mingfx::BVH Class Reference

Detailed Description

A Bounding Volume Hierarchy (BVH) data structure that can be used to accelerate ray-object intersection tests by carving up space into a hierarchy of partitions represented in a tree.

Each node of the tree is represented as an AABB (Axis-Aligned Bounding Box) that contains all of the nodes under it. Different objects can be stored inside each bounding box. For example, when a BVH is created for a mesh, each leaf node can contain a AABB that contains just a single triangle. Or, when a BVH is created for an entire scene, you could have each leaf node contain an entire mesh or other object within the scene. In each case, use AABB's set_user_data() and user_data() methods to store a handle for whetever you want to store inside the nodes.

Definition at line 40 of file bvh.h.

#include <bvh.h>

Public Member Functions
	BVH ()
	Initializes the class with an empty hierarchy. More...
virtual	~BVH ()
void	CreateFromMesh (const Mesh &mesh)
	Creates a bounding volume hierarchy where each leaf node contains a single triangle from the mesh. More...
void	CreateFromListOfBoxes (const std::vector< AABB > &boxes)
	Creates a BVH where each leaf node contains one of the boxes passed in to the function. More...
std::vector< int >	IntersectAndReturnUserData (const Ray &r) const
	Traverse the BVH to find leaf nodes whose AABBs are intersected by the ray. More...

Constructor & Destructor Documentation

BVH()

mingfx::BVH::BVH

(

)

Initializes the class with an empty hierarchy.

~BVH()

virtual mingfx::BVH::~BVH ( )

virtual

Member Function Documentation

CreateFromListOfBoxes()

void mingfx::BVH::CreateFromListOfBoxes

(

const std::vector< AABB > &

boxes

)

Creates a BVH where each leaf node contains one of the boxes passed in to the function.

CreateFromMesh()

void mingfx::BVH::CreateFromMesh

(

const Mesh &

mesh

)

Creates a bounding volume hierarchy where each leaf node contains a single triangle from the mesh.

For leaf nodes, the triangle index can be retrieved with:

int tri_id = leafnode->box.user_data();

The user_data will be -1 for non-leaf nodes. Once the structure has been created, it can be used to perform fast ray-mesh intersection tests. See Ray::FastIntersectMesh().

IntersectAndReturnUserData()

std::vector<int> mingfx::BVH::IntersectAndReturnUserData

(

const Ray &

r

)

const

Traverse the BVH to find leaf nodes whose AABBs are intersected by the ray.

These are candidates to test more thoroughly using whatever ray-object intersection test is appropriate for the objects stored inside the AABB. This routine returns the user_data for each AABB leaf node. In the case of a BVH created using CreateFromMesh, this means it stores the indices to the mesh triangles that should be tested for ray-triangle intersection.

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

• src/bvh.h