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When I first began programming, I thought that code to draw a circle was gonna be the hardest thing ever. :wink:
Well - it may be slow, but it works. Just curious - what other methods of drawing circles are there? And what does the QB's intrinsic CIRCLE use?

Code:
SUB DC (X%,Y%,Radius%,C%)

    DO WHILE Degrees% < 361

        Radians!=(3.14159 / 180) * Degrees%

        PlotX!=Radius% * SIN(Radians!)

        PlotY!=Radius% * COS(Radians!)

        PSET (X% + PlotX!,Y% - PlotY!),C%

        Degrees%=Degrees% + 1

    LOOP

END SUB

Hey Zack...here's what I came up with when I wondered the same thing. Note my slow line is the squareroot call...I wonder if it can be done with no calls to expensive functions??? Or...using only Boolean logic...Cheers

Code:
'***********************************************

'*Mango-2001

'*This program draws circles the hard way...No Trig..and integers only

'*without using the circle command.  You can slow it down to see what it does

'*by deleting the comment markers of the "slowme" section of the code.

'***********************************************

SCREEN 12

DEFINT A-Z

DO

x = RND * 640      ' x cord

y = RND * 480      ' y cord

c = RND * 15       'color

r = RND * 100      'radius

sin45 = .70711 * r

FOR a = 0 TO sin45

  b = SQR((r * r) - (a * a))

  PSET (x + a, y + b), c

  PSET (x - a, y + b), c

  PSET (x + a, y - b), c

  PSET (x - a, y - b), c

  PSET (x + b, y + a), c

  PSET (x + b, y - a), c

  PSET (x - b, y + a), c

  PSET (x - b, y - a), c

'++++++++++USE THE FOLLOWING LINE TO SLOW THE CODE & SEE HOW IT WORKS++++++++

'FOR slow = 1 TO 100: FOR slow2 = 1 TO 3000: NEXT slow2: NEXT slow

'++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

NEXT a

LOOP UNTIL INKEY$ <> ""

This compares the methods...

Code:
DECLARE SUB Mcirc (x%, y%, r%, c%) 

DECLARE SUB Zcirc (x%, y%, radius%, c%) 

DECLARE SUB Pcirc (xc%, yc%, radius%, colr%) 

SCREEN 12 

CLS 

timer2 = TIMER + 1 

DO: LOOP WHILE TIMER < timer2 

secs = 1 

'default method 

RANDOMIZE 0 

timeme = TIMER + secs 

DO WHILE timeme > TIMER 

  CIRCLE (RND * 640, RND * 480), RND * 100, RND * 16 

  countDeflt = countDeflt + 1 

LOOP 

CLS 

'Mango's method 

RANDOMIZE 0 

timeme = TIMER + secs 

DO WHILE timeme > TIMER 

  CALL Mcirc(RND * 640, RND * 480, RND * 100, RND * 16) 

  countMango = countMango + 1 

LOOP 

CLS 

'Zack's method 

RANDOMIZE 0 

timeme = TIMER + secs 

DO WHILE timeme > TIMER 

  CALL Zcirc(RND * 640, RND * 480, RND * 100, RND * 16) 

  countZacko = countZacko + 1 

LOOP 

CLS 

'Plasma's method 

RANDOMIZE 0 

timeme = TIMER + secs 

DO WHILE timeme > TIMER 

  CALL Pcirc(RND * 640, RND * 480, RND * 100, RND * 16) 

  countPlasm = countPlasm + 1 

LOOP 

PRINT "default gets"; countDeflt / secs; "circles/sec" 

PRINT "Mango gets"; countMango / secs; "circles/sec" 

PRINT "Zack gets"; countZacko / secs; "circles/sec" 

PRINT "Plasma gets"; countPlasm / secs; "circles/sec" 

END 

DEFINT A-Z 

SUB Mcirc (x, y, r, c) 

 a = .707 * r 

 WHILE a 

  b = SQR((r * r) - (a * a)) 

  PSET (x + a, y + b), c 

  PSET (x - a, y + b), c 

  PSET (x + a, y - b), c 

  PSET (x - a, y - b), c 

  PSET (x + b, y - a), c 

  PSET (x + b, y + a), c 

  PSET (x - b, y + a), c 

  PSET (x - b, y - a), c 

  a = a - 1 

 WEND 

END SUB 

SUB Pcirc (xc, yc, radius, colr) 

  x = radius 

  sum = 1 - radius 

  do 

    pset (xc+x, yc+y), colr 

    pset (xc+y, yc+x), colr 

    pset (xc-y, yc+x), colr 

    pset (xc-x, yc+y), colr 

    pset (xc-x, yc-y), colr 

    pset (xc-y, yc-x), colr 

    pset (xc+y, yc-x), colr 

    pset (xc+x, yc-y), colr 

    if y >= x then 

      exit do 

    elseif sum > 0 then 

      sum = sum - x - x + 2 

      x = x - 1 

    end if 

    sum = sum + y + y + 3 

    y = y + 1 

  loop 

END SUB 

SUB Zcirc (x%, y%, radius%, c%) 

   DO WHILE Degrees% < 361 

      Radians! = (3.14159 / 180) * Degrees% 

      PlotX! = radius% * SIN(Radians!) 

