Floodit (BBC Micro) by David Payne

Flood It

The object of this puzzle game is to change all of the blocks to the same colour in 25 moves or less.

At the start of the game all of the blocks are randomly coloured.

In each move you change the colour of the top left block, all orthogonally connected blocks of the same colour will also change to the new colour.

Keys:

1 - Red

2 - Green

3 - Yellow

4 - Blue

5 - Magenta

6 - Cyan

variables used (all variables are global)

a(29,14) - the 2d array containing the block colours

r - used to seed the pseudo random number generator

x,y - the x and y coordinates of a block

e - the maximum moves allowed (25)

c - loop counter when displaying the colour keys, also later used for old colour

m - the number of moves made

d - new colour

z - set to 4 when all blocks are the same colour, 0 if not

q - when this is set to 1 display the block instead of doing the flood fill

Program explanation (referring to the expanded version)

initialisation section

10MODE2

disable cursor

11VDU23,1,0;0;0;0;

define the graphics character for the block

12!&C00=-1

13!&C04=-1

14DIMa(29,14)

seed the pseudo random number generator

15r=RND(-TIME)

select a random colour for each block, display the blocks (2 characters per block)

16FORy=0TO29

20FORx=0TO14

21a(y,x)=RND(6)

22VDU17,a(y DIV2,x),224

23NEXT

24PRINT

25NEXT

set maximum moves allowed

26e=25

27COLOUR7

30PRINT"Moves: 0/";e

set a small text window, display the colour keys in it

31VDU28,17,2,19,0,17,0

32FORc=49TO54

33VDU17,c+80,c

34NEXT

clear text window, set colours back to default palette

35VDU26,20

initialise move counter to 0

40m=0

main game loop

41REPEAT

set old colour to top left block colour

42c=a(0,0)

get a valid key press for new colour (d) must not be same as old colour

43REPEAT

44d=GET-48

45UNTILd>0ANDd<7ANDd<>c

perform a flood fill starting at top left block, changing blocks from colour c to colour d

46x=0

47y=0

48PROCf

increment move counter

49m=m+1

display move counter

50VDU17,7,31,7+(m>9),30

51PRINT;m;

check if all blocks are now colour d

52z=4

53FORy=0TO14

54FORx=0TO14

55z=z ANDa(y,x)=d

56NEXT,

end game when all blocks have been changed to colour d or maximum number of moves have been made

60UNTILz ORm=e

display win/lose message

61PRINT"/";e;" You ";MID$("losewin!",z+1,4);

enable cursor

62VDU23,1,1;0;0;0;

end program

63END

flood fill algorithm

70DEFPROCf

set block to new colour

71a(y,x)=d

display it

72q=1

73GOSUB80

74q=0

if block to the left is colour c then continue flood fill in that direction

75IFx>0THENIFa(y,x-1)=c THENx=x-1:PROCf:x=x+1

if q then display top half of block

if block to the right is colour c then continue flood fill in that direction

80IFq THENVDU31,x,y*2,17,d,224 ELSEIFx<14THENIFa(y,x+1)=c THENx=x+1:PROCf:x=x-1

if q then display bottom half of block

if block above is colour c then continue flood fill in that direction

90IFq THENVDU8,10,224:RETURN ELSEIFy>0THENIFa(y-1,x)=c THENy=y-1:PROCf:y=y+1

if block below is colour c then continue flood fill in that direction

100IFy<14ANDa(y+1,x)=c THENy=y+1:PROCf:y=y-1:ENDPROC ELSEENDPROC