float angle_normalized_v2v2(const float v1[2], const float v2[2])
{
/* this is the same as acos(dot_v3v3(v1, v2)), but more accurate */
if (dot_v2v2(v1, v2) < 0.0f) {
float vec[2];
vec[0]= -v2[0];
vec[1]= -v2[1];
return (float)M_PI - 2.0f*saasin(len_v2v2(vec, v1)/2.0f);
}
else
return 2.0f*(float)saasin(len_v2v2(v2, v1)/2.0f);
}
float angle_normalized_v2v2(const float v1[2], const float v2[2])
{
/* double check they are normalized */
BLI_ASSERT_UNIT_V2(v1);
BLI_ASSERT_UNIT_V2(v2);
/* this is the same as acos(dot_v3v3(v1, v2)), but more accurate */
if (dot_v2v2(v1, v2) >= 0.0f) {
return 2.0f * saasin(len_v2v2(v1, v2) / 2.0f);
}
else {
float v2_n[2];
negate_v2_v2(v2_n, v2);
return (float)M_PI - 2.0f * saasin(len_v2v2(v1, v2_n) / 2.0f);
}
}
float angle_normalized_v3v3(const float v1[3], const float v2[3])
{
/* double check they are normalized */
BLI_ASSERT_UNIT_V3(v1);
BLI_ASSERT_UNIT_V3(v2);
/* this is the same as acos(dot_v3v3(v1, v2)), but more accurate */
if (dot_v3v3(v1, v2) < 0.0f) {
float vec[3];
vec[0] = -v2[0];
vec[1] = -v2[1];
vec[2] = -v2[2];
return (float)M_PI - 2.0f * (float)saasin(len_v3v3(vec, v1) / 2.0f);
}
else
return 2.0f * (float)saasin(len_v3v3(v2, v1) / 2.0f);
}
