/// <summary>
/// 通过距离起点的距离，获取线上的点的坐标、斜率、圆心到坐标的单位向量（垂直于斜率)
/// </summary>
public void GetSampleAtDistance(float distance, out Vector3 position, out Vector3 tangent, out Vector3 emit)
{
LinkedListNode <PBCircleNode> listNode = nodes.First;
PBCircleNode startNode = null;
PBCircleNode endNode = null;
while (listNode != null)
{
if (distance < listNode.Value.distance)
{
startNode = listNode.Previous.Value;
endNode = listNode.Value;
break;
}
listNode = listNode.Next;
}
if (startNode == null)
{
throw new ArgumentException(string.Format("Distance must be less than curve length. Curve length: {0}, distance: {1}",
nodes.Last.Value.distance, distance));
}
float t = (distance - startNode.distance) / (endNode.distance - startNode.distance);
if (startNode.ConnectLine(endNode))
{
//直线
position = Vector3.Lerp(startNode.position, endNode.position, t);
tangent = startNode.tangent;
emit = (startNode.position - startNode.circle.center).normalized;
}
else
{
//圆弧
PBCircle circle = startNode.circle;
float angle = startNode.angle + t * startNode.deltaAngle(endNode);
Vector3 r = Quaternion.AngleAxis(angle, circle.forward) * circle.up;
r.Normalize();
position = circle.center + r * circle.radius;
tangent = Quaternion.AngleAxis(angle, circle.forward) * (-circle.right);
emit = r;
}
}
public static LinkedList <PBCircleNode> Build(PBCircle[] circles, PBCircleCurveType type)
{
LinkedList <PBCircleNode> nodes = null;
switch (type)
{
case PBCircleCurveType.OneCircle:
nodes = BuildForOne(circles);
break;
case PBCircleCurveType.Line:
nodes = BuildForLine(circles);
break;
case PBCircleCurveType.Enclosed:
nodes = BuildForEnclosed(circles);
break;
}
//compute distance for nodes
LinkedListNode <PBCircleNode> listNode = nodes.First;
listNode.Value.distance = 0;
listNode = listNode.Next;
while (listNode != null)
{
PBCircleNode node = listNode.Value;
PBCircleNode preNode = listNode.Previous.Value;
if (node.ConnectLine(preNode))
{
//直线
node.distance = preNode.distance + Vector3.Distance(node.position, preNode.position);
//Debug.Log(">>>>>>>1 distance: " + node.distance);
}
else
{
//圆弧
float radius = node.circle.radius;
node.distance = preNode.distance + preNode.deltaAngle(node) * Mathf.Deg2Rad * radius;
//Debug.Log(">>>>>>>2 distance: " + node.distance);
}
listNode = listNode.Next;
}
return(nodes);
}