buildPlaneVectors function
Sets u
and v
to be two vectors orthogonal to each other and
planeNormal
.
Implementation
void buildPlaneVectors(final Vector3 planeNormal, Vector3 u, Vector3 v) {
if (planeNormal.z.abs() > math.sqrt1_2) {
// choose u in y-z plane
final a = planeNormal.y * planeNormal.y + planeNormal.z * planeNormal.z;
final k = 1.0 / math.sqrt(a);
u
..x = 0.0
..y = -planeNormal.z * k
..z = planeNormal.y * k;
v
..x = a * k
..y = -planeNormal[0] * (planeNormal[1] * k)
..z = planeNormal[0] * (-planeNormal[2] * k);
} else {
// choose u in x-y plane
final a = planeNormal.x * planeNormal.x + planeNormal.y * planeNormal.y;
final k = 1.0 / math.sqrt(a);
u
..x = -planeNormal[1] * k
..y = planeNormal[0] * k
..z = 0.0;
v
..x = -planeNormal[2] * (planeNormal[0] * k)
..y = planeNormal[2] * (-planeNormal[1] * k)
..z = a * k;
}
}