void GenerateSegment(
CurveBase curve,
List <FrenetFrame> frames,
List <Vector3> vertices,
List <Vector3> normals,
List <Vector4> tangents,
int index
)
{
// 0.0 ~ 1.0
float u = 1f * index / tubularSegments;
Vector3 p = curve.GetPointAt(u);
FrenetFrame fr = frames[index];
Vector3 N = fr.Normal;
Vector3 B = fr.Binormal;
for (int j = 0; j <= radialSegments; j++)
{
// 0.0 ~ 2π
float rad = 1f * j / radialSegments * PI2;
// 円周に沿って均等に頂点を配置する
float cos = Mathf.Cos(rad), sin = Mathf.Sin(rad);
Vector3 v = (cos * N + sin * B).normalized;
vertices.Add(p + radius * v);
normals.Add(v);
Vector3 tangent = fr.Tangent;
tangents.Add(new Vector4(tangent.x, tangent.y, tangent.z, 0f));
}
}
public TreeSegment(FrenetFrame frame, Vector3 position, float radius)
{
this.frame = frame;
this.position = position;
this.radius = radius;
}
public List <FrenetFrame> ComputeFrenetFrames(int segments, Vector3 normal, Vector3 binormal, bool closed = false)
{
var tangents = new Vector3[segments + 1];
var normals = new Vector3[segments + 1];
var binormals = new Vector3[segments + 1];
for (int i = 0; i <= segments; i++)
{
var u = (1f * i) / segments;
tangents[i] = GetTangentAt(u).normalized;
}
normals[0] = normal;
binormals[0] = binormal;
float theta;
for (int i = 1; i <= segments; i++)
{
// copy previous
normals[i] = normals[i - 1];
binormals[i] = binormals[i - 1];
var axis = Vector3.Cross(tangents[i - 1], tangents[i]);
if (axis.magnitude > float.Epsilon)
{
axis.Normalize();
float dot = Vector3.Dot(tangents[i - 1], tangents[i]);
theta = Mathf.Acos(Mathf.Clamp(dot, -1f, 1f));
normals[i] = Quaternion.AngleAxis(theta * Mathf.Rad2Deg, axis) * normals[i];
}
binormals[i] = Vector3.Cross(tangents[i], normals[i]).normalized;
}
if (closed)
{
theta = Mathf.Acos(Mathf.Clamp(Vector3.Dot(normals[0], normals[segments]), -1f, 1f));
theta /= segments;
if (Vector3.Dot(tangents[0], Vector3.Cross(normals[0], normals[segments])) > 0f)
{
theta = -theta;
}
for (int i = 1; i <= segments; i++)
{
normals[i] = (Quaternion.AngleAxis(Mathf.Deg2Rad * theta * i, tangents[i]) * normals[i]);
binormals[i] = Vector3.Cross(tangents[i], normals[i]);
}
}
var frames = new List <FrenetFrame>();
int n = tangents.Length;
for (int i = 0; i < n; i++)
{
var frame = new FrenetFrame(tangents[i], normals[i], binormals[i]);
frames.Add(frame);
}
return(frames);
}
public TreeSegment(FrenetFrame frame, Vector3 position)
{
this.frame = frame;
this.position = position;
}
