DetourCommon.h File Reference

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Functions
General helper functions
template<class T >
void	dtSwap (T &a, T &b)
	Swaps the values of the two parameters.
template<class T >
T	dtMin (T a, T b)
	Returns the minimum of two values.
template<class T >
T	dtMax (T a, T b)
	Returns the maximum of two values.
template<class T >
T	dtAbs (T a)
	Returns the absolute value.
template<class T >
T	dtSqr (T a)
	Returns the square of the value.
template<class T >
T	dtClamp (T v, T mn, T mx)
	Clamps the value to the specified range.
float	dtSqrt (float x)
	Returns the square root of the value.
Vector helper functions.
void	dtVcross (float *dest, const float *v1, const float *v2)
	Derives the cross product of two vectors. (v1 x v2)
float	dtVdot (const float *v1, const float *v2)
	Derives the dot product of two vectors. (v1 . v2)
void	dtVmad (float *dest, const float *v1, const float *v2, const float s)
	Performs a scaled vector addition. (v1 + (v2 * s))
void	dtVlerp (float *dest, const float *v1, const float *v2, const float t)
	Performs a linear interpolation between two vectors. (v1 toward v2)
void	dtVadd (float *dest, const float *v1, const float *v2)
	Performs a vector addition. (v1 + v2)
void	dtVsub (float *dest, const float *v1, const float *v2)
	Performs a vector subtraction. (v1 - v2)
void	dtVscale (float *dest, const float *v, const float t)
	Scales the vector by the specified value. (v * t)
void	dtVmin (float *mn, const float *v)
	Selects the minimum value of each element from the specified vectors.
void	dtVmax (float *mx, const float *v)
	Selects the maximum value of each element from the specified vectors.
void	dtVset (float *dest, const float x, const float y, const float z)
	Sets the vector elements to the specified values.
void	dtVcopy (float *dest, const float *a)
	Performs a vector copy.
float	dtVlen (const float *v)
	Derives the scalar length of the vector.
float	dtVlenSqr (const float *v)
	Derives the square of the scalar length of the vector. (len * len)
float	dtVdist (const float *v1, const float *v2)
	Returns the distance between two points.
float	dtVdistSqr (const float *v1, const float *v2)
	Returns the square of the distance between two points.
float	dtVdist2D (const float *v1, const float *v2)
	Derives the distance between the specified points on the xz-plane.
float	dtVdist2DSqr (const float *v1, const float *v2)
	Derives the square of the distance between the specified points on the xz-plane.
void	dtVnormalize (float *v)
	Normalizes the vector.
bool	dtVequal (const float *p0, const float *p1)
	Performs a 'sloppy' colocation check of the specified points.
float	dtVdot2D (const float *u, const float *v)
	Derives the dot product of two vectors on the xz-plane. (u . v)
float	dtVperp2D (const float *u, const float *v)
	Derives the xz-plane 2D perp product of the two vectors. (uz*vx - ux*vz)
Computational geometry helper functions.
float	dtTriArea2D (const float *a, const float *b, const float *c)
	Derives the signed xz-plane area of the triangle ABC, or the relationship of line AB to point C.
bool	dtOverlapQuantBounds (const unsigned short amin[3], const unsigned short amax[3], const unsigned short bmin[3], const unsigned short bmax[3])
	Determines if two axis-aligned bounding boxes overlap.
bool	dtOverlapBounds (const float *amin, const float *amax, const float *bmin, const float *bmax)
	Determines if two axis-aligned bounding boxes overlap.
void	dtClosestPtPointTriangle (float *closest, const float *p, const float *a, const float *b, const float *c)
	Derives the closest point on a triangle from the specified reference point.
bool	dtClosestHeightPointTriangle (const float *p, const float *a, const float *b, const float *c, float &h)
	Derives the y-axis height of the closest point on the triangle from the specified reference point.
bool	dtIntersectSegmentPoly2D (const float *p0, const float *p1, const float *verts, int nverts, float &tmin, float &tmax, int &segMin, int &segMax)
bool	dtPointInPolygon (const float *pt, const float *verts, const int nverts)
	Determines if the specified point is inside the convex polygon on the xz-plane.
bool	dtDistancePtPolyEdgesSqr (const float *pt, const float *verts, const int nverts, float *ed, float *et)
float	dtDistancePtSegSqr2D (const float *pt, const float *p, const float *q, float &t)
void	dtCalcPolyCenter (float *tc, const unsigned short *idx, int nidx, const float *verts)
	Derives the centroid of a convex polygon.
bool	dtOverlapPolyPoly2D (const float *polya, const int npolya, const float *polyb, const int npolyb)
	Determines if the two convex polygons overlap on the xz-plane.
Miscellaneous functions.
unsigned int	dtNextPow2 (unsigned int v)
unsigned int	dtIlog2 (unsigned int v)
int	dtAlign4 (int x)
int	dtOppositeTile (int side)
void	dtSwapByte (unsigned char *a, unsigned char *b)
void	dtSwapEndian (unsigned short *v)
void	dtSwapEndian (short *v)
void	dtSwapEndian (unsigned int *v)
void	dtSwapEndian (int *v)
void	dtSwapEndian (float *v)
void	dtRandomPointInConvexPoly (const float *pts, const int npts, float *areas, const float s, const float t, float *out)

