Attributes

Manipulating mesh attributes. More...

Classes
class	AttributeBase
	Base handle for attributes. More...
class	Attribute< ValueType_ >
	Derived attribute class that stores the actual information. More...
class	IndexedAttribute< ValueType_, Index_ >
	Derived attribute class that stores the actual information. More...

Macros
#define	LA_ATTRIBUTE_X(mode, data)
	X Macro arguments for the Attribute<> class. More...
#define	LA_ATTRIBUTE_INDEX_X(mode, data)
	X Macro arguments for the Attribute<> class. More...
#define	LA_ATTRIBUTE_SCALAR_X(mode, data)
	X Macro arguments for the Attribute<> class. More...
#define	LA_X_attribute_make_value_type(_, ValueType)

Typedefs
using	AttributeId = uint32_t
	Identified to be used to access an attribute. More...

Enumerations
enum	AttributeElement : int {   Vertex = (1 << 0) , Facet = (1 << 1) , Edge = (1 << 2) , Corner = (1 << 3) ,   Value = (1 << 4) , Indexed = (1 << 5) }
	Type of element to which the attribute is attached. More...
enum class	AttributeUsage : uint16_t {   Vector = (1 << 0) , Scalar = (1 << 1) , Position = (1 << 2) , Normal = (1 << 3) ,   Tangent = (1 << 4) , Bitangent = (1 << 5) , Color = (1 << 6) , UV = (1 << 7) ,   VertexIndex = (1 << 8) , FacetIndex = (1 << 9) , CornerIndex = (1 << 10) , EdgeIndex = (1 << 11) ,   String = (1 << 12) }
	Usage tag indicating how the attribute should behave under mesh transformations. More...
enum class	AttributeCreatePolicy { ErrorIfReserved , Force }
	Policy for attribute creation with reserved attribute names. More...
enum class	AttributeGrowthPolicy { ErrorIfExternal , AllowWithinCapacity , WarnAndCopy , SilentCopy }
	Policy for growing external attribute buffers. More...
enum class	AttributeShrinkPolicy { ErrorIfExternal , IgnoreIfExternal , WarnAndCopy , SilentCopy }
	Policy for shrinking external attribute buffers. More...
enum class	AttributeWritePolicy { ErrorIfReadOnly , WarnAndCopy , SilentCopy }
	Policy for attempting to write to read-only external buffers. More...
enum class	AttributeExportPolicy { CopyIfExternal , CopyIfUnmanaged , KeepExternalPtr , ErrorIfExternal }
	Policy for exporting attributes that are views onto external buffers. More...
enum class	AttributeCopyPolicy { CopyIfExternal , KeepExternalPtr , ErrorIfExternal }
	Policy for copying attribute that are views onto external buffers. More...
enum class	AttributeDeletePolicy { ErrorIfReserved , Force }
	Policy for attribute deletion of reserved attribute names. More...
enum class	AttributeValueType : uint8_t { LA_X_attribute_value_type_enum }
	Enum describing at runtime the value type of an attribute. More...

Functions
constexpr AttributeId	invalid_attribute_id ()
	Invalid attribute id.
template<typename ValueType >
constexpr AttributeValueType	make_attribute_value_type ()
	Creates an enum describing an attribute value type. More...

Detailed Description

Manipulating mesh attributes.

Please read our user guide for an introduction.

Macro Definition Documentation

LA_ATTRIBUTE_X

#define LA_ATTRIBUTE_X	(		mode,
			data
	)

#include <lagrange/AttributeTypes.h>

Value:

    LA_X_##mode(data, int8_t) \
    LA_X_##mode(data, int16_t) \
    LA_X_##mode(data, int32_t) \
    LA_X_##mode(data, int64_t) \
    LA_X_##mode(data, uint8_t) \
    LA_X_##mode(data, uint16_t) \
    LA_X_##mode(data, uint32_t) \
    LA_X_##mode(data, uint64_t) \
    LA_X_##mode(data, float) \
    LA_X_##mode(data, double)

X Macro arguments for the Attribute<> class.

Since other modules might need to explicitly instantiate their own functions, this file is a public header.

Use in a .cpp as follows:

#include <lagrange/AttributeTypes.h>
#define LA_X_foo(_, ValueType) template void my_function(const Attribute<ValueType> &);
LA_ATTRIBUTE_X(foo, 0)

The optional data argument can forwarded to other macros, in order to implement cartesian products when instantiating nested types.

Parameters

mode	Suffix to apply to the LA_X_* macro.
data	Data to be passed around as the first argument of the X macro.

Returns

Expansion of LA_X_##mode() for each type to be instantiated.

