diff options
-rw-r--r-- | source/blender/blenlib/BLI_math_rotation.h | 20 | ||||
-rw-r--r-- | source/blender/blenlib/intern/math_rotation.c | 49 | ||||
-rw-r--r-- | source/blender/bmesh/operators/bmo_primitive.c | 28 |
3 files changed, 83 insertions, 14 deletions
diff --git a/source/blender/blenlib/BLI_math_rotation.h b/source/blender/blenlib/BLI_math_rotation.h index 192ad482a69..fef51fa780e 100644 --- a/source/blender/blenlib/BLI_math_rotation.h +++ b/source/blender/blenlib/BLI_math_rotation.h @@ -176,6 +176,26 @@ void mat3_to_quat_is_ok(float q[4], const float mat[3][3]); /* Other. */ +/** + * Utility function that performs `sinf` & `cosf` where the quadrants of the circle + * will have exactly matching values when their sign is flipped. + * This works as long as the denominator can be divided by 2 or 4, + * otherwise `sinf` & `cosf` are used without any additional logic. + * + * Besides adjustments to precision, this function is the equivalent of: + * \code {.c} + * float phi = (2 * M_PI) * (float)i / (float)denominator; + * *r_sin = sinf(phi); + * *r_cos = cosf(phi); + * \endcode + * + * \param numerator: An integer factor in [0..denominator] (inclusive). + * \param denominator: The faction denominator (typically the number of segments of the circle). + * \param r_sin: The resulting sine. + * \param r_cos: The resulting cosine. + */ +void sin_cos_from_fraction(const int numerator, const int denominator, float *r_sin, float *r_cos); + void print_qt(const char *str, const float q[4]); #define print_qt_id(q) print_qt(STRINGIFY(q), q) diff --git a/source/blender/blenlib/intern/math_rotation.c b/source/blender/blenlib/intern/math_rotation.c index 92223bdf1d5..f0bfc7c21e1 100644 --- a/source/blender/blenlib/intern/math_rotation.c +++ b/source/blender/blenlib/intern/math_rotation.c @@ -915,6 +915,55 @@ float tri_to_quat(float q[4], const float a[3], const float b[3], const float c[ return len; } +void sin_cos_from_fraction(const int numerator, const int denominator, float *r_sin, float *r_cos) +{ + BLI_assert((numerator <= denominator) && (denominator > 0)); + if ((denominator & 3) == 0) { + const int denominator_4 = denominator / 4; + if (numerator <= denominator_4) { + /* Fall through. */ + } + else { + if (numerator <= denominator_4 * 2) { + const float phi = (float)(2.0 * M_PI) * + ((float)(numerator - denominator_4) / (float)denominator); + *r_sin = cosf(phi); + *r_cos = -sinf(phi); + } + else if (numerator <= denominator_4 * 3) { + const float phi = (float)(2.0 * M_PI) * + ((float)(numerator - (denominator_4 * 2)) / (float)denominator); + *r_sin = -sinf(phi); + *r_cos = -cosf(phi); + } + else { + const float phi = (float)(2.0 * M_PI) * + ((float)(numerator - (denominator_4 * 3)) / (float)denominator); + *r_cos = sinf(phi); + *r_sin = -cosf(phi); + } + return; + } + } + else if ((denominator & 1) == 0) { + const int denominator_2 = denominator / 2; + if (numerator <= denominator_2) { + /* Fall through. */ + } + else { + const float phi = (float)(2.0 * M_PI) * + ((float)(numerator - denominator_2) / (float)denominator); + *r_sin = -sinf(phi); + *r_cos = -cosf(phi); + return; + } + } + + const float phi = (float)(2.0 * M_PI) * ((float)numerator / (float)denominator); + *r_sin = sinf(phi); + *r_cos = cosf(phi); +} + void print_qt(const char *str, const float q[4]) { printf("%s: %.3f %.3f %.3f %.3f\n", str, q[0], q[1], q[2], q[3]); diff --git a/source/blender/bmesh/operators/bmo_primitive.c b/source/blender/bmesh/operators/bmo_primitive.c index 432c7590f3c..2ed0964d735 100644 --- a/source/blender/bmesh/operators/bmo_primitive.c +++ b/source/blender/bmesh/operators/bmo_primitive.c @@ -855,12 +855,12 @@ void bmo_create_uvsphere_exec(BMesh *bm, BMOperator *op) /* one segment first */ for (a = 0; a <= tot; a++) { /* Going in this direction, then edge extruding, makes normals face outward */ - /* Calculate with doubles for higher precision, see: T87779. */ - const float phi = M_PI * ((double)a / (double)tot); + float sin_phi, cos_phi; + sin_cos_from_fraction(a, tot, &sin_phi, &cos_phi); vec[0] = 0.0; - vec[1] = rad * sinf(phi); - vec[2] = rad * cosf(phi); + vec[1] = rad * sin_phi; + vec[2] = rad * cos_phi; eve = BM_vert_create(bm, vec, NULL, BM_CREATE_NOP); BMO_vert_flag_enable(bm, eve, VERT_MARK); @@ -1262,11 +1262,9 @@ void bmo_create_circle_exec(BMesh *bm, BMOperator *op) for (a = 0; a < segs; a++) { /* Going this way ends up with normal(s) upward */ - - /* Calculate with doubles for higher precision, see: T87779. */ - const float phi = (2.0 * M_PI) * ((double)a / (double)segs); - vec[0] = -radius * sinf(phi); - vec[1] = radius * cosf(phi); + sin_cos_from_fraction(a, segs, &vec[0], &vec[1]); + vec[0] *= -radius; + vec[1] *= radius; vec[2] = 0.0f; mul_m4_v3(mat, vec); v1 = BM_vert_create(bm, vec, NULL, BM_CREATE_NOP); @@ -1394,15 +1392,17 @@ void bmo_create_cone_exec(BMesh *bm, BMOperator *op) for (int i = 0; i < segs; i++) { /* Calculate with doubles for higher precision, see: T87779. */ - const float phi = (2.0 * M_PI) * ((double)i / (double)segs); - vec[0] = rad1 * sinf(phi); - vec[1] = rad1 * cosf(phi); + float sin_phi, cos_phi; + sin_cos_from_fraction(i, segs, &sin_phi, &cos_phi); + + vec[0] = rad1 * sin_phi; + vec[1] = rad1 * cos_phi; vec[2] = -depth_half; mul_m4_v3(mat, vec); v1 = BM_vert_create(bm, vec, NULL, BM_CREATE_NOP); - vec[0] = rad2 * sinf(phi); - vec[1] = rad2 * cosf(phi); + vec[0] = rad2 * sin_phi; + vec[1] = rad2 * cos_phi; vec[2] = depth_half; mul_m4_v3(mat, vec); v2 = BM_vert_create(bm, vec, NULL, BM_CREATE_NOP); |