neuray API Programmer's Manual

mi::neuraylib::ITriangle_mesh Class Reference

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Description

Interface representing a triangle mesh. Triangle meshes are represented in an indexed format where triangles are triples of indices pointing into an array of points. Points and triangles are stored with consecutive indices, starting with the index 0 each. Both, points and triangles, can then be referred to by their index numbers. For type safety, triangle indices are represented using mi::neuraylib::Triangle_handle instead of plain integers.

In addition to regular attributes (see mi::neuraylib::IAttribute_set), meshes can also have mesh attributes. In contrast to regular attributes which exist only once per object, mesh attributes are always a vector of values with one vector element per primitive, per point, or per vertex (see mi::neuraylib::Mesh_attribute_name and mi::neuraylib::IAttribute_vector for details).

Per-primitive attributes can be directly used with the methods of this interface, namely create_attribute_vector(), access_attribute_vector(), edit_attribute_vector(), and attach_attribute_vector().

Per-point and per-vertex attributes require the use of a connectivity instead. Per-point attributes use the mesh connectivity (see edit_mesh_connectivity() and related methods), whereas per-vertex attributes use custom connectivities (see create_connectivity() and related methods).

This mesh interface supports the incremental construction of a mesh. Points and triangles can be added one at a time and in alternating order, if so desired. The only constraint is that triangles shall only refer to point indices of points that have been added already. Triangles can only be added or modified while the mesh connectivity is attached. This implies that per-point attributes (using the mesh connectivity) can only be created or modified before or after the triangles are added, not during that process.

The deletion of once added elements is not supported.

See also the "approx" attribute on mi::neuraylib::IAttribute_set for information how to control the tessellation of the triangle mesh.

See also:

mi::neuraylib::ITriangle_connectivity

mi::neuraylib::IAttribute_vector

Example: Create a mesh with a single triangle with one normal and three texture coordinates 

‎ // The points of the triangle
 mi::Float32_3 point[3];
 point[0] = mi::Float32_3( 0.0f, 0.0f, 0.0f);
 point[1] = mi::Float32_3( 1.0f, 0.0f, 0.0f);
 point[2] = mi::Float32_3( 1.0f, 1.0f, 0.0f);

 // The normal of the triangle
 mi::Float32_3 normal( 0.0f, 0.0f, 1.0f);

 // The texture coordinates for the triangle
 mi::Float32_2 tex_coord[3];
 tex_coord[0] = mi::Float32_2( 0.0f, 0.0f);
 tex_coord[1] = mi::Float32_2( 1.0f, 0.0f);
 tex_coord[2] = mi::Float32_2( 1.0f, 1.0f);

 mi::base::Handle< mi::neuraylib::ITriangle_mesh> mesh(
    transaction->create<mi::neuraylib::ITriangle_mesh>( "Triangle_mesh"));

 // Create the points of the mesh
 for( mi::Uint32 i = 0; i < 3; ++i)
     mesh->append_point( point[i]);

 // Create the triangle and specify the mapping of its vertices to points
 mi::neuraylib::Triangle_handle triangle_handle(
     mesh->append_triangle( mi::neuraylib::Triangle_point_indices( 0, 1, 2)));

 // Access the mesh connectivity
 mi::base::Handle< mi::neuraylib::ITriangle_connectivity> mesh_connectivity(
    mesh->edit_mesh_connectivity());

 // Create an attribute vector for 2-dimensional texture coordinates
 mi::base::Handle< mi::neuraylib::IAttribute_vector> texture_coordinates(
     mesh_connectivity->create_attribute_vector( mi::neuraylib::ATTR_TEXTURE, 2));
 for( mi::Uint32 i = 0; i < 3; ++i)
     texture_coordinates->append_float32( &tex_coord[i].x, 2);
 mesh_connectivity->attach_attribute_vector( texture_coordinates.get());

 // Attach the mesh connectivity back to mesh
 mesh->attach_mesh_connectivity( mesh_connectivity.get());

 // Create a custom connectivity for normals to share the same normal for all vertices
 mi::base::Handle< mi::neuraylib::ITriangle_connectivity> normal_connectivity(
     mesh->create_connectivity( mi::neuraylib::CONNECTIVITY_MAP_GENERIC));
 normal_connectivity->set_triangle_indices( triangle_handle, 0, 0, 0);

 // Create an attribute vector for normals
 mi::base::Handle< mi::neuraylib::IAttribute_vector> normals(
     normal_connectivity->create_attribute_vector( mi::neuraylib::ATTR_NORMAL, 1));
 normals->append_vector3( normal);
 normal_connectivity->attach_attribute_vector( normals.get());

 // Attach the custom connectivity to the mesh
 mesh->attach_connectivity( normal_connectivity.get());
mi::base::Interface_declare\< ..., neuraylib::IScene_element \>Mixin class template for deriving new interface declarations. Common base interface for all scene elements.Common base interface for all scene elements. mi::base::Interface_declare\< ..., neuraylib::IAttribute_set \>Mixin class template for deriving new interface declarations. The attribute set comprises all attributes attached to a database element.The attribute set comprises all attributes attached to a database element. mi::base::Interface_declare\< ... \>Mixin class template for deriving new interface declarations. The basic extensible interface.The basic extensible interface.

