TriangleMesh Class Reference

A special class to store a triangle mesh with a separate material per triangle. More...

#include <triangle_mesh.hpp>

Classes
class	RigidBodyTriangleMesh

Public Member Functions
	TriangleMesh (bool can_be_transformed)
	Constructor: Initialises all data structures with zero.
	~TriangleMesh ()
	Destructor: delete all allocated data structures.
void	addTriangle (const btVector3 &t1, const btVector3 &t2, const btVector3 &t3, const btVector3 &n1, const btVector3 &n2, const btVector3 &n3, const Material *m)
	Adds a triangle to the bullet mesh.
void	createCollisionShape (bool create_collision_object=true, const char *serialized_bhv=NULL)
	Creates a collision body only, which can be used for raycasting, but has no physical properties.
void	createPhysicalBody (float friction, btCollisionObject::CollisionFlags flags=(btCollisionObject::CollisionFlags) 0, const char *serializedBhv=NULL)
	Creates the physics body for this triangle mesh.
void	removeAll ()
	Removes the created body and/or collision object from the physics world.
void	removeCollisionObject ()
btVector3	getInterpolatedNormal (unsigned int index, const btVector3 &position) const
	Interpolates the normal at the given position for the triangle with a given index.
void	setBody (btRigidBody *body)
	In case of physical objects of shape 'exact', the physical body is created outside of the mesh.
const btRigidBody *	getBody () const
const Material *	getMaterial (int n) const
const btCollisionShape &	getCollisionShape () const
btCollisionShape &	getCollisionShape ()
bool	castRay (const btVector3 &from, const btVector3 &to, btVector3 *xyz, const Material **material, btVector3 *normal=NULL, bool interpolate_normal=false) const
	Casts a ray from 'from' to 'to'.
void	getTriangle (unsigned int indx, btVector3 *p1, btVector3 *p2, btVector3 *p3) const
	Returns the points of the 'indx' triangle.
void	getNormals (unsigned int indx, btVector3 *n1, btVector3 *n2, btVector3 *n3) const
	Returns the normals of the triangle with the given index.
float	getP1P2P3 (unsigned int indx) const
	Returns basically the area of the triangle, which is needed when smoothing the normals.
void	copyFrom (const TriangleMesh &tm)

Private Attributes
UserPointer	m_user_pointer
std::vector< const Material * >	m_triangleIndex2Material
btRigidBody *	m_body
bool	m_free_body
	Keep track if the physical body was created here or not.
btCollisionObject *	m_collision_object
btTriangleMesh	m_mesh
btVector3	dummy1
btVector3	dummy2
btDefaultMotionState *	m_motion_state
btCollisionShape *	m_collision_shape
AlignedArray< btVector3 >	m_normals
	The three normals for each triangle.
AlignedArray< float >	m_p1p2p3
	Pre-compute value used in smoothing.
bool	m_can_be_transformed
	If the rigid body can be transformed (which means that normalising the normals need to update the vertices and normals used according to the current transform of the body.

Detailed Description

A special class to store a triangle mesh with a separate material per triangle.

Member Function Documentation

addTriangle()

void TriangleMesh::addTriangle	(	const btVector3 &	t1,
		const btVector3 &	t2,
		const btVector3 &	t3,
		const btVector3 &	n1,
		const btVector3 &	n2,
		const btVector3 &	n3,
		const Material *	m
	)

Adds a triangle to the bullet mesh.

It also stores the material used for this triangle, and the three normals.

Parameters

t1,t2,t3	Points of the triangle.
n1,n2,n3	Normals at the corresponding points.
m	Material used for this triangle

castRay()

bool TriangleMesh::castRay	(	const btVector3 &	from,
		const btVector3 &	to,
		btVector3 *	xyz,
		const Material **	material,
		btVector3 *	normal = NULL,
		bool	interpolate_normal = false
	)		const

Casts a ray from 'from' to 'to'.

If a triangle of this mesh was hit, xyz and material will be set.

Parameters

from/to	The from and to position for the raycast.
xyz	The position in world where the ray hit.
material	The material of the mesh that was hit.
normal	The intrapolated normal at that position.
interpolate_normal	If true, the returned normal is the interpolated based on the three normals of the triangle and the location of the hit point (which is more compute intensive, but results in much smoother results).

Returns

True if a triangle was hit, false otherwise (and no output variable will be set.

A special ray result class that stores the index of the triangle that was hit.

Stores the index of the triangle that was hit.

createCollisionShape()

void TriangleMesh::createCollisionShape	(	bool	create_collision_object = true,
		const char *	serialized_bhv = NULL
	)

Creates a collision body only, which can be used for raycasting, but has no physical properties.

Parameters

serialized_bhv

if non-null, load the serialized bhv from file instead of builing it on the fly

createPhysicalBody()

void TriangleMesh::createPhysicalBody	(	float	friction,
		btCollisionObject::CollisionFlags	flags = (btCollisionObject::CollisionFlags)0,
		const char *	serializedBhv = NULL
	)

Creates the physics body for this triangle mesh.

If the body already exists (because it was created by a previous call to createBody) it is first removed from the world. This is used by loading the track where a physics body is used to determine the height of terrain. To have an optimised rigid body including all static objects, the track is then removed and all objects together with the track is converted again into a single rigid body. This avoids using irrlicht (or the graphics engine) for height of terrain detection).

Parameters

friction	Friction to be used for this TriangleMesh.
flags	Additional collision flags (default 0).
serializedBhv	if non-NULL, the bhv is deserialized instead of being calculated on the fly

getInterpolatedNormal()

btVector3 TriangleMesh::getInterpolatedNormal	(	unsigned int	index,
		const btVector3 &	position
	)		const

Interpolates the normal at the given position for the triangle with a given index.

The position must be inside of the given triangle.

Parameters

index	Index of the triangle to use.
position	The position for which to interpolate the normal.

getNormals()

void TriangleMesh::getNormals ( unsigned int  indx, btVector3 *  n1, btVector3 *  n2, btVector3 *  n3  ) const

inline

Returns the normals of the triangle with the given index.

Parameters

indx	Index of the triangle to get the three normals of.

Returns

n1,n2,n3 The three normals.

getTriangle()

void TriangleMesh::getTriangle ( unsigned int  indx, btVector3 *  p1, btVector3 *  p2, btVector3 *  p3  ) const

inline

Returns the points of the 'indx' triangle.

Parameters

indx	Index of the triangle to get.
p1,p2,p3	On return the three points of the triangle.

removeAll()

void TriangleMesh::removeAll

(

)

Removes the created body and/or collision object from the physics world.

This is used when creating a temporary rigid body of the main track to get bullet raycasts. Then the main track is removed, and the track (main track including all additional objects which were loaded later) is converted again.

setBody()

void TriangleMesh::setBody ( btRigidBody *  body )

inline

In case of physical objects of shape 'exact', the physical body is created outside of the mesh.

Since raycasts need the body's world transform, the body can be set using this function. This will also cause the body not to be freed (since it will be freed as part of the physical object).

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

• physics/triangle_mesh.hpp
• physics/triangle_mesh.cpp