Winding Manipulation

Data Structures
struct	winding_s

Macros
#define	ON_EPSILON   0.05

Typedefs
typedef struct winding_s	winding_t

Functions
winding_t *	BaseWindingForPlane (const struct plane_s *p)
	Create a very large four-point winding with all point on the plane. More...
winding_t *	ClipWinding (winding_t *in, struct plane_s *split, qboolean keepon)
	Clip the winding to the plain. More...
winding_t *	CopyWinding (const winding_t *w)
	Create a new winding with the same points as the given winding. More...
winding_t *	CopyWindingReverse (const winding_t *w)
	Create a new winding with the reverse points of the given winding. More...
void	DivideWinding (winding_t *in, struct plane_s *split, winding_t **front, winding_t **back)
	Divide a winding by a plane, producing one or two windings. More...
void	FreeWinding (winding_t *w)
	Free the winding. More...
winding_t *	NewWinding (int points)
	Create a new, empty winding with space for the specified number of points. More...
winding_t *	WindingVectors (const winding_t *w, int unit)
	Create a new "winding" that holds the unit vectors of the edges of the given winding. More...

Detailed Description

Macro Definition Documentation

#define ON_EPSILON   0.05

Typedef Documentation

typedef struct winding_s winding_t

Function Documentation

winding_t* BaseWindingForPlane

(

const struct plane_s *

p

)

Create a very large four-point winding with all point on the plane.

The winding will be a box with aligned with the axes of the plane. The order of yhe points is clockwise when viewed from the front side of the plane.

In terms of s and t, the axes of the plane will be such that t (up) is the projection of either the z-axis or the x-axis (whichever is "closer"), and s is to the right (n = s cross t).

Parameters

p	The plane on which to create the winding.

Returns

The new winding.

Note

It is the caller's responsibiltiy to free the new winding.

winding_t* ClipWinding	(	winding_t *	in,
		struct plane_s *	split,
		qboolean	keepon
	)

Clip the winding to the plain.

The new winding will be the part of the input winding that is on the front side of the plane.

The direction of the winding is preserved.

Note

It is the caller's responsibiltiy to free the new winding.

The input winding will be freed.

Parameters

in	The winding to be clipped.
split	The plane by which the winding will be clipped.
keepon	If true, an exactly on-plane winding will be saved, otherwise it will be clipped away.

Returns

The new winding representing the part of the input winding on the font side of the plane, or NULL if the winding has been clipped away.

winding_t* CopyWinding

(

const winding_t *

w

)

Create a new winding with the same points as the given winding.

Parameters

w	The winding to copy.

Returns

The new winding.

Note

It is the caller's responsibiltiy to free the new winding.

winding_t* CopyWindingReverse

(

const winding_t *

w

)

Create a new winding with the reverse points of the given winding.

This is useful when a winding for the back side of a plane is required.

Parameters

w	The winding to copy.

Returns

The new winding.

Note

It is the caller's responsibiltiy to free the new winding.

void DivideWinding	(	winding_t *	in,
		struct plane_s *	split,
		winding_t **	front,
		winding_t **	back
	)

Divide a winding by a plane, producing one or two windings.

Note

The original winding is not damaged or freed.

If one of front or back is NULL, the other will point to the input winding.

If neither front nor back are NULL, then both will be new windings and the caller will be responsible for freeing them.

Parameters

in	The winding to be divided.
split	The plane by which the winding will be divided.
front	Set to the part of the input winding that is in front of the plane, or NULL if no part of the winding is in front of the plane.
back	Set to the part of the input winding that is behind the plane, or NULL if no part of the winding is behind the plane.

void FreeWinding

(

winding_t *

w

)

Free the winding.

Parameters

w	The winding to be freed.

winding_t* NewWinding

(

int

points

)

Create a new, empty winding with space for the specified number of points.

Parameters

points

The number of points for which to leave space.

Returns

The new winding.

Note

It is the caller's responsibiltiy to free the new winding.

winding_t* WindingVectors	(	const winding_t *	w,
		int	unit
	)

Create a new "winding" that holds the unit vectors of the edges of the given winding.

Parameters

w	The winding to convert.
unit	If true, normalize the vectors.

Returns

The "winding" holding the (unit) vectors.

Note

It is the caller's responsibiltiy to free the new winding.