Car geometry: TurnPlayerAround

       Name: TurnPlayerAround                                        [Show more]
       Type: Subroutine
   Category: Car geometry
    Summary: Turn the player around and initialise the specified number of
             track segments in the new direction
    Context: See this subroutine in context in the source code
 References: This subroutine is called as follows:
             * ChangeDirection calls TurnPlayerAround
             * MovePlayerBack calls TurnPlayerAround


 Arguments:

   X                    The number of track segments to initialise in the new
                        direction


 Returns:

   directionFacing      Bit 7 is flipped to point us in the opposite direction


.TurnPlayerAround

 LDA directionFacing    \ Flip bit 7 of directionFacing to denote that our car
 EOR #%10000000         \ is facing in the other direction
 STA directionFacing

 JSR UpdateCurveVector  \ If this is a curved track section, update the value of
                        \ thisVectorNumber to the next segment vector along the
                        \ track in the new direction we are facing

 STX segmentCounter     \ We now want to initialise X track segments in the new
                        \ direction, so set a loop counter in segmentCounter
                        \ that starts from X and counts down

.turn1

 JSR GetTrackSegment    \ Initialise the next track segment in the track segment
                        \ buffer

 DEC segmentCounter     \ Decrement the loop counter

 BNE turn1              \ Loop back until we have set all X track segments

 RTS                    \ Return from the subroutine