using UnityEngine;

[ExecuteInEditMode]
public class ShowMeshNormals : MonoBehaviour
{
    public float length = 0.0125f;

    SkinnedMeshRenderer smr;
    Mesh bakedMesh;

    void OnDrawGizmos()
    {
        if (!smr)
            smr = GetComponent<SkinnedMeshRenderer>();
        if (!bakedMesh)
            bakedMesh = new Mesh();

        smr.BakeMesh(bakedMesh);

        var vertices = bakedMesh.vertices;
        var normals = bakedMesh.normals;

        for (int i = 0; i < vertices.Length; i++)
        {
            Vector3 worldPos = transform.TransformPoint(vertices[i]);
            Vector3 worldNormal = transform.TransformDirection(normals[i]);
            Gizmos.color = new Color(
                worldNormal.normalized.x * 0.5f + 0.5f,
                worldNormal.normalized.y * 0.5f + 0.5f,
                worldNormal.normalized.z * 0.5f + 0.5f
            );
            Gizmos.DrawLine(worldPos, worldPos + worldNormal * length);
        }
    }
}