1.1 --- a/build.py	Thu Sep 08 22:10:06 2011 +0200
     1.2 +++ b/build.py	Fri Sep 09 00:02:02 2011 +0200
     1.3 @@ -47,6 +47,8 @@
     1.4      out_uef_file = sys.argv[1]
     1.5      
     1.6      # Memory map
     1.7 +    # 0FE0 enemy x locations in the current room
     1.8 +    # 0FF0 enemy x locations in the current room
     1.9      # 1000 completion screen
    1.10      # 1780 title screen
    1.11      # 1F00 CODE

     2.1 --- a/mapcode.oph	Thu Sep 08 22:10:06 2011 +0200
     2.2 +++ b/mapcode.oph	Fri Sep 09 00:02:02 2011 +0200
     2.3 @@ -569,6 +569,101 @@
     2.4      clc
     2.5      rts
     2.6  
     2.7 +create_enemy_positions:
     2.8 +
     2.9 +    lda #31     ; counter
    2.10 +    sta $7e
    2.11 +
    2.12 +    lda #1      ; x
    2.13 +    sta $70
    2.14 +
    2.15 +    lda #1      ; y
    2.16 +    sta $71
    2.17 +
    2.18 +    lda #$a7
    2.19 +    sta $72
    2.20 +    lda #$57
    2.21 +    sta $73
    2.22 +
    2.23 +    ldx #15     ; offset into position areas
    2.24 +    ldy #0
    2.25 +
    2.26 +    create_enemy_positions_loop:
    2.27 +
    2.28 +        jsr unlimited_values
    2.29 +        and #7
    2.30 +        sta $80     ; store temporarily
    2.31 +
    2.32 +        lda $72
    2.33 +        adc $80
    2.34 +        sta $72     ; update the offset into the room data
    2.35 +        clc
    2.36 +
    2.37 +        lda $70
    2.38 +        adc $80     ; update x
    2.39 +        cmp #10
    2.40 +        bpl create_enemy_positions_next_row
    2.41 +
    2.42 +        sta $70     ; store x
    2.43 +        jmp create_enemy_positions_check_tile
    2.44 +
    2.45 +        create_enemy_positions_next_row:
    2.46 +
    2.47 +        sec
    2.48 +        sbc #10
    2.49 +        sta $70     ; store the x position on the next row
    2.50 +        clc
    2.51 +
    2.52 +        lda $71
    2.53 +        adc #1      ; update the y position
    2.54 +        cmp #10
    2.55 +        bpl create_enemy_positions_to_top
    2.56 +
    2.57 +        sta $71     ; store the y position for the next row
    2.58 +        jmp create_enemy_positions_check_tile
    2.59 +
    2.60 +        create_enemy_positions_to_top:
    2.61 +
    2.62 +        lda #1      ; reset the x, y and offset values
    2.63 +        sta $70
    2.64 +        sta $71
    2.65 +        lda #$a7
    2.66 +        sta $72
    2.67 +
    2.68 +        create_enemy_positions_check_tile:
    2.69 +
    2.70 +        lda ($72),y
    2.71 +        cmp #0
    2.72 +        bne create_enemy_positions_next
    2.73 +
    2.74 +        lda $70
    2.75 +        sta $0fe0,x                     ; store the x value
    2.76 +
    2.77 +        lda $71
    2.78 +        sta $0ff0,x                     ; store the y value
    2.79 +
    2.80 +        dex
    2.81 +        bmi create_enemy_positions_exit
    2.82 +
    2.83 +        create_enemy_positions_next:
    2.84 +        clc
    2.85 +        dec $7e
    2.86 +        bpl create_enemy_positions_loop
    2.87 +
    2.88 +    ; The position areas were not filled. Write invalid values into the
    2.89 +    ; first area for the emerge routine to find.
