Fix for two defects as follows:
- The IO mapping traverser was not setting inVisit, and would skip some AST nodes.
Depending on the order of nodes, this could have prevented the binding from
showing up in the generated SPIR-V.
- If a uniform array was flattened, each of the flattened scalars from the array
is still a (now-scalar) uniform. It was being converted to a temporary.
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.
