When compiling with -march=znver4 (or any arch with FMA), GCC's default
-ffp-contract=fast contracts a*b+c into FMA opportunistically. The same
inline math function compiled in the shared library and in the test
binary can get different FMA contraction decisions due to different
optimization contexts, producing bit-different FP results.
Three API tests compare C++ direct calls (inlined into test TU) against
C API wrapper calls (through libassimp.so) using EXPECT_EQ (bit-exact),
which fails when the compiler contracts differently across TUs.
Verified via disassembly: the library uses vfnmadd FMA instructions
(3 roundings) while the test binary uses separate vmulss+vsubss
(6 roundings) for the same computation.
Replace EXPECT_EQ with Equal(epsilon) for the three affected tests:
- aiMatrix3FromToTest: use machine epsilon (~1.19e-7)
- aiMatrix4FromToTest: use machine epsilon (~1.19e-7)
- aiQuaternionFromNormalizedQuaternionTest: use 1e-4 because FMA
differences in 1.0-x*x-y*y-z*z can flip a near-zero residual's sign,
causing w=0 vs w=sqrt(tiny)≈1e-4
Fixes#6246
Co-authored-by: Chris de Claverie <declaverie@gmail.com>
Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>
Co-authored-by: Kim Kulling <kimkulling@users.noreply.github.com>
* Update copyright year and project version
- Fixes version in lib
* Update copyright year to 2026
* Update copyright year to 2026 in Version.cpp
* Update copyright year and version patch test
* Fix copyright year
* Adapt copyrights
* Make color single precision
* Fix the unittests for double precision
* Fix merge issues
* Fix issues with Vertex + Color4
* Fix vertex operator, some tests are still red.
* Fix identity matrix check
Adds an extra epsilon value to check the matrix4x4 identity. The method is also used to export to GLTF/GLTF2 format to check node transformation matrices. The epsilon value can be set using AI_CONFIG_CHECK_IDENTITY_MATRIX_EPSILON with the default value set to 10e-3f for backward compatibility of legacy code.
* Fix type of float values in the unit test
* Update matrix4x4.inl
Fix typo
* Update matrix4x4.inl
Remove dead code.
* Add isIdentity-Test
* Update AssimpAPITest_aiMatrix4x4.cpp
---------
Co-authored-by: Kim Kulling <kimkulling@users.noreply.github.com>
Tested:
$ cmake -DASSIMP_DOUBLE_PRECISION=1 -DASSIMP_BUILD_MDL_IMPORTER=0 ..; make
The MDL importer is disabled due to the fact that there is some float-only code
in MDL. This also means bin/assimp and bin/unit would not link successfully with
the above build flags.
- (1) Changed randomized math structure values to predefined values to prevent cases that could potentially lead to division by zero.
- (2) Removed unused variable(s) due to (1).
- (3) Renamed variable(s) for better clarity.
