RaycastHit.textureCoord

설명

The uv texture coordinate at the impact point.

This can be used for 3D texture painting or drawing bullet marks. If the collider is no mesh collider, zero Vector2 will be returned.

using UnityEngine;
using System.Collections;

public class ExampleClass : MonoBehaviour {
    public Camera cam;
    void Start() {
        cam = GetComponent<Camera>();
    }
    void Update() {
        if (!Input.GetMouseButton(0))
            return;
        
        RaycastHit hit;
        if (!Physics.Raycast(cam.ScreenPointToRay(Input.mousePosition), out hit))
            return;
        
        Renderer rend = hit.transform.GetComponent<Renderer>();
        MeshCollider meshCollider = hit.collider as MeshCollider;
        if (rend == null || rend.sharedMaterial == null || rend.sharedMaterial.mainTexture == null || meshCollider == null)
            return;
        
        Texture2D tex = rend.material.mainTexture as Texture2D;
        Vector2 pixelUV = hit.textureCoord;
        pixelUV.x *= tex.width;
        pixelUV.y *= tex.height;
        tex.SetPixel((int)pixelUV.x, (int)pixelUV.y, Color.black);
        tex.Apply();
    }
}

See Also: Physics.Raycast, Physics.Linecast, Physics.RaycastAll.