Flight model: ProcessLanding (Part 5 of 7)

       Name: ProcessLanding (Part 5 of 7)                            [Show more]
       Type: Subroutine
   Category: Flight model
    Summary: If we are taxiing with the undercarriage down, restrict pitching
             and tilt the plane backwards
  Deep dive: Take-offs and landings
    Context: See this subroutine in context in the source code
 References: No direct references to this subroutine in this source file


 If we are taxiing with the undercarriage down, then the plane gets set to the
 default tilt of 9.84 degrees (as the undercarriage is taller than the rear
 tail wheel).


.clan9

                        \ If we get here then we are on the ground and the
                        \ undercarriage is down

 LDX xRotationHi        \ If the high byte of the plane's rotation in the x-axis
 BMI clan8              \ is negative, jump to clan8 to return from the
                        \ subroutine as the plane is already tilted backwards

 CPX #7                 \ If the high byte of the plane's rotation in the x-axis
 BCC clan8              \ is positive and less than 7, jump to clan8 to return
                        \ from the subroutine

 LDA #7                 \ Set (xRotationHi xRotationLo) = (7 0), which is the
 STA xRotationHi        \ default tilt of the plane - the undercarriage is
 LDA #0                 \ taller than the rear tail wheel, so the whole plane
 STA xRotationLo        \ points up by 7/256 = 9.84 degrees when its wheels are
                        \ on the ground

 LDX xTurnTop           \ If the high byte of the xTurn rate is positive, jump
 BPL clan7              \ to clan7 to stop the plane from pitching and return
                        \ from the subroutine

 RTS                    \ Return from the subroutine