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| author | Tim Foley <tfoleyNV@users.noreply.github.com> | 2020-05-11 14:57:05 -0700 |
|---|---|---|
| committer | GitHub <noreply@github.com> | 2020-05-11 14:57:05 -0700 |
| commit | f5dfa1ed6a51809e8593f5f2abc292ab39f35dcb (patch) | |
| tree | 1ed0ec39036e65241e64be40ff07a418a23d891c | |
| parent | 798f3bc2236ce81499b05662dc11e7c071e7cde8 (diff) | |
Add GLSL translation for HLSL fmod() (#1342)
The existing code was assuming `fmod()` was available as a builtin in GLSL, which isn't true. It also isn't possible to translate the HLSL `fmod()` to the GLSL `mod()` since the two have slightly different semantics.
This change introduces a definition for `fmod(x,y)` that amounts to `x - y*trunc(x/y)` which should agree with the HLSL version except in corner cases (e.g., there are some cases where the HLSL version returns `-0` and this one will return `0`).
| -rw-r--r-- | source/slang/hlsl.meta.slang | 7 | ||||
| -rw-r--r-- | tests/cross-compile/fmod.slang | 28 | ||||
| -rw-r--r-- | tests/cross-compile/fmod.slang.expected.txt | 4 |
3 files changed, 36 insertions, 3 deletions
diff --git a/source/slang/hlsl.meta.slang b/source/slang/hlsl.meta.slang index c0dba51e3..fcd028b6e 100644 --- a/source/slang/hlsl.meta.slang +++ b/source/slang/hlsl.meta.slang @@ -1325,14 +1325,15 @@ matrix<double, N, M> fma(matrix<double, N, M> a, matrix<double, N, M> b, matrix< // Floating point remainder of x/y __generic<T : __BuiltinFloatingPointType> __target_intrinsic(hlsl) -__target_intrinsic(glsl) __target_intrinsic(cuda, "$P_fmod($0, $1)") __target_intrinsic(cpp, "$P_fmod($0, $1)") -T fmod(T x, T y); +T fmod(T x, T y) +{ + return x - y * trunc(x/y); +} __generic<T : __BuiltinFloatingPointType, let N : int> __target_intrinsic(hlsl) -__target_intrinsic(glsl) vector<T, N> fmod(vector<T, N> x, vector<T, N> y) { VECTOR_MAP_BINARY(T, N, fmod, x, y); diff --git a/tests/cross-compile/fmod.slang b/tests/cross-compile/fmod.slang new file mode 100644 index 000000000..94d733e66 --- /dev/null +++ b/tests/cross-compile/fmod.slang @@ -0,0 +1,28 @@ +// fmod.slang + +// Ensure that HLSL `fmod` works and produces +// expected output on Vulkan/GLSL. + +//TEST(compute):COMPARE_COMPUTE:-dx11 -compute +//TEST(compute):COMPARE_COMPUTE:-vk -compute + +//TEST_INPUT:cbuffer(data=[4 0 0 0]):name=C +cbuffer C +{ + int y; +} + +int test(int x) +{ + return int(fmod(float(x), float(y))); +} + +//TEST_INPUT:ubuffer(data=[-7 -2 2 7], stride=4):out,name outputBuffer +RWStructuredBuffer<int> outputBuffer; + +[numthreads(4, 1, 1)] +void computeMain(uint3 dispatchThreadID : SV_DispatchThreadID) +{ + uint tid = dispatchThreadID.x; + outputBuffer[tid] = test(outputBuffer[tid]); +} diff --git a/tests/cross-compile/fmod.slang.expected.txt b/tests/cross-compile/fmod.slang.expected.txt new file mode 100644 index 000000000..02a433b0b --- /dev/null +++ b/tests/cross-compile/fmod.slang.expected.txt @@ -0,0 +1,4 @@ +FFFFFFFD +FFFFFFFE +2 +3 |