Subdivision surfaces. More...

Classes
struct	SharpnessResults
	Attribute ids returned by the `compute_sharpness` function. More...

struct	SharpnessOptions
	Input options for the `compute_sharpness` function. More...

class	InterpolatedAttributes
	Helper class to select which attributes to interpolate. More...

struct	SubdivisionOptions
	Mesh subdivision options. More...

Enumerations
enum class	SchemeType { Bilinear , CatmullClark , Loop }
	Subdivision scheme. More...

enum class	VertexBoundaryInterpolation { None , EdgeOnly , EdgeAndCorner }
	Boundary Interpolation Rules. More...

enum class	FaceVaryingInterpolation { None , CornersOnly , CornersPlus1 , CornersPlus2 , Boundaries , All }
	Face-varying Interpolation Rules. More...

enum class	RefinementType { Uniform , EdgeAdaptive }
	Topology refinement method. More...

Functions
template<typename Scalar, typename Index>
SharpnessResults	compute_sharpness (SurfaceMesh< Scalar, Index > &mesh, const SharpnessOptions &options={})
	Compute subdivision options to handle sharp edges and vertices based on existing mesh attributes.

template<typename Scalar, typename Index>
SurfaceMesh< Scalar, Index >	subdivide_mesh (const SurfaceMesh< Scalar, Index > &mesh, const SubdivisionOptions &options={})
	Evaluates the subdivision surface of a polygonal mesh.

template<typename Scalar, typename Index>
SurfaceMesh< Scalar, Index >	midpoint_subdivision (const SurfaceMesh< Scalar, Index > &mesh)
	Performs one step of midpoint subdivision for triangle meshes.

template<typename Scalar, typename Index>
SurfaceMesh< Scalar, Index >	sqrt_subdivision (const SurfaceMesh< Scalar, Index > &mesh)
	Performs one step of sqrt(3)-subdivision.

Detailed Description

Subdivision surfaces.

Enumeration Type Documentation

◆ SchemeType

enum class SchemeType

strong

#include <lagrange/subdivision/mesh_subdivision.h>

Subdivision scheme.

Enumerator

CatmullClark

Bilinear subdivision scheme.

Useful to subdivide a mesh prior to applying a displacement map. Catmull-Clark is more widely used and suited to quad-dominant meshes.

Loop

Loop is preferred for (and requires) purely triangulated meshes.

◆ VertexBoundaryInterpolation

enum class VertexBoundaryInterpolation

strong

#include <lagrange/subdivision/mesh_subdivision.h>

Boundary Interpolation Rules.

Boundary interpolation rules control how subdivision and the limit surface behave for faces adjacent to boundary edges and vertices.

Enumerator
None	No boundary edge interpolation is applied by default; boundary faces are tagged as holes so that the boundary vertices continue to support the adjacent interior faces, but no surface corresponding to the boundary faces is generated; boundary faces can be selectively interpolated by sharpening all boundary edges incident the vertices of the face.
EdgeOnly	A sequence of boundary vertices defines a smooth curve to which the limit surface along boundary faces extends.
EdgeAndCorner	Similar to edge-only but the smooth curve resulting on the boundary is made to interpolate corner vertices (vertices with exactly one incident face)

◆ FaceVaryingInterpolation

enum class FaceVaryingInterpolation

strong

#include <lagrange/subdivision/mesh_subdivision.h>

Face-varying Interpolation Rules.

Face-varying interpolation rules control how face-varying data is interpolated both in the interior of face-varying regions (smooth or linear) and at the boundaries where it is discontinuous (constrained to be linear or "pinned" in a number of ways). Where the topology is continuous and the interpolation chosen to be smooth, the behavior of face-varying interpolation will match that of the vertex interpolation.

Enumerator
None	Smooth everywhere the mesh is smooth.
CornersOnly	Linearly interpolate (sharpen or pin) corners only.
CornersPlus1	CornersOnly + sharpening of junctions of 3 or more regions.
CornersPlus2	CornersPlus2 + sharpening of darts and concave corners.
Boundaries	Linear interpolation along all boundary edges and corners.
All	Linear interpolation everywhere (boundaries and interior)

◆ RefinementType

enum class RefinementType

strong

#include <lagrange/subdivision/mesh_subdivision.h>

Topology refinement method.

