Contains a ray-vs-shape collider. More...

#include <RayCollider.h>

Inheritance diagram for ParaEngine::CRayCollider:

Public Member Functions
bool	Collide (const CShapeRay &world_ray, const CShapeAABB &world_AABB, const Matrix4 *world=NULL)
	Generic stabbing query for generic OPCODE models. More...

bool	Collide (const CShapeRay &world_ray, const CShapeOBB &world_oob)

bool	Intersect (const CShapeRay &world_ray, const CShapeAABB &world_AABB, float pDist, const Matrix4 world=NULL)

bool	Intersect (const CShapeRay &world_ray, const CShapeOBB &world_oob, float *pDist)

void	SetCulling (bool flag)
	Settings: enable or disable back face culling. More...

void	SetMaxDist (float max_dist)
	Settings: sets the higher distance bound. More...

Public Member Functions inherited from ParaEngine::Collider
BOOL	GetContactStatus () const
	Gets the last collision status after a collision query. More...

BOOL	FirstContactEnabled () const
	Gets the "first contact" mode. More...

BOOL	TemporalCoherenceEnabled () const
	Gets the temporal coherence mode. More...

BOOL	ContactFound () const
	Checks a first contact has already been found. More...

BOOL	TemporalHit () const
	Checks there's been an early exit due to temporal coherence;. More...

BOOL	SkipPrimitiveTests () const
	Checks primitive tests are enabled;. More...

void	SetFirstContact (bool flag)
	Reports all contacts (false) or first contact only (true) More...

void	SetTemporalCoherence (bool flag)
	Enable/disable temporal coherence. More...

void	SetPrimitiveTests (bool flag)
	Enable/disable primitive tests. More...

Protected Member Functions
bool	RayAABBOverlap (const Vector3 &center, const Vector3 &extents)
	Computes a ray-AABB overlap test using the separating axis theorem. More...

bool	SegmentAABBOverlap (const Vector3 &center, const Vector3 &extents)
	Computes a segment-AABB overlap test using the separating axis theorem. More...

bool	RayTriOverlap (const Vector3 &vert0, const Vector3 &vert1, const Vector3 &vert2)

bool	InitQuery (const CShapeRay &world_ray, const Matrix4 *world=NULL)
	Initializes a stabbing query : More...

Protected Member Functions inherited from ParaEngine::Collider
virtual void	InitQuery ()
	Initializes a query.

Protected Attributes
Vector3	mOrigin
	Ray origin.

Vector3	mDir
	Ray direction (normalized)

Vector3	mFDir
	fabsf(mDir)

Vector3	mData

Vector3	mData2

Vector3	mCenterCoeff

Vector3	mExtentsCoeff

float	mMaxDist
	Valid segment on the ray.

bool	mCulling
	Stab culled faces or not.

Protected Attributes inherited from ParaEngine::Collider
DWORD	mFlags
	Bit flags.

Detailed Description

Contains a ray-vs-shape collider.

This class performs a stabbing query on an AABB, OOB, i.e. does a ray-mesh collision. Note: this is a reduced version for OPCODE - Optimized Collision Detection in ODE.

HIGHER DISTANCE BOUND:

If P0 and P1 are two 3D points, let's define:
- d = distance between P0 and P1
- Origin    = P0
- Direction = (P1 - P0) / d = normalized direction vector
- A parameter t such as a point P on the line (P0,P1) is P = Origin + t * Direction
- t = 0  -->  P = P0
- t = d  -->  P = P1

Then we can define a general "ray" as:

    struct Ray
    {
        Point   Origin;
        Point   Direction;
    };

But it actually maps three different things:
- a segment,   when 0 <= t <= d
- a half-line, when 0 <= t < +infinity, or -infinity < t <= d
- a line,      when -infinity < t < +infinity

In Opcode, we support segment queries, which yield half-line queries by setting d = +infinity.
We don't support line-queries. If you need them, shift the origin along the ray by an appropriate margin.

In short, the lower bound is always 0, and you can setup the higher bound "d" with RayCollider::SetMaxDist().

