这个代码是从官网的一个Demo中扒出来的，Demo中代码较多，好多用不到，不利于查看核心代码
核心代码
using UnityEngine;
using System.Collections;
using System.Collections.Generic;
#if UNITY_EDITOR
using UnityEditor;
#endif
public class WaypointCircuit : MonoBehaviour {
public WaypointList waypointList = new WaypointList();
[SerializeField] bool smoothRoute = true;
int numPoints;
Vector3[] points;
float[] distances;
public float editorVisualisationSubsteps = 100;
public float Length { get; private set; }
public Transform[] Waypoints { get { return waypointList.items; } }
//this being here will save GC allocs
int p0n;
int p1n;
int p2n;
int p3n;
private float i;
Vector3 P0;
Vector3 P1;
Vector3 P2;
Vector3 P3;
// Use this for initialization
void Awake () {
if (Waypoints.Length > 1)
{
CachePositionsAndDistances();
}
numPoints = Waypoints.Length;
}
public RoutePoint GetRoutePoint(float dist)
{
// position and direction
Vector3 p1 = GetRoutePosition(dist);
Vector3 p2 = GetRoutePosition(dist + 0.1f);
Vector3 delta = p2-p1;
return new RoutePoint( p1, delta.normalized );
}
public Vector3 GetRoutePosition(float dist)
{
int point = 0;
if (Length == 0)
{
Length = distances[distances.Length-1];
}
dist = Mathf.Repeat(dist,Length);
while (distances[point] < dist) { ++point; }
// get nearest two points, ensuring points wrap-around start & end of circuit
p1n = ((point-1) + numPoints) % numPoints;
p2n = point;
// found point numbers, now find interpolation value between the two middle points
i = Mathf.InverseLerp(distances[p1n],distances[p2n],dist);
if (smoothRoute)
{
// smooth catmull-rom calculation between the two relevant points
// get indices for the surrounding 2 points, because
// four points are required by the catmull-rom function
p0n = ((point-2) + numPoints) % numPoints;
p3n = (point+1) % numPoints;
// 2nd point may have been the 'last' point - a dupe of the first,
// (to give a value of max track distance instead of zero)
// but now it must be wrapped back to zero if that was the case.
p2n = p2n % numPoints;
P0 = points[ p0n ];
P1 = points[ p1n ];
P2 = points[ p2n ];
P3 = points[ p3n ];
return CatmullRom(P0,P1,P2,P3,i);
} else {
// simple linear lerp between the two points:
p1n = ((point-1) + numPoints) % numPoints;
p2n = point;
return Vector3.Lerp ( points[p1n], points[p2n], i );
}
}
Vector3 CatmullRom(Vector3 _P0, Vector3 _P1, Vector3 _P2, Vector3 _P3, float _i)
{
// comments are no use here... it's the catmull-rom equation.
// Un-magic this, lord vector!
return 0.5f * ( (2 * _P1) + (-_P0 + _P2) * _i + (2*_P0 - 5*_P1 + 4*_P2 - _P3) * _i*_i + (-_P0 + 3*_P1 - 3*_P2 + _P3) * _i*_i*_i );
}
void CachePositionsAndDistances()
{
// transfer the position of each point and distances between points to arrays for
// speed of lookup at runtime
points = new Vector3[Waypoints.Length+1];
distances = new float[Waypoints.Length+1];
float accumulateDistance = 0;
for (int i = 0; i<points.Length; ++i) {
var t1 = Waypoints[(i)% Waypoints.Length ];
var t2 = Waypoints[(i+1)% Waypoints.Length ];
if (t1 != null && t2 != null)
{
Vector3 p1 = t1.position;
Vector3 p2 = t2.position;
points[i] = Waypoints[i % Waypoints.Length].position;
distances[i] = accumulateDistance;
accumulateDistance += (p1 - p2).magnitude;
}
}
}
void OnDrawGizmos()
{
DrawGizmos(false);
}
void OnDrawGizmosSelected()
{
DrawGizmos(true);
}
void DrawGizmos(bool selected)
{
waypointList.circuit = this;
if (Waypoints.Length > 1)
{
numPoints = Waypoints.Length;
CachePositionsAndDistances();
Length = distances[distances.Length-1];
Gizmos.color = selected ? Color.yellow : new Color(1,1,0,0.5f);
Vector3 prev = Waypoints[0].position;
if (smoothRoute)
{
for (float dist=0; dist<Length; dist += Length/editorVisualisationSubsteps)
{
Vector3 next = GetRoutePosition(dist+1);
Gizmos.DrawLine( prev, next );
prev = next;
}
Gizmos.DrawLine( prev, Waypoints[0].position );
} else {
for (int n=0; n<Waypoints.Length; ++n)
{
Vector3 next = Waypoints[(n+1) % Waypoints.Length].position;
