More snakes

A slightly improved version of the snakes program - now with more snakes.
Snakes are drawn in reverse, so it looks like they are crawling over each other rather than under.  It is the little things in life that matter.

[Upon opening the Well of the Souls and peering down]

Sallah: Indy, why does the floor move?

Indiana: Give me your torch.

[Indy takes the torch and drops it in]

Indiana: Snakes. Why'd it have to be snakes?

Sallah: Asps... very dangerous. You go first.

     REM Snake Walk 2
     REM T Street
     REM 2014-11-12
     REM slightly improved snake program, now
     REM with more snakes!
     MODE 10  : OFF
     SCREEN_WIDTH% = 1440
     SCREEN_HEIGHT% = 1152

     REM snake parameters
     SNAKE_RADIUS% = 16 : REM size of the segments
     SEGMENTS% = 26 : REM don't change to larger than this

     REM create each snake
     DIM snake1{ x%(SEGMENTS%-1), y%(SEGMENTS%-1),  head%, tail%, dir%, red%, green% }
     DIM snake2{} = snake1{}
     DIM snake3{} = snake1{}
     DIM snake4{} = snake1{}
     DIM snake5{} = snake1{}
     DIM snake6{} = snake1{}
     DIM snake7{} = snake1{}
     DIM snake8{} = snake1{}

     REM setup the initial conditions for the snake
     PROC_initialSnake( snake1{} )
     PROC_initialSnake( snake2{} )
     PROC_initialSnake( snake3{} )
     PROC_initialSnake( snake4{} )
     PROC_initialSnake( snake5{} )
     PROC_initialSnake( snake6{} )
     PROC_initialSnake( snake7{} )
     PROC_initialSnake( snake8{} )

     REM main loop
     REPEAT
       *refresh off
       PROC_drawSnake( snake1{} )
       PROC_drawSnake( snake2{})
       PROC_drawSnake( snake3{})
       PROC_drawSnake( snake4{})
       PROC_drawSnake( snake5{})
       PROC_drawSnake( snake6{})
       PROC_drawSnake( snake7{})
       PROC_drawSnake( snake8{})

       *refresh on

       PROC_moveSnake( snake1{} )
       PROC_moveSnake( snake2{} )
       PROC_moveSnake( snake3{} )
       PROC_moveSnake( snake4{} )
       PROC_moveSnake( snake5{} )
       PROC_moveSnake( snake6{} )
       PROC_moveSnake( snake7{} )
       PROC_moveSnake( snake8{} )

       WAIT 5 : REM wait a 'mo
       CLS

     UNTIL FALSE


     DEFPROC_initialSnake( this{} )
     LOCAL i%
     REM intial position of snake
     FOR i% = 0 TO SEGMENTS%-1
       this.x%(i%) = i% + 8
       this.y%(i%) = 12
     NEXT
     this.head% = SEGMENTS%-1
     this.tail% = 0
     this.dir% = RND(4) : REM initial direction
     this.red% = RND(255-SEGMENTS%*6)   : REM colour of snake
     this.green% = RND(255-SEGMENTS%*6) : REM colour of snake
     ENDPROC


     DEFPROC_drawSnake( this{} )
     REM plots one snake on the screen
     LOCAL colCycle%
     LOCAL i%
     LOCAL ok%
     i% = this.tail%
     WHILE NOTok%
       COLOUR 2, this.red%+colCycle%*6, this.green%+colCycle%*6, 0
       GCOL 0,2
       colCycle% +=1
       PROC_circle( this.x%(i%), this.y%(i%) )
       i% += 1
       IF i% >= SEGMENTS% THEN i% = 0
       IF i% = this.head% THEN
         ok% = TRUE
         PROC_circle( this.x%(i%), this.y%(i%) )
       ENDIF
     ENDWHILE
     ENDPROC


     DEFPROC_moveSnake( this{} )
     LOCAL dir%, ok%
     LOCAL newHead%, newTail%
     LOCAL checkx%, checky%

     newHead% = this.head% + 1
     IF newHead%=SEGMENTS% THEN
       newHead% = 0
     ENDIF
     newTail% = this.tail% + 1
     IF newTail% =SEGMENTS% THEN
       newTail% = 0
     ENDIF


     REPEAT
       ok% = TRUE
       REM check snake is not going back on itself
       REPEAT
         dir% = RND(4)
       UNTIL FN_dirOk(dir%, this.dir% )