Methods related to points

virtual Uint32 append_point( const Float32_3_struct& p) =0
Adds a point p to the end of all points and returns the index of the new point. More...
virtual Uint32 append_point( const Float64_3_struct& p) =0
Adds a point p to the end of all points and returns the index of the new point. More...
virtual Sint32 point( Uint32 index, Float32_3_struct& p) const =0
Returns the coordinates of the point of index index in the output parameter p. More...
virtual Sint32 point( Uint32 index, Float64_3_struct& p) const =0
Returns the coordinates of the point of index index in the output parameter p. More...
virtual Uint32 points_capacity() const =0
Returns the number of points for which space is allocated in the mesh. More...
virtual Uint32 points_size() const =0
Returns the number of points in the mesh.
virtual void reserve_points( Uint32 n) =0
Reserves space for at least n points. More...
virtual Sint32 set_point( Uint32 index, const Float32_3_struct& p) =0
Sets the point of index index to the new point p. More...
virtual Sint32 set_point( Uint32 index, const Float64_3_struct& p) =0
Sets the point of index index to the new point p. More...

Methods related to triangles

virtual Triangle_handle_struct append_triangle( const Triangle_point_indices_struct& triangle) =0
Adds a triangle to the mesh. More...
virtual void reserve_triangles( Uint32 n) =0
Reserves space for at least n triangles. More...
virtual Sint32 set_triangle( Triangle_handle_struct hnd, const Triangle_point_indices_struct& triangle) =0
Modifies a triangle of the mesh. More...
virtual Triangle_point_indices_struct triangle_point_indices( Triangle_handle_struct hnd) const =0
Returns the triple of indices describing the vertices of the triangle of index i. More...
virtual Uint32 triangles_capacity() const =0
Returns the number of triangles for which space is allocated in the mesh. More...
virtual Uint32 triangles_size() const =0
Returns the number of triangles.

Methods related to the mesh connectivity

virtual const ITriangle_connectivity* access_mesh_connectivity() const =0
Returns the mesh connectivity. More...
virtual Sint32 attach_mesh_connectivity( ITriangle_connectivity* connectivity) =0
Attaches the mesh connectivity to the mesh. More...
virtual ITriangle_connectivity* edit_mesh_connectivity() =0
Detaches and returns the mesh connectivity. More...

Methods related to custom connectivities

virtual const ITriangle_connectivity* access_connectivity( Mesh_attribute_name name) const =0
Returns the connectivity for a given mesh attribute. More...
virtual Sint32 attach_connectivity( ITriangle_connectivity* connectivity) =0
Attaches a given connectivity to the mesh. More...
virtual ITriangle_connectivity* create_connectivity( Connectivity_map_type map_type = CONNECTIVITY_MAP_GENERIC) =0
Creates a new connectivity for non-per-primitive attributes. More...
virtual ITriangle_connectivity* edit_connectivity( Mesh_attribute_name name) =0
Detaches and returns the connectivity for a given mesh attribute. More...
virtual Sint32 remove_connectivity( Mesh_attribute_name name) =0
Removes the connectivity for a non-per-primitive mesh attribute. More...

Methods related to per-primitive attributes

virtual const IAttribute_vector* access_attribute_vector( Mesh_attribute_name name) const =0
Returns a per-primitive mesh attribute. More...
virtual Sint32 attach_attribute_vector( IAttribute_vector* attribute_vector) =0
Attaches a given per-primitive mesh attribute to the mesh. More...
virtual IAttribute_vector* create_attribute_vector( Mesh_attribute_name name, Uint32 dim = 1) =0
Creates a per-primitive mesh attribute. More...
virtual IAttribute_vector* edit_attribute_vector( Mesh_attribute_name name) =0
Detaches and returns a per-primitive mesh attribute. More...
virtual bool  has_attribute( Mesh_attribute_name name) const =0
Indicates whether the mesh has a particular mesh attribute (per-primitive or other types). More...
virtual Sint32 remove_attribute_vector( Mesh_attribute_name name) =0
Removes a per-primitive mesh attribute. More...

