A couple of demos from Star Maker

[B+]

Code: [Select]

'Star Maker 2 more demos.sdlbas [B+=MGA] 2016-06-03

'demo1 shows star fills for various number of points

'demo2 have fun seeding stars, move mouse around to drop seeds,
'the closer to bottom of screen the more likely a star will spring from the seed

option qbasic

const pi = acos(-1)
const radians = pi/180    'to convert an angle measured in degrees to and angle measure in radians, just mutiply by this
const xmax = 1200
const ymax = 700
const cx = xmax/2
const cy = ymax/2

setdisplay(xmax, ymax, 32, 1)
setcaption("Star Maker")
autoback(-2)

sub Star(x, y, rInner, rOuter, nPoints, angleOffset, TFfill)
    ' x, y are same as for circle,
    ' rInner is center circle radius
    ' rOuter is the outer most point of star
    ' nPoints is the number of points,
    ' angleOffset = angle offset IN DEGREES, it will be converted to radians in sub
    ' this is to allow us to spin the polygon of n sides
    ' TFfill filled True or False (1 or 0)
    pAngle = radians * (360 / nPoints)
radAngleOffset = radians * angleOffset
    x1 = x + rInner * cos(radAngleOffset)
    y1 = y + rInner * sin(radAngleOffset)
    for i = 0 to nPoints - 1
        x2 = x + rOuter * cos(i * pAngle + radAngleOffset + .5 * pAngle)
        y2 = y + rOuter * sin(i * pAngle + radAngleOffset + .5 * pAngle)
        x3 = x + rInner * cos((i + 1) * pAngle + radAngleOffset)
        y3 = y