Enumerator

Uniform

Each facet is subdivided a fixed number of time.

EdgeAdaptive

Each facet is subdivided adaptively according to the mesh curvature.

Highly curved regions will be refined more. Best suited for rendering applications. Each facet is tessellated based on a target edge length and max subdiv level. Best suited to produce meshes with a uniform edge length when the input mesh has varying facet sizes.

Function Documentation

◆ compute_sharpness()

template<typename Scalar, typename Index>

SharpnessResults compute_sharpness	(	SurfaceMesh< Scalar, Index > &	mesh,
		const SharpnessOptions &	options = {} )

#include <lagrange/subdivision/compute_sharpness.h>

Compute subdivision options to handle sharp edges and vertices based on existing mesh attributes.

This function performs the following operations:

Find an attribute to use as indexed normals to define sharp edges.
If not found, compute indexed corner normals based on a user-defined feature angle threshold.
Compute edge and vertex sharpness float attributes based on indexed normals topology.

The mesh is modified in place to add the necessary attributes. If no indexed normal attribute is found, and no autosmooth feature angle threshold is provided, then no sharpness information is computed.

Note: Please ensure that relevant input indexed normals are properly welded before calling this function.

Parameters

[in,out]	mesh	Input mesh to prepare for subdivision.
[in]	options	Input options for computing sharpness information.

Template Parameters

Scalar	Mesh scalar type.
Index	Mesh index type.

Returns: Normal, edge and vertex sharpness attribute ids.

◆ subdivide_mesh()

template<typename Scalar, typename Index>

SurfaceMesh< Scalar, Index > subdivide_mesh	(	const SurfaceMesh< Scalar, Index > &	mesh,
		const SubdivisionOptions &	options = {} )

#include <lagrange/subdivision/mesh_subdivision.h>

Evaluates the subdivision surface of a polygonal mesh.

Parameters

[in]	mesh	Input mesh to subdivide.
[in]	options	Subdivision options.

Template Parameters

Scalar	Mesh scalar type.
Index	Mesh index type.

Returns: Subdivided mesh.

◆ midpoint_subdivision()

template<typename Scalar, typename Index>

SurfaceMesh< Scalar, Index > midpoint_subdivision ( const SurfaceMesh< Scalar, Index > & mesh )

#include <lagrange/subdivision/midpoint_subdivision.h>

Performs one step of midpoint subdivision for triangle meshes.

Note: This function currently does not remap any mesh attribute.

Parameters

[in,out] mesh Input mesh to subdivide.

Template Parameters

Scalar	Mesh scalar type.
Index	Mesh index type.

Returns: Subdivided mesh.

◆ sqrt_subdivision()

template<typename Scalar, typename Index>

SurfaceMesh< Scalar, Index > sqrt_subdivision ( const SurfaceMesh< Scalar, Index > & mesh )

#include <lagrange/subdivision/sqrt_subdivision.h>

Performs one step of sqrt(3)-subdivision.

Implementation based on:

Kobbelt, Leif. "√3-subdivision." Proceedings of the 27th annual conference on Computer graphics and interactive techniques. 2000. https://doi.org/10.1145/344779.344835

Note: This function currently does not remap any mesh attribute.

Parameters

[in] mesh Input mesh to subdivide. Only triangle meshes are supported.

Template Parameters

Scalar	Mesh scalar type.
Index	Mesh index type.

Returns: Subdivided mesh.

Classes

Enumerations

Functions

Detailed Description

Enumeration Type Documentation

◆ SchemeType

◆ VertexBoundaryInterpolation

◆ FaceVaryingInterpolation

◆ RefinementType

Function Documentation

◆ compute_sharpness()

◆ subdivide_mesh()

◆ midpoint_subdivision()

◆ sqrt_subdivision()