由于我最近才开始研究网格，它们如何工作，如何工作等等，所以我决定使用自己的计算来创建一个圆的网格。不幸的是，这确实非常慢！
所以我正在寻找改进的技巧，以使其仅变慢（因为这可能是最好的……）
这是我用来生成圆的代码：
public static void createCircle(MeshFilter meshFilter, float innerRadius, float outerRadius, Color color, float xPosition = 0, float yPosition = 0, float startDegree = 0, float endDegree = 360, int points = 100)
{
Mesh mesh = meshFilter.mesh;
mesh.Clear();
//These values will result in no (or very ugly in the case of points < 10) circle, so let's safe calculation and just return an empty mesh!
if (startDegree == endDegree || points < 10 || innerRadius >= outerRadius || innerRadius < 0 || outerRadius <= 0)
{
return;
}
//The points for the full circle shall be whatever is given but if its not the full circle we dont need all the points!
points = (int)(Mathf.Abs(endDegree - startDegree) / 360f * points);
//We always need an uneven number of points!
if (points % 2 != 0) { points++; }
Vector3[] vertices = new Vector3[points];
float degreeStepSize = (endDegree - startDegree) * 2 / (points - 3);
float halfRadStepSize = (degreeStepSize) * Mathf.Deg2Rad / 2f;
float startRad = Mathf.Deg2Rad * startDegree;
float endRad = Mathf.Deg2Rad * endDegree;
//Let's save the vector at the beginning and the one on the end to make a perfectly straight line
vertices[0] = new Vector3(Mathf.Sin(startRad) * outerRadius + xPosition, Mathf.Cos(startRad) * outerRadius + yPosition, 0);
vertices[vertices.Length - 1] = new Vector3(Mathf.Sin(endRad) * innerRadius + xPosition, Mathf.Cos(endRad) * innerRadius + yPosition, 0);
for (int i = 1; i < vertices.Length - 1; i++)
{
//Pure coinsidence that saved some calculatons. Half Step Size is the same as what would needed to be calculated here!
float rad = (i - 1) * halfRadStepSize + startRad;
if (i % 2 == 0)
{
vertices[i] = new Vector3(Mathf.Sin(rad) * outerRadius + xPosition, Mathf.Cos(rad) * outerRadius + yPosition, 0);
}
else
{
vertices[i] = new Vector3(Mathf.Sin(rad) * innerRadius + xPosition, Mathf.Cos(rad) * innerRadius + yPosition, 0);
}
}
mesh.vertices = vertices;
int[] tri = new int[(vertices.Length - 2) * 3];
for (int i = 0; i < (vertices.Length - 2); i++)
{
int index = i * 3;
if (i % 2 == 0)
{
tri[index + 0] = i + 0;
tri[index + 1] = i + 2;
tri[index + 2] = i + 1;
}
else
{
tri[index + 0] = i + 0;
tri[index + 1] = i + 1;
tri[index + 2] = i + 2;
}
}
mesh.triangles = tri;
Vector3[] normals = new Vector3[vertices.Length];
Color[] colors = new Color[vertices.Length];
for (int i = 0; i < vertices.Length; i++)
{
normals[i] = Vector3.forward;
colors[i] = color;
}
mesh.normals = normals;
mesh.colors = colors;
meshFilter.mesh = mesh;
}
我知道我“只能使用Unity附带的LineRenderer，它比您将要编写的任何东西都快”，但这不是重点。 我正在尝试理解网格，并查看可以在哪里调整代码以提高其性能。
谢谢您的帮助！
答案 0 :(得分：1)
通过删除额外的内存分配，您几乎可以使速度提高一倍。由于Vector3是一种值类型，因此在分配数组时已经分配了它们。 Vector3.forward还会每次分配一个新的Vector3，我们可以重复使用它。
public static void createCircle(MeshFilter meshFilter, float innerRadius, float outerRadius, Color color, float xPosition = 0, float yPosition = 0, float startDegree = 0, float endDegree = 360, int points = 100)
{
Mesh mesh = meshFilter.mesh;
mesh.Clear();
//These values will result in no (or very ugly in the case of points < 10) circle, so let's safe calculation and just return an empty mesh!
if (startDegree == endDegree || points < 10 || innerRadius >= outerRadius || innerRadius < 0 || outerRadius <= 0)
{
return;
}
//The points for the full circle shall be whatever is given but if its not the full circle we dont need all the points!
points = (int)(Mathf.Abs(endDegree - startDegree) / 360f * points);
//We always need an uneven number of points!
if (points % 2 != 0) { points++; }
Vector3[] vertices = new Vector3[points];
float degreeStepSize = (endDegree - startDegree) * 2 / (points - 3);
float halfRadStepSize = (degreeStepSize) * Mathf.Deg2Rad / 2f;
float startRad = Mathf.Deg2Rad * startDegree;
float endRad = Mathf.Deg2Rad * endDegree;
//Let's save the vector at the beginning and the one on the end to make a perfectly straight line
vertices[0] = new Vector3(Mathf.Sin(startRad) * outerRadius + xPosition, Mathf.Cos(startRad) * outerRadius + yPosition, 0);
vertices[vertices.Length - 1] = new Vector3(Mathf.Sin(endRad) * innerRadius + xPosition, Mathf.Cos(endRad) * innerRadius + yPosition, 0);
for (int i = 1; i < vertices.Length - 1; i++)
{
//Pure coinsidence that saved some calculatons. Half Step Size is the same as what would needed to be calculated here!
float rad = (i - 1) * halfRadStepSize + startRad;
if (i % 2 == 0)
{
vertices[i].x = Mathf.Sin(rad) * outerRadius + xPosition;
vertices[i].y = Mathf.Cos(rad) * outerRadius + yPosition;
vertices[i].z = 0;
}
else
{
vertices[i].x = Mathf.Sin(rad) * innerRadius + xPosition;
vertices[i].y = Mathf.Cos(rad) * innerRadius + yPosition;
vertices[i].z = 0;;
}
}
mesh.vertices = vertices;
int[] tri = new int[(vertices.Length - 2) * 3];
for (int i = 0; i < (vertices.Length - 2); i++)
{
int index = i * 3;
if (i % 2 == 0)
{
tri[index + 0] = i + 0;
tri[index + 1] = i + 2;
tri[index + 2] = i + 1;
}
else
{
tri[index + 0] = i + 0;
tri[index + 1] = i + 1;
tri[index + 2] = i + 2;
}
}
mesh.triangles = tri;
Vector3[] normals = new Vector3[vertices.Length];
Color[] colors = new Color[vertices.Length];
var f = Vector3.forward;
for (int i = 0; i < vertices.Length; i++)
{
normals[i].x= f.x;
normals[i].y= f.y;
normals[i].z= f.z;
colors[i] = color;
}
mesh.normals = normals;
mesh.colors = colors;
meshFilter.mesh = mesh;
}