Fragment shaders that require explicit early fragment tests are incompatible
with specifying depth and stencil values within the shader. If explicit early
fragment tests is specified, remove the depth and stencil outputs from the
output structure, and replace them with dummy local variables.
Add CompilerMSL:uses_explicit_early_fragment_test() function to consolidate
testing for whether early fragment tests are required.
Add two unit tests for depth-out with, and without, early fragment tests.
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.
This is somewhat awkward to support, but the best effort we can do here
is to analyze various Load/Store opcodes and deduce the ideal overall
alignment based on this. This is not a 100% perfect solution, but should
be correct for any reasonable use case.
Also fix various nitpicks with BDA support while I'm at it.
Apparently, it's legal to use a selection construct where both paths
branch to same location, but a different merge point is used.
This breaks many assumptions the variable scope analyzer makes.
The only logical way to generate code for this scenario is to treat the
selection construct as a trivial switch construct with only a default
case.
Only emit user(locnN) for tess builtin input variables, and allow output builtin
to emit user(clip/cullN). Previously, output builtin would emit location if
input builtin also existed.
Previous test for SPIRVCrossDecorationPhysicalTypePacked on parent struct
when unpacking member struct was too restrictive, and not needed as long
as padding compensates.
Populate member_type_index_redirection as reverse lookup, not forward lookup.
Move use of member_type_index_redirection from CompilerMSL::to_member_reference()
to CompilerGLSL::access_chain_internal() to access all redirected type info,
not just name.
Promote to short instead and do simple casts on load/store instead.
Not 100% complete fix since structs can contain booleans, but this is
getting into pretty ridiculously complicated territory.
Additional usecases include array and vector indexing, variable declarations,
loop initializers, function return values, switch statement evaluations,
and various specialized MSL operations.
Ultimately, we might consider refactoring CompilerMSL::to_expression()
to always take into consideration possible unpacking behavior.
Refactor CompilerGLSL::to_enclosed_unpacked_expression()
for conciseness and consistency with similar functionality.
