PistonDevelopers
piston_collada does not respect the differences between IDREF_array, Name_array and SIDREF_array
Expectation
The COLLADA-Specification lists different ways to reference nodes.
Among them are the elements IDREF_array(page 5-44), Name_array(page 5-94) and SIDREF_array(page 5-130).
To correctly treat them, piston_collada should use their values as references to the attributes id, name and sid respectively.
Problem
Currently piston_collada loads a Name_array with the joint_names here:
https://github.com/PistonDevelopers/piston_collada/blob/591b66761c0c9a12a98e700b7a0d39edb649f9fc/src/document.rs#L508-L509
and then later compares them with Joint.name here:
https://github.com/PistonDevelopers/piston_collada/blob/591b66761c0c9a12a98e700b7a0d39edb649f9fc/src/document.rs#L667-L678
But Joint.name was set the id attribute here:
https://github.com/PistonDevelopers/piston_collada/blob/591b66761c0c9a12a98e700b7a0d39edb649f9fc/src/document.rs#L460
This bug is not caught by the existing cache files, because name and id are the same there.
The incorrect handling is not only a derivation from the spec, but leads to incorrect handling of actual exported collada files.
In the following examples from other projects, is visible that both Blender and ColladaMaya may set the the name attribute to a different value then the idattribute and mean the name attribute in Name_array.
Example1
In three.js is the following example, where the Name_array with the joints here:
https://github.com/mrdoob/three.js/blob/c7d06c02e302ab9c20fe8b33eade4b61c6712654/examples/models/collada/skin_and_morph.dae#L385-L393
refers to the node here, where the referenced name joint1 is in the name attribute and not the id attribute:
https://github.com/mrdoob/three.js/blob/c7d06c02e302ab9c20fe8b33eade4b61c6712654/examples/models/collada/skin_and_morph.dae#L552-L555
Example2
As a more complex example, where blender does this, serves the following file from the game 0AD, where the Name_array here:
https://github.com/0ad/0ad/blob/412f1d0da275a12df16e140fca7523590e5f7cfe/binaries/data/mods/public/art/meshes/skeletal/elephant_asian_male.dae#L86-L88
references the nodes from here onwards always by there name:
https://github.com/0ad/0ad/blob/412f1d0da275a12df16e140fca7523590e5f7cfe/binaries/data/mods/public/art/meshes/skeletal/elephant_asian_male.dae#L449-L474