LA_ATTRIBUTE_INDEX_X

#define LA_ATTRIBUTE_INDEX_X	(		mode,
			data
	)

#include <lagrange/AttributeTypes.h>

Value:

    LA_X_##mode(data, int8_t) \
    LA_X_##mode(data, int16_t) \
    LA_X_##mode(data, int32_t) \
    LA_X_##mode(data, int64_t) \
    LA_X_##mode(data, uint8_t) \
    LA_X_##mode(data, uint16_t) \
    LA_X_##mode(data, uint32_t) \
    LA_X_##mode(data, uint64_t)

X Macro arguments for the Attribute<> class.

Usage is similar to LA_ATTRIBUTE_X, but it will only iterate over integral value types.

Use in a .cpp as follows:

#include <lagrange/AttributeTypes.h>
#define LA_X_foo(_, IndexType) template void my_function(const Attribute<IndexType> &);
LA_ATTRIBUTE_INDEX_X(foo, 0)

The optional data argument can forwarded to other macros, in order to implement cartesian products when instantiating nested types.

Parameters

mode	Suffix to apply to the LA_X_* macro.
data	Data to be passed around as the first argument of the X macro.

Returns

Expansion of LA_X_##mode() for each type to be instantiated.

LA_ATTRIBUTE_SCALAR_X

#define LA_ATTRIBUTE_SCALAR_X	(		mode,
			data
	)

#include <lagrange/AttributeTypes.h>

Value:

    LA_X_##mode(data, float) \
    LA_X_##mode(data, double)

X Macro arguments for the Attribute<> class.

Usage is similar to LA_ATTRIBUTE_X, but it will only iterate over floating points value types.

Use in a .cpp as follows:

#include <lagrange/AttributeTypes.h>
#define LA_X_foo(_, IndexType) template void my_function(const Attribute<IndexType> &);
LA_ATTRIBUTE_SCALAR_X(foo, 0)

The optional data argument can forwarded to other macros, in order to implement cartesian products when instantiating nested types.

Parameters

mode	Suffix to apply to the LA_X_* macro.
data	Data to be passed around as the first argument of the X macro.

Returns

Expansion of LA_X_##mode() for each type to be instantiated.

LA_X_attribute_make_value_type

#define LA_X_attribute_make_value_type	(		_,
			ValueType
	)

#include <lagrange/AttributeValueType.h>

Value:

    template <>                                                         \
    constexpr AttributeValueType make_attribute_value_type<ValueType>() \
    {                                                                   \
        return AttributeValueType::e_##ValueType;                       \
    }

Typedef Documentation

AttributeId

using AttributeId = uint32_t

#include <lagrange/AttributeFwd.h>

Identified to be used to access an attribute.

Attribute names are mapped to a unique identified when created. These unique identifiers can be used to more efficiently access the data (rather than rehashing the string every time).

Enumeration Type Documentation

AttributeElement

enum AttributeElement : int

#include <lagrange/AttributeFwd.h>

Type of element to which the attribute is attached.

Enumerator
Vertex	Per-vertex mesh attributes.
Facet	Per-facet mesh attributes.
Edge	Per-edge mesh attributes.
Corner	Per-corner mesh attributes.
Value	Values that are not attached to a specific element. Used by indexed attributes to store value buffers. It is the responsibility of the user to resize each value attribute as needed.
Indexed	Indexed mesh attributes.

AttributeUsage

enum class AttributeUsage : uint16_t

strong

#include <lagrange/AttributeFwd.h>

Usage tag indicating how the attribute should behave under mesh transformations.

This tag mostly serves as a hint, and does not impact how the attribute is stored/loaded.

Todo:

Add skinning weights + others?

Enumerator
Vector	Mesh attribute can have any number of channels (including 1 channel).
Scalar	Mesh attribute must have exactly 1 channel.
Position	Mesh attribute must have exactly dim channels.
Normal	Mesh attribute can have dim or dim + 1 channels.
Tangent	Mesh attribute can have dim or dim + 1 channels.
Bitangent	Mesh attribute can have dim or dim + 1 channels.
Color	Mesh attribute can have 1, 2, 3 or 4 channels.
UV	Mesh attribute must have exactly 2 channels.
VertexIndex	Single channel integer attribute indexing a mesh vertex.
FacetIndex	Single channel integer attribute indexing a mesh facet.
CornerIndex	Single channel integer attribute indexing a mesh corner.
EdgeIndex	Single channel integer attribute indexing a mesh edge.
String	Mesh attribute is a metadata string (stored as a uint8_t buffer).