       REM check that snake will not move off the screen
       CASE dir% OF
         WHEN 1
           checkx% = this.x%(this.head%) +1
         WHEN 2
           checkx%  = this.x%(this.head%) -1
         WHEN 3
           checky% = this.y%(this.head%) + 1
         WHEN 4
           checky% = this.y%(this.head%) -1
       ENDCASE

       IF dir% = 1 THEN
         IF checkx%*SNAKE_RADIUS%*2 > SCREEN_WIDTH% THEN
           ok% = FALSE
         ENDIF
       ENDIF
       IF dir% = 2 THEN
         IF checkx%*SNAKE_RADIUS%*2 <= SNAKE_RADIUS%*2 THEN
           ok% = FALSE
         ENDIF
       ENDIF
       IF dir% = 3 THEN
         IF checky%*SNAKE_RADIUS%*2 > SCREEN_HEIGHT% THEN
           ok% = FALSE
         ENDIF
       ENDIF
       IF dir% = 4 THEN
         IF checky%*SNAKE_RADIUS%*2 <= SNAKE_RADIUS%*2 THEN
           ok% = FALSE
         ENDIF
       ENDIF

     UNTIL ok%

     REM snake has made a valid random move
     CASE dir% OF
       WHEN 1
         this.x%(newHead%) = this.x%(this.head%) +1
         this.y%(newHead%) = this.y%(this.head%)
       WHEN 2
         this.x%(newHead%) = this.x%(this.head%) -1
         this.y%(newHead%) = this.y%(this.head%)

       WHEN 3
         this.y%(newHead%) = this.y%(this.head%) +1
         this.x%(newHead%) = this.x%(this.head%)

       WHEN 4
         this.y%(newHead%) = this.y%(this.head%) -1
         this.x%(newHead%) = this.x%(this.head%)

     ENDCASE

     this.head% = newHead%
     this.tail% = newTail%
     this.dir% = dir%
     ENDPROC


     DEFFN_dirOk( direction%, current% )
     REM check snake not moving back on itself
     IF ABS(direction%-current%) = 1 AND direction%+current% <> 5 THEN
       = FALSE
     ELSE
       = TRUE
     ENDIF


     DEFPROC_circle( x%, y% )
     CIRCLE FILL x%*SNAKE_RADIUS%*2, y%*SNAKE_RADIUS%*2, SNAKE_RADIUS%
     ENDPROC

Random Walk 3 - snakes!!

Remember the old Nokia game "SNAKE"?  Well, I decided to make a snake-like program in BB4W for today's random walk.  The program produces a number of snakes on the screen which then move randomly around.  Yes, you can have more than one snake.  Yes, they don't walk off the edge (that bit was quite tricky which is why this program took over an hour to code).  The snakes are different random colours, with the strongest colours indicated the heads.  Oh, and two other rules: snakes CAN move over each other, and themselves, but they cannot turn immediately back on themselves.

Enjoy!

Indiana: There's a big snake in the plane, Jock!

Jock: Oh, that's just my pet snake Reggie.

Indiana: I hate snakes, Jock! I hate 'em!

Jock: Come on! Show a little backbone, will ya!

     REM Snake Walk 1
     REM T Street
     REM 2014-11-12
     MODE 10  : OFF
     SCREEN_WIDTH% = 1440
     SCREEN_HEIGHT% = 1152

     REM snake parameters
     SNAKE_RADIUS% = 16 : REM size of the segments
     SEGMENTS% = 20 : REM don't change to larger than this

     REM create each snake
     DIM snake1{ x%(SEGMENTS%-1), y%(SEGMENTS%-1),  head%, tail%, dir%, red%, green% }
     DIM snake2{} = snake1{}
     DIM snake3{} = snake1{}
     DIM snake4{} = snake1{}
     DIM snake5{} = snake1{}

     REM setup the initial conditions for the snake
     PROC_initialSnake( snake1{} )
     PROC_initialSnake( snake2{} )
     PROC_initialSnake( snake3{} )
     PROC_initialSnake( snake4{} )
     PROC_initialSnake( snake5{} )

     REM main loop
     REPEAT
       *refresh off
       PROC_drawSnake( snake1{} )
       PROC_drawSnake( snake2{})
       PROC_drawSnake( snake3{})
       PROC_drawSnake( snake4{})
       PROC_drawSnake( snake5{})
       *refresh on

       PROC_moveSnake( snake1{} )
       PROC_moveSnake( snake2{} )
       PROC_moveSnake( snake3{} )
       PROC_moveSnake( snake4{} )
       PROC_moveSnake( snake5{} )

