MCore::Ray Class Reference

#include <Ray.h>

Public Member Functions
MCORE_INLINE	Ray ()
MCORE_INLINE	Ray (const AZ::Vector3 &org, const AZ::Vector3 &endPoint)
MCORE_INLINE	Ray (const AZ::Vector3 &org, const AZ::Vector3 &endPoint, const AZ::Vector3 &dir)
MCORE_INLINE void	Set (const AZ::Vector3 &org, const AZ::Vector3 &endPoint)
MCORE_INLINE void	SetOrigin (const AZ::Vector3 &org)
MCORE_INLINE void	SetDest (const AZ::Vector3 &dest)
MCORE_INLINE const AZ::Vector3 &	GetOrigin () const
MCORE_INLINE const AZ::Vector3 &	GetDest () const
MCORE_INLINE const AZ::Vector3 &	GetDirection () const
bool	Intersects (const BoundingSphere &s, AZ::Vector3 *intersectA=nullptr, AZ::Vector3 *intersectB=nullptr) const
bool	Intersects (const PlaneEq &p, AZ::Vector3 *intersect=nullptr) const
bool	Intersects (const AZ::Vector3 &p1, const AZ::Vector3 &p2, const AZ::Vector3 &p3, AZ::Vector3 *intersect=nullptr, float *baryU=nullptr, float *baryV=nullptr) const
MCORE_INLINE float	Length () const

Detailed Description

The Ray template/class. A ray is normally an infinite line, starting at a given point (the origin) and heading into a given direction. However, this template does not represent an infinite line, but a finite line, since that will be a lot more useful. This means we have an origin, which is the starting point and a destination, which is the end point. This automatically gives us a direction vector too. So basically we now have a finite ray, which is just a 3D line. We can use rays mainly to perform intersection tests. This class provides you with methods to calculate interection information between the ray and bounding spheres, axis aligned bounding boxes, triangles and planes. More intersection tests might be added in a later stage. Or they have already been added, but this documentation should be updated :) Example fields where rays are (often) used are: collision and hit detection, raytracing images, global illumination, lightmap generation, pathtracing, real-time volumetric effects, lensflares, etc.

Constructor & Destructor Documentation

Ray() [1/3]

MCORE_INLINE MCore::Ray::Ray ( )

inline

Default constructor. Does NOT initialize any members. So this would not be a valid ray.

Ray() [2/3]

MCORE_INLINE MCore::Ray::Ray ( const AZ::Vector3 &  org, const AZ::Vector3 &  endPoint  )

inline

Constructor which sets the start and end point of the ray.

Parameters

org	The origin of the ray.
endPoint	The end (destination) point of the ray.

Ray() [3/3]

MCORE_INLINE MCore::Ray::Ray ( const AZ::Vector3 &  org, const AZ::Vector3 &  endPoint, const AZ::Vector3 &  dir  )

inline

Constructor which sets the origin, destination point and direction.

Parameters

org	The origin of the ray, so where it starts.
endPoint	The destination point of the ray, so where it should end.
dir	The normalized direction vector of the ray, which should be (endPoint - startPoint).Normalize()

Member Function Documentation

GetDest()

MCORE_INLINE const AZ::Vector3& MCore::Ray::GetDest ( ) const

inline

Get the destination of the ray.

Returns

The destination point of the ray, so where it ends.

GetDirection()

MCORE_INLINE const AZ::Vector3& MCore::Ray::GetDirection ( ) const

inline

Get the direction of the ray.

Returns

The normalized direction vector of the ray, so the direction its heading to.

GetOrigin()

MCORE_INLINE const AZ::Vector3& MCore::Ray::GetOrigin ( ) const

inline

Get the origin of the ray.

Returns

The origin of the ray, so where it starts.

Intersects() [1/3]

bool MCore::Ray::Intersects	(	const AZ::Vector3 &	p1,
		const AZ::Vector3 &	p2,
		const AZ::Vector3 &	p3,
		AZ::Vector3 *	intersect = nullptr,
		float *	baryU = nullptr,
		float *	baryV = nullptr
	)		const

Perform a ray/triangle intersection test.

Parameters

p1	The first point of the triangle.
p2	The second point of the triangle.
p3	The third point of the triangle.
intersect	If not nullptr, the intersection point will be stored in here, in case of an intersection.
baryU	If not nullptr, the 'u' barycentric coordinate will be stored in here.
baryV	If not nullptr, the 'v' barycentric coordinate will be stored in here.

Returns

Returns true in case of an intersection, otherwise false. If there is no intersection, 'intersect', 'baryU' and 'baryV' will not be modified. You can calculate the uv or normal or whatsoever at the intersection point by using the baryU and baryV values.

The calculation goes like:

valueAtIntersectionPoint = (1-u-v)*A + u*B + v*C;

Where u and v are the values written in baryU and baryV and A, B and C are the three 'attributes' on the 3 points of the triangle. For example the three vertex normals or uv coordinates or colors. Where A is the attribute linked with 'p1', B the attribute linked with 'p2' and C the attribute linked with 'p3'.

To make it easy for you, we created a function caled BarycentricInterpolate() which takes the required parameters and returns the attribute value at the given barycentric coordinates for you. The usage would now be:

valueAtIntersectionPoint = BarycentricInterpolate<Vector3>(u, v, A, B, C);

Where A, B and C could be the vertex normals of the triangle for example. You can easily also calculate the intersection point yourself by using the u and v, by doing this:

intersectionPoint = BarycentricInterpolate<Vector3>(u, v, p1, p2, p3);

See also

BarycentricInterpolate

Intersects() [2/3]

bool MCore::Ray::Intersects	(	const BoundingSphere &	s,
		AZ::Vector3 *	intersectA = nullptr,
		AZ::Vector3 *	intersectB = nullptr
	)		const

Perform a ray/sphere intersection test.

Parameters

s	The bounding sphere to test with.
intersectA	If not nullptr, the closest intersection point will be stored in this vector, in case of an intersection.
intersectB	If not nullptr, the farthest intersection point will be stored in this vector, in case of an intersection.

Returns

Returns true when an intersection occured, otherwise false. If there is no intersection, 'intersectA' and 'intersectB' won't be changed.

Intersects() [3/3]

bool MCore::Ray::Intersects	(	const PlaneEq &	p,
		AZ::Vector3 *	intersect = nullptr
	)		const

Perform a ray/plane intersection test.

Parameters

p	The plane to test with.
intersect	If not nullptr, the intersection point will be stored in this vector, in case of an intersection.

Returns

Returns true when an intersection occured, otherwise false. If there is no intersection, 'intersect' will not be changed.

Length()

MCORE_INLINE float MCore::Ray::Length ( ) const

inline

Calculates the length of the ray.

Returns

The length of the ray.

Set()

MCORE_INLINE void MCore::Ray::Set ( const AZ::Vector3 &  org, const AZ::Vector3 &  endPoint  )

inline

Set the origin and destination point (end point) of the ray. The direction vector will be calculated automatically.

Parameters

org	The origin of the ray, so the start point.
endPoint	The destination of the ray, so the end point.

SetDest()

MCORE_INLINE void MCore::Ray::SetDest ( const AZ::Vector3 &  dest )

inline

Set the destination point of the ray.

Parameters

dest	The destination of the ray.

SetOrigin()

MCORE_INLINE void MCore::Ray::SetOrigin ( const AZ::Vector3 &  org )

inline

Set the origin of the ray, so the start point. The direction will automatically be updated as well.

Parameters

org	The origin.

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

• Gems/EMotionFX/Code/MCore/Source/Ray.h