BBC BASIC for Windows
Programming >> Graphics and Games >> Pixel Vortex
http://bb4w.conforums.com/index.cgi?board=graphics&action=display&num=1422140764
Pixel Vortex
Post by rtr2 on Jan 24th, 2015, 10:06pm

Here's something which started off as a QBasic program, was then translated into Just BASIC, and which I have now translated into BBC BASIC (with a degree of licence). Nothing particularly special but an interesting effect, and purely BASIC code:

Code:
      REM Original QBasic program ANTONI18.BAS by Antoni Gual
      REM Translated to Just BASIC by Andy Amaya
      REM Translated to BBC BASIC by Richard Russell

      MODE 20
      GCOL 1
      OFF

      amp=24 : yi=-27
      r1=255 : g1=240 : b1=32
      r2=96  : g2=32  : b2=0
      dr = (r1-r2)/(amp*2)
      dg = (g1-g2)/(amp*2)
      db = (b1-b2)/(amp*2)
      FOR y = yi TO yi+2*amp+1
        oy = y : ox = 0
        COLOUR 1,r1,g1,b1
        FOR x = 0 TO 7 STEP PI/amp
          nx = x*24 : ny = SIN(x)*amp+y
          LINE ox*2,oy*2,nx*2,ny*2
          LINE ox*2,oy*2+98,nx*2,ny*2+98
          LINE ox*2,oy*2+196,nx*2,ny*2+196
          ox = nx : oy = ny
        NEXT
        r1-=dr : g1-=dg : b1-=db
      NEXT
      FOR x = 0 TO 1600 STEP 300
        FOR y = 0 TO 1200 STEP 194
          RECTANGLE 0, 0, 300, 194 TO x, y
        NEXT
      NEXT
      PROCvortex
      VDU 20
      FOR x = 0 TO 1600 STEP 40
        FOR y = 0 TO 1200 STEP 40
          GCOL RND(15)
          RECTANGLE FILL x, y, 40, 40
        NEXT
      NEXT
      PROCvortex
      GCOL 1 : CLS
      COLOUR 1,0,0,255     : RECTANGLE FILL 0, 100, 100, -100
      COLOUR 1,64,160,255  : PLOT 85,100,100
      COLOUR 1,192,192,255 : RECTANGLE FILL 14, 14, 76, 76
      COLOUR 1,0,128,255   : RECTANGLE FILL 12, 12, 76, 76
      COLOUR 1,192,192,255 : RECTANGLE FILL 24, 24, 52, 52
      COLOUR 1,0,0,255     : RECTANGLE FILL 26, 78, 52, -52
      COLOUR 1,64,160,255  : PLOT 85,24,24
      COLOUR 1,0,0,192     : RECTANGLE FILL 36,36,28,28
      FOR x = 0 TO 1600 STEP 100
        FOR y = 0 TO 1200 STEP 100
          RECTANGLE 0, 0, 100, 100 TO x, y
        NEXT
      NEXT
      PROCvortex
      COLOUR 0,0,0,255   : COLOUR 1,64,0,255  : COLOUR 2,128,0,255 : COLOUR 3,192,0,255
      COLOUR 4,255,0,255 : COLOUR 5,255,0,192 : COLOUR 6,255,0,128 : COLOUR 7,255,0,64
      COLOUR 8,255,0,0   : COLOUR 9,255,64,0  : COLOUR 10,255,128,0: COLOUR 11,255,192,0
      COLOUR 12,255,255,0: COLOUR 13,192,255,0: COLOUR 14,128,255,0: COLOUR 15,64,255,0
      c = 1
      FOR r = 1000 TO 20 STEP -20
        GCOL c MOD 16
        CIRCLE FILL 800, 600, r
        c += 1
      NEXT
      PROCvortex
      RUN
      END

      DEF PROCvortex
      LOCAL j, w, xmid, ymid
      WAIT 100
      w = 3000*RND(1)
      FOR j = 1 TO 10000
        w += .3
        xmid = 360 + SIN(w * .007) * 333
        ymid = 280 + SIN(w * .011) * 261
        RECTANGLE (xmid-SIN(w)*28)*2, (ymid+COS(w)*20)*2, 160, 160 TO \
        \         (xmid-SIN(w-.05)*27.16)*2, (ymid+COS(w-.04)*19.4)*2
        WAIT 0
      NEXT
      ENDPROC
Re: Pixel Vortex
Post by lancegary on Jan 24th, 2015, 11:02pm

It is interesting.

The thought that went through my mind is how science is often the process of undoing the vortex. For example taking the pattern after the vortex has distorted it and trying to recover the original pattern. And that would be guessing the nature of the vortex transformation and then retracing it's path and undoing the transformation. I suppose even cryptography is like deciphering the transformation and undoing it. Or William Davis's peneplane hypothesis in geomorphology where landscape is understood as the transformation wrought upon a hypothetical land plane by water and wind...

Thanks,

Lance
Re: Pixel Vortex
Post by David Williams on Jan 26th, 2015, 07:38am

Nice effect smiley


David.
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