src/spaceship.asm

@@ -9,43 +9,35 @@
 .import read_controller
 
 .proc nmi_handler
-
-  PHP
-  PHA
-  TXA
-  PHA
-  TYA
-  PHA
-
-  ; copy sprite data to OAM
   LDA #$00
   STA OAMADDR
   LDA #$02
   STA OAMDMA
 
-  ; set PPUCTRL
-  LDA ppuctrl_settings
-  STA PPUCTRL
+  ;Update tiles *after* DMA transfer
+  JSR update_player
+  JSR draw_player
+  JSR read_controller
 
-  ; set scroll values
-  LDA #$00 ; X scroll first
+
+  LDA scroll
+  CMP #$00
+  BNE set_scroll_positions
+
+  LDA ppucrtl_settings
+  EOR #%00000010
+  STA ppucrtl_settings
+  STA PPUCTRL
+  LDA #240
+  STA scroll
+
+set_scroll_positions:
+  LDA #$00
   STA PPUSCROLL
+  DEC scroll
   LDA scroll
   STA PPUSCROLL
 
-  ; all done
-  LDA #$00
-  STA sleeping
-
-  LDA#$00
-  STA sleeping
-  
-  PLA
-  TAY
-  PLA
-  TAX
-  PLA
-  PLP
   RTI
 .endproc
 
@@ -168,6 +160,9 @@ done_checking:
 .export main
 .proc main
 
+  LDA #239
+  STA scroll
+
   LDX PPUSTATUS
   LDX #$3f
   STX PPUADDR
@@ -241,7 +236,7 @@ insideloop2:
   BNE outsideloop2
 
   LDA #%10010000
-  STA ppuctrl_settings
+  STA ppucrtl_settings
   STA PPUCTRL
 
 vblankwait: ; wait for another vblank before continuing
@@ -252,34 +247,8 @@ vblankwait: ; wait for another vblank before continuing
   STA PPUCTRL
   LDA #%00011110 ; turn on screen
   STA PPUMASK
-
-mainloop:
-  ;Update tiles *after* DMA transfer
-  JSR update_player
-  JSR draw_player
-  JSR read_controller
-
-  ; Check if PPUCTRL needs to change
-  LDA scroll ; did we reach the end of a nametable?
-  BNE update_scroll
-  ; if yes,
-  ; Update base nametable
-  LDA ppuctrl_settings
-  EOR #%00000010 ; flip bit 1 to its opposite
-  STA ppuctrl_settings
-  ; Reset scroll to 240
-  LDA #240
-  STA scroll
-update_scroll:
-  DEC scroll
-
-  ; Done processing; wait for next Vblank
-  INC sleeping
-sleep:
-  LDA sleeping
-  BNE sleep
-
-  JMP mainloop
+forever:
+  JMP forever
 .endproc
 
 .segment "ZEROPAGE"
@@ -288,30 +257,11 @@ player_y: .res 1
 pointerLo: .res 1
 pointerHi: .res 1
 scroll: .res 1
-ppuctrl_settings: .res 1
+ppucrtl_settings: .res 1
 pad1: .res 1
 .exportzp player_x, player_y
 .exportzp pad1
 
-sleeping: .res 1
-
-NUM_ENEMIES = 5
-; enemy object pool
-enemy_x_pos: .res NUM_ENEMIES
-enemy_y_pos: .res NUM_ENEMIES
-enemy_x_vels: .res NUM_ENEMIES
-enemy_y_vels: .res NUM_ENEMIES
-enemy_flags: .res NUM_ENEMIES
-
-; player bullet pool
-bullet_xs: .res 3
-bullet_ys: .res 3
-
-;export all pools
-.exportzp enemy_x_pos, enemy_y_pos
-.exportzp enemy_x_vels, enemy_y_vels
-.exportzp enemy_flags
-
 .segment "RODATA"
 palettes: .incbin "background.pal"