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).
void	combine_edges (EggMesherStrip &other, int remove_sides)
	Removes the edges from the given strip and appends them to our own.
void	convert_to_type (PrimType want_type)
	Converts the EggMesherStrip from whatever form it is--triangle, quad, or quadstrip--into a tristrip or quadstrip.
float	coplanarity (const EggMesherStrip &other) const
	Returns the degree to which the two strips are coplanar.
int	count_neighbors () const
	Returns the number of neighbors the strip shares.
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.
bool	find_ideal_mate (EggMesherStrip &mate, EggMesherEdge &common_edge, const EggVertexPool *vertex_pool)
	Searches our neighbors for the most suitable mate.
const EggMesherEdge *	find_opposite_edge (const EggMesherEdge *edge) const
	Returns the first edge found that shares no vertices with the given edge.
const EggMesherEdge *	find_opposite_edge (int vi) const
	Returns the first edge found that does not contain the given vertex.
int	find_uncommon_vertex (const EggMesherEdge *edge) const
	Returns the first vertex found that is not shared by the given edge.
EggMesherEdge	get_head_edge () const
	Returns an EggMesherEdge which represents the leading edge in the quadstrip or tristrip.
EggMesherEdge	get_tail_edge () const
	Returns an EggMesherEdge which represents the trailing edge in the quadstrip or tristrip.
bool	invert ()
	Reverses the facing of a quadstrip by reversing pairs of vertices.
bool	is_coplanar_with (const EggMesherStrip &other, float threshold) const
	Returns true if the strip and the other strip are coplanar, within the indicated threshold.
bool	is_odd () const
	Returns true if the tristrip or quadstrip contains an odd number of pieces.
bool	mate (const EggVertexPool *vertex_pool)
	Finds a neighboring strip and joins up with it to make a larger strip.
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.
bool	operator!= (const EggMesherStrip &other) const
bool	operator== (const EggMesherStrip &other) const
	Defines equality for strips.
void	output (ostream &out) const
	Formats the vertex for output in some sensible way.
void	output_neighbors (ostream &out) const
	Writes all the neighbor indexes to the ostream.
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.
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.
	PT (EggPrimitive) make_prim(const EggVertexPool *vertex_pool)
void	remove_all_edges ()
	Removes all active edges from the strip.
void	rotate_back ()
	Rotates a triangle or quad by bringing its last vertex to the front.
void	rotate_forward ()
	Rotates a triangle or quad by bringing its first vertex to the back.
void	rotate_to_back (const EggMesherEdge *edge)
	Rotates a triangle or quad so that the given edge is last in the vertex list.
void	rotate_to_front (const EggMesherEdge *edge)
	Rotates a triangle or quad so that the given edge is first in the vertex list.
int	type_category () const
	Returns an integer which gives a heuristic about the similarity of different strip types.
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.
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.
static bool	mate_pieces (EggMesherEdge common_edge, EggMesherStrip &front, EggMesherStrip &back, const EggVertexPool vertex_pool)
	Connects two pieces of arbitrary type, if possible.
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).
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.
Public Attributes
Edges	_edges
bool	_flat_shaded
int	_index
MesherOrigin	_origin
bool	_planar
Normald	_plane_normal
float	_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

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 1094 of file eggMesherStrip.cxx.

Referenced by invert(), and mate_strips().

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 1280 of file eggMesherStrip.cxx.

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

Referenced by mate_pieces().

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 1209 of file eggMesherStrip.cxx.

Referenced by mate_strips().

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 803 of file eggMesherStrip.cxx.

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

Referenced by mate_pieces().

float 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.

Referenced by is_coplanar_with(), and pick_mate().

int EggMesherStrip::count_neighbors ( ) const

Returns the number of neighbors the strip shares.

Definition at line 881 of file eggMesherStrip.cxx.

Referenced by output(), and pick_mate().

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 986 of file eggMesherStrip.cxx.

References EggMesherEdge::contains_vertex().

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 447 of file eggMesherStrip.cxx.

References pick_mate().

Referenced by mate().

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 943 of file eggMesherStrip.cxx.

References EggMesherEdge::contains_vertex().

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 963 of file eggMesherStrip.cxx.

References EggMesherEdge::contains_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 917 of file eggMesherStrip.cxx.

Referenced by convex_quad(), and mate_pieces().

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.

Referenced by combine_edges(), and mate_strips().

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.

Referenced by combine_edges(), and mate_strips().

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 1106 of file eggMesherStrip.cxx.

References can_invert().

Referenced by mate_strips(), and must_invert().

bool EggMesherStrip::is_coplanar_with	(	const EggMesherStrip &	other,
		float	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().

bool EggMesherStrip::is_odd ( ) const

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

Definition at line 1136 of file eggMesherStrip.cxx.

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

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 414 of file eggMesherStrip.cxx.

References find_ideal_mate(), and mate_pieces().

Referenced by measure_sheet().

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 481 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 mate().

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 632 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().

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 182 of file eggMesherStrip.cxx.

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

Referenced by measure_sheet().

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 767 of file eggMesherStrip.cxx.

References invert(), and is_odd().

Referenced by mate_strips().

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.

void EggMesherStrip::output ( ostream & out ) const

Formats the vertex for output in some sensible way.

Definition at line 1444 of file eggMesherStrip.cxx.

References count_neighbors(), and output_neighbors().

void EggMesherStrip::output_neighbors ( ostream & out ) const

Writes all the neighbor indexes to the ostream.

Definition at line 897 of file eggMesherStrip.cxx.

Referenced by output().

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