Re: [PATCH v5 0/2] MR179: vkd3d-shader/hlsl: Add support for ddx(), ddy() intrinsics.

[Giovanni Mascellani (＠giomasce)]

On Thu Apr 27 14:22:18 2023 +0000, Ethan Lee wrote:
> Oddly enough this doesn't seem to pass on RADV with a 7900XTX, but just barely:
> shader_runner:1197: Running tests from a Unix build
> shader_runner:1199: Compiling shaders with vkd3d-shader and executing
> with Vulkan
> shader_runner:601: Section [test], line 19: Test failed: Got
> {-7.52500343e+00, -1.56500721e+00, 1.50500488e+00, 0.00000000e+00},
> expected {-7.52500916e+00, -1.56500244e+00, 1.50500488e+00,
> 0.00000000e+00} at (150, 150).
> shader_runner:1202: Compiling shaders with vkd3d-shader and executing
> with vkd3d
> shader_runner:612: Driver name: radv, driver info: Mesa 23.2.0-devel.
> shader_runner:601: Section [test], line 19: Test failed: Got
> {-7.52500343e+00, -1.56500721e+00, 1.50500488e+00, 0.00000000e+00},
> expected {-7.52500916e+00, -1.56500244e+00, 1.50500488e+00,
> 0.00000000e+00} at (150, 150).
> shader_runner: 149 tests executed (2 failures, 0 skipped, 0 todo, 0 bugs).
> FAIL tests/ddxddy.shader_test (exit status: 1)

I would have hoped that 8 ULPs were enough for having a common idea of the first derivatives of a quadratic polynomial, but it seems video card producers decided differently. I don't think there is much we can do about, except for raising our tolerance (which is the number at the end of the `probe` command).