---

Function Documentation

template<class T >

T dtAbs

(

T

a

)

[inline]

Returns the absolute value.

Parameters:

[in]

a

The value.

Returns:

The absolute value of the specified value.

Definition at line 55 of file DetourCommon.h.

int dtAlign4

(

int

x

)

[inline]

Definition at line 435 of file DetourCommon.h.

void dtCalcPolyCenter	(	float *	tc,
		const unsigned short *	idx,
		int	nidx,
		const float *	verts
	)

Derives the centroid of a convex polygon.

Parameters:

[out]	tc	The centroid of the polgyon. [(x, y, z)]
[in]	idx	The polygon indices. [(vertIndex) * nidx]
[in]	nidx	The number of indices in the polygon. [Limit: >= 3]
[in]	verts	The polygon vertices. [(x, y, z) * vertCount]

template<class T >

T dtClamp	(	T	v,
		T	mn,
		T	mx
	)		[inline]

Clamps the value to the specified range.

Parameters:

[in]	v	The value to clamp.
[in]	mn	The minimum permitted return value.
[in]	mx	The maximum permitted return value.

Returns:

The value, clamped to the specified range.

Definition at line 67 of file DetourCommon.h.

bool dtClosestHeightPointTriangle	(	const float *	p,
		const float *	a,
		const float *	b,
		const float *	c,
		float &	h
	)

Derives the y-axis height of the closest point on the triangle from the specified reference point.

Parameters:

[in]	p	The reference point from which to test. [(x, y, z)]
[in]	a	Vertex A of triangle ABC. [(x, y, z)]
[in]	b	Vertex B of triangle ABC. [(x, y, z)]
[in]	c	Vertex C of triangle ABC. [(x, y, z)]
[out]	h	The resulting height.

void dtClosestPtPointTriangle	(	float *	closest,
		const float *	p,
		const float *	a,
		const float *	b,
		const float *	c
	)

Derives the closest point on a triangle from the specified reference point.

Parameters:

[out]	closest	The closest point on the triangle.
[in]	p	The reference point from which to test. [(x, y, z)]
[in]	a	Vertex A of triangle ABC. [(x, y, z)]
[in]	b	Vertex B of triangle ABC. [(x, y, z)]
[in]	c	Vertex C of triangle ABC. [(x, y, z)]

bool dtDistancePtPolyEdgesSqr	(	const float *	pt,
		const float *	verts,
		const int	nverts,
		float *	ed,
		float *	et
	)

float dtDistancePtSegSqr2D	(	const float *	pt,
		const float *	p,
		const float *	q,
		float &	t
	)

unsigned int dtIlog2

(

unsigned int

v

)

[inline]

Definition at line 423 of file DetourCommon.h.

bool dtIntersectSegmentPoly2D	(	const float *	p0,
		const float *	p1,
		const float *	verts,
		int	nverts,
		float &	tmin,
		float &	tmax,
		int &	segMin,
		int &	segMax
	)

template<class T >

T dtMax	(	T	a,
		T	b
	)		[inline]

Returns the maximum of two values.

Parameters:

[in]	a	Value A
[in]	b	Value B

Returns:

The maximum of the two values.

Definition at line 50 of file DetourCommon.h.

template<class T >

T dtMin	(	T	a,
		T	b
	)		[inline]

Returns the minimum of two values.

Parameters:

[in]	a	Value A
[in]	b	Value B

Returns:

The minimum of the two values.

