HlslSourceCompatibilityTests previously flattened only bare vector returns to
scalar leaves. Values() now recurses through struct fields of any type, so a
struct return (invariant 8's one shape, e.g. CultCellular) is compared field
by field down to bit-for-bit scalars, exactly like a vector return already
was. Components() stays scoped to scalar-typed fields, since it only ever
builds function arguments and must not recurse.
TransformHlslToCSharp gains transformation 5: struct fields gain `public`,
since HLSL has no field access-modifier concept and a C# struct's fields
default to private, which would hide them from Values()' reflection. The old
wrap-in-a-class transformation is renumbered 6. design.md's transformation
list documents both, matching design.md:92's numbered list.
StructReturnComparisonRejectsAMismatchedField is the extension's own test: two
hand-built structs with the same shape (mirroring a real mirror-vs-C#
comparison) prove the field-by-field, bit-for-bit walk actually rejects a
struct whose leaf field differs, or whose nested vector's own component
differs, not just a length check.
EveryMirrorFunctionMatchesCSharpMath and HlslMirrorTests' required-symbol list
now cover cultmath_smin_grad and cultmath_cellular; the mirrored-function
count moves from 28 to 30.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
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