Sine's, a graphics curio

[Rod]

This is a conversion of Spec BASIC code posted on Carl's BASIC facebook page. Nice.

   nomainwin
   WindowWidth =800
   WindowHeight =600
   UpperLeftX = int((DisplayWidth-WindowWidth)/2)
   UpperLeftY = int((DisplayHeight-WindowHeight)/2)
   open "Sins" for graphics_nsb as #1
   #1 "down ; fill black ; trapclose [quit]"

   pi = acs(-1)

   for a=0 to 7
       for b=0 TO 7
           #1 "color ";(a+b)/2*51;" 128 192"
           for i=0 to 2*pi step .004
               #1 "set ";x(a,b,i);" ";y(a,b,i)
           next i
       next b
   next a
   #1 "getbmp bac 0 0 800 600 ; backcolor white"

   [loop]
   #1 "discard ; drawbmp bac 0 0"
   for a=0 to 7
       for b=0 TO 7
       #1 "place ";x(a,b,i);" ";y(a,b,i);" ; circlefilled 3"
       next b
   next a
   i=i+.02
   scan
   goto [loop]


   [quit]
   close #1
   end

function x(a,b,i)
   x=190+60*a+28*SIN ((a+1)*i)
end function

function y(a,b,i)
   y=30+60*b-28*COS ((b+1)*i)
end function



[Carl Gundel]

Apr 16, 2022 11:06:57 GMT -5 Rod said:

This is a conversion of Spec BASIC code posted on Carl's BASIC facebook page. Nice.

That's fun.

[tenochtitlanuk]

Neat demo. And to think that 60+ years ago we had to make Lissajous figures with a sand pendulum!



And the excitement of building a cathode ray oscilloscope with Army-surplus 3.5 inch screen and old TV valves in about 1967. x/t, but also x/y so could show Lissajous figures once I'd built a sine wave generator- but I had to photograph the screen and develop/print for permanent records. Rapidly learned to treat UK mains 240V with respect... happy days!

[tsh73]

Just made EXE and send it along.
Using of background just brilliant.

[dkl]

Brilliant .....Love It!

[Rod]

I tried a proper hsv2rgb function. I used tsh73's code. The initial drawing was slow because there was too much detail.


  nomainwin
   WindowWidth =800
   WindowHeight =600
   UpperLeftX = int((DisplayWidth-WindowWidth)/2)
   UpperLeftY = int((DisplayHeight-WindowHeight)/2)
   open "Sins" for graphics_nsb as #1
   #1 "down ; fill black ; trapclose [quit]"

   pi = acs(-1)

   for a=0 to 7
       for b=0 TO 7
           #1 "color ";hsvtorgb$((a+b)/2*51,1,1)
           for i=0 to 2*pi step .04
               #1 "set ";x(a,b,i);" ";y(a,b,i)
           next i
       next b
   next a
   #1 "getbmp bac 0 0 800 600 ; backcolor white"

   [loop]
   #1 "discard ; drawbmp bac 0 0"
   for a=0 to 7
       for b=0 TO 7
       #1 "place ";x(a,b,i);" ";y(a,b,i);" ; circlefilled 3"
       next b
   next a
   i=i+.02
   scan
   goto [loop]


   [quit]
   close #1
   end

function hsvtorgb$(h,s,v)
   'tsh73
   'Input: (h,s,v)
   'h in the range [0, 360), indicating the angle, in degrees of the hue
   's and v varying between 0 and 1, representing the saturation and value, respectively
   'Output: r,g,b  [0,1]
   'and to be useful, R G B [0 255]
   'or to JB RGB$ as "R G B" string.

   hi = int(h/60) mod 6
   f = h/60 -  int(h/60)
   p = v*(1-s)
   q= v*(1-f*s)
   t = v*(1-(1-f)*s)
   select case hi
   case 0
       r = v: g = t: b = p
   case 1
       r = q: g = v: b = p
   case 2
       r = p: g = v: b = t
   case 3
       r = p: g = q: b = v
   case 4
       r = t: g = p: b = v
   case 5
       r = v: g = p: b = q
   end select
   R = int(r*255)
   G = int(g*255)
   B = int(b*255)
   hsvtorgb$ = R;" ";G;" ";B
end function

function x(a,b,i)
   x=190+60*a+28*SIN ((a+1)*i)
end function

function y(a,b,i)
   y=30+60*b-28*COS ((b+1)*i)
end function