Support for texturing geometry with Iops #1
Description
In order to replicate the canonical Nuke 3D workflow, we need to support the use of Iop networks as shader inputs for geometry, either on their own or as part of an Sdr-based shader network.
Supporting this workflow in Hydra will require pre-rendering Iops and then somehow handing the result off to the render delegate as part of a material network. However, while I believe HdStorm supports directly consuming HdTexture BPrims for texture input, most renderers only support consuming textures from files. Thus, the only way I can think of to do this in a universal way will be using some kind of an on-disk texture arena.
We should also investigate whether we can use Hydra's ExtComputation system to only render the input Iops on demand.