
 
void rotate_to_back (const EggMesherEdge *edge)
 Rotates a triangle or quad so that the given edge is last in the vertex list. More...
 
void rotate_to_front (const EggMesherEdge *edge)
 Rotates a triangle or quad so that the given edge is first in the vertex list. More...
 
int type_category () const
 Returns an integer which gives a heuristic about the similarity of different strip types. More...
 
bool would_reverse_tail (PrimType want_type) const
 Returns true if convert_to_type() would reverse the tail edge of the given strip, false otherwise. More...
 

Static Public Member Functions

static bool convex_quad (EggMesherEdge *common_edge, EggMesherStrip &front, EggMesherStrip &back, const EggVertexPool *vertex_pool)
 Returns true if the quad that would be formed by connecting coplanar tris front and back along common_edge is convex, false otherwise. More...
 
static bool mate_pieces (EggMesherEdge *common_edge, EggMesherStrip &front, EggMesherStrip &back, const EggVertexPool *vertex_pool)
 Connects two pieces of arbitrary type, if possible. More...
 
static bool mate_strips (EggMesherEdge *common_edge, EggMesherStrip &front, EggMesherStrip &back, PrimType type)
 Stitches two strips together, producing in "front" a new strip of the indicated type (quadstrip or tristrip). More...
 
static bool must_invert (const EggMesherStrip &front, const EggMesherStrip &back, bool will_reverse_back, PrimType type)
 Returns false if the strips can be mated as they currently are. More...
 

Public Attributes

Edges _edges
 
bool _flat_shaded
 
int _index
 
MesherOrigin _origin
 
bool _planar
 
LNormald _plane_normal
 
PN_stdfloat _plane_offset
 
Prims _prims
 
int _row_distance
 
int _row_id
 
MesherStatus _status
 
PrimType _type
 
Verts _verts
 

Detailed Description

Represents a triangle strip or quad strip in progress, as assembled by the mesher.

It might also represent a single polygon such as a triangle or quad, since that's how strips generally start out.

Definition at line 33 of file eggMesherStrip.h.

Member Function Documentation

◆ can_invert()

bool EggMesherStrip::can_invert ( ) const

Returns true if the strip can be inverted (reverse its facing direction).

Generally, this is true for quadstrips and false for tristrips.

Definition at line 1096 of file eggMesherStrip.cxx.

References invert().

Referenced by invert(), mate_strips(), and rotate_to_back().

◆ combine_edges()

void EggMesherStrip::combine_edges ( EggMesherStrip other,
int  remove_sides 
)

Removes the edges from the given strip and appends them to our own.

If remove_sides is true, then removes all the edges except the head and the tail.

Definition at line 1282 of file eggMesherStrip.cxx.

References get_head_edge(), get_tail_edge(), is_odd(), and remove_all_edges().

Referenced by convert_to_type(), and mate_pieces().

◆ convert_to_type()

void EggMesherStrip::convert_to_type ( EggMesherStrip::PrimType  want_type)

Converts the EggMesherStrip from whatever form it is–triangle, quad, or quadstrip–into a tristrip or quadstrip.

Definition at line 1211 of file eggMesherStrip.cxx.

References combine_edges().

Referenced by mate_strips(), and would_reverse_tail().

◆ convex_quad()

bool EggMesherStrip::convex_quad ( EggMesherEdge common_edge,
EggMesherStrip front,
EggMesherStrip back,
const EggVertexPool vertex_pool 
)
static

Returns true if the quad that would be formed by connecting coplanar tris front and back along common_edge is convex, false otherwise.

Definition at line 805 of file eggMesherStrip.cxx.

References count_neighbors(), find_uncommon_vertex(), EggVertex::get_pos3(), and EggVertexPool::get_vertex().

Referenced by mate_pieces(), and must_invert().

◆ coplanarity()

PN_stdfloat EggMesherStrip::coplanarity ( const EggMesherStrip other) const
inline

Returns the degree to which the two strips are coplanar.