    2.90 +
    2.91 +    lda #0
    2.92 +    create_enemy_positions_fill_loop:
    2.93 +
    2.94 +        sta $0fe0,x
    2.95 +        dex
    2.96 +        bpl create_enemy_positions_fill_loop
    2.97 +
    2.98 +    create_enemy_positions_exit:
    2.99 +    clc
   2.100 +    rts
   2.101 +
   2.102  plot:               ; $70,$71=source address
   2.103                      ; $72,$73=destination address
   2.104      ldy #$1f
   2.105 @@ -2149,103 +2244,23 @@
   2.106      clc
   2.107      rts
   2.108  
   2.109 -emerge_x_position:              ; returns A=position
   2.110 -
   2.111 -    jsr unlimited_values
   2.112 -    lda $5184
   2.113 -    jmp emerge_position_common
   2.114 -
   2.115 -emerge_y_position:              ; returns A=position
   2.116 -
   2.117 -    jsr unlimited_values
   2.118 -    lda $5182
   2.119 -    ; run on into the next routine
   2.120 -
   2.121 -emerge_position_common:
   2.122 -
   2.123 -    cmp #3
   2.124 -    bpl emerge_position_common_not_first_area
   2.125 -
   2.126 -    lda $7d
   2.127 -    and #7
   2.128 -    cmp #6
   2.129 -    bpl emerge_position_common_first_area_truncate
   2.130 -
   2.131 -    adc #4
   2.132 -    rts
   2.133 -
   2.134 -    emerge_position_common_first_area_truncate:
   2.135 -    clc
   2.136 -    lda #8
   2.137 -    rts
   2.138 -
   2.139 -    emerge_position_common_not_first_area:
   2.140 -    cmp #7
   2.141 -    bpl emerge_position_common_third_area
   2.142 -
   2.143 -    lda $7d
   2.144 -    cmp #5
   2.145 -    bmi emerge_position_common_lower_second_area
   2.146 -
   2.147 -    clc
   2.148 -    lda $7d
   2.149 -    and #3
   2.150 -    adc #6
   2.151 -    rts
   2.152 -
   2.153 -    emerge_position_common_lower_second_area:
   2.154 -    clc
   2.155 -
   2.156 -    lda $7d
   2.157 -    and #3
   2.158 -    rts
   2.159 -
   2.160 -    emerge_position_common_third_area:
   2.161 -    clc
   2.162 -
   2.163 -    lda $7d
   2.164 -    and #7
   2.165 -    cmp #6
   2.166 -    bpl emerge_position_common_third_area_truncate
   2.167 -
   2.168 -    rts
   2.169 -
   2.170 -    emerge_position_common_third_area_truncate:
   2.171 -    clc
   2.172 -    lda #5
   2.173 -    rts
   2.174 -
   2.175  emerge_character:           ; $74,$75=character address
   2.176  
   2.177      lda #63
   2.178      sta $3dff
   2.179  
   2.180 -    lda #3      ; try three tiles to find a space
   2.181 -    sta $81
   2.182 -    emerge_character_loop:
   2.183 -
   2.184 -        jsr emerge_y_position   ; obtain a y position
   2.185 -        tax
   2.186 -        jsr emerge_x_position   ; obtain an x position
   2.187 -        sta $80                 ; temporary
   2.188 -        tay
   2.189 -
   2.190 -        lda room_row_offsets_low,x
   2.191 -        sta $70
   2.192 -        lda #$57
   2.193 -        sta $71
   2.194 -        lda ($70),y             ; load the tile
   2.195 -
   2.196 -        cmp #0
   2.197 -        beq emerge_character_space_found
   2.198 -
   2.199 -        dec $81
   2.200 -        bpl emerge_character_loop
   2.201 -
   2.202 -    bne emerge_character_exit
   2.203 -
   2.204 -    emerge_character_space_found:
   2.205 -    ; There is a space in the room, so add an emerging enemy.
   2.206 +    jsr unlimited_values
   2.207 +    and #$0f
   2.208 +    tax
   2.209 +    lda $0fe0,x
   2.210 +    cmp #0                  ; check for an invalid value and exit if found
   2.211 +    beq emerge_character_exit
   2.212 +
   2.213 +    sta $80                 ; temporary
   2.214 +    lda $0ff0,x
   2.215 +    tax
   2.216 +
   2.217 +    ; Add an emerging enemy.