Methods related to the bounding box

virtual const Float32_3_struct& get_bbox_max() const =0
Returns maximal corner of the bounding box.
virtual const Float32_3_struct& get_bbox_min() const =0
Returns minimal corner of the bounding box.
virtual Bbox3_struct get_tight_bbox( const Float64_4_4_struct& transformation_matrix) const =0
Returns the bounding box of the triangle mesh after transformation. More...

Methods related to displacement

virtual Float32 get_maximum_displacement() const =0
Returns the maximum displacement of the triangle mesh. More...
virtual void set_maximum_displacement( Float32 displacement) =0
Sets the maximum displacement of the triangle mesh. More...

Member Functions

virtual const IAttribute_vector* mi::​neuraylib::​ITriangle_mesh::access_attribute_vector( Mesh_attribute_name name) const [pure virtual]

Returns a per-primitive mesh attribute.

Parameters

name
The name of the attribute, see Mesh_attribute_name. The attribute must be a per-primitive attribute.

Returns

The requested attribute vector, or NULL in case of failure.

virtual const ITriangle_connectivity* mi::​neuraylib::​ITriangle_mesh::access_connectivity( Mesh_attribute_name name) const [pure virtual]

Returns the connectivity for a given mesh attribute.

Parameters

name
The name of the attribute to return the connectivity for, see Mesh_attribute_name.

Returns

The connectivity for name , or NULL if there is no such attribute, or the attribute is a per-primitive attribute.

virtual const ITriangle_connectivity* mi::​neuraylib::​ITriangle_mesh::access_mesh_connectivity() const [pure virtual]

Returns the mesh connectivity.

Returns

The mesh connectivity, or NULL if it currently not attached.

virtual Uint32 mi::​neuraylib::​ITriangle_mesh::append_point( const Float32_3_struct& p) [pure virtual]

Adds a point p to the end of all points and returns the index of the new point. The mesh class provides several overloaded versions for different parameter types. No information about the underlying storage is specified. The caller should use the best matching call for the caller's data representation.

virtual Uint32 mi::​neuraylib::​ITriangle_mesh::append_point( const Float64_3_struct& p) [pure virtual]

Adds a point p to the end of all points and returns the index of the new point. The mesh class provides several overloaded versions for different parameter types. No information about the underlying storage is specified. The caller should use the best matching call for the caller's data representation.

virtual Triangle_handle_struct mi::​neuraylib::​ITriangle_mesh::append_triangle( const Triangle_point_indices_struct& triangle) [pure virtual]

Adds a triangle to the mesh. This method requires that the mesh connectivity is attached. Afterwards all other connectivities and attributes must be updated accordingly.

Note:

For best performance it is recommended to sort the triangles by their material index such that when looping over all triangles the material index changes as infrequently as possible.

Parameters

triangle
The vertex indices of the new triangle.

Returns

A handle for the new triangle, or a default-constructed handle in case of failure, i.e., the mesh connectivity has been detached, or at least one triangle point index is too large.

virtual Sint32 mi::​neuraylib::​ITriangle_mesh::attach_attribute_vector( IAttribute_vector* attribute_vector) [pure virtual]

Attaches a given per-primitive mesh attribute to the mesh. The attribute vector must not be used any longer after it has been attached.

See also:

create_attribute_vector(), edit_attribute_vector()

Returns

  • 0: Success.
  • -1: Invalid parameters (NULL pointer).
  • -2: The attribute vector has not been acquired from this mesh.
  • -3: The attribute vector is not a per-primitive attribute vector.
  • -4: The attribute vector is a per-primitive attribute vector and the number of elements does not match the number of triangles of the mesh.
  • -5: An attribute of the same name is already attached to the mesh (or to one of its connectivities).
virtual Sint32 mi::​neuraylib::​ITriangle_mesh::attach_connectivity( ITriangle_connectivity* connectivity) [pure virtual]

Attaches a given connectivity to the mesh. This implicitly binds all attributes of the connectivity to the mesh. The connectivity must not be used any longer after it has been attached.

See also:

create_connectivity(), edit_connectivity()

Returns

  • 0: Success.
  • -1: Invalid parameters (NULL pointer).
  • -2: The connectivity has not been created by or acquired from this mesh.
  • -3: The connectivity is already attached to the mesh.
  • -4: The connectivity is inconsistent (at least one index is too large for one of the attached attribute vectors).
virtual Sint32 mi::​neuraylib::​ITriangle_mesh::attach_mesh_connectivity( ITriangle_connectivity* connectivity) [pure virtual]

Attaches the mesh connectivity to the mesh. This implicitly binds all attributes of the connectivity to the mesh. The connectivity must not be used any longer after it has been attached.

