SPIR-V allows an image to be marked as a depth image, but with a non-depth
format. Such images should be read or sampled as vectors instead of scalars,
except when they are subject to compare operations.
Don't mark an OpSampledImage as using a compare operation just because the
image contains a depth marker. Instead, require that a compare operation
is actually used on that image.
Compiler::image_is_comparison() was really testing whether an image is a
depth image, since it incorporates the depth marker. Rename that function
to is_depth_image(), to clarify what it is really testing.
In Compiler::is_depth_image(), do not treat an image as a depth image
if it has been explicitly marked with a color format, unless the image
is subject to compare operations.
In CompilerMSL::to_function_name(), test for compare operations
specifically, rather than assuming them from the depth-image marker.
CompilerGLSL and CompilerMSL still contain a number of internal tests that
use is_depth_image() both for testing for a depth image, and for testing
whether compare operations are being used. I've left these as they are
for now, but these should be cleaned up at some point.
Add unit tests for fetch/sample depth images with color formats and no compare ops.
Emit block members directly in the IO structs and sort them.
Ensures we can get some kind of stable order between stages.
To complete the story, we'll need to be able to inject unused inputs /
builtins, or eliminate unused outputs (probably easiest solution).
We'll need to force a temporary and mark it as precise.
MSL is a little weird here, but we can piggyback on top of the invariant
float math option here to force fma() operations everywhere.
We have been interchanging spv and SPIRV_Cross_ for a while, which
causes weirdness since we don't explicitly ban SPIRV_Cross identifiers,
as these identifiers are generally used for interface variable
workarounds.
In some cases, we need to get a literal value from a spec constant op.
Mostly relevant when emitting buffers, so implement a 32-bit integer
scalar subset of the evaluator. Can be extended as needed to support
evaluating any specialization constant operation.
- Do not silently drop reserved identifiers in the parser. This makes it
possible to reflect identifiers which are reserved by the
cross-compiler module.
- Instead of dropping the name, emit _RESERVED_IDENTIFIER_FIXUP in the
source to make it clear that a name has been rewritten.
- Document what is reserved and not.
