DHARTAPI.RayTracing.EmbreeBVH Class Reference

A Bounding Volume Hierarchy for the EmbreeRaytracer. More...

Inheritance diagram for DHARTAPI.RayTracing.EmbreeBVH:

Public Member Functions
	EmbreeBVH (MeshInfo MI, bool use_precise=false)
	Generate a BVH for an instance of MeshInfo. More...
	EmbreeBVH (MeshInfo[] MI)
	Construct a BVH from an array of meshes. More...
void	AddMesh (MeshInfo MI)
	Add a new mesh to the BVH. More...
void	AddMesh (MeshInfo[] MI)
	Multiple new meshes to the BVH. More...
Public Member Functions inherited from DHARTAPI.NativeUtils.NativeObject
void	UpdatePressure (int new_pressure)
	Update the pressure of this object.

Protected Member Functions
override bool	ReleaseHandle ()
	Free the native memory managed by this class. More...

Additional Inherited Members
Public Attributes inherited from DHARTAPI.NativeUtils.NativeObject
int	pressure
	the size of the object pointed to in unmanaged memory in bytes. Used to exert pressure on the GC. More...
Properties inherited from DHARTAPI.NativeUtils.NativeObject
override bool	IsInvalid [get]
	There is no way to invalidate this class without destroying it, so will always return false.

Detailed Description

A Bounding Volume Hierarchy for the EmbreeRaytracer.

Upon calling the constructor for this class, a Bounding Volume Hierarchy is generated for the RayTracing.EmbreeRaytracer. Without this structure, the raytracer cannot be used.

Remarks

A more detailed description of Embree's BVH is available in intel's paper: Embree: A Kernel Framework for Efficient CPU Ray Tracing http://cseweb.ucsd.edu/~ravir/274/15/papers/a143-wald.pdf.

See also

EmbreeRaytracer for functions to use this BVH for ray intersections.

Constructor & Destructor Documentation

EmbreeBVH() [1/2]

DHARTAPI.RayTracing.EmbreeBVH.EmbreeBVH	(	MeshInfo	MI,
		bool	use_precise = false
	)

Generate a BVH for an instance of MeshInfo.

Parameters

MI	Mesh to generate the BVH from.
use_precise	Increase the accuracy of all ray intersections at the cost of performance.

Exceptions

Exception

Embree failed to create a BVH for the given mesh.

Example

 
            // Load an OBJ from a filepath  into a new meshinfo instance
            string good_mesh_path = "ExampleModels/plane.obj";
            MeshInfo Mesh = OBJLoader.LoadOBJ(good_mesh_path, CommonRotations.Yup_To_Zup);
 
            // Construct a BVH from the mesh
            EmbreeBVH BVH = new EmbreeBVH(Mesh);
 

EmbreeBVH() [2/2]

DHARTAPI.RayTracing.EmbreeBVH.EmbreeBVH

(

MeshInfo[]

MI

)

Construct a BVH from an array of meshes.

\params MI Meshes to build the BVH from.

References DHARTAPI.NativeUtils.NativeObject.pressure, and DHARTAPI.NativeUtils.NativeObject.UpdatePressure().

Member Function Documentation

AddMesh() [1/2]

void DHARTAPI.RayTracing.EmbreeBVH.AddMesh

(

MeshInfo

MI

)

Add a new mesh to the BVH.

Parameters

MI	Meshinfo to add to this bvh. The ID of this MeshInfo will be updated if that ID is already occupied by another mesh in the BVH.

Example

Demonstrating that the BVH changes after the addition of new meshes.

 
            // Load a lot of submeshes from sponza
            var MeshInfos = OBJLoader.LoadOBJSubmeshes("ExampleModels/sponza.obj", GROUP_METHOD.BY_GROUP);
            var Plane = OBJLoader.LoadOBJ("ExampleModels/plane.obj");
            
            // Construct a BVH from the plane
            EmbreeBVH bvh = new EmbreeBVH(Plane);
           