Definition at line 44 of file DetourCommon.h.

unsigned int dtNextPow2

(

unsigned int

v

)

[inline]

Definition at line 411 of file DetourCommon.h.

int dtOppositeTile

(

int

side

)

[inline]

Definition at line 437 of file DetourCommon.h.

bool dtOverlapBounds	(	const float *	amin,
		const float *	amax,
		const float *	bmin,
		const float *	bmax
	)		[inline]

Determines if two axis-aligned bounding boxes overlap.

Parameters:

[in]	amin	Minimum bounds of box A. [(x, y, z)]
[in]	amax	Maximum bounds of box A. [(x, y, z)]
[in]	bmin	Minimum bounds of box B. [(x, y, z)]
[in]	bmax	Maximum bounds of box B. [(x, y, z)]

Returns:

True if the two AABB's overlap.

See also:

dtOverlapQuantBounds

Definition at line 347 of file DetourCommon.h.

bool dtOverlapPolyPoly2D	(	const float *	polya,
		const int	npolya,
		const float *	polyb,
		const int	npolyb
	)

Determines if the two convex polygons overlap on the xz-plane.

Parameters:

[in]	polya	Polygon A vertices. [(x, y, z) * npolya]
[in]	npolya	The number of vertices in polygon A.
[in]	polyb	Polygon B vertices. [(x, y, z) * npolyb]
[in]	npolyb	The number of vertices in polygon B.

Returns:

True if the two polygons overlap.

bool dtOverlapQuantBounds	(	const unsigned short	amin[3],
		const unsigned short	amax[3],
		const unsigned short	bmin[3],
		const unsigned short	bmax[3]
	)		[inline]

Determines if two axis-aligned bounding boxes overlap.

Parameters:

[in]	amin	Minimum bounds of box A. [(x, y, z)]
[in]	amax	Maximum bounds of box A. [(x, y, z)]
[in]	bmin	Minimum bounds of box B. [(x, y, z)]
[in]	bmax	Maximum bounds of box B. [(x, y, z)]

Returns:

True if the two AABB's overlap.

See also:

dtOverlapBounds

Definition at line 330 of file DetourCommon.h.

bool dtPointInPolygon	(	const float *	pt,
		const float *	verts,
		const int	nverts
	)

Determines if the specified point is inside the convex polygon on the xz-plane.

Parameters:

[in]	pt	The point to check. [(x, y, z)]
[in]	verts	The polygon vertices. [(x, y, z) * nverts]
[in]	nverts	The number of vertices. [Limit: >= 3]

Returns:

True if the point is inside the polygon.

void dtRandomPointInConvexPoly	(	const float *	pts,
		const int	npts,
		float *	areas,
		const float	s,
		const float	t,
		float *	out
	)

template<class T >

T dtSqr

(

T

a

)

[inline]

Returns the square of the value.

Parameters:

[in]

a

The value.

Returns:

The square of the value.

Definition at line 60 of file DetourCommon.h.

float dtSqrt

(

float

x

)

Returns the square root of the value.

Parameters:

[in]

x

The value.

Returns:

The square root of the vlaue.

template<class T >

void dtSwap	(	T &	a,
		T &	b
	)		[inline]

Swaps the values of the two parameters.

Parameters:

[in,out]	a	Value A
[in,out]	b	Value B

Definition at line 38 of file DetourCommon.h.

void dtSwapByte	(	unsigned char *	a,
		unsigned char *	b
	)		[inline]

Definition at line 439 of file DetourCommon.h.

void dtSwapEndian

(

unsigned int *

v

)

[inline]

Definition at line 458 of file DetourCommon.h.

void dtSwapEndian

(

unsigned short *

v

)

[inline]

Definition at line 446 of file DetourCommon.h.

void dtSwapEndian

(

short *

v

)

[inline]

Definition at line 452 of file DetourCommon.h.

void dtSwapEndian

(

float *

v

)

[inline]

Definition at line 470 of file DetourCommon.h.

void dtSwapEndian

(

int *

v

)

[inline]

Definition at line 464 of file DetourCommon.h.

float dtTriArea2D	(	const float *	a,
		const float *	b,
		const float *	c
	)		[inline]

Derives the signed xz-plane area of the triangle ABC, or the relationship of line AB to point C.

