Template Class BVHTree

• Defined in File BVH.hpp

Nested Relationships

Nested Types

• Struct BVHTree::AABB

• Struct BVHTree::BVHInner

• Struct BVHTree::BVHLeaf

• Struct BVHTree::BVHNode

• Struct BVHTree::Triangle

Class Documentation

template<typename BaseVecT>
class BVHTree

Implementation of an Bounding Volume Hierarchy Tree used for ray casting.

This class generates a BVHTree from the given triangle mesh represented by vertices and faces. AABB are used as bounding volumes. The Tree Contains inner nodes and leaf nodes. The leaf nodes are grouped into inner nodes using the surface area heuristic. The tree is represented in two ways: the normal tree structure and the cache friendly index representation.

Template Parameters:

BaseVecT –

Public Functions

BVHTree(const vector<float> &vertices, const vector<uint32_t> &faces)

Constructs the tree itself and it’s cache friendly representation.

Parameters:

• vertices – Vertices of mesh to create tree for

• faces – Faces of mesh to create tree for

BVHTree(const floatArr vertices, size_t n_vertices, const indexArray faces, size_t n_faces)

BVHTree(const MeshBufferPtr mesh)

const vector<uint32_t> &getTriIndexList() const

Returns:

Index list (for getTrianglesIntersectionData) of triangles in the leaf nodes

const vector<float> &getLimits() const

Returns:

Boundaries of the the AABB of all nodes

const vector<uint32_t> &getIndexesOrTrilists() const

Returns:

Four values per node:

1. value: 1st bit of first value indicates, wether the current node is a leaf node or inner node. If it’s a leaf node the rest of the bits indicate the number of triangles in this node.

2. value: Only set, if the node is an inner node. Indicates the start index of the left sub tree in this vector.

3. value: Only set, if the node is an inner node. Indicates the start index of the right sub tree in this vector.

4. value: Only set, if the node is a leaf node. Contains the start index for triangles in getTriIndexList

const vector<float> &getTrianglesIntersectionData() const

Returns precalculated values for the triangle intersection tests.

Returns:

16 values per triangle: 1-3: x, y, z of normal 4: normal.dot(point1) 5-7: x, y, z of edge plane vector 1 8: scalar product of point 1 and edge plane vector 1 9-11: x, y, z of edge plane vector 2 12: scalar product of point 2 and edge plane vector 2 13-15: x, y, z of edge plane vector 3 16: scalar product of point 3 and edge plane vector 3

const uint32_t getMaxDepth() const noexcept

Returns the depth of the tree at its deepest node.