Attribute Computations

Collaboration diagram for Attribute Computations:

Variables
const TfToken	computeValue
	Computes the provider attribute's value.
const TfToken	computeResolvedValue
	Computes the provider attribute's resolved value as authored in scene description.
const TfToken	computePath
	Computes the provider's scene path.

Detailed Description

Builtin computations for computing information about attributes.

Variable Documentation

computePath

const TfToken computePath

Computes the provider's scene path.

Returns

the path of the provider object, as an SdfPath.

Example

self.PrimComputation(_tokens->pathAsString)
    .Callback<std::string>(+[](const VdfContext &ctx) {
        return ctx.GetInputValue<SdfPath>(
            ExecBuiltinComputations->computePath).GetString();
    })
    .Inputs(
        Computation(ExecBuiltinComputations->computePath)
    );

Definition at line 158 of file builtinComputations.h.

computeResolvedValue

const TfToken computeResolvedValue

Computes the provider attribute's resolved value as authored in scene description.

This computation always produces the resolved value of an attribute, even if an attribute has registered an attribute expression.

Returns

a value whose type is the provider attribute's scalar value type.

Example

self.PrimComputation(_tokens->myComputation)
    .Callback<double>(&_MyCallback)
    .Inputs(
        Attribute(_tokens->myAttribute)
            .Computation(ExecBuiltinComputations->computeResolvedValue)
    );

Definition at line 138 of file builtinComputations.h.

computeValue

const TfToken computeValue

Computes the provider attribute's value.

The computed value is produced by the first of the following sources that can be resolved:

1. An attribute expression, if registered, defines the attribute's computed value.
2. If the provider owns exactly one connection that targets another attribute of the same type that is valid (i.e. it is active, loaded, defined, and non-abstract), then its computed value is the computed value of the targeted attribute.
3. Otherwise, the computed value is the resolved value of the provider.

Returns

a value whose type is the provider attribute's scalar value type. If the attribute has registered an attribute expression, this may produce a value of any type.

Note

The computation provider must be an attribute.

Example

self.PrimComputation(_tokens->myComputation)
    .Callback<double>(&_MyCallback)
    .Inputs(
        Attribute(_tokens->myAttribute)
            .Computation<double>(ExecBuiltinComputations->computeValue)
            .Required()
    );

Definition at line 114 of file builtinComputations.h.