       WAIT 5 : REM wait a 'mo
       CLS

     UNTIL FALSE


     DEFPROC_initialSnake( this{} )
     LOCAL i%
     REM intial position of snake
     FOR i% = 0 TO SEGMENTS%-1
       this.x%(i%) = i% + 8
       this.y%(i%) = 12
     NEXT
     this.head% = SEGMENTS%-1
     this.tail% = 0
     this.dir% = RND(4) : REM initial direction
     this.red% = RND(255-SEGMENTS%*6)   : REM colour of snake
     this.green% = RND(255-SEGMENTS%*6) : REM colour of snake
     ENDPROC


     DEFPROC_drawSnake( this{} )
     REM plots one snake on the screen
     LOCAL colCycle%
     LOCAL i%
     LOCAL ok%
     i% = this.head%
     WHILE NOTok%
       COLOUR 2, this.red%+colCycle%*6, this.green%+colCycle%*6, 0
       GCOL 0,2
       colCycle% +=1
       PROC_circle( this.x%(i%), this.y%(i%) )
       i% -= 1
       IF i% <0 THEN i% = SEGMENTS%-1
       IF i% = this.tail% THEN
         ok% = TRUE
         PROC_circle( this.x%(i%), this.y%(i%) )
       ENDIF
     ENDWHILE
     ENDPROC


     DEFPROC_moveSnake( this{} )
     LOCAL dir%, ok%
     LOCAL newHead%, newTail%
     LOCAL checkx%, checky%

     newHead% = this.head% + 1
     IF newHead%=SEGMENTS% THEN
       newHead% = 0
     ENDIF
     newTail% = this.tail% + 1
     IF newTail% =SEGMENTS% THEN
       newTail% = 0
     ENDIF


     REPEAT
       ok% = TRUE
       REM check snake is not going back on itself
       REPEAT
         dir% = RND(4)
       UNTIL FN_dirOk(dir%, this.dir% )

       REM check that snake will not move off the screen
       CASE dir% OF
         WHEN 1
           checkx% = this.x%(this.head%) +1
         WHEN 2
           checkx%  = this.x%(this.head%) -1
         WHEN 3
           checky% = this.y%(this.head%) + 1
         WHEN 4
           checky% = this.y%(this.head%) -1
       ENDCASE

       IF dir% = 1 THEN
         IF checkx%*SNAKE_RADIUS%*2 > SCREEN_WIDTH% THEN
           ok% = FALSE
         ENDIF
       ENDIF
       IF dir% = 2 THEN
         IF checkx%*SNAKE_RADIUS%*2 <= SNAKE_RADIUS%*2 THEN
           ok% = FALSE
         ENDIF
       ENDIF
       IF dir% = 3 THEN
         IF checky%*SNAKE_RADIUS%*2 > SCREEN_HEIGHT% THEN
           ok% = FALSE
         ENDIF
       ENDIF
       IF dir% = 4 THEN
         IF checky%*SNAKE_RADIUS%*2 <= SNAKE_RADIUS%*2 THEN
           ok% = FALSE
         ENDIF
       ENDIF

     UNTIL ok%

     REM snake has made a valid random move
     CASE dir% OF
       WHEN 1
         this.x%(newHead%) = this.x%(this.head%) +1
         this.y%(newHead%) = this.y%(this.head%)
       WHEN 2
         this.x%(newHead%) = this.x%(this.head%) -1
         this.y%(newHead%) = this.y%(this.head%)

       WHEN 3
         this.y%(newHead%) = this.y%(this.head%) +1
         this.x%(newHead%) = this.x%(this.head%)

       WHEN 4
         this.y%(newHead%) = this.y%(this.head%) -1
         this.x%(newHead%) = this.x%(this.head%)

     ENDCASE

     this.head% = newHead%
     this.tail% = newTail%
     this.dir% = dir%
     ENDPROC


     DEFFN_dirOk( direction%, current% )
     REM check snake not moving back on itself
     IF ABS(direction%-current%) = 1 AND direction%+current% <> 5 THEN
       = FALSE
     ELSE
       = TRUE
     ENDIF


     DEFPROC_circle( x%, y% )
     CIRCLE FILL x%*SNAKE_RADIUS%*2, y%*SNAKE_RADIUS%*2, SNAKE_RADIUS%
     ENDPROC

Five Nokia snakes moving randomly around the screen.  Have fun changing the size and lengths of the snakes.