diff options
Diffstat (limited to 'source/blender/blenlib/intern/math_vector_inline.c')
| -rw-r--r-- | source/blender/blenlib/intern/math_vector_inline.c | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/source/blender/blenlib/intern/math_vector_inline.c b/source/blender/blenlib/intern/math_vector_inline.c index 08687a1ab47..715e2e65c96 100644 --- a/source/blender/blenlib/intern/math_vector_inline.c +++ b/source/blender/blenlib/intern/math_vector_inline.c @@ -753,6 +753,16 @@ MINLINE void cross_v3_v3v3(float r[3], const float a[3], const float b[3]) r[2] = a[0] * b[1] - a[1] * b[0]; } +/* cross product suffers from severe precision loss when vectors are + * nearly parallel or opposite; doing the computation in double helps a lot */ +MINLINE void cross_v3_v3v3_hi_prec(float r[3], const float a[3], const float b[3]) +{ + BLI_assert(r != a && r != b); + r[0] = (float)((double)a[1] * (double)b[2] - (double)a[2] * (double)b[1]); + r[1] = (float)((double)a[2] * (double)b[0] - (double)a[0] * (double)b[2]); + r[2] = (float)((double)a[0] * (double)b[1] - (double)a[1] * (double)b[0]); +} + /* Newell's Method */ /* excuse this fairly specific function, * its used for polygon normals all over the place |