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| author | Gwendal Grignou <gwendal@chromium.org> | 2018-12-19 09:08:12 -0800 |
|---|---|---|
| committer | chrome-bot <chrome-bot@chromium.org> | 2019-02-28 11:01:47 -0800 |
| commit | 068c46513aac5ecfb06489191fad9fd60e5d750c (patch) | |
| tree | 3241f63ceb44735e9482495b935f648c191562cf /common/math_util.c | |
| parent | 265eceed674b7208fa303d0cfd5345b9113342da (diff) | |
| download | chrome-ec-068c46513aac5ecfb06489191fad9fd60e5d750c.tar.gz | |
math: Add/expose some vector operation
Expose dot procdut and cros product for vector operations.
BUG=b:120346412
BRANCH=none
TEST=compile, check unit tests.
Change-Id: Ief50f31aa6105dc2f0d92caf8b7473a7e141eb45
Signed-off-by: Gwendal Grignou <gwendal@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/1387923
Commit-Ready: ChromeOS CL Exonerator Bot <chromiumos-cl-exonerator@appspot.gserviceaccount.com>
Diffstat (limited to 'common/math_util.c')
| -rw-r--r-- | common/math_util.c | 27 |
1 files changed, 23 insertions, 4 deletions
diff --git a/common/math_util.c b/common/math_util.c index 5e45f9efad..1a29c63d49 100644 --- a/common/math_util.c +++ b/common/math_util.c @@ -148,6 +148,28 @@ int vector_magnitude(const intv3_t v) return int_sqrtf(sum); } +/* cross_product only works if the vectors magnitudes are around 1<<16. */ +void cross_product(const intv3_t v1, const intv3_t v2, intv3_t v) +{ + v[X] = (fp_inter_t)v1[Y] * v2[Z] - (fp_inter_t)v1[Z] * v2[Y]; + v[Y] = (fp_inter_t)v1[Z] * v2[X] - (fp_inter_t)v1[X] * v2[Z]; + v[Z] = (fp_inter_t)v1[X] * v2[Y] - (fp_inter_t)v1[Y] * v2[X]; +} + +fp_inter_t dot_product(const intv3_t v1, const intv3_t v2) +{ + return (fp_inter_t)v1[X] * v2[X] + + (fp_inter_t)v1[Y] * v2[Y] + + (fp_inter_t)v1[Z] * v2[Z]; +} + +void vector_scale(intv3_t v, fp_t s) +{ + v[X] = fp_mul(v[X], s); + v[Y] = fp_mul(v[Y], s); + v[Z] = fp_mul(v[Z], s); +} + fp_t cosine_of_angle_diff(const intv3_t v1, const intv3_t v2) { fp_inter_t dotproduct; @@ -157,10 +179,7 @@ fp_t cosine_of_angle_diff(const intv3_t v1, const intv3_t v2) * Angle between two vectors is acos(A dot B / |A|*|B|). To return * cosine of angle between vectors, then don't do acos operation. */ - - dotproduct = (fp_inter_t)v1[0] * v2[0] + - (fp_inter_t)v1[1] * v2[1] + - (fp_inter_t)v1[2] * v2[2]; + dotproduct = dot_product(v1, v2); denominator = (fp_inter_t)vector_magnitude(v1) * vector_magnitude(v2); |