Parameters:

[in]	a	Vertex A. [(x, y, z)]
[in]	b	Vertex B. [(x, y, z)]
[in]	c	Vertex C. [(x, y, z)]

Returns:

The signed xz-plane area of the triangle.

The vertices are projected onto the xz-plane, so the y-values are ignored.

This is a low cost function than can be used for various purposes. Its main purpose is for point/line relationship testing.

In all cases: A value of zero indicates that all vertices are collinear or represent the same point. (On the xz-plane.)

When used for point/line relationship tests, AB usually represents a line against which the C point is to be tested. In this case:

A positive value indicates that point C is to the left of line AB, looking from A toward B.
A negative value indicates that point C is to the right of lineAB, looking from A toward B.

When used for evaluating a triangle:

The absolute value of the return value is two times the area of the triangle when it is projected onto the xz-plane.

A positive return value indicates:

• The vertices are wrapped in the normal Detour wrap direction.
• The triangle's 3D face normal is in the general up direction.

A negative return value indicates:

• The vertices are reverse wrapped. (Wrapped opposite the normal Detour wrap direction.)
• The triangle's 3D face normal is in the general down direction.

Definition at line 314 of file DetourCommon.h.

void dtVadd	(	float *	dest,
		const float *	v1,
		const float *	v2
	)		[inline]

Performs a vector addition. (v1 + v2)

Parameters:

[out]	dest	The result vector. [(x, y, z)]
[in]	v1	The base vector. [(x, y, z)]
[in]	v2	The vector to add to v1. [(x, y, z)]

Definition at line 126 of file DetourCommon.h.

void dtVcopy	(	float *	dest,
		const float *	a
	)		[inline]

Performs a vector copy.

Parameters:

[out]	dest	The result. [(x, y, z)]
[in]	a	The vector to copy. [(x, y, z)]

Definition at line 188 of file DetourCommon.h.

void dtVcross	(	float *	dest,
		const float *	v1,
		const float *	v2
	)		[inline]

Derives the cross product of two vectors. (v1 x v2)

Parameters:

[out]	dest	The cross product. [(x, y, z)]
[in]	v1	A Vector [(x, y, z)]
[in]	v2	A vector [(x, y, z)]

Definition at line 82 of file DetourCommon.h.

float dtVdist	(	const float *	v1,
		const float *	v2
	)		[inline]

Returns the distance between two points.

Parameters:

[in]	v1	A point. [(x, y, z)]
[in]	v2	A point. [(x, y, z)]

Returns:

The distance between the two points.

Definition at line 215 of file DetourCommon.h.

float dtVdist2D	(	const float *	v1,
		const float *	v2
	)		[inline]

Derives the distance between the specified points on the xz-plane.

Parameters:

[in]	v1	A point. [(x, y, z)]
[in]	v2	A point. [(x, y, z)]

Returns:

The distance between the point on the xz-plane.

The vectors are projected onto the xz-plane, so the y-values are ignored.

Definition at line 241 of file DetourCommon.h.

float dtVdist2DSqr	(	const float *	v1,
		const float *	v2
	)		[inline]

Derives the square of the distance between the specified points on the xz-plane.

Parameters:

[in]	v1	A point. [(x, y, z)]
[in]	v2	A point. [(x, y, z)]

Returns:

The square of the distance between the point on the xz-plane.

Definition at line 252 of file DetourCommon.h.

float dtVdistSqr	(	const float *	v1,
		const float *	v2
	)		[inline]

Returns the square of the distance between two points.

Parameters:

[in]	v1	A point. [(x, y, z)]
[in]	v2	A point. [(x, y, z)]

Returns:

The square of the distance between the two points.

Definition at line 227 of file DetourCommon.h.

float dtVdot	(	const float *	v1,
		const float *	v2
	)		[inline]

Derives the dot product of two vectors. (v1 . v2)

Parameters:

[in]	v1	A Vector [(x, y, z)]
[in]	v2	A vector [(x, y, z)]

Returns:

The dot product.

Definition at line 93 of file DetourCommon.h.

float dtVdot2D	(	const float *	u,
		const float *	v
	)		[inline]

Derives the dot product of two vectors on the xz-plane. (u . v)

Parameters:

[in]	u	A vector [(x, y, z)]
[in]	v	A vector [(x, y, z)]

Returns:

The dot product on the xz-plane.

The vectors are projected onto the xz-plane, so the y-values are ignored.