See also:

edit_mesh_connectivity()

Returns

  • 0: Success.
  • -1: Invalid parameters (NULL pointer).
  • -2: The mesh connectivity has not been acquired from this mesh.
  • -3: The mesh connectivity of this mesh has already been attached.
  • -4: The mesh connectivity is inconsistent (at least one index is too large for the number of points or one of the attached attribute vectors).
  • -5: The connectivity is not a mesh connectivity.
virtual IAttribute_vector* mi::​neuraylib::​ITriangle_mesh::create_attribute_vector( Mesh_attribute_name name, Uint32 dim = 1) [pure virtual]

Creates a per-primitive mesh attribute. The attribute is not yet attached to the mesh. It needs to be attached before it is released.

See also:

attach_attribute_vector()

Parameters

name
The name of the attribute, see Mesh_attribute_name. The attribute must be a per-primitive attribute.
dim
Dimension of an attribute value. Only used for those attributes that have user specifiable dimensions.

Returns

The requested attribute vector, or NULL in case of failure.

virtual ITriangle_connectivity* mi::​neuraylib::​ITriangle_mesh::create_connectivity( Connectivity_map_type map_type = CONNECTIVITY_MAP_GENERIC) [pure virtual]

Creates a new connectivity for non-per-primitive attributes. The attribute is not yet attached to the mesh. It needs to be attached before it is released.

See also:

attach_connectivity()

virtual IAttribute_vector* mi::​neuraylib::​ITriangle_mesh::edit_attribute_vector( Mesh_attribute_name name) [pure virtual]

Detaches and returns a per-primitive mesh attribute. The attribute needs to be reattached before it is released. Otherwise, the attribute is effectively removed from the mesh.

See also:

attach_attribute_vector()

Parameters

name
The name of the attribute, see Mesh_attribute_name. The attribute must be a per-primitive attribute.

Returns

The requested attribute vector, or NULL in case of failure.

virtual ITriangle_connectivity* mi::​neuraylib::​ITriangle_mesh::edit_connectivity( Mesh_attribute_name name) [pure virtual]

Detaches and returns the connectivity for a given mesh attribute. The connectivity needs to be reattached before it is released.

See also:

attach_connectivity()

Parameters

name
The name of the attribute to return the connectivity for, see Mesh_attribute_name.

Returns

The connectivity for name , or NULL if there is no such attribute, or the attribute is a per-primitive attribute.

virtual ITriangle_connectivity* mi::​neuraylib::​ITriangle_mesh::edit_mesh_connectivity() [pure virtual]

Detaches and returns the mesh connectivity. The connectivity needs to be reattached before it is released.

See also:

attach_mesh_connectivity()

Returns

The mesh connectivity, or NULL if it currently not attached.

virtual const Float32_3_struct& mi::​neuraylib::​ITriangle_mesh::get_bbox_max() const [pure virtual]

Returns maximal corner of the bounding box.

virtual const Float32_3_struct& mi::​neuraylib::​ITriangle_mesh::get_bbox_min() const [pure virtual]

Returns minimal corner of the bounding box.

virtual Float32 mi::​neuraylib::​ITriangle_mesh::get_maximum_displacement() const [pure virtual]

Returns the maximum displacement of the triangle mesh.

See also:

set_maximum_displacement()

virtual Bbox3_struct mi::​neuraylib::​ITriangle_mesh::get_tight_bbox( const Float64_4_4_struct& transformation_matrix) const [pure virtual]

Returns the bounding box of the triangle mesh after transformation.

Parameters

transformation_matrix
The transformation matrix
virtual bool mi::​neuraylib::​ITriangle_mesh::has_attribute( Mesh_attribute_name name) const [pure virtual]

Indicates whether the mesh has a particular mesh attribute (per-primitive or other types).

Parameters

name
The name of the attribute to query, see Mesh_attribute_name.

Returns

true if the mesh has this attribute, false otherwise.

virtual Sint32 mi::​neuraylib::​ITriangle_mesh::point( Uint32 index, Float32_3_struct& p) const [pure virtual]

Returns the coordinates of the point of index index in the output parameter p. The mesh class provides several overloaded versions for different parameter types. No information about the underlying storage is specified. The caller should use the best matching call for the caller's data representation.

Returns

  • 0: Success.
  • -1: index is out of bounds.
virtual Sint32 mi::​neuraylib::​ITriangle_mesh::point( Uint32 index, Float64_3_struct& p) const [pure virtual]

Returns the coordinates of the point of index index in the output parameter p. The mesh class provides several overloaded versions for different parameter types. No information about the underlying storage is specified. The caller should use the best matching call for the caller's data representation.