AttributeCreatePolicy

enum class AttributeCreatePolicy

strong

#include <lagrange/AttributeFwd.h>

Policy for attribute creation with reserved attribute names.

By default, attribute names starting with "$" are reserved for internal use. Creating a reserved attribute name requires an explicit policy flag to be passed to the appropriate function.

Enumerator
ErrorIfReserved	Default deletion policy, throw an exception if attribute name is reserved.
Force	Force creation of reserved attribute names.

AttributeGrowthPolicy

enum class AttributeGrowthPolicy

strong

#include <lagrange/AttributeFwd.h>

Policy for growing external attribute buffers.

If we need to add elements to an external attribute buffer, and we have reached the capacity of the provided span, we can either throw an exception (default behavior), or warn and create an internal copy of the buffer data.

Enumerator
ErrorIfExternal	Throws an exception when trying to grow an external buffer (even if the new size is. still within the buffer capacity).
AllowWithinCapacity	Allow attribute growth as long as it remains within the capacity of the external. buffer. Will throw an error if a reallocation is needed.
WarnAndCopy	Logs a warning and copy the buffer data if it grows beyond the buffer capacity.
SilentCopy	Silently copy the buffer data if it grows beyond the buffer capacity.

AttributeShrinkPolicy

enum class AttributeShrinkPolicy

strong

#include <lagrange/AttributeFwd.h>

Policy for shrinking external attribute buffers.

This policy controls what happens when calling shrink_to_fit() to save memory. Shrinkage can happen either when mesh elements have been removed by another operation, or if the attribute has been created with additional capacity.

Enumerator
ErrorIfExternal	Throws an exception when trying to shrink an external buffer (even if the new size is. still within the buffer capacity). This is the default policy.
IgnoreIfExternal	Ignore external buffers when trying to shrink an attribute.
WarnAndCopy	Logs a warning and creates an internal copy of the buffer data when shrinking below capacity.
SilentCopy	Silently copy the buffer data when shrinking below capacity.

AttributeWritePolicy

enum class AttributeWritePolicy

strong

#include <lagrange/AttributeFwd.h>

Policy for attempting to write to read-only external buffers.

By default any write operation on a read-only external buffer will throw an exception. Alternatively, we can issue a warning a perform a copy of the buffer data.

Enumerator
ErrorIfReadOnly	Throws an exception when trying to write to a read-only buffer.
WarnAndCopy	Logs a warning and copy the buffer data.
SilentCopy	Silently copy the buffer data.

AttributeExportPolicy

enum class AttributeExportPolicy

strong

#include <lagrange/AttributeFwd.h>

Policy for exporting attributes that are views onto external buffers.

By default, a copy is created, meaning we can use the resulting pointer to manage the lifetime of the allocated data.

Enumerator
CopyIfExternal	Copy the buffer during export if the attribute points to an external buffer.
CopyIfUnmanaged	Copy the buffer during export if the attribute points to an unmanaged external buffer.
KeepExternalPtr	Keep the raw pointer to the external buffer data. Use with caution.
ErrorIfExternal	Throw an exception if the attribute points to an external buffer.

AttributeCopyPolicy

enum class AttributeCopyPolicy

strong

#include <lagrange/AttributeFwd.h>

Policy for copying attribute that are views onto external buffers.

By default, a copy is created, meaning we can use the copied attribute to manage the lifetime of the allocated data.

Enumerator
CopyIfExternal	Copy the buffer during copy if the attribute points to an external buffer.
KeepExternalPtr	Keep the raw pointer to the external buffer data. Use with caution.
ErrorIfExternal	Throw an exception if the attribute points to an external buffer.

AttributeDeletePolicy

enum class AttributeDeletePolicy

strong

#include <lagrange/AttributeFwd.h>

Policy for attribute deletion of reserved attribute names.

By default, attribute names starting with "$" are reserved for internal use. Deleting a reserved attribute name requires an explicit policy flag to be passed to the appropriate function.

Enumerator
ErrorIfReserved	Default deletion policy, throw an exception if attribute name is reserved.
Force	Force deletion of reserved attribute names.

AttributeValueType

enum class AttributeValueType : uint8_t

strong

#include <lagrange/AttributeValueType.h>

Enum describing at runtime the value type of an attribute.

This can be accessed from the base attribute class and enables safe downcasting without global RTTI.

Function Documentation

make_attribute_value_type()

constexpr AttributeValueType make_attribute_value_type ( )

constexpr

#include <lagrange/AttributeValueType.h>

Creates an enum describing an attribute value type.

Template Parameters

ValueType

Value type of the attribute to convert to enum.

Returns

Enum describing the input value type.