            // Cast rays and print the results
            Debug.WriteLine("--- Just Plane---");
            Vector3D[] origins = { new Vector3D(1, 1, 1), new Vector3D(1, 1, 1) };
            Vector3D[] directions = { new Vector3D(0, 0, -1), new Vector3D(0, -1, 0) };
            bool[] results = EmbreeRaytracer.IntersectOccluded(bvh, origins, directions);
 
            string out_str = directions[0].ToString() + (results[0] ? "Intersected" : "Did not Intersect") + "\n";
            out_str += directions[1].ToString() + (results[1] ? "Intersected" : "Did not Intersect");
            Debug.WriteLine(out_str);
            
            // Add meshes to the BVH
            bvh.AddMesh(MeshInfos);
 
            // Cast rays again and see if the second ray connects
            Debug.WriteLine("--- After Addition---");
            bool[] post_addition_results = EmbreeRaytracer.IntersectOccluded(bvh, origins, directions);
            string post_addition_out_str = directions[0].ToString() + (post_addition_results[0] ? "Intersected" : "Did not Intersect") + "\n";
            post_addition_out_str += directions[1].ToString() + (post_addition_results[1] ? "Intersected" : "Did not Intersect");
 
            Debug.WriteLine(post_addition_out_str);
 

 --- Just Plane---
(0, 0, -1)Did not Intersect
(0, -1, 0)Intersected
--- After Addition---
(0, 0, -1)Intersected
(0, -1, 0)Intersected

References DHARTAPI.NativeUtils.NativeObject.pressure, and DHARTAPI.NativeUtils.NativeObject.UpdatePressure().

AddMesh() [2/2]

void DHARTAPI.RayTracing.EmbreeBVH.AddMesh

(

MeshInfo[]

MI

)

Multiple new meshes to the BVH.

Parameters

MI	Meshinfo to add to this bvh. The ID of this MeshInfo will be updated if that ID is already occupied by another mesh in the BVH.

Example

Demonstrating that the BVH changes after the addition of new meshes.

 
            // Load a lot of submeshes from sponza
            var MeshInfos = OBJLoader.LoadOBJSubmeshes("ExampleModels/sponza.obj", GROUP_METHOD.BY_GROUP);
            var Plane = OBJLoader.LoadOBJ("ExampleModels/plane.obj");
            
            // Construct a BVH from the plane
            EmbreeBVH bvh = new EmbreeBVH(Plane);
           
            // Cast rays and print the results
            Debug.WriteLine("--- Just Plane---");
            Vector3D[] origins = { new Vector3D(1, 1, 1), new Vector3D(1, 1, 1) };
            Vector3D[] directions = { new Vector3D(0, 0, -1), new Vector3D(0, -1, 0) };
            bool[] results = EmbreeRaytracer.IntersectOccluded(bvh, origins, directions);
 
            string out_str = directions[0].ToString() + (results[0] ? "Intersected" : "Did not Intersect") + "\n";
            out_str += directions[1].ToString() + (results[1] ? "Intersected" : "Did not Intersect");
            Debug.WriteLine(out_str);
            
            // Add meshes to the BVH
            bvh.AddMesh(MeshInfos);
 
            // Cast rays again and see if the second ray connects
            Debug.WriteLine("--- After Addition---");
            bool[] post_addition_results = EmbreeRaytracer.IntersectOccluded(bvh, origins, directions);
            string post_addition_out_str = directions[0].ToString() + (post_addition_results[0] ? "Intersected" : "Did not Intersect") + "\n";
            post_addition_out_str += directions[1].ToString() + (post_addition_results[1] ? "Intersected" : "Did not Intersect");
 
            Debug.WriteLine(post_addition_out_str);
 

 --- Just Plane---
(0, 0, -1)Did not Intersect
(0, -1, 0)Intersected
--- After Addition---
(0, 0, -1)Intersected
(0, -1, 0)Intersected

References DHARTAPI.NativeUtils.NativeObject.pressure, and DHARTAPI.NativeUtils.NativeObject.UpdatePressure().

ReleaseHandle()

override bool DHARTAPI.RayTracing.EmbreeBVH.ReleaseHandle ( )

protected

Free the native memory managed by this class.

Note

the garbage collector will handle this automatically

Warning

Do not attempt to use this class after freeing it!

Returns

True. This is guaranteed to execute properly.

---

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

• src/Csharp/packages/raytracer/src/EmbreeBVH.cs