      PlotY! = radius% * COS(Radians!) 

      PSET (x% + PlotX!, y% - PlotY!), c% 

      Degrees% = Degrees% + 1 

   LOOP 

END SUB

Square roots are slow. Tongue

Code:
defint a-z

sub circle2 (xc, yc, radius, colr)

  x = radius

  sum = 1 - radius

  do

    pset (xc+x, yc+y), colr

    pset (xc+y, yc+x), colr

    pset (xc-y, yc+x), colr

    pset (xc-x, yc+y), colr

    pset (xc-x, yc-y), colr

    pset (xc-y, yc-x), colr

    pset (xc+y, yc-x), colr

    pset (xc+x, yc-y), colr

    if y >= x then

      exit do

    elseif sum > 0 then

      sum = sum - 2 * x + 2

      x = x - 1

    end if

    sum = sum + 2 * y + 3

    y = y + 1

  loop

end sub

(This is the same method that QB uses, btw)

Quote:Square roots are slow.

Plasma...I tweaked mine a bit...looks the same speed as yours!!! May be different if it's compiled, though...dunno...

EDIT!!! Holy Cow...Your's and mine are *SLOWER* compiled than translated???!!!??!?!?!???!!!

What gives??

Quote:
Plasma Wrote:Square roots are slow.
EDIT!!! Holy Cow...Your's and mine are *SLOWER* compiled than translated???!!!??!?!?!???!!!

What gives??

That happens all the time for me.

Anyway - and what formula does QB use?

Read plasma's post above more carefully ^^^

Quote:
Mango Wrote:
Plasma Wrote:Square roots are slow.
EDIT!!! Holy Cow...Your's and mine are *SLOWER* compiled than translated???!!!??!?!?!???!!!

What gives??
That happens all the time for me.

Anyway - and what formula does QB use?

It's called the "bresenham" circle method. He also made a "bresenham" line method.

Plasma's would be fast because of the less calc. His code only calculates 1/8th of the circle and plots in each 8th-drant(1/2 of a quadrant if there is such a term).

Thanks, DP, didn't notice that bit.

Yes, the Bresenham circle. I've heard of it - now I have to figure out how to draw lines (Bresenham or not).

Offtopic:
What would be faster, x*2 or x+x?

They use different operations right? So one of them mus be a tiny bit faster.

How does the CPU calculate * anyways? Does it convert it to + like:

Code:
7*8 = 8+8+8+8+8+8+8

If so, then using + directly would be faster, right?

And what about: x^y (power of)

Code:
2^8 = 2*2*2*2*2*2*2*2

Which is:

Code:
+ 2 + 2 + 2 + 2 + 2 + 2 + 2 + 2 + 2

+ 2 + 2 + 2 + 2 + 2 + 2 + 2 + 2 + 2

+ 2 + 2 + 2 + 2 + 2 + 2 + 2 + 2 + 2

+ 2 + 2 + 2 + 2 + 2 + 2 + 2 + 2 + 2

+ 2 + 2 + 2 + 2 + 2 + 2 + 2 + 2 + 2

+ 2 + 2 + 2 + 2 + 2 + 2 + 2 + 2 + 2

+ 2 + 2 + 2 + 2 + 2 + 2 + 2 + 2 + 2

+ 2 + 2 + 2 + 2 + 2 + 2 + 2 + 2 + 2

+ 2 + 2 + 2 + 2 + 2 + 2 + 2 + 2 + 2

+ 2 + 2 + 2 + 2 + 2 + 2 + 2 + 2 + 2

+ 2 + 2 + 2 + 2 + 2 + 2 + 2 + 2 + 2

+ 2 + 2 + 2 + 2 + 2 + 2 + 2 + 2 + 2

+ 2 + 2 + 2 + 2 + 2 + 2 + 2

Which is:
2*128

Which is:
8*32

Which is:
16*16

Which is:
32*8

Which is:
64*4

Which is:
64+64+64+64

Which is:
256

So, how would the computer optimize it? What would be the fastest way to calculate it? 2^8 or using a number of +?

And what is fastest: * or / (assuming whole integers as factors and results)

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Zack

Mango

Mango

Plasma

Mango

Zack

KiZ

relsoft

Zack

Z!re