c# - Unity project character only moving one way no matter where you touch on an IOS device -

this code movement when touch on ios device in 2d game creating in unity. when run game loads when touch right moves left , when touch left moves left.

i have used screentoworldpoint told use dont seem work move 1 direction

 void playerwalkmobile() {      // force push player     float force = 0.0f;     // players velocity     float velocity = mathf.abs(getcomponent<rigidbody2d>().velocity.x);      if (input.touchcount > 0)     {          counttouches++;          touch h = input.touches[0];          vector2 position = camera.main.screentoworldpoint(new vector2(h.position.x, h.position.y));          debug.log("the postion of touch " + h.position);            if (position.x > 0)         {              // if velocity of player less maxvelocity             if (velocity < maxvelocity)                 force = speed;              // turn player face right             vector3 scale = transform.localscale;             scale.x = 1;             transform.localscale = scale;              // animate walk             animator.setinteger("walk", 1);          }         else if (position.x < 0)         {              // if velocity of player less maxvelocity             if (velocity < maxvelocity)                 force = -speed;              // turn player face right             vector3 scale = transform.localscale;             scale.x = -1;             transform.localscale = scale;              // animate walk             animator.setinteger("walk", 1);          }         // add force rigid body move player         getcomponent<rigidbody2d>().addforce(new vector2(force, 0));          // set idle animation         if (h.phase == touchphase.ended)             animator.setinteger("walk", 0);      } // if input.touchcount > 0  } 

in debug touches on place 0.0 far left of screen everywhere else minus position of touch (-1093.7, 1048.3)

i thought

vector2 position = camera.main.screentoworldpoint(new vector2(h.position.x, h.position.y)); 

was supposed make 0.0 centre