Previously, the binding auto-mapping facility was free to use any unused
binding. This change makes auto-bindings use the same offset value as
explicit bindings.
In HLSL array sizes need not be provided explicitly in all circumstances.
For example, this is valid (note no number between the [ ]):
// no explicit array size
uniform float g_array[] = { 1, 2, 3, 4, 5 };
This PR does not attempt to validate most invalid cases.
A new test is added to verify the resulting linker objects.
This PR adds a GLSL equivalent to the HLSL binding mapping tests for offsets and auto-numbering.
The shaders are as equivalent as possible. The bindings of the base results match exactly
between the two.
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 checkin adds a --flatten-uniform-arrays option which can break
uniform arrays of samplers, textures, or UBOs up into individual
scalars named (e.g) myarray[0], myarray[1], etc. These appear as
individual linkage objects.
Code notes:
- shouldFlatten internally calls shouldFlattenIO, and shouldFlattenUniform,
but is the only flattening query directly called.
- flattenVariable will handle structs or arrays (but not yet arrayed structs;
this is tested an an error is generated).
- There's some error checking around unhandled situations. E.g, flattening
uniform arrays with initializer lists is not implemented.
- This piggybacks on as much of the existing mechanism for struct flattening
as it can. E.g, it uses the same flattenMap, and the same
flattenAccess() method.
- handleAssign() has been generalized to cope with either structs or arrays.
- Extended test infrastructure to test flattening ability.
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.