   2.218  
   2.219      ldy #0
   2.220      lda #3
   2.221 @@ -3379,47 +3394,52 @@
   2.222      clc
   2.223      rts
   2.224  
   2.225 -move_characters:
   2.226 +emerge_characters:
   2.227  
   2.228      lda #$8c            ; set the character address
   2.229      sta $74
   2.230      lda #$51
   2.231      sta $75
   2.232  
   2.233 -    move_characters_loop:
   2.234 +    emerge_characters_loop:
   2.235  
   2.236          ldy #0
   2.237          lda ($74),y
   2.238          cmp #0
   2.239 -        bne move_characters_read_character
   2.240 -
   2.241 +        bne emerge_characters_next
   2.242 +
   2.243 +        jmp emerge_character    ; optimise away the rts
   2.244 +
   2.245 +        emerge_characters_next:
   2.246 +        clc
   2.247 +
   2.248 +        ; Examine the next character.
   2.249          lda $74
   2.250 +        adc #6
   2.251 +
   2.252          cmp #$a4
   2.253 -        bpl move_characters_read_character
   2.254 -
   2.255 -        ; See if it is time to generate a new enemy.
   2.256 -        lda $3dff
   2.257 -        cmp #0
   2.258 -        bne move_characters_next
   2.259 -
   2.260 -        lda $3df0           ; player demise - no more enemies
   2.261 -        and #$40
   2.262 -        bne move_characters_next
   2.263 -
   2.264 -        jsr emerge_character
   2.265 -        jmp move_characters_next
   2.266 -
   2.267 -        move_characters_read_character:
   2.268 -        clc
   2.269 -
   2.270 -        move_characters_not_projectile:
   2.271 +        bpl emerge_characters_exit
   2.272 +        sta $74
   2.273 +        jmp emerge_characters_loop
   2.274 +
   2.275 +    emerge_characters_exit:
   2.276 +    clc
   2.277 +    rts
   2.278 +
   2.279 +move_characters:
   2.280 +
   2.281 +    lda #$8c            ; set the character address
   2.282 +    sta $74
   2.283 +    lda #$51
   2.284 +    sta $75
   2.285 +
   2.286 +    move_characters_loop:
   2.287 +
   2.288 +        ldy #0
   2.289 +        lda ($74),y
   2.290          cmp #3
   2.291          bne move_characters_not_emerge_explode
   2.292  
   2.293 -        lda $3dfe           ; check motion counter
   2.294 -        and #3
   2.295 -        bne move_characters_next
   2.296 -
   2.297          jsr emerge_explode
   2.298          jmp move_characters_next
   2.299  
   2.300 @@ -3427,14 +3447,6 @@
   2.301          cmp #8
   2.302          bmi move_characters_next
   2.303  
   2.304 -        lda $3dfe           ; check motion counter
   2.305 -        and #3
   2.306 -        bne move_characters_next
   2.307 -
   2.308 -        lda $3df0           ; player demise - no enemy motion
   2.309 -        and #$40
   2.310 -        bne move_characters_next
   2.311 -
   2.312          jsr move_enemy
   2.313  
   2.314          move_characters_next:
   2.315 @@ -5299,6 +5311,7 @@
   2.316                  sta $79
   2.317                  jsr plot_room
   2.318                  jsr set_room_palette
   2.319 +                jsr create_enemy_positions
   2.320                  jsr add_treasure
   2.321  
   2.322                  jsr plot_the_player
   2.323 @@ -5316,8 +5329,6 @@
   2.324                      jsr reset_unplot_buffer
   2.325                      jsr reset_plot_buffer
   2.326  
   2.327 -                    jsr move_characters
   2.328 -
   2.329                      jsr move_projectile
   2.330  
   2.331                      lda $3df0   ; is player out of strength?
   2.332 @@ -5350,6 +5361,22 @@
   2.333  
   2.334                      room_loop_player_move:
   2.335  
   2.336 +                    ; See if it is time to generate a new enemy.
   2.337 +                    lda $3dff
   2.338 +                    cmp #0
   2.339 +                    bne no_emerge_characters
   2.340 +                    jsr emerge_characters
   2.341 +
   2.342 +                    no_emerge_characters:
   2.343 +
   2.344 +                    lda $3dfe           ; check motion counter
   2.345 +                    and #3
   2.346 +                    bne no_move_characters
   2.347 +                    jsr move_characters
   2.348 +
   2.349 +                    no_move_characters:
   2.350 +                    clc
   2.351 +
   2.352                      jsr check_fire_key
   2.353                      jsr move_player
   2.354                      bcs after_room_loop     ; check if we are leaving the level