Returns

  • 0: Success.
  • -1: index is out of bounds.
virtual Uint32 mi::​neuraylib::​ITriangle_mesh::points_capacity() const [pure virtual]

Returns the number of points for which space is allocated in the mesh. One can add points_capacity() - points_size() many points to the mesh before internal reallocation may become necessary.

See also:

reserve_points().

virtual Uint32 mi::​neuraylib::​ITriangle_mesh::points_size() const [pure virtual]

Returns the number of points in the mesh.

virtual Sint32 mi::​neuraylib::​ITriangle_mesh::remove_attribute_vector( Mesh_attribute_name name) [pure virtual]

Removes a per-primitive mesh attribute.

Parameters

name
The name of the attribute, see Mesh_attribute_name. The attribute must be a per-primitive attribute.

Returns

  • 0: Success.
  • -1: There is no per-primitive attribute of the given name.
virtual Sint32 mi::​neuraylib::​ITriangle_mesh::remove_connectivity( Mesh_attribute_name name) [pure virtual]

Removes the connectivity for a non-per-primitive mesh attribute. If there are several mesh attributes attached to the same connectivity, only the given mesh attribute will be removed and the connectivity itself remains. Otherwise, removal of the connectivity implies removal of the corresponding mesh attribute.

Parameters

name
The name of the attribute to remove the connectivity for, see Mesh_attribute_name.

Returns

  • 0: Success.
  • -1: There is no connectivity for the given mesh attribute.
virtual void mi::​neuraylib::​ITriangle_mesh::reserve_points( Uint32 n) [pure virtual]

Reserves space for at least n points. Sets the internal capacity to at least n points before reallocation may become necessary. The number of points currently stored is not changed by this method.

See also:

points_capacity().

virtual void mi::​neuraylib::​ITriangle_mesh::reserve_triangles( Uint32 n) [pure virtual]

Reserves space for at least n triangles. Sets the internal capacity to at least n triangles before reallocation may become necessary. The number of triangles currently stored is not changed by this method.

See also:

triangles_capacity().

virtual void mi::​neuraylib::​ITriangle_mesh::set_maximum_displacement( Float32 displacement) [pure virtual]

Sets the maximum displacement of the triangle mesh. This value is the maximum absolute value of any displacement applied to the object (defaults to 0.0). The bounding box of the object will be expanded all around by this value.

virtual Sint32 mi::​neuraylib::​ITriangle_mesh::set_point( Uint32 index, const Float32_3_struct& p) [pure virtual]

Sets the point of index index to the new point p. The mesh class provides several overloaded versions for different parameter types. No information about the underlying storage is specified. The caller should use the best matching call for the caller's data representation.

Returns

  • 0: Success.
  • -1: index is out of bounds.
virtual Sint32 mi::​neuraylib::​ITriangle_mesh::set_point( Uint32 index, const Float64_3_struct& p) [pure virtual]

Sets the point of index index to the new point p. The mesh class provides several overloaded versions for different parameter types. No information about the underlying storage is specified. The caller should use the best matching call for the caller's data representation.

Returns

  • 0: Success.
  • -1: index is out of bounds.
virtual Sint32 mi::​neuraylib::​ITriangle_mesh::set_triangle( Triangle_handle_struct hnd, const Triangle_point_indices_struct& triangle) [pure virtual]

Modifies a triangle of the mesh.

Note:

For best performance it is recommended to sort the triangles by their material index such that when looping over all triangles the material index changes as infrequently as possible.

Note:

The append_point() function call returns the index of a newly added point.

Parameters

hnd
The triangle to modify.
triangle
The new vertex indices of the triangle.

Returns

  • 0: Success:
  • -1: hnd is out of bounds.
  • -2: The mesh connectivity has been detached.
  • -3: At least one triangle point index is too large.
virtual Triangle_point_indices_struct mi::​neuraylib::​ITriangle_mesh::triangle_point_indices( Triangle_handle_struct hnd) const [pure virtual]

Returns the triple of indices describing the vertices of the triangle of index i. If the mesh connectivity is not attached, the triple (0,0,0) is returned.

virtual Uint32 mi::​neuraylib::​ITriangle_mesh::triangles_capacity() const [pure virtual]

Returns the number of triangles for which space is allocated in the mesh. One can add triangles_capacity() - triangles_size() many triangles to the mesh before internal reallocation may become necessary.

See also:

reserve_triangles().

virtual Uint32 mi::​neuraylib::​ITriangle_mesh::triangles_size() const [pure virtual]

Returns the number of triangles.