pseudo code:
Select( Entity_that_Player_is_walking_on )
Case Wood: PlaySound( "footstep_wood" )
Case Iron: PlaySound( "footstep_iron" )
Case Sand: PlaySound( "footstep_sand" )
Case Snow: PlaySound( "footstep_snow" )
End Select
Select( Entity_that_Player_is_walking_on )
Case Wood: PlaySound( "footstep_wood" )
Case Iron: PlaySound( "footstep_iron" )
Case Sand: PlaySound( "footstep_sand" )
Case Snow: PlaySound( "footstep_snow" )
End Select