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| author | Tim Foley <tfoleyNV@users.noreply.github.com> | 2020-01-28 12:35:13 -0800 |
|---|---|---|
| committer | Tim Foley <tim.foley.is@gmail.com> | 2020-01-28 12:35:13 -0800 |
| commit | 8b3e3beea66d9773adf11ea2e163577d649f3d7c (patch) | |
| tree | 51b4f3967d5db5494f98f6f9bf870ef2096929f5 /tests/compute/matrix-layout-structured-buffer.slang | |
| parent | b3e0b0d491c55bfdc1c40d26a421910103c1b9f2 (diff) | |
Fix layout for structured buffers of matrices (#1184)
When using row-major layout (via command-line or API option), the following sort of declaration:
```hlsl
StructuredBuffer<float4x4> gBuffer;
... gBuffer[i] ...
```
Generates unexpected results when compiled to DXBC via fxc or DXIL via dxc, because the fxc/dxc compilers do not respect the matrix layout mode in this specific case (a structured buffer of matrices). Instead, they always use column-major layout, even if row-major was requested by the user.
A user can work around this behavior by wrapping the matrix in a `struct`:
```hlsl
struct Wrapper { float4x4 wrapped; }
SturcturedBuffer<Wrapper> gBuffer;
... gBuffer[i].wrapped ...
```
This change simply automates that workaround when compiling for an HLSL-based downstream compiler, so that we get the same behavior across all our backends.
The change adds a test case to confirm the behavior across multiple targets, but it turns out we also had a test checked in that confirmed the buggy (or at least surprising) fxc/dxc behavior, so that one had its baselines changed and can work as a regression test for this fix as well.
Diffstat (limited to 'tests/compute/matrix-layout-structured-buffer.slang')
| -rw-r--r-- | tests/compute/matrix-layout-structured-buffer.slang | 17 |
1 files changed, 4 insertions, 13 deletions
diff --git a/tests/compute/matrix-layout-structured-buffer.slang b/tests/compute/matrix-layout-structured-buffer.slang index 36596424d..bb7dbb381 100644 --- a/tests/compute/matrix-layout-structured-buffer.slang +++ b/tests/compute/matrix-layout-structured-buffer.slang @@ -1,18 +1,9 @@ // matrix-layout-structured-buffer.slang -// This test is set up to confirm that `StructuredBuffer` types are -// always laid out column-major by fxc/dxc, even when row-major layout has been -// requested globally. -// -// This behavior should be considered a bug in Slang because either: -// -// 1. we should report reflection layout information that acknowledges this behavior, or -// 2. we should alter our HLSL output passed to fxc/dxc to provide consistent -// behavior that matches our reflection data. -// -// For now this test exists to document the situation. It's output can/should -// be updated if we decide to fix the underlying problem by taking option (2). -// +// This test confirms that we apply the matrix layout +// mode requested by the user, even in the case of structured +// buffers of matrices, where fxc/dxc do *not* respect +// the matrix layout mode by default. //TEST(compute):COMPARE_COMPUTE_EX:-slang -compute -xslang -matrix-layout-row-major //TEST(compute):COMPARE_COMPUTE_EX:-slang -compute -xslang -matrix-layout-column-major |