Main game loop: FinishLandscape

       Name: FinishLandscape                                         [Show more]
       Type: Subroutine
   Category: Main game loop
    Summary: Add the player's energy to the landscape number to get the number
             of the next landscape and display that landscape's secret code
    Context: See this subroutine in context in the source code
 References: This subroutine is called as follows:
             * MainGameLoop calls FinishLandscape


.FinishLandscape

 SED                    \ Set the D flag to switch arithmetic to binary coded
                        \ decimal (BCD), so the call to GetPlayerEnergyBCD and
                        \ the following addition are all done in BCD

 JSR GetPlayerEnergyBCD \ Set A to the player's energy in BCD

 CLC                    \ Set (Y X) = landscapeNumber(Hi Lo) + A
 ADC landscapeNumberLo  \
 TAX                    \ This addition is done in BCD so the result is a new
 LDA landscapeNumberHi  \ landscape number that's also in BCD (which we need to
 ADC #0                 \ do as landscape numbers are in BCD)
 TAY

 CLD                    \ Clear the D flag to switch arithmetic to normal

 JSR InitialiseSeeds    \ Initialise the seed number generator to generate the
                        \ sequence of seed numbers for the landscape number in
                        \ (Y X) and set maxNumberOfEnemies and the landscapeZero
                        \ flag accordingly

                        \ We set bit 7 of doNotPlayLandscape when the landscape
                        \ was completed in the PerformHyperspace routine, so the
                        \ following calls to GenerateLandscape and SpawnPlayer
                        \ return normally, without previewing the landscape
                        \ (GenerateLandscape) or starting the game (SpawnPlayer)

 JSR GenerateLandscape  \ Call GenerateLandscape to generate the landscape

 JSR SpawnEnemies       \ Calculate the number of enemies for this landscape,
                        \ add them to the landscape and set the palette
                        \ accordingly

 JSR SpawnPlayer        \ Add the player and trees to the landscape

 LDA #&80               \ Call DrawTitleScreen with A = &80 to draw the screen
 JSR DrawTitleScreen    \ showing the landscape's secret code

 LDX #5                 \ Print text token 5: Print "SECRET ENTRY CODE" at
 JSR PrintTextToken     \ (64, 768), "LANDSCAPE" at (192, 704), move cursor
                        \ right

 JMP PrintLandscapeNum  \ Print the four-digit landscape (0000 to 9999) and
                        \ return from the subroutine using a tail call