Main loop: MainLoop (Part 5 of 6)

       Name: MainLoop (Part 5 of 6)                                  [Show more]
       Type: Subroutine
   Category: Main loop
    Summary: The main game loop: the competition race
  Deep dive: Program flow of the main game loop
    Context: See this subroutine in context in the source code
 References: No direct references to this subroutine in this source file


 This part of the main loop heads to the track to run the actual race. We
 print the driver table showing the grid positions, and set the grid row for
 any human drivers. We then start a loop, running a race for each human player,
 and asking for the number of laps in the race for the first such race. The
 loop concludes in the next part of the main loop.


.game8

 LDX raceClass          \ Set X to the race class

 JSR GetSectionSteering \ Set up the optimum steering for each section for this
                        \ race class, storing the results in sectionSteering

 LDX #26                \ Print token 26, which is a double-height header with
 JSR PrintToken         \ the text "STANDARD OF RACE"

 JSR PrintRaceClass     \ Print the race class

 JSR WaitForSpace       \ Print a prompt and wait for SPACE to be pressed

.game9

 LDX #2                 \ Print the driver table, showing lap times, under the
 LDA #0                 \ heading "GRID POSITIONS", so this shows the drivers
 JSR PrintDriverTable   \ in their starting positions on the grid

                        \ We now make a copy of the driversInOrder list into
                        \ driversInOrder2, so we can retrieve it below, and at
                        \ the same time we set the correct grid row for any
                        \ human players, depending on their starting position
                        \ on the grid (there are two cars per grid row)

 LDY #19                \ Set up a counter in Y so we can work through the
                        \ drivers in order, from the back of the grid to the
                        \ front

.game10

 LDA driversInOrder,Y   \ Copy the Y-th position from driversInOrder to
 STA driversInOrder2,Y  \ driversInOrder2, setting A to the number of the driver
                        \ in position Y

 CMP lowestPlayerNumber \ If A < lowestPlayerNumber, then driver A is one of the
 BCC game11             \ computer-controlled drivers, so jump to game11 to skip
                        \ setting the grid number for the driver

                        \ If we get here then driver A is a human player

 TAX                    \ Set X = the player's driver number

 LDA positionNumber,Y   \ Set A = the position of the player on the grid

 LSR A                  \ Set the driver's grid row to A / 2, so the first two
 STA driverGridRow,X    \ drivers are on grid row 0, then the next two are on
                        \ grid row 1, and so on

.game11

 DEY                    \ Decrement the counter

 BPL game10             \ Loop back until we have saved all the positions

 LDA competitionStarted \ If competitionStarted <> 0, then the competition has
 BNE game12             \ already started, so jump to game12 to skip the lap
                        \ selection process

 LDX #28                \ Print token 28, which shows a menu with the following
 JSR PrintToken         \ options:
                        \
                        \   Prompt = SELECT NUMBER OF LAPS
                        \
                        \   1 = 5 laps
                        \
                        \   2 = 10 laps
                        \
                        \   3 = 20 laps

 LDA #20                \ Set numberOfPlayers = 20 - lowestPlayerNumber
 SEC                    \
 SBC lowestPlayerNumber \ so numberOfPlayers is 1 if there is one player, 2 if
 STA numberOfPlayers    \ there are two players, and so on

 LDX #3                 \ Fetch the menu choice into X (0 to 2)
 JSR GetMenuOption

 LDA lapsFromOption,X   \ Convert the menu choice (0 to 2) into the number of
 STA numberOfLaps       \ laps (5, 10, 20) using the lapsFromOption lookup, and
                        \ store the result in numberOfLaps

 STX lapsMenuOption     \ Store the menu choice (0 to 2) in lapsMenuOption

.game12

 LDA #20                \ We now work our way through the human players so each
 STA currentPlayer      \ one can race in turn, so set currentPlayer to 20 so
                        \ it gets decremented to 19 for the first player

.game13

 DEC currentPlayer      \ Decrement currentPlayer to move on to the next player

 JSR PrintDriverPrompt  \ Print the "DRIVER ->" prompt and the player's name

 LDX #19                \ We now restore the grid positions we saved above, so
                        \ set a counter in X

.game14

 LDA driversInOrder2,X  \ Restore the X-th position from driversInOrder2 to
 STA driversInOrder,X   \ driversInOrder

 DEX                    \ Decrement the counter

 BPL game14             \ Loop back until we have restored all the positions

 JSR ResetBestLapTimes  \ Reset the best lap times to 10:00.0 for all drivers

 LDA #%10000000         \ Head to the track to choose the wing settings and
 JSR HeadToTrack+2      \ start the race (as bit 7 of A is set), returning here
                        \ when the race is finished