创建一个星形组件并自定义其编辑器属性（二）【转】

奔跑的小兔

现在我们建立一个新的材质球，命名为Star，将Shader设置为我们刚刚编写的Star，并且将这个材质球赋予My First Star。
添加材质球之后








顶点着色默认是白色，所以我们的多边形现在变成了白色。我们想要一个更漂亮的星星。所以我们来为每个点定义一种颜色。
我们再添加一个frequency属性，这样我们就能让程序自动重复点的序列，而不用我们逐个定义全部的点。这个选项取代了numberOfPoints。
我们在最后需要确认frequency属性是否正确，并且星星至少拥有一个点。如果没有，我们的代码就可能出错。
Why check both for null and the length?
When freshly created, our star component won't have an array yet. It's also technically possible for scripts to explicitly set our array to null later on. We need to watch out for that, to prevent errors. Only if the array does exists do we go ahead and check its length as well.
using UnityEngine;
[RequireComponent(typeof(MeshFilter), typeof(MeshRenderer))]
public class Star : MonoBehaviour {
public Vector3[] points;
public int frequency = 1;
private Mesh mesh;
private Vector3[] vertices;
private int[] triangles;
void Start () {
GetComponent<MeshFilter>().mesh = mesh = new Mesh();
mesh.name = "Star Mesh";
if(frequency < 1){
frequency = 1;
}
if(points == null || points.Length == 0){
points = new Vector3[]{ Vector3.up};
}

int numberOfPoints = frequency * points.Length;
vertices = new Vector3[numberOfPoints + 1];
triangles = new int[numberOfPoints * 3];
float angle = -360f / numberOfPoints;
for(int iF = 0, v = 1, t = 1; iF < frequency; iF++){
for(int iP = 0; iP < points.Length; iP += 1, v += 1, t += 3){
vertices[v] = Quaternion.Euler(0f, 0f, angle * (v - 1)) * points[iP];
triangles[t] = v;
triangles[t + 1] = v + 1;
}
}
triangles[triangles.Length - 1] = 1;

mesh.vertices = vertices;
mesh.triangles = triangles;
}
}
配置好的点










我们需要些颜色！如果把全部的顶点都指定相同的颜色就很简单，但这样太无聊了。我们来试试给每个顶点分配一个颜色。我们需要一个数组来保存这些颜色数据，而且必须保持颜色和顶点的数量一致。这有点小麻烦，我们干脆换成另外一种方式，在Star类中建立一个新的类，这个类可以保存一个顶点的颜色和位置。然后我们可以用这个类的数组来代替vector数组。
这类叫Point，如果在Star类之外使用，就是Star.Point。在Star里面Point就可以了。为了让Unity能够将Point序列化，我们为Point添加System.Serializable特性。
为什么不用结构体?
Because Star.Point is so lightweight and its data is always needed all at once, it would make sense to use a s***ct type and avoid the overhead that objects add. However, Unity does not support serialization of custom s***ct types. So you're stuck using classes to bundle data you want to store.
If you're really concerned about the object overhead and possible null errors, you can always store the offset and color data in two separate arrays. However, then you would need to make sure that these arrays always stay synchronized. While that is definitely doable, the class approach is simpler. That's why I use it in this tutorial.
using System;
using UnityEngine;
[RequireComponent(typeof(MeshFilter), typeof(MeshRenderer))]
public class Star : MonoBehaviour {
[Serializable]
public class Point {
public Color color;
public Vector3 offset;
}
public Point[] points;
public int frequency = 1;
private Mesh mesh;
private Vector3[] vertices;
private Color[] colors;
private int[] triangles;
void Start () {
GetComponent<MeshFilter>().mesh = mesh = new Mesh();
mesh.name = "Star Mesh";
if(frequency < 1){
frequency = 1;
}
if(points == null || points.Length == 0){
points = new Point[]{ new Point()};
}
int numberOfPoints = frequency * points.Length;
vertices = new Vector3[numberOfPoints + 1];
colors = new Color[numberOfPoints + 1];
triangles = new int[numberOfPoints * 3];
float angle = -360f / numberOfPoints;
for(int iF = 0, v = 1, t = 1; iF < frequency; iF++){
for(int iP = 0; iP < points.Length; iP += 1, v += 1, t += 3){
vertices[v] = Quaternion.Euler(0f, 0f, angle * (v - 1)) * points[iP].offset;
colors[v] = points[iP].color;
triangles[t] = v;
triangles[t + 1] = v + 1;
}
}
triangles[triangles.Length - 1] = 1;

mesh.vertices = vertices;
mesh.colors = colors;
mesh.triangles = triangles;
}
}



有了颜色之后










最后是关于中心点的。现在，我们还没有给它设置颜色，所以它一直保持着透明。让我们来为它添加一个颜色属性，最终，这个星星看上去变漂亮了。
using System;
using UnityEngine;
[RequireComponent(typeof(MeshFilter), typeof(MeshRenderer))]
public class Star : MonoBehaviour {
[Serializable]
public class Point {
public Color color;
public Vector3 offset;
}
public Point[] points;
public int frequency = 1;
public Color centerColor;
private Mesh mesh;
private Vector3[] vertices;
private Color[] colors;
private int[] triangles;
void Start () {
GetComponent<MeshFilter>().mesh = mesh = new Mesh();
mesh.name = "Star Mesh";
if(frequency < 1){
frequency = 1;
}
if(points == null || points.Length == 0){
points = new Point[]{ new Point()};
}
int numberOfPoints = frequency * points.Length;
vertices = new Vector3[numberOfPoints + 1];
colors = new Color[numberOfPoints + 1];
triangles = new int[numberOfPoints * 3];
float angle = -360f / numberOfPoints;
colors[0] = centerColor;
for(int iF = 0, v = 1, t = 1; iF < frequency; iF++){
for(int iP = 0; iP < points.Length; iP += 1, v += 1, t += 3){
vertices[v] = Quaternion.Euler(0f, 0f, angle * (v - 1)) * points[iP].offset;
colors[v] = points[iP].color;
triangles[t] = v;
triangles[t + 1] = v + 1;
}
}
triangles[triangles.Length - 1] = 1;
mesh.vertices = vertices;
mesh.colors = colors;
mesh.triangles = triangles;
}
}