Gizmos.DrawLine( prev, next );
prev = next;
}
}
}
}
[System.Serializable]
public class WaypointList
{
public WaypointCircuit circuit;
public Transform[] items = new Transform[0];
}
public struct RoutePoint
{
public Vector3 position;
public Vector3 direction;
public RoutePoint(Vector3 position, Vector3 direction)
{
this.position = position;
this.direction = direction;
}
}
}
#if UNITY_EDITOR
[CustomPropertyDrawer (typeof(WaypointCircuit.WaypointList))]
public class WaypointListDrawer : PropertyDrawer
{
float lineHeight = 18;
float spacing = 4;
public override void OnGUI (Rect position, SerializedProperty property, GUIContent label)
{
EditorGUI.BeginProperty (position, label, property);
float x = position.x;
float y = position.y;
float inspectorWidth = position.width;
// Draw label
// Don't make child fields be indented
var indent = EditorGUI.indentLevel;
EditorGUI.indentLevel = 0;
var items = property.FindPropertyRelative ("items");
string[] titles = new string[] { "Transform", "", "", "" };
string[] props = new string[] { "transform", "^", "v", "-" };
float[] widths = new float[] { .7f, .1f, .1f, .1f };
float lineHeight = 18;
bool changedLength = false;
if (items.arraySize > 0)
{
for (int i=-1; i<items.arraySize; ++i) {
var item = items.GetArrayElementAtIndex (i);
float rowX = x;
for (int n=0; n<props.Length; ++n)
{
float w = widths[n] * inspectorWidth;
// Calculate rects
Rect rect = new Rect (rowX, y, w, lineHeight);
rowX += w;
if (i == -1)
{
EditorGUI.LabelField(rect, titles[n]);
} else {
if (n==0)
{
EditorGUI.ObjectField(rect, item.objectReferenceValue, typeof(Transform), true);
} else {
if (GUI.Button (rect, props[n]))
{
switch (props[n])
{
case "-":
items.DeleteArrayElementAtIndex(i);
items.DeleteArrayElementAtIndex(i);
changedLength = true;
break;
case "v":
if (i > 0) items.MoveArrayElement(i,i+1);
break;
case "^":
if (i < items.arraySize-1) items.MoveArrayElement(i,i-1);
break;
}
}
}
}
}
y += lineHeight + spacing;
if (changedLength)
{
break;
}
}
} else {
// add button
var addButtonRect = new Rect ((x + position.width) - widths[widths.Length-1]*inspectorWidth, y, widths[widths.Length-1]*inspectorWidth, lineHeight);
if (GUI.Button (addButtonRect, "+")) {
items.InsertArrayElementAtIndex(items.arraySize);
}
y += lineHeight + spacing;
}
// add all button
var addAllButtonRect = new Rect (x, y, inspectorWidth, lineHeight);
if (GUI.Button (addAllButtonRect, "Assign using all child objects"))
{
var circuit = property.FindPropertyRelative("circuit").objectReferenceValue as WaypointCircuit;
var children = new Transform[ circuit.transform.childCount ];
int n=0; foreach (Transform child in circuit.transform) children[n++] = child;
System.Array.Sort( children, new TransformNameComparer() );
circuit.waypointList.items = new Transform[children.Length];
for (n=0; n<children.Length; ++n)
{
circuit.waypointList.items[n] = children[n];
}
}
y += lineHeight + spacing;
// rename all button
var renameButtonRect = new Rect (x, y, inspectorWidth, lineHeight);
if (GUI.Button (renameButtonRect, "Auto Rename numerically from this order")) {
var circuit = property.FindPropertyRelative("circuit").objectReferenceValue as WaypointCircuit;
int n=0; foreach (Transform child in circuit.waypointList.items) child.name = "Waypoint "+(n++).ToString("000");
}
y += lineHeight + spacing;
// Set indent back to what it was
EditorGUI.indentLevel = indent;
EditorGUI.EndProperty ();
}
public override float GetPropertyHeight (SerializedProperty property, GUIContent label)
{
SerializedProperty items = property.FindPropertyRelative ("items");
float lineAndSpace = lineHeight + spacing;
return 40 + (items.arraySize * lineAndSpace) + lineAndSpace;
}
// comparer for check distances in ray cast hits
public class TransformNameComparer: IComparer
{
public int Compare(object x, object y) {
return ((Transform)x).name.CompareTo(((Transform)y).name);
}
}
}
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