extern vec3_t v_origin, v_angles;

void CStudioModelRenderer::StudioFormatAttachment( int nAttachment, bool bInverse )

{

  float worldx = tan( (float)gHUD.m_iFOV * M_PI / 360.0 );

  float viewx = tan( m_flViewmodelFov * M_PI / 360.0 );

  // aspect ratio cancels out, so only need one factor

  // the difference between the screen coordinates of the 2 systems is the ratio

  // of the coefficients of the projection matrices (tan (fov/2) is that coefficient)

  float factor = worldx / viewx;

  vec3_t vForward, vRight, vUp;

  AngleVectors( v_angles, vForward, vRight, vUp );

  // Get the coordinates in the viewer's space.

  Vector tmp = m_pCurrentEntity->attachment[nAttachment] - v_origin;

  Vector vTransformed( DotProduct( vRight, tmp ), DotProduct( vUp, tmp ), DotProduct( vForward, tmp ) );

  // Now squash X and Y.

  if ( bInverse )

  {

    if ( factor != 0 )

    {

      vTransformed.x /= factor;

      vTransformed.y /= factor;

    }

    else

    {

      vTransformed.x = 0.0f;

      vTransformed.y = 0.0f;

    }

  }

  else

  {

    vTransformed.x *= factor;

    vTransformed.y *= factor;

  }

  // Transform back to world space.

  Vector vOut = (vRight * vTransformed.x) + (vUp * vTransformed.y) + (vForward * vTransformed.z);

  m_pCurrentEntity->attachment[nAttachment] = v_origin + vOut;

}