unity按照给定法线方向生成半球体mesh
时间: 2023-05-23 19:00:54 浏览: 74
可以使用Unity自带的Mesh类,通过指定半径和细分度来生成半球体。然后使用法线方向限制生成的顶点,再使用几何数据计算出法线、UV、三角形等信息,最后将这些信息填入Mesh中即可。具体实现代码可以参考网上的教程或者借助开源库。
相关问题
写一个unity按照给定法线方向生成半球体mesh的脚本
可以使用以下脚本实现:
```
using UnityEngine;
public class HalfSphereMeshGenerator : MonoBehaviour
{
[SerializeField] private int numLongitudeSections = 10;
[SerializeField] private int numLatitudeSections = 10;
[SerializeField] private float radius = 1f;
[SerializeField] private Vector3 upDirection = Vector3.up;
private void Start()
{
Mesh mesh = new Mesh();
Vector3[] vertices = new Vector3[numLongitudeSections * (numLatitudeSections + 1)];
int[] triangles = new int[numLongitudeSections * numLatitudeSections * 6];
for (int lat = 0; lat <= numLatitudeSections; lat++)
{
float theta = lat * Mathf.PI / numLatitudeSections;
float sinTheta = Mathf.Sin(theta);
float cosTheta = Mathf.Cos(theta);
for (int lon = 0; lon < numLongitudeSections; lon++)
{
float phi = lon * 2f * Mathf.PI / numLongitudeSections;
float sinPhi = Mathf.Sin(phi);
float cosPhi = Mathf.Cos(phi);
Vector3 direction = new Vector3(sinTheta * cosPhi, cosTheta, sinTheta * sinPhi);
Vector3 normal = Quaternion.FromToRotation(upDirection, direction) * upDirection;
vertices[lat * numLongitudeSections + lon] = normal * radius;
}
}
int index = 0;
for (int lat = 0; lat < numLatitudeSections; lat++)
{
for (int lon = 0; lon < numLongitudeSections; lon++)
{
int first = lat * numLongitudeSections + lon;
int second = first + numLongitudeSections;
triangles[index++] = first;
triangles[index++] = second + 1;
triangles[index++] = second;
triangles[index++] = first;
triangles[index++] = first + 1;
triangles[index++] = second + 1;
}
}
mesh.vertices = vertices;
mesh.triangles = triangles;
mesh.RecalculateNormals();
GetComponent<MeshFilter>().mesh = mesh;
}
}
```
这个脚本使用给定法线方向和半径,按照给定的经度和纬度划分数量,生成半球体的网格。您可以将它附加到一个 GameObject 上,然后通过检查器中的参数进行自定义设置。
unity沿着给定三维向量方向生成半球体mesh
你可以使用以下代码来生成一个半球体 mesh。
```
using UnityEngine;
public class HalfSphere : MonoBehaviour {
public int segments = 12;
public float radius = 1f;
public Vector3 axis = Vector3.up;
void Start() {
Mesh mesh = new Mesh();
mesh.name = "Half Sphere";
Vector3[] vertices = new Vector3[segments * (segments / 2 + 1) + 1];
int[] triangles = new int[segments * (segments / 2) * 6];
Vector2[] uv = new Vector2[vertices.Length];
float segmentSize = Mathf.PI / segments;
float segmentAngle, radius2d, xz;
Vector3 pt;
int v = 0;
int t = 0;
// top point
vertices[0] = Vector3.up * radius;
uv[0] = Vector3.up;
for (int y = 1; y <= segments / 2; y++) {
segmentAngle = segmentSize * y;
radius2d = radius * Mathf.Cos(segmentAngle);
pt.y = radius * Mathf.Sin(segmentAngle);
for (int x = 0; x < segments; x++) {
xz = x * segmentSize;
pt.x = radius2d * Mathf.Sin(xz);
pt.z = radius2d * Mathf.Cos(xz);
vertices[v + 1] = pt;
uv[v + 1] = new Vector2(x / (float)segments, y / (float)(segments / 2));
v++;
if (y == 1) {
triangles[t] = 0;
triangles[t + 1] = v + 1;
triangles[t + 2] = v;
t += 3;
}
else if (x != 0) {
triangles[t] = v - segments - 1;
triangles[t + 1] = v - segments;
triangles[t + 2] = v;
t += 3;
}
if (x == segments - 1) {
triangles[t] = v - segments;
triangles[t + 1] = v - segments * 2 + 1;
triangles[t + 2] = v - segments + 1;
t += 3;
}
}
}
// bottom point
vertices[v + 1] = Vector3.down * radius;
uv[vertices.Length - 1] = Vector3.zero;
mesh.vertices = vertices;
mesh.triangles = triangles;
mesh.uv = uv;
mesh.RecalculateNormals();
transform.rotation = Quaternion.FromToRotation(Vector3.up, axis);
transform.GetComponent<MeshFilter>().mesh = mesh;
transform.GetComponent<MeshRenderer>().material = new Material(Shader.Find("Standard"));
}
```
使用这个脚本,你可以通过提供一个方向向量来生成半球体 mesh,如下:
```
public Vector3 direction = Vector3.forward;
void Start() {
Vector3 up = Vector3.up;
if (Mathf.Abs(Vector3.Dot(up, direction)) == 1) {
up = Vector3.right;
}
Vector3 axis = Vector3.Cross(direction, up).normalized;
transform.rotation = Quaternion.LookRotation(direction, axis);
HalfSphere halfSphere = gameObject.AddComponent<HalfSphere>();
halfSphere.axis = direction;
}
```