0.0 is exactly coplanar; numbers somewhat larger than zero indicate less coplanar. 1.0 is at right angles; 2.0 is exactly backfacing. If either strip is not itself planar, 3.0 is returned.

Definition at line 59 of file eggMesherStrip.I.

References type_category().

Referenced by is_coplanar_with(), and pick_mate().

◆ count_neighbors()

int EggMesherStrip::count_neighbors ( ) const

Returns the number of neighbors the strip shares.

Definition at line 883 of file eggMesherStrip.cxx.

References output_neighbors().

Referenced by convex_quad(), output(), and pick_mate().

◆ find_adjacent_edge()

const EggMesherEdge * EggMesherStrip::find_adjacent_edge ( const EggMesherEdge edge) const

Returns the first edge found that shares exactly one vertex with the given edge.

In a quad, this will be one of two edges adjacent to the given edge.

Definition at line 988 of file eggMesherStrip.cxx.

References EggMesherEdge::contains_vertex(), and rotate_to_front().

Referenced by find_opposite_edge().

◆ find_ideal_mate()

bool EggMesherStrip::find_ideal_mate ( EggMesherStrip *&  mate,
EggMesherEdge *&  common_edge,
const EggVertexPool vertex_pool 
)

Searches our neighbors for the most suitable mate.

Returns true if one is found, false if we have no neighbors.

Definition at line 449 of file eggMesherStrip.cxx.

References mate_pieces(), and pick_mate().

Referenced by mate(), and EggMesher::mesh().

◆ find_opposite_edge() [1/2]

const EggMesherEdge * EggMesherStrip::find_opposite_edge ( int  vi) const

Returns the first edge found that does not contain the given vertex.

In a tri, this will be the edge opposite the given vertex.

Definition at line 945 of file eggMesherStrip.cxx.

References EggMesherEdge::contains_vertex().

Referenced by find_uncommon_vertex().

◆ find_opposite_edge() [2/2]

const EggMesherEdge * EggMesherStrip::find_opposite_edge ( const EggMesherEdge edge) const

Returns the first edge found that shares no vertices with the given edge.

In a quad, this will be the edge opposite the given edge.

Definition at line 965 of file eggMesherStrip.cxx.

References EggMesherEdge::contains_vertex(), and find_adjacent_edge().

◆ find_uncommon_vertex()

int EggMesherStrip::find_uncommon_vertex ( const EggMesherEdge edge) const

Returns the first vertex found that is not shared by the given edge.

Definition at line 919 of file eggMesherStrip.cxx.

References find_opposite_edge().

Referenced by convex_quad(), mate_pieces(), and output_neighbors().

◆ get_head_edge()

EggMesherEdge EggMesherStrip::get_head_edge ( ) const
inline

Returns an EggMesherEdge which represents the leading edge in the quadstrip or tristrip.

This EggMesherEdge will not have pointer equality with any shared EggMesherEdge.

Definition at line 126 of file eggMesherStrip.I.

References get_tail_edge().

Referenced by combine_edges(), mate_strips(), and rotate_back().

◆ get_tail_edge()

EggMesherEdge EggMesherStrip::get_tail_edge ( ) const
inline

Returns an EggMesherEdge which represents the trailing edge in the quadstrip or tristrip.

This EggMesherEdge will not have pointer equality with any shared EggMesherEdge.

Definition at line 142 of file eggMesherStrip.I.

References operator==().

Referenced by combine_edges(), get_head_edge(), and mate_strips().

◆ invert()

bool EggMesherStrip::invert ( )

Reverses the facing of a quadstrip by reversing pairs of vertices.

Returns true if successful, false if failure (for instance, on a tristrip).

Definition at line 1108 of file eggMesherStrip.cxx.

References can_invert(), and is_odd().

Referenced by can_invert(), mate_strips(), and must_invert().

