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 EggMesherEdge *	find_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 EggMesherEdge *	find_opposite_edge (int vi) const
	Returns the first edge found that does not contain the given vertex. More...

const EggMesherEdge *	find_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 (std::ostream &out) const
	Formats the vertex for output in some sensible way. More...

void	output_neighbors (std::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 30 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 1030 of file eggMesherStrip.cxx.

Referenced by invert(), and mate_strips().

◆ 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 1203 of file eggMesherStrip.cxx.

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

◆ 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 1134 of file eggMesherStrip.cxx.

Referenced by mate_strips().

◆ 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 766 of file eggMesherStrip.cxx.

References find_uncommon_vertex().

◆ 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 49 of file eggMesherStrip.I.

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 838 of file eggMesherStrip.cxx.

Referenced by 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 929 of file eggMesherStrip.cxx.

References EggMesherEdge::contains_vertex().

◆ 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 427 of file eggMesherStrip.cxx.

References mate(), and pick_mate().

◆ 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 892 of file eggMesherStrip.cxx.

◆ 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 909 of file eggMesherStrip.cxx.

References EggMesherEdge::contains_vertex().

◆ 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 869 of file eggMesherStrip.cxx.

Referenced by convex_quad().

◆ 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 104 of file eggMesherStrip.I.

Referenced by combine_edges(), and mate_strips().

◆ 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 117 of file eggMesherStrip.I.

Referenced by combine_edges(), 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 1039 of file eggMesherStrip.cxx.

References can_invert().

Referenced by 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 38 of file eggMesherStrip.I.

References coplanarity().

◆ is_odd()

bool EggMesherStrip::is_odd ( ) const

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

Definition at line 1066 of file eggMesherStrip.cxx.

Referenced by combine_edges(), 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 398 of file eggMesherStrip.cxx.

Referenced by find_ideal_mate(), and 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 459 of file eggMesherStrip.cxx.

◆ 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 602 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().

◆ 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 173 of file eggMesherStrip.cxx.

References mate(), and pick_sheet_mate().

◆ 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 733 of file eggMesherStrip.cxx.

References 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 129 of file eggMesherStrip.I.

◆ output()

void EggMesherStrip::output ( std::ostream & out ) const

Formats the vertex for output in some sensible way.

Definition at line 1353 of file eggMesherStrip.cxx.

◆ output_neighbors()

void EggMesherStrip::output_neighbors ( std::ostream & out ) const

Writes all the neighbor indexes to the ostream.

Definition at line 852 of file eggMesherStrip.cxx.

◆ 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 1271 of file eggMesherStrip.cxx.

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

Referenced by find_ideal_mate().

◆ 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 1325 of file eggMesherStrip.cxx.

Referenced by measure_sheet().

◆ 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 1252 of file eggMesherStrip.cxx.

◆ rotate_back()

void EggMesherStrip::rotate_back ( )

inline

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

Definition at line 92 of file eggMesherStrip.I.

◆ rotate_forward()

void EggMesherStrip::rotate_forward ( )

inline

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

Definition at line 83 of file eggMesherStrip.I.

◆ 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 989 of file eggMesherStrip.cxx.

Referenced by mate_strips().

◆ 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 949 of file eggMesherStrip.cxx.

Referenced by 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 61 of file eggMesherStrip.I.

Referenced by pick_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 1083 of file eggMesherStrip.cxx.

Referenced by mate_strips().

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

panda/src/egg/eggMesherStrip.h
panda/src/egg/eggMesherStrip.cxx
panda/src/egg/eggMesherStrip.I

Public Types

Public Member Functions

Static Public Member Functions

Public Attributes

Detailed Description

Member Function Documentation

◆ can_invert()

◆ combine_edges()

◆ convert_to_type()

◆ convex_quad()

◆ coplanarity()

◆ count_neighbors()

◆ find_adjacent_edge()

◆ find_ideal_mate()

◆ find_opposite_edge() [1/2]

◆ find_opposite_edge() [2/2]

◆ find_uncommon_vertex()

◆ get_head_edge()

◆ get_tail_edge()

◆ invert()

◆ is_coplanar_with()

◆ is_odd()

◆ mate()

◆ mate_pieces()

◆ mate_strips()

◆ measure_sheet()

◆ must_invert()

◆ operator==()

◆ output()

◆ output_neighbors()

◆ pick_mate()

◆ pick_sheet_mate()

◆ remove_all_edges()

◆ rotate_back()

◆ rotate_forward()

◆ rotate_to_back()

◆ rotate_to_front()

◆ type_category()

◆ would_reverse_tail()