Definition at line 289 of file DetourCommon.h.

bool dtVequal	(	const float *	p0,
		const float *	p1
	)		[inline]

Performs a 'sloppy' colocation check of the specified points.

Parameters:

[in]	p0	A point. [(x, y, z)]
[in]	p1	A point. [(x, y, z)]

Returns:

True if the points are considered to be at the same location.

Basically, this function will return true if the specified points are close enough to eachother to be considered colocated.

Definition at line 276 of file DetourCommon.h.

float dtVlen

(

const float *

v

)

[inline]

Derives the scalar length of the vector.

Parameters:

[in]

v

The vector. [(x, y, z)]

Returns:

The scalar length of the vector.

Definition at line 198 of file DetourCommon.h.

float dtVlenSqr

(

const float *

v

)

[inline]

Derives the square of the scalar length of the vector. (len * len)

Parameters:

[in]

v

The vector. [(x, y, z)]

Returns:

The square of the scalar length of the vector.

Definition at line 206 of file DetourCommon.h.

void dtVlerp	(	float *	dest,
		const float *	v1,
		const float *	v2,
		const float	t
	)		[inline]

Performs a linear interpolation between two vectors. (v1 toward v2)

Parameters:

[out]	dest	The result vector. [(x, y, x)]
[in]	v1	The starting vector.
[in]	v2	The destination vector.
[in]	t	The interpolation factor. [Limits: 0 <= value <= 1.0]

Definition at line 115 of file DetourCommon.h.

void dtVmad	(	float *	dest,
		const float *	v1,
		const float *	v2,
		const float	s
	)		[inline]

Performs a scaled vector addition. (v1 + (v2 * s))

Parameters:

[out]	dest	The result vector. [(x, y, z)]
[in]	v1	The base vector. [(x, y, z)]
[in]	v2	The vector to scale and add to v1. [(x, y, z)]
[in]	s	The amount to scale v2 by before adding to v1.

Definition at line 103 of file DetourCommon.h.

void dtVmax	(	float *	mx,
		const float *	v
	)		[inline]

Selects the maximum value of each element from the specified vectors.

Parameters:

[in,out]	mx	A vector. (Will be updated with the result.) [(x, y, z)]
[in]	v	A vector. [(x, y, z)]

Definition at line 168 of file DetourCommon.h.

void dtVmin	(	float *	mn,
		const float *	v
	)		[inline]

Selects the minimum value of each element from the specified vectors.

Parameters:

[in,out]	mn	A vector. (Will be updated with the result.) [(x, y, z)]
[in]	v	A vector. [(x, y, z)]

Definition at line 158 of file DetourCommon.h.

void dtVnormalize

(

float *

v

)

[inline]

Normalizes the vector.

Parameters:

[in,out]

v

The vector to normalize. [(x, y, z)]

Definition at line 261 of file DetourCommon.h.

float dtVperp2D	(	const float *	u,
		const float *	v
	)		[inline]

Derives the xz-plane 2D perp product of the two vectors. (uz*vx - ux*vz)

Parameters:

[in]	u	The LHV vector [(x, y, z)]
[in]	v	The RHV vector [(x, y, z)]

Returns:

The dot product on the xz-plane.

The vectors are projected onto the xz-plane, so the y-values are ignored.

Definition at line 300 of file DetourCommon.h.

void dtVscale	(	float *	dest,
		const float *	v,
		const float	t
	)		[inline]

Scales the vector by the specified value. (v * t)

Parameters:

[out]	dest	The result vector. [(x, y, z)]
[in]	v	The vector to scale. [(x, y, z)]
[in]	t	The scaling factor.

Definition at line 148 of file DetourCommon.h.

void dtVset	(	float *	dest,
		const float	x,
		const float	y,
		const float	z
	)		[inline]

Sets the vector elements to the specified values.

Parameters:

[out]	dest	The result vector. [(x, y, z)]
[in]	x	The x-value of the vector.
[in]	y	The y-value of the vector.
[in]	z	The z-value of the vector.

Definition at line 180 of file DetourCommon.h.

void dtVsub	(	float *	dest,
		const float *	v1,
		const float *	v2
	)		[inline]

Performs a vector subtraction. (v1 - v2)

Parameters:

[out]	dest	The result vector. [(x, y, z)]
[in]	v1	The base vector. [(x, y, z)]
[in]	v2	The vector to subtract from v1. [(x, y, z)]

Definition at line 137 of file DetourCommon.h.