Start and end: DEATH

       Name: DEATH                                                   [Show more]
       Type: Subroutine
   Category: Start and end
    Summary: Display the death screen
  Deep dive: Splitting the main loop in the NES version
    Context: See this subroutine in context in the source code
 References: This subroutine is called as follows:
             * CheckAltitude calls DEATH
             * Main flight loop (Part 9 of 16) calls DEATH
             * Main flight loop (Part 15 of 16) calls DEATH
             * OOPS calls DEATH


 We have been killed, so display the chaos of our destruction above a "GAME
 OVER" sign, and clean up the mess ready for the next attempt.


.DEATH

 JSR ResetMusicAfterNMI ; Wait for the next NMI before resetting the current
                        ; tune to 0 (no tune) and stopping the music

 JSR EXNO3              ; Make the sound of us dying

 JSR RES2               ; Reset a number of flight variables and workspaces

 ASL DELTA              ; Divide our speed in DELTA by 4
 ASL DELTA

 LDA #0                 ; Set the tile number for the left edge of the box to
 STA boxEdge1           ; the blank tile, so the box around the space view
                        ; disappears

 STA boxEdge2           ; Set the tile number for the right edge of the box to
                        ; the blank tile, so the box around the space view
                        ; disappears

 STA autoPlayDemo       ; Disable auto-play by setting autoPlayDemo to zero, in
                        ; case we die during the auto-play combat demo

 LDA #$C4               ; Clear the screen and set the view type in QQ11 to $95
 JSR TT66               ; (Game Over screen)

 JSR ClearDashEdge_b6   ; Clear the right edge of the dashboard

 JSR CopyNameBuffer0To1 ; Copy the contents of nametable buffer 0 to nametable
                        ; buffer

 JSR SetScreenForUpdate ; Get the screen ready for updating by hiding all
                        ; sprites, after fading the screen to black if we are
                        ; changing view

 LDA #0                 ; Set showIconBarPointer to 0 to indicate that we should
 STA showIconBarPointer ; hide the icon bar pointer

 LDA #$C4               ; Configure the PPU for view type $C4 (Game Over screen)
 JSR SendViewToPPU_b3

 LDA #$00               ; Set the view type in QQ11 to $00 (Space view with no
 STA QQ11               ; font loaded)

 STA QQ11a              ; Set the old view type in QQ11a to $00 (Space view with
                        ; no fonts loaded)

 LDA firstFreePattern   ; Tell the NMI handler to send pattern entries from the
 STA firstPattern       ; first free pattern onwards, so we don't waste time
                        ; resending the static patterns we have already sent

 LDA #116               ; Tell the NMI handler to only clear nametable entries
 STA maxNameTileToClear ; up to tile 116 * 8 = 800 (i.e. up to the end of tile
                        ; row 28)

 LDX #8                 ; Tell the NMI handler to send nametable entries from
 STX firstNameTile      ; tile 8 * 8 = 64 onwards (i.e. from the start of tile
                        ; row 2)

 LDA #104               ; Set the screen height variables for a screen height of
 JSR SetScreenHeight    ; 208 (i.e. 2 * 104)

                        ; Next we fill the scannerNumber table with non-zero
                        ; entries so when we spawn ships for the death screen,
                        ; they don't appear on the scanner because the scanner
                        ; number table doesn't have any free slots

 LDY #8                 ; Set an index in Y to work through the eight entries
                        ; in the scannerNumber table

 LDA #1                 ; Set A = 1 to use as the value for every ship in the
                        ; scannerNumber table, which is non-zero so the NWSHP
                        ; routine will skip the scanner configuration for any
                        ; ships we spawn

.deaf1

 STA scannerNumber,Y    ; Set the Y-th scannerNumber entry to 1

 DEY                    ; Decrement the index in Y

 BNE deaf1              ; Loop back until we have set entries 1 to 8 in the
                        ; table to 1, so nothing spawns on the scanner

 JSR nWq                ; Create a cloud of stardust containing the correct
                        ; number of dust particles (i.e. NOSTM of them)

                        ; We now give our ship a random amount of roll by
                        ; setting all the various alpha angle variables

 JSR DORND              ; Set A and X to random numbers

 AND #%10000111         ; Set the roll angle in ALPHA to the random number,
 STA ALPHA              ; reduced to the range 0 to 7, and with a random sign

 AND #7                 ; Set the magnitude of roll angle alpha in ALP1 to the
 STA ALP1               ; same value, but with the sign bit cleared (so ALP1
                        ; contains the magnitude of the roll)

 LDA ALPHA              ; Set the sign of the roll angle alpha in ALP2 to the
 AND #%10000000         ; sign of ALPHA (so ALP2 contains the sign of the roll)
 STA ALP2

 EOR #%10000000         ; Set the sign of the roll angle alpha in ALP2+1 to the
 STA ALP2+1             ; flipped sign of ALPHA (so ALP2 contains the flipped
                        ; sign of the roll)

.D1

 JSR Ze                 ; Call Ze to initialise INWK to a potentially hostile
                        ; ship, and set A and X to random values

 LSR A                  ; Set A = A / 4, so A is now between 0 and 63, and
 LSR A                  ; store in byte #0 (x_lo)
 STA INWK

 LDY #$00               ; Set the view type in QQ11 to $00 (Space view with no
 STY QQ11               ; font loaded)

 STY INWK+1             ; Set the following to 0: x_hi, y_hi, z_hi and the AI
 STY INWK+4             ; flag (no AI or E.C.M. and not hostile)
 STY INWK+7
 STY INWK+32

 DEY                    ; Set Y = 255

 STY MCNT               ; Reset the main loop counter to 255, so all timer-based
                        ; calls will be stopped

 EOR #%00101010         ; Flip bits 1, 3 and 5 in A (x_lo) to get another number
 STA INWK+3             ; between 48 and 63, and store in byte #3 (y_lo)

 ORA #%01010000         ; Set bits 4 and 6 of A to bump it up to between 112 and
 STA INWK+6             ; 127, and store in byte #6 (z_lo)

 TXA                    ; Set A to the random number in X and keep bits 0-3 and
 AND #%10001111         ; the sign in bit 7 to get a number between -15 and +15,
 STA INWK+29            ; and store in byte #29 (roll counter) to give our ship
                        ; a gentle roll with damping

 LDY #64                ; Set the laser count to 64 to act as a counter in the
 STY LASCT              ; D2 loop below, so this setting determines how long the
                        ; death animation lasts (it's 64 * 2 iterations of the
                        ; main flight loop)

 SEC                    ; Set the C flag

 ROR A                  ; This sets A to a number between 0 and +7, which we
 AND #%10000111         ; store in byte #30 (the pitch counter) to give our ship
 STA INWK+30            ; a very gentle downwards pitch with damping

 LDX #OIL               ; Set X to #OIL, the ship type for a cargo canister

 LDA XX21-1+2*PLT       ; Fetch the byte from location XX21 - 1 + 2 * PLT, which
                        ; equates to XX21 + 7 (the high byte of the address of
                        ; SHIP_PLATE), which seems a bit odd. It might make more
                        ; sense to do LDA (XX21-2+2*PLT) as this would fetch the
                        ; first byte of the alloy plate's blueprint (which
                        ; determines what happens when alloys are destroyed),
                        ; but there aren't any brackets, so instead this always
                        ; returns $D0, which is never zero, so the following
                        ; BEQ is never true. (If the brackets were there, then
                        ; we could stop plates from spawning on death by setting
                        ; byte #0 of the blueprint to 0... but then scooping
                        ; plates wouldn't give us alloys, so who knows what this
                        ; is all about?)

 BEQ D3                 ; If A = 0, jump to D3 to skip the following instruction

 BCC D3                 ; If the C flag is clear, which will be random following
                        ; the above call to Ze, jump to D3 to skip the following
                        ; instruction

 DEX                    ; Decrement X, which sets it to #PLT, the ship type for
                        ; an alloy plate

.D3

 JSR fq1                ; Call fq1 with X set to #OIL or #PLT, which adds a new
                        ; cargo canister or alloy plate to our local bubble of
                        ; universe and points it away from us with double DELTA
                        ; speed (i.e. 6, as DELTA was set to 3 by the call to
                        ; RES2 above). INF is set to point to the new arrival's
                        ; ship data block in K%

 JSR DORND              ; Set A and X to random numbers and extract bit 7 from A
 AND #%10000000

 LDY #31                ; Store this in byte #31 of the ship's data block, so it
 STA (INF),Y            ; has a 50% chance of marking our new arrival as being
                        ; killed (so it will explode)

 LDA FRIN+6             ; The call we made to RES2 before we entered the loop at
 BEQ D1                 ; D1 will have reset all the ship slots at FRIN, so this
                        ; checks to see if the seventh slot is empty, and if it
                        ; is we loop back to D1 to add another canister, until
                        ; we have added seven of them

 LDA #8                 ; Set our speed in DELTA to 8, so the camera moves
 STA DELTA              ; forward slowly

 LDA #12                ; Set the text row for in-flight messages in the space
 STA messYC             ; view to row 12

 LDA #146               ; Print recursive token 146 ("{all caps}GAME OVER") in
 LDY #120               ; the middle of the screen and leave it there for 120
 JSR PrintMessage       ; ticks of the DLY counter

 JSR HideMostSprites    ; Hide all sprites except for sprite 0 and the icon bar
                        ; pointer

 LDA #30                ; Set the laser count to 30 to act as a counter in the
 STA LASCT              ; D2 loop below, so this setting determines how long the
                        ; death animation lasts

.D2

 JSR FlipDrawingPlane   ; Flip the drawing bitplane so we draw into the bitplane
                        ; that isn't visible on-screen

 JSR FlightLoop4To16    ; Display in-flight messages, call parts 4 to 12 of the
                        ; main flight loop for each ship slot, and finish off
                        ; with parts 13 to 16 of the main flight loop

 JSR ClearDashEdge_b6   ; Clear the right edge of the dashboard

 LDA #%11001100         ; Set the bitplane flags for the drawing bitplane to the
 JSR SetDrawPlaneFlags  ; following:
                        ;
                        ;   * Bit 2 set   = send tiles up to end of the buffer
                        ;   * Bit 3 set   = clear buffers after sending data
                        ;   * Bit 4 clear = we've not started sending data yet
                        ;   * Bit 5 clear = we have not yet sent all the data
                        ;   * Bit 6 set   = send both pattern and nametable data
                        ;   * Bit 7 set   = send data to the PPU
                        ;
                        ; Bits 0 and 1 are ignored and are always clear
                        ;
                        ; This configures the NMI to send nametable and pattern
                        ; data for the drawing bitplane to the PPU during VBlank

 DEC LASCT              ; Decrement the counter in LASCT, which we set above,
                        ; so for each loop around D2, we decrement LASCT by 5
                        ; (the main loop decrements it by 4, and this one makes
                        ; it 5)

 BNE D2                 ; Loop back to call the main flight loop again, until we
                        ; have called it 127 times

 JMP DEATH2             ; Jump to DEATH2 to reset and restart the game