diff options
author | Sybren A. Stüvel <sybren@blender.org> | 2020-06-16 16:36:08 +0300 |
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committer | Sybren A. Stüvel <sybren@blender.org> | 2020-06-18 11:37:46 +0300 |
commit | 46e4cdf7884f997f8a2c9c8b06429fd8da917f2a (patch) | |
tree | 4f6e5d7cfe9711e2e27b51db93d4d2dffb4ef840 | |
parent | 099d47f8a310ca6b89adb4e61cc7ec15cc9c11d9 (diff) |
Tests: added simple unittests for matrix interpolation
The interpolation of 4x4 and 3x3 matrices will fail when the rotation
component has a singularity, i.e. when there is one axis mirrored. Two
mirrored axes are just a rotation of 180 degrees around the third, and
three mirrored axes are such a rotation + a single axis mirror. To
prepare for a fix, I first wanted to cover the basic functionality with
a few unit tests.
These tests check that `interpolate(A, B, alpha)` always returns `A` for
`alpha=0`, always return `B` for `alpha=1`, and something in between for
`alpha=0.5`.
-rw-r--r-- | tests/gtests/blenlib/BLI_math_matrix_test.cc | 77 | ||||
-rw-r--r-- | tests/gtests/blenlib/CMakeLists.txt | 1 |
2 files changed, 78 insertions, 0 deletions
diff --git a/tests/gtests/blenlib/BLI_math_matrix_test.cc b/tests/gtests/blenlib/BLI_math_matrix_test.cc new file mode 100644 index 00000000000..0baccf9ee60 --- /dev/null +++ b/tests/gtests/blenlib/BLI_math_matrix_test.cc @@ -0,0 +1,77 @@ +/* Apache License, Version 2.0 */ + +#include "testing/testing.h" + +#include "BLI_math_matrix.h" + +TEST(math_matrix, interp_m4_m4m4_regular) +{ + /* Test 4x4 matrix interpolation without singularity, i.e. without axis flip. */ + + /* Transposed matrix, so that the code here is written in the same way as print_m4() outputs. */ + /* This matrix represents T=(0.1, 0.2, 0.3), R=(40, 50, 60) degrees, S=(0.7, 0.8, 0.9) */ + float matrix_a[4][4] = { + {0.224976f, -0.333770f, 0.765074f, 0.100000f}, + {0.389669f, 0.647565f, 0.168130f, 0.200000f}, + {-0.536231f, 0.330541f, 0.443163f, 0.300000f}, + {0.000000f, 0.000000f, 0.000000f, 1.000000f}, + }; + transpose_m4(matrix_a); + + float matrix_i[4][4]; + unit_m4(matrix_i); + + float result[4][4]; + const float epsilon = 1e-6; + interp_m4_m4m4(result, matrix_i, matrix_a, 0.0f); + EXPECT_M4_NEAR(result, matrix_i, epsilon); + + interp_m4_m4m4(result, matrix_i, matrix_a, 1.0f); + EXPECT_M4_NEAR(result, matrix_a, epsilon); + + /* This matrix is based on the current implementation of the code, and isn't guaranteed to be + * correct. It's just consistent with the current implementation. */ + float matrix_halfway[4][4] = { + {0.690643f, -0.253244f, 0.484996f, 0.050000f}, + {0.271924f, 0.852623f, 0.012348f, 0.100000f}, + {-0.414209f, 0.137484f, 0.816778f, 0.150000f}, + {0.000000f, 0.000000f, 0.000000f, 1.000000f}, + }; + + transpose_m4(matrix_halfway); + interp_m4_m4m4(result, matrix_i, matrix_a, 0.5f); + EXPECT_M4_NEAR(result, matrix_halfway, epsilon); +} + +TEST(math_matrix, interp_m3_m3m3_singularity) +{ + /* A singluarity means that there is an axis mirror in the rotation component of the matrix. This + * is reflected in its negative determinant. + * + * The interpolation of 4x4 matrices performs linear interpolation on the translation component, + * and then uses the 3x3 interpolation function to handle rotation and scale. As a result, this + * test for a singularity in the rotation matrix only needs to test the 3x3 case. */ + + /* Transposed matrix, so that the code here is written in the same way as print_m4() outputs. */ + /* This matrix represents R=(4, 5, 6) degrees, S=(-1, 1, 1) */ + float matrix_a[3][3] = { + {-0.990737f, -0.098227f, 0.093759f}, + {-0.104131f, 0.992735f, -0.060286f}, + {0.087156f, 0.069491f, 0.993768f}, + }; + transpose_m3(matrix_a); + EXPECT_NEAR(-1.0f, determinant_m3_array(matrix_a), 1e-6); + + float matrix_i[3][3]; + unit_m3(matrix_i); + + float result[3][3]; + const float epsilon = 1e-6; + interp_m3_m3m3(result, matrix_i, matrix_a, 0.0f); + EXPECT_M3_NEAR(result, matrix_i, epsilon); + + /* This fails for matrices with a negative determinant, i.e. with an axis mirror in the rotation + * component. See T77154. */ + // interp_m3_m3m3(result, matrix_i, matrix_a, 1.0f); + // EXPECT_M3_NEAR(result, matrix_a, epsilon); +} diff --git a/tests/gtests/blenlib/CMakeLists.txt b/tests/gtests/blenlib/CMakeLists.txt index 8ddb2702b83..31c8e983292 100644 --- a/tests/gtests/blenlib/CMakeLists.txt +++ b/tests/gtests/blenlib/CMakeLists.txt @@ -60,6 +60,7 @@ BLENDER_TEST(BLI_math_base "bf_blenlib") BLENDER_TEST(BLI_math_bits "bf_blenlib") BLENDER_TEST(BLI_math_color "bf_blenlib") BLENDER_TEST(BLI_math_geom "bf_blenlib") +BLENDER_TEST(BLI_math_matrix "bf_blenlib") BLENDER_TEST(BLI_math_vector "bf_blenlib") BLENDER_TEST(BLI_memiter "bf_blenlib") BLENDER_TEST(BLI_optional "bf_blenlib") |