This PR adds the ability to offset sampler, texture, and UBO bindings
from provided base bindings, and to auto-number bindings that are not
provided with explicit register numbers. The mechanism works as
follows:
- Offsets may be given on the command line for all stages, or
individually for one or more single stages, in which case the
offset will be auto-selected according to the stage being
compiled. There is also an API to set them. The new command line
options are --shift-sampler-binding, --shift-texture-binding, and
--shift-UBO-binding.
- Uniforms which are not given explicit bindings in the source code
are auto-numbered if and only if they are in live code as
determined by the algorithm used to build the reflection
database, and the --auto-map-bindings option is given. This auto-numbering
avoids using any binding slots which were explicitly provided in
the code, whether or not that explicit use was live. E.g, "uniform
Texture1D foo : register(t3);" with --shift-texture-binding 10 will
reserve binding 13, whether or not foo is used in live code.
- Shorter synonyms for the command line options are available. See
the --help output.
The testing infrastructure is slightly extended to allow use of the
binding offset API, and two new tests spv.register.(no)autoassign.frag are
added for comparing the resulting SPIR-V.
