圆柱体的顶点有顶面、底面和侧面三部分。
1、获得顶点的数据集合
protected override Vector3[] GetVertices()
{
int curIndex = 0;//当前索引
int arrayLen = (_circularSideCount + 1) * 2 + _circularSideCount * 2 + 2;//数组的长度
var vertices = new Vector3[arrayLen];
//底面
vertices[curIndex++] = new Vector3(0, -_height * 0.5f, 0) - _verticeOffset; ;//圆心
for (int i = 0; i < _circularSideCount; i++)
{
var rad = i * 1.0f / _circularSideCount * Mathf.PI * 2;//弧度
var cos = Mathf.Cos(rad) * _radius;
var sin = Mathf.Sin(rad) * _radius;
vertices[curIndex++] = new Vector3(cos, -_height * 0.5f, sin) - _verticeOffset;
}
//顶面
vertices[curIndex++] = new Vector3(0, _height * 0.5f, 0) - _verticeOffset; ;//圆心
for (int i = 0; i < _circularSideCount; i++)
{
var rad = i * 1.0f / _circularSideCount * Mathf.PI * 2;//弧度
var cos = Mathf.Cos(rad) * _radius;
var sin = Mathf.Sin(rad) * _radius;
vertices[curIndex++] = new Vector3(cos, _height * 0.5f, sin) - _verticeOffset;
}
//侧面
int sideStartIndex = curIndex;
for (int i = 0; i < _circularSideCount; i++)
{
var rad = i * 1.0f / _circularSideCount * Mathf.PI * 2;//弧度
var cos = Mathf.Cos(rad) * _radius;
var sin = Mathf.Sin(rad) * _radius;
vertices[curIndex++] = new Vector3(cos, -_height * 0.5f, sin) - _verticeOffset;
vertices[curIndex++] = new Vector3(cos, _height * 0.5f, sin) - _verticeOffset;
}
vertices[curIndex++] = vertices[sideStartIndex];
vertices[curIndex] = vertices[sideStartIndex + 1];
return vertices;
}
2、获得法线方向的数据集合
protected override Vector3[] GetNormals()
{
int curIndex = 0;
int arrayLen = (_circularSideCount + 1) * 2 + _circularSideCount * 2 + 2;
var normals = new Vector3[arrayLen];
//底面
for (int i = 0; i <= _circularSideCount; i++)
{
normals[curIndex++] = Vector3.down;
}
//顶面
for (int i = 0; i <= _circularSideCount; i++)
{
normals[curIndex++] = Vector3.up;
}
//侧面
for (int i = 0; i <= _circularSideCount; i++)
{
float rad = i * 1.0f / _circularSideCount * Mathf.PI * 2;
var cos = Mathf.Cos(rad);
var sin = Mathf.Sin(rad);
normals[curIndex++] = new Vector3(cos, 0, sin);
normals[curIndex++] = new Vector3(cos, 0, sin);
}
return normals;
}
3、获得三角面顶点的索引
protected override int[] GetTriangles()
{
int curIndex = 0;
int arrayLen = _circularSideCount * 3 + _circularSideCount * 3 + _circularSideCount * 3 * 2;
var triangles = new int[arrayLen];
//底面
for (int i = 1; i < _circularSideCount; i++)
{
triangles[curIndex++] = 0;
triangles[curIndex++] = i;
triangles[curIndex++] = i + 1;
}
triangles[curIndex++] = 0;
triangles[curIndex++] = _circularSideCount;
triangles[curIndex++] = 1;
//顶面
for (int i = _circularSideCount + 2; i < _circularSideCount * 2 + 1; i++)
{
triangles[curIndex++] = _circularSideCount + 1;
triangles[curIndex++] = i + 1;
triangles[curIndex++] = i;
}
triangles[curIndex++] = _circularSideCount + 1;
triangles[curIndex++] = _circularSideCount + 2;
triangles[curIndex++] = _circularSideCount * 2 + 1;
//侧面
int startIndex = _circularSideCount * 2 + 2;
for (int i = 0; i < _circularSideCount; i++)
{
triangles[curIndex++] = startIndex;
triangles[curIndex++] = startIndex + 1;
triangles[curIndex++] = startIndex + 3;
triangles[curIndex++] = startIndex + 3;
triangles[curIndex++] = startIndex + 2;
triangles[curIndex++] = startIndex;
startIndex += 2;
}
return triangles;
}
4、 获得UV坐标的数据集合
protected override Vector2[] GetUVs()
{
int curIndex = 0;
int arrayLen = (_circularSideCount + 1) * 2 + (_circularSideCount + 1) * 2;
var uvs = new Vector2[arrayLen];
//底面
uvs[curIndex++] = new Vector2(0.5f, 0.5f);
for (int i = 0; i < _circularSideCount; i++)
{
var rad = i * 1.0f / _circularSideCount * Mathf.PI * 2;
var cos = Mathf.Cos(rad);
var sin = Mathf.Sin(rad);
uvs[curIndex++] = new Vector2(cos, sin) * 0.5f + new Vector2(0.5f, 0.5f);
}
//顶面
uvs[curIndex++] = new Vector2(0.5f, 0.5f);
for (int i = 0; i < _circularSideCount; i++)
{
var rad = i * 1.0f / _circularSideCount * Mathf.PI * 2;
var cos = Mathf.Cos(rad);
var sin = Mathf.Sin(rad);
uvs[curIndex++] = new Vector2(cos, sin) * 0.5f + new Vector2(0.5f, 0.5f);
}
//侧面
float value = 1.0f / _circularSideCount;
for (int i = 0; i <= _circularSideCount; i++)
{
uvs[curIndex++] = new Vector2(i * value, 0);
uvs[curIndex++] = new Vector2(i * value, 1);
}
return uvs;
}
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