#include "fbgfx.bi"

Dim As Double x, y, angle

ScreenRes 800, 600, 32,,fb.gfx_alpha_primitives
line(0,0)-(800,600),rgb(0,64,128),bf

for S as double = (16*255)/256 to 0 step -1/32
  For angle = 0 To 3.1415 Step 1/256

      x = 16 * (Sin(angle))^3
      y = 13 * Cos(angle) - 5 * Cos(2 * angle) - 2 * Cos(3 * angle) - Cos(4 * angle)
      x = S * x : y = S * y

      var iX = cint(int(x)), iY=cint(int(y))
      var fX = x-iX, fY = y-iY

      'dim as long iG=sqr(x*x+y*y)*.1,iR=128+S*8,iB=64-S*4
      dim as long iR=abs(X\2)+128,iB=16+angle*64,iG=abs(Y)*.9
      const iAlpha = 128

      pset ((400+iX)  , (300-iY)  ), RGBA(iR, iG, iB, (1-fX)*(1-fY)*iAlpha)
      pset ((400+iX)+1, (300-iY)  ), RGBA(iR, iG, iB, (  fX)*(1-fY)*iAlpha)
      pset ((400+iX)  , (300-iY)-1), RGBA(iR, iG, iB, (1-fX)*(  fY)*iAlpha)
      pset ((400+iX)+1, (300-iY)-1), RGBA(iR, iG, iB, (  fX)*(  fY)*iAlpha)

      pset ((400-iX)  , (300-iY)  ), RGBA(iR, iG, iB, (1-fX)*(1-fY)*iAlpha)
      pset ((400-iX)-1, (300-iY)  ), RGBA(iR, iG, iB, (  fX)*(1-fY)*iAlpha)
      pset ((400-iX)  , (300-iY)-1), RGBA(iR, iG, iB, (1-fX)*(  fY)*iAlpha)
      pset ((400-iX)-1, (300-iY)-1), RGBA(iR, iG, iB, (  fX)*(  fY)*iAlpha)

  Next angle
  sleep 30
next S

Sleep
End