DefinitionDataInput

definition-taxonomy §DTX-S1b — the definition data table as the input of a libeval program.

In the namespace construct::eval. Declared in src/libs/libconstruct/construct/eval/SdfSceneGraphBuilder.hpp.

Detailed description

The table is a run-time array input of the program, named construct::shader::kDefinitionDataTableName, and libeval gives it a storage block of its own on every backend (SUP-50). The program's code reads it through the accessor of construct::shader::DefinitionDataTable::ProgramInput. The table is set once, after the compile, and every evaluation reads it: a single evaluation, a ThreadCopy and every row of a batch.

A table in the code as a constant array is the other way, and it is slow: glslang copies a constant array that the code indexes with a variable into a local variable at each call, so each defData() call would copy the whole table.