We directly use an instance of RangeDescriptor to avoid incurring
the memory cost of using a StagingBuffer here. It's unnecessary
since these stencils will always be 32bits large.
These two classes represent our first foray into stencil
construction. One of them standardizes PcloudAmbience stencils
across all stimbuffs, and the other specifies the internal
memory constraints and requirements for a LivoxGen1 device's
stencils.