Query   |segment            |half-line      |line
--------|-------------------|---------------|----------------
Usages  |-shadow feelers    |-raytracing    |-
        |-sweep tests       |-in/out tests  |

FIRST CONTACT:

- You can setup "first contact" mode or "all contacts" mode with RayCollider::SetFirstContact().
- In "first contact" mode we return as soon as the ray hits one face. If can be useful e.g. for shadow feelers, where
you want to know whether the path to the light is free or not (a boolean answer is enough).
- In "all contacts" mode we return all faces hit by the ray.

TEMPORAL COHERENCE:

- You can enable or disable temporal coherence with RayCollider::SetTemporalCoherence().
- It currently only works in "first contact" mode.
- If temporal coherence is enabled, the previously hit triangle is cached during the first query. Then, next queries
start by colliding the ray against the cached triangle. If they still collide, we return immediately.

CLOSEST HIT:

- You can enable or disable "closest hit" with RayCollider::SetClosestHit().
- It currently only works in "all contacts" mode.
- If closest hit is enabled, faces are sorted by distance on-the-fly and the closest one only is reported.

BACKFACE CULLING:

- You can enable or disable backface culling with RayCollider::SetCulling().
- If culling is enabled, ray will not hit back faces (only front faces).

Member Function Documentation

§ Collide()

bool CRayCollider::Collide	(	const CShapeRay &	world_ray,
		const CShapeAABB &	world_AABB,
		const Matrix4 *	world = `NULL`
	)

Generic stabbing query for generic OPCODE models.

After the call, access the results:

with GetContactStatus()
in the user-provided destination array

Parameters

world_ray	[in] stabbing ray in world space
model	[in] Opcode model to collide with
world	[in] model's world matrix, or null
cache	[in] a possibly cached face index, or null

Returns: true if success

Warning: SCALE NOT SUPPORTED. The matrices must contain rotation & translation parts only.

§ InitQuery()

bool CRayCollider::InitQuery	(	const CShapeRay &	world_ray,
		const Matrix4 *	world = `NULL`
	)

protected

Initializes a stabbing query :

reset stats & contact status
compute ray in local space
check temporal coherence

Parameters

world_ray	[in] stabbing ray in world space
world	[in] object's world matrix, or null

Returns: TRUE if we can return immediately

Warning: SCALE NOT SUPPORTED. The matrix must contain rotation & translation parts only.

§ Intersect()

bool CRayCollider::Intersect	(	const CShapeRay &	world_ray,
		const CShapeAABB &	world_AABB,
		float *	pDist,
		const Matrix4 *	world = `NULL`
	)

See also: Collide(). This function not only test if the ray and the box intersect, but also returns the intersection point

Parameters

pDist distance to the nearest face is returned.

§ RayAABBOverlap()

bool CRayCollider::RayAABBOverlap	(	const Vector3 &	center,
		const Vector3 &	extents
	)

protected

Computes a ray-AABB overlap test using the separating axis theorem.

Ray is cached within the class.

Parameters

center	[in] AABB center
extents	[in] AABB extents

Returns: true on overlap

§ SegmentAABBOverlap()

bool CRayCollider::SegmentAABBOverlap	(	const Vector3 &	center,
		const Vector3 &	extents
	)

protected

Computes a segment-AABB overlap test using the separating axis theorem.

Segment is cached within the class.

Parameters

center	[in] AABB center
extents	[in] AABB extents

Returns: true on overlap

§ SetCulling()

void CRayCollider::SetCulling ( bool flag )

Settings: enable or disable back face culling.

Parameters

flag	[in] true to enable back face culling

See also: SetClosestHit(bool flag); SetMaxDist(float max_dist); SetDestination(StabbedFaces* sf)

§ SetMaxDist()

void CRayCollider::SetMaxDist ( float max_dist )

Settings: sets the higher distance bound.

Parameters

max_dist [in] higher distance bound. Default = maximal value, for ray queries (else segment)

See also: SetClosestHit(bool flag); SetCulling(bool flag)

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

Client/trunk/ParaEngineClient/3dengine/RayCollider.h
Client/trunk/ParaEngineClient/3dengine/RayCollider.cpp

Public Member Functions

Protected Member Functions

Protected Attributes

Detailed Description

Member Function Documentation

§ Collide()

§ InitQuery()

§ Intersect()

§ RayAABBOverlap()

§ SegmentAABBOverlap()

§ SetCulling()

§ SetMaxDist()