Fractal-like Patterns

[GWS]

Hi,

I love this type of program, which generates amazing patterns from just a few mathematical equations.

I came across the algorithm on another site, and translated it to CB, which is much easier to understand.

Code Select Expand


' Mathematical Patterns - GWS Aug 2011

def w:window
def i,n,red,grn,blu:int
def wW,wH,dots,xpos,ypos:int
def col[20,4],repeat,run:int
def a,b,c,x,y,z,j,xfocus,yfocus:float

autodefine = "off"
getscreensize wW,wH

window w, -wW,-wH, wW, wH,0,0 ,"CB Fractal Patterns", handler
centerwindow w
setwindowcolor w,rgb(0,0,0)

xfocus = wW * 0.47
yfocus = wH * 0.45

run = 1

control w,"B,Exit,2*(wW - 60)/3,wH * 0.85,60,30,@CTLBTNFLAT, 1"
control w,"B,Next,(wW - 60)/3,wH * 0.85,60,30,@CTLBTNFLAT, 2"
for i = 1 to 2
  setcontrolcolor w,i,rgb(124,171,255),rgb(0,80,180)
next i

' set up random colors ..
for i = 0 to 15
red = rnd(255) : grn = rnd(255) : blu = rnd(255)
col[i,1] = red : col[i,2] = grn : col[i,3] = blu
next i

draw

waituntil run = 0
closewindow w
end

SUB handler
select @CLASS
case @IDCLOSEWINDOW
run = 0
case @IDCONTROL
select @CONTROLID
' clicking the Exit button ...
case 1
run = 0
case 2
' clicking the new image button ...
setwindowcolor w,rgb(0,0,0)
draw
endselect
endselect
return

sub draw

for repeat = 1 to rnd(5)
' set up some random starting positions ..
a = rnd(1.0)
b = 0.9998
c = 2 - 2 * a

dots = 15000

x = 0 : j = 0
y = rnd(1.0)*12 + 0.1

' calculate and draw the points ..
for i = 0 to dots
z = x
x = b * y + j
j = a * x + c * (x^2)/(1 + x^2)
y = j - z
xpos = x*20 + xfocus
ypos = y*20 + yfocus
pset w,xpos,ypos,rgb(col[i/1000,1],col[i/1000,2],col[i/1000,3])
next i

next repeat

return
       


Hope you like it, I've included the .exe for those unfortunate folk who haven't discovered CB yet 

Graham

[Edit: I've randomised the repeat loop - I think it looks nicer ..  ]

[aurelCB]

Well that is really cool Graham

PS...Look into my translation

[GWS]

He! he .. glad you liked it. 

It's one of the things I like about Basic, that it can be so easily understood and ported to pretty well any Basic dialect.

Your version looks fine 

all the best,

Graham

[sapero]

Graham, I love this kind of programs!
Have converted it to IWB and it ran just fine. Modified a bit the draw function to use a cached device context, and that boosted it to turbo

Note: the following is for IWBasic

Code Select Expand

sub draw
int hdcOld = w.m_hPrintDC ' added
w.m_hPrintDC = GETHDC(w)

' the original code goes here

int hdc = w.m_hPrintDC ' added
w.m_hPrintDC = hdcOld
RELEASEHDC(w, hdc)
endsub

The trick above changes the GETHDC and RELEASEHDC functions called from within PSET command, to use the preinitialized printer device context.

[GWS]

Hi Sapero,

Pardon me chuckling ..  .. I wouldn't know a 'cached device context' if it walked up and kicked me .. 

But I'm pleased you found it interesting   

Could you post the IWB version in the IWB area, so folks can see what speed really looks like.

IWB's graphics are very impressive - one of the reasons it's well worth buying.
I shall use it a bit more once the copy protection scheme is sorted.

Of course, CB - the little cheapo Basic - will always be my favourite.  It should have had much improved graphics facilities, and a compile feature if my funded commissions had been carried out.  Unfortunately, that never materialised.  Ah well! .. have to be thankful for what we've got.

best wishes,

Graham

[Rock Ridge Farm (Larry)]

We may yet get to updating Cbasic - it is on my to-do list.

Larry

[pistol350]

The difference in terms of speed is "STRIKING!" 

[GWS]

Larry .. 

Graham