c# - Raycast returns null -

code generates error:

void update() {     if (input.touchcount > 0)     {         raycasthit2d hit = physics2d.raycast(camera.main.screentoworldpoint(input.gettouch(0).position), vector2.zero);         if (hit && hit.collider != null && hit.collider.name == "lefttaparea")         {             hit.transform.name = "hit";         }     } } 

it says wrong string:

raycasthit2d hit = physics2d.raycast(camera.main.screentoworldpoint(input.gettouch(0).position), vector2.zero);

error:

nullreferenceexception: object reference not set instance of object leftscript.update () (at assets/leftscript.cs:16)

the thing can return null in code camera.main.screentoworldpoint. means camera.main null. camera.main initialized, camera must have maincamera tag.

select camera gameobject change tag maincamera.

if don't want camera in maincamera tag, can find wit directly gameobject.find camera component it.

camera cam;  void start() {     cam = gameobject.find("nameofcameragameobject").getcomponent<camera>(); }  void update() {     if (input.touchcount > 0)     {         raycasthit2d hit = physics2d.raycast(cam.screentoworldpoint(input.gettouch(0).position), vector2.zero);         if (hit && hit.collider != null && hit.collider.name == "lefttaparea")         {             hit.transform.name = "hit";         }     } }