' Plasmagenerator f�r PowerBasic 3.00
' von Robert Seidel

Rauheit! = 2
SHARED Rauheit!
DEFINT a-z
RANDOMIZE TIMER
! MOV AX, &h0013
! INT &h10
DEF SEG = &hA000

SUB NewCol(xa, ya, x, y, xb, yb)
 col = ABS(xa - xb) + ABS(ya - yb)
 col = RND * Rauheit! * col - col
 col = col + XPOINT(xa, ya) + XPOINT(xb, yb)
 SHIFT RIGHT col, 1
 IF col < 1  THEN col = 1
 IF col > 180 THEN col = 1
 IF XPOINT(x, y) = 0 THEN XPSET x, y, col
END SUB

SUB SubDivide(x1, y1, x2, y2)
 IF NOT (x2 - x1 < 2 AND y2 - y1 < 2) THEN
  x = (x1 + x2)
  SHIFT RIGHT x, 1
  y = (y1 + y2)
  SHIFT RIGHT y, 1
  NewCol x1, y1, x, y1, x2, y1
  NewCol x2, y1, x2, y, x2, y2
  NewCol x1, y2, x, y2, x2, y2
  NewCol x1, y1, x1, y, x1, y2
  col =  XPOINT(x1, y1) + XPOINT(x2, y1) + XPOINT(x2, y2) + XPOINT(x1, y2)
  SHIFT RIGHT col, 2
  XPSET x, y, col
  SubDivide x1, y1, x, y
  SubDivide x, y1, x2, y
  SubDivide x, y, x2, y2
  Subdivide x1, y, x, y2
 END IF
END SUB

SUB XPSET(x, y, col)
POKE 320 * y + x, col
END SUB

FUNCTION XPOINT(x, y) AS BYTE
XPOINT = PEEK(320 * y + x)
END FUNCTION

SUB SetRGB(Nr, r, g, b)
 OUT &h3C8, Nr
 OUT &h3C9, r
 OUT &h3C9, g
 OUT &h3C9, b
END SUB

SUB SetCol(j)
FOR i = 1 TO 63
 SetRGB i+j,0,63-i,i
 SetRGB i+63+j,i,0,63-i
 SetRGB i+126+j,63-i,i,0
NEXT
END SUB

SetCol 0
Subdivide 0 , 0 , 320 , 199
WHILE NOT INSTAT
 SetCol j
 INCR j
 DELAY .0275
WEND
SCREEN 0