ZXASCII
AUTO -1
PROG demos:graphics/ultraviolet
CHANGED FALSE
10 REM Ultraviolet
20 RADIANS: PAPER 0: palette 0,0,0,64: stroke 2: CLS: SCREEN LOCK
30 sz=50,ns=10,fr=.5,tr=20,dm=.25,tn=.98,ph=RND*tau,amp=85,frq=.015,ofs=285,md=1
40 DIM sp(tr),fr(tr),nd(tr,sz,4):
 mx=MOUSEx,my=MOUSEy
50 FOR i=1 TO tr:
    sp(i)=(.45+.025*(i/tr))+(RND*.1)-.05,
    fr(i)=fr+(RND*.01)-.005:
    FOR j=1 TO sz:
       nd(i,j,1)=mx,
       nd(i,j,2)=my:
    NEXT j:
 NEXT i
60 mx=(MOUSEx+(mx*(md-1)))/md,my=(MOUSEy+(my*(md-1)))/md
70 FOR i=1 TO tr:
    INK i:
    s=sp(i),nd(i,1,3)+=(mx-nd(i,1,1))*s,
    nd(i,1,4)+=(my-nd(i,1,2))*s
80    FOR j=1 TO sz:
       IF j>1 THEN
          nd(i,j,3)+=((nd(i,j-1,1)-nd(i,j,1))*s)+(nd(i,j-1,3)*dm),
          nd(i,j,4)+=((nd(i,j-1,2)-nd(i,j,2))*s)+(nd(i,j-1,4)*dm):
       END IF:
       nd(i,j,3)*=fr,nd(i,j,4)*=fr,
       nd(i,j,1)+=nd(i,j,3),
       nd(i,j,2)+=nd(i,j,4),
       s*=tn:
    NEXT j
90    MOVE TO nd(i,1,1),nd(i,1,2):
    FOR j=1 TO sz-2:
       CURVE nd(i,j,1),nd(i,j,2) TO (nd(i,j,1)+nd(i,j+1,1))*.5,(nd(i,j,2)+nd(i,j+1,2))*.5,ns:
    NEXT j:
    CURVE nd(i,j,1),nd(i,j,2) TO nd(i,j+1,1),nd(i,j+1,2),ns:
 NEXT i
100 ph+=frq,h=(ofs+SIN ph*amp) MOD 360:
 FOR f=1 TO tr:
    PALETTE HSV f,(h+((90/tr)*f)) MOD 360,255-(64/tr)*f,255:
 NEXT f:
 WAIT SCREEN: CLS:
 GO TO 60