◆ is_coplanar_with()

bool EggMesherStrip::is_coplanar_with ( const EggMesherStrip other,
PN_stdfloat  threshold 
) const
inline

Returns true if the strip and the other strip are coplanar, within the indicated threshold.

See coplanarity().

Definition at line 45 of file eggMesherStrip.I.

References coplanarity().

Referenced by mate_pieces().

◆ is_odd()

bool EggMesherStrip::is_odd ( ) const

Returns true if the tristrip or quadstrip contains an odd number of pieces.

Definition at line 1138 of file eggMesherStrip.cxx.

References would_reverse_tail().

Referenced by combine_edges(), invert(), mate_strips(), and must_invert().

◆ mate()

bool EggMesherStrip::mate ( const EggVertexPool vertex_pool)

Finds a neighboring strip and joins up with it to make a larger strip.

Returns true if mating was successful or at least possible, false if the strip has no neighbors.

Definition at line 416 of file eggMesherStrip.cxx.

References find_ideal_mate(), and mate_pieces().

Referenced by measure_sheet().

◆ mate_pieces()

bool EggMesherStrip::mate_pieces ( EggMesherEdge common_edge,
EggMesherStrip front,
EggMesherStrip back,
const EggVertexPool vertex_pool 
)
static

Connects two pieces of arbitrary type, if possible.

Returns true if successful, false if failure.

Definition at line 483 of file eggMesherStrip.cxx.

References combine_edges(), EggMesherEdge::contains_vertex(), convex_quad(), find_uncommon_vertex(), is_coplanar_with(), mate_strips(), EggMesherEdge::remove(), and rotate_to_back().

Referenced by find_ideal_mate(), mate(), measure_sheet(), and EggMesher::mesh().

◆ mate_strips()

bool EggMesherStrip::mate_strips ( EggMesherEdge common_edge,
EggMesherStrip front,
EggMesherStrip back,
EggMesherStrip::PrimType  type 
)
static

Stitches two strips together, producing in "front" a new strip of the indicated type (quadstrip or tristrip).

The front strip stores the result, and the back strip is emptied on success.

Returns true if successful, false if failure (generally because of incorrect polarity of tristrips), in which case nothing has changed (or at least, not much).

Definition at line 634 of file eggMesherStrip.cxx.

References can_invert(), convert_to_type(), get_head_edge(), get_tail_edge(), invert(), is_odd(), EggMesherEdge::matches(), must_invert(), rotate_to_back(), rotate_to_front(), and would_reverse_tail().

Referenced by mate_pieces().

◆ measure_sheet()

void EggMesherStrip::measure_sheet ( const EggMesherEdge edge,
int  new_row,
int &  num_prims,
int &  num_rows,
int  first_row_id,
int  this_row_id,
int  this_row_distance 
)

Determines the extents of the quadsheet that can be derived by starting with this strip, and searching in the direction indicated by the given edge.

Definition at line 184 of file eggMesherStrip.cxx.

References mate(), mate_pieces(), measure_sheet(), and pick_sheet_mate().

Referenced by measure_sheet().

◆ must_invert()

bool EggMesherStrip::must_invert ( const EggMesherStrip front,
const EggMesherStrip back,
bool  will_reverse_back,
EggMesherStrip::PrimType  type 
)
static

Returns false if the strips can be mated as they currently are.

Returns true if the back strip must be inverted first.

Definition at line 769 of file eggMesherStrip.cxx.

References convex_quad(), invert(), and is_odd().

Referenced by mate_strips().

◆ operator==()

bool EggMesherStrip::operator== ( const EggMesherStrip other) const
inline

Defines equality for strips.

This actually tests only pointer equality; it's used only when removing a strip from the list.

Definition at line 157 of file eggMesherStrip.I.

Referenced by get_tail_edge().

◆ output()

void EggMesherStrip::output ( ostream &  out) const

Formats the vertex for output in some sensible way.

Definition at line 1446 of file eggMesherStrip.cxx.

References count_neighbors(), and output_neighbors().

Referenced by pick_sheet_mate().

◆ output_neighbors()

void EggMesherStrip::output_neighbors ( ostream &  out) const

Writes all the neighbor indexes to the ostream.

Definition at line 899 of file eggMesherStrip.cxx.

References find_uncommon_vertex().

Referenced by count_neighbors(), and output().

◆ pick_mate()

bool EggMesherStrip::pick_mate ( const EggMesherStrip a_strip,
const EggMesherStrip b_strip,
const EggMesherEdge a_edge,
const EggMesherEdge b_edge,
const EggVertexPool vertex_pool 
) const

Defines an ordering to select neighbors to mate with.

This compares strip a with strip b and returns true if strip a is the preferable choice, false if strip b.

Definition at line 1358 of file eggMesherStrip.cxx.

References EggMesherEdge::compute_length(), coplanarity(), count_neighbors(), pick_sheet_mate(), and type_category().

Referenced by find_ideal_mate(), and remove_all_edges().

◆ pick_sheet_mate()

bool EggMesherStrip::pick_sheet_mate ( const EggMesherStrip a_strip,
const EggMesherStrip b_strip 
) const

Defines an ordering to select neighbors to follow when measuring out a quadsheet.

This is only called when three or more prims share a single edge, which should be rarely–generally only when coplanar polys are going on.

Definition at line 1416 of file eggMesherStrip.cxx.

References output(), and type_category().

Referenced by measure_sheet(), and pick_mate().

◆ remove_all_edges()

void EggMesherStrip::remove_all_edges ( )

Removes all active edges from the strip.

This effectively renders it ineligible to mate with anything else.

Definition at line 1336 of file eggMesherStrip.cxx.

References pick_mate().

Referenced by combine_edges().

◆ rotate_back()

void EggMesherStrip::rotate_back ( )
inline

Rotates a triangle or quad by bringing its last vertex to the front.

Definition at line 111 of file eggMesherStrip.I.

References get_head_edge().

Referenced by rotate_forward(), rotate_to_back(), and rotate_to_front().

◆ rotate_forward()

void EggMesherStrip::rotate_forward ( )
inline

Rotates a triangle or quad by bringing its first vertex to the back.

Definition at line 99 of file eggMesherStrip.I.

References rotate_back().

Referenced by rotate_to_back(), rotate_to_front(), and type_category().

◆ rotate_to_back()

void EggMesherStrip::rotate_to_back ( const EggMesherEdge edge)

Rotates a triangle or quad so that the given edge is last in the vertex list.

Definition at line 1052 of file eggMesherStrip.cxx.

References can_invert(), rotate_back(), and rotate_forward().

Referenced by mate_pieces(), mate_strips(), and rotate_to_front().

◆ rotate_to_front()

void EggMesherStrip::rotate_to_front ( const EggMesherEdge edge)

Rotates a triangle or quad so that the given edge is first in the vertex list.

Definition at line 1010 of file eggMesherStrip.cxx.

References rotate_back(), rotate_forward(), and rotate_to_back().

Referenced by find_adjacent_edge(), and mate_strips().

◆ type_category()

int EggMesherStrip::type_category ( ) const
inline

Returns an integer which gives a heuristic about the similarity of different strip types.

In general, closer numbers are more similar.

Definition at line 74 of file eggMesherStrip.I.

References rotate_forward().

Referenced by coplanarity(), pick_mate(), and pick_sheet_mate().

◆ would_reverse_tail()

bool EggMesherStrip::would_reverse_tail ( EggMesherStrip::PrimType  want_type) const

Returns true if convert_to_type() would reverse the tail edge of the given strip, false otherwise.

Definition at line 1157 of file eggMesherStrip.cxx.

References convert_to_type().

Referenced by is_odd(), and mate_strips().


The documentation for this class was generated from the following files: