1.1 --- a/build.py	Sun Oct 05 02:11:53 2014 +0200
     1.2 +++ b/build.py	Sun Oct 05 02:15:45 2014 +0200
     1.3 @@ -90,9 +90,7 @@
     1.4  tiles = map(lambda tile: makelevels.tile_ref[tile], makelevels.tile_order)
     1.5  
     1.6  char_sprites = ["images/g-left1.png", "images/g-left2.png",
     1.7 -                "images/g-right1.png", "images/g-right2.png",
     1.8 -                "images/b-left1.png", "images/b-left2.png",
     1.9 -                "images/b-right1.png", "images/b-right2.png"]
    1.10 +                "images/b-left1.png", "images/b-left2.png"]
    1.11  
    1.12  monster_sprites = ["images/bat1.png", "images/bat2.png",
    1.13                   "images/spider1.png", "images/spider2.png"]
    1.14 @@ -423,8 +421,10 @@
    1.15          makesprites.read_sprites(life_sprites, life_sprites_address)
    1.16      char_data += life_sprites_data
    1.17      
    1.18 -    player_data, player_sprite_offsets = \
    1.19 +    player_data, player_sprite_file_offsets = \
    1.20          makesprites.read_sprites(char_sprites, char_area_address + len(char_data))
    1.21 +    player_sprite_offsets = player_sprite_file_offsets + \
    1.22 +        map(lambda x: x + len(player_data), player_sprite_file_offsets)
    1.23      char_data += player_data
    1.24      
    1.25      panel_address = 0x3000

     2.1 --- a/loader.oph	Sun Oct 05 02:11:53 2014 +0200
     2.2 +++ b/loader.oph	Sun Oct 05 02:15:45 2014 +0200
     2.3 @@ -45,7 +45,11 @@
     2.4      ldy #>sprites_block
     2.5      jsr $ffdd
     2.6  
     2.7 +    jsr copy_alt_sprites
     2.8 +    jsr reverse_character
     2.9 +
    2.10      ; Clear the screen.
    2.11 +
    2.12      lda #12
    2.13      jsr $ffee
    2.14  
    2.15 @@ -380,9 +384,27 @@
    2.16      clc
    2.17      jmp plot8x24_y0
    2.18  
    2.19 +copy_alt_sprites:
    2.20 +
    2.21 +    ; The definitions passed to the loader and main code provide addresses for
    2.22 +    ; the sprites in this order: <left> <right> <left alt> <right alt>
    2.23 +    ; The data has this order:   <left> <left alt>
    2.24 +    ; We copy the alternative set out of the way so that we can create a right
    2.25 +    ; facing set of sprites.
    2.26 +    ldx #95
    2.27 +    copy_alt_sprites_loop:
    2.28 +
    2.29 +        lda player_right1,x
    2.30 +        sta player_left_alt1,x
    2.31 +        dex
    2.32 +        bpl copy_alt_sprites_loop
    2.33 +
    2.34 +    clc
    2.35 +    rts
    2.36 +
    2.37  switch_characters:
    2.38  
    2.39 -    ; Switch the left and right sprites.
    2.40 +    ; Switch the left sprites.
    2.41      ldx #95
    2.42      switch_characters_left_loop:
    2.43  
    2.44 @@ -391,19 +413,82 @@
    2.45          sta player_left1,x
    2.46          tya
    2.47          sta player_left_alt1,x
    2.48 -
    2.49 -        ldy player_right1,x
    2.50 -        lda player_right_alt1,x
    2.51 -        sta player_right1,x
    2.52 -        tya
    2.53 -        sta player_right_alt1,x
    2.54 -
    2.55          dex
    2.56          bpl switch_characters_left_loop
    2.57  
    2.58 +reverse_character:
    2.59 +
    2.60 +    lda #<reverse_lookup
    2.61 +    sta $70
    2.62 +    lda #>reverse_lookup
    2.63 +    sta $71
    2.64 +
    2.65 +    ldx #95
    2.66 +    reverse_character_loop1:
    2.67 +
    2.68 +        lda player_left1,x
    2.69 +        pha
    2.70 +        and #$0f                ; Select the first set of bits.
    2.71 +        tay
    2.72 +        lda ($70),y             ; Look up the reversed value.
    2.73 +        sta $74
    2.74 +
    2.75 +        pla
    2.76 +        and #$f0                ; Select the second set of bits.
    2.77 +        lsr
    2.78 +        lsr
    2.79 +        lsr
    2.80 +        lsr
    2.81 +        tay
    2.82 +        lda ($70),y             ; Look up the reversed value.
    2.83 +        asl
    2.84 +        asl
    2.85 +        asl
    2.86 +        asl
    2.87 +        ora $74
    2.88 +        sta player_right1,x
    2.89 +
    2.90 +        dex
    2.91 +        bpl reverse_character_loop1
    2.92 +
    2.93 +    lda #<player_right1
    2.94 +    sta $70
    2.95 +    adc #8
    2.96 +    sta $72
    2.97 +    lda #>player_right1
    2.98 +    sta $71
    2.99 +    adc #0
   2.100 +    sta $73
   2.101 +    clc
   2.102 +
   2.103 +    ldy #0
   2.104 +    reverse_character_loop2:
   2.105 +
   2.106 +        ldx #7
   2.107 +        reverse_character_loop2a:
   2.108 +
   2.109 +            lda ($70),y
   2.110 +            pha
   2.111 +            lda ($72),y
   2.112 +            sta ($70),y
   2.113 +            pla
   2.114 +            sta ($72),y
   2.115 +
   2.116 +            iny
   2.117 +            dex
   2.118 +            bpl reverse_character_loop2a
   2.119 +
   2.120 +        tya
   2.121 +        adc #8
   2.122 +        tay
   2.123 +        cpy #96
   2.124 +        bne reverse_character_loop2
   2.125 +
   2.126      clc
   2.127      rts
   2.128  
   2.129 +reverse_lookup: .byte $0, $8, $4, $c, $2, $a, $6, $e, $1, $9, $5, $d, $3, $b, $7, $f
   2.130 +
   2.131  tiles_block: .byte <tiles_file_name, >tiles_file_name
   2.132               .byte sprite_area_low, sprite_area_high, 0, 0
   2.133               .byte sprite_area_low, sprite_area_high, 0, 0