NUM_ENEMIES = 4 ;======================= ; move enemies ;======================= move_enemies: ldy #0 move_enemies_loop: ; only move if out lda enemy_data+ENEMY_DATA_OUT,Y beq done_move_enemy ; check if falling ; check if moving right/left ; lda enemy_data+ENEMY_DATA_X,Y ; clc ; adc #1 ; sta enemy_data+ENEMY_DATA_X,Y ; cmp #36 ; bcc done_move_enemy ; lda #0 ; sta enemy_data+ENEMY_DATA_OUT,Y done_move_enemy: iny cpy #NUM_ENEMIES bne move_enemies_loop rts ;======================= ; draw and move enemies ;======================= draw_enemies: ldy #0 draw_enemies_loop: ; see if out lda enemy_data+ENEMY_DATA_OUT,Y beq done_draw_enemy ; check if on screen ; lda TILEMAP_X ; cmp enemy_data+ENEMY_DATA_TILEX,Y ; bcs done_draw_enemy ; clc ; adc #14 ; cmp enemy_data+ENEMY_DATA_TILEX,Y ; bcc done_draw_enemy ; lda TILEMAP_Y ; cmp enemy_data+ENEMY_DATA_TILEY,Y ; bcs done_draw_enemy ; clc ; adc #10 ; cmp enemy_data+ENEMY_DATA_TILEY,Y ; bcc done_draw_enemy ; set X and Y value ; convert tile values to X,Y ; X = (ENEMY_TILE_X-TILEX)*2 + 6 ; lda enemy_data+ENEMY_DATA_TILEX,Y ; sec ; sbc TILEMAP_X ; asl ; clc ; adc #4 ; sta XPOS ; Y = (ENEMY_TILE_Y-TILEY)*4 ; lda enemy_data+ENEMY_DATA_TILEY,Y ; sec ; sbc TILEMAP_Y ; asl ; asl ; sta YPOS ; see if exploding ; lda enemy_data+ENEMY_DATA_EXPLODING,Y ; beq draw_proper_enemy ;draw_exploding_enemy: ; asl ; tax ; lda enemy_explosion_sprites,X ; sta INL ; lda enemy_explosion_sprites+1,X ; sta INH ; lda FRAMEL ; and #$3 ; bne done_exploding ; move to next frame ; lda enemy_data+ENEMY_DATA_EXPLODING,Y ; clc ; adc #1 ; sta enemy_data+ENEMY_DATA_EXPLODING,Y ; cmp #4 ; bne done_exploding ; lda #0 ; sta enemy_data+ENEMY_DATA_OUT,Y ;done_exploding: ; jmp draw_enemy ; otherwise draw proper sprite draw_proper_enemy: ; lda enemy_data+ENEMY_DATA_TYPE,Y ; tax ; lda enemy_sprites,X ; sta INL ; lda enemy_sprites+1,X ; sta INH lda #yorp_sprite_walking_right sta INH lda enemy_data+ENEMY_DATA_X,Y sta XPOS lda enemy_data+ENEMY_DATA_Y,Y sta YPOS draw_enemy: tya pha jsr put_sprite_crop pla tay done_draw_enemy: tya clc adc #8 tay cpy #(NUM_ENEMIES*8) beq exit_draw_enemy jmp draw_enemies_loop exit_draw_enemy: rts enemy_explosion_sprites: .word enemy_explosion_sprite1 .word enemy_explosion_sprite1 .word enemy_explosion_sprite2 .word enemy_explosion_sprite3 enemy_explosion_sprite1: .byte 2,2 .byte $d9,$d9 .byte $9d,$9d enemy_explosion_sprite2: .byte 2,2 .byte $9A,$9A .byte $A9,$A9 enemy_explosion_sprite3: .byte 2,2 .byte $7A,$5A .byte $A5,$A7 ENEMY_YORP = 0 ENEMY_DATA_OUT = 0 ENEMY_DATA_EXPLODING = 1 ENEMY_DATA_TYPE = 2 ENEMY_DATA_DIRECTION = 3 ENEMY_DATA_TILEX = 4 ENEMY_DATA_TILEY = 5 ENEMY_DATA_X = 6 ENEMY_DATA_Y = 7 enemy_data: enemy0: ; 156,92 (-80,-12) -> 76,80 -> (/4,/4) -> 19,20 .byte 1 ; out .byte 0 ; exploding .byte ENEMY_YORP ; type .byte $ff ; direction .byte 19,20 ; tilex,tiley .byte 10,10 ; x,y enemy1: ; 272,92 (-80,-12) -> 192,80 -> (/4,/4) -> 48,20 .byte 0 ; out .byte 0 ; exploding .byte ENEMY_YORP ; type .byte $ff ; direction .byte 48,20 ; tilex,tiley .byte 0,0 ; x,y enemy2: ; 156,112 (-80,-12) -> 76,100 -> (/4,/4) -> 19,25 .byte 0 ; out .byte 0 ; exploding .byte ENEMY_YORP ; type .byte $ff ; direction .byte 19,25 ; tilex,tiley .byte 0,0 ; x,y enemy3: ; 184,116 (-80,-12) -> 104,104 -> (/4,/4) -> 26,26 .byte 0 ; out .byte 0 ; exploding .byte ENEMY_YORP ; type .byte $ff ; direction .byte 26,26 ; tilex,tiley .byte 0,0 ; x,y