Unity中实现2D圆形网格的需求及现有代码求助

Hey there! I’ve looked at your problem, and adding a circle mesh with a dynamic CircleMesh function (callable in Update) is totally doable—let’s break this down step by step.

Core Idea #

A smooth 2D circle mesh is just a collection of triangular "slices" (sectors) radiating from a central point. The more segments you use, the smoother the circle will look. We’ll generate vertices for the center and each point on the circle’s circumference, create triangle indices to connect them, then update both the MeshFilter and PolygonCollider2D.

Updated Script Additions #

First, add these public variables to your existing CreateMesh script to control the circle’s properties:

public float circleRadius = 1f;
public int circleSegments = 16; // Higher = smoother circle, minor performance cost

Now here’s the CircleMesh function you can call directly in Update:

public void CircleMesh()
{
    Mesh mesh = new Mesh();
    mesh.name = "Circle Mesh";

    List<Vector3> vertices = new List<Vector3>();
    List<int> triangles = new List<int>();

    // Add central vertex
    vertices.Add(Vector3.zero);

    // Generate circumference vertices using trigonometry
    for (int i = 0; i <= circleSegments; i++)
    {
        float angle = (float)i / circleSegments * Mathf.PI * 2f;
        float x = Mathf.Cos(angle) * circleRadius;
        float y = Mathf.Sin(angle) * circleRadius;
        vertices.Add(new Vector3(x, y, 0f));
    }

    // Create triangle indices for each sector (center -> current vertex -> next vertex)
    for (int i = 1; i <= circleSegments; i++)
    {
        triangles.Add(0);
        triangles.Add(i);
        triangles.Add(i + 1);
    }

    // Assign data to the mesh and recalculate critical properties
    mesh.vertices = vertices.ToArray();
    mesh.triangles = triangles.ToArray();
    mesh.RecalculateNormals();
    mesh.RecalculateBounds();

    // Update the Mesh Filter component
    GetComponent<MeshFilter>().mesh = mesh;

    // Update the PolygonCollider2D (only needs perimeter points)
    PolygonCollider2D collider = GetComponent<PolygonCollider2D>();
    if (collider != null)
    {
        List<Vector2> colliderPoints = new List<Vector2>();
        for (int i = 1; i <= circleSegments; i++)
        {
            colliderPoints.Add(new Vector2(vertices[i].x, vertices[i].y));
        }
        collider.points = colliderPoints.ToArray();
    }
}

Integrate with Your Existing Logic #

To tie this into your current MeshType system, update your Update method to handle the new "circle" case:

void Update()
{
    switch(MeshType)
    {
        case "tri":
            // Your existing triangle mesh logic here
            break;
        case "box":
            // Your existing box mesh logic here
            break;
        case "circle":
            CircleMesh();
            break;
    }
}

Key Notes #

• Performance: 16-32 segments strike a great balance between smoothness and performance. Adjust based on your needs.
• Dynamic Updates: Changing circleRadius or circleSegments in the Inspector will instantly refresh the mesh and collider since this runs in Update.
• Collider Optimization: We skip the central vertex for the PolygonCollider2D because 2D colliders only need the outer perimeter to form a closed, functional shape.

内容的提问来源于stack exchange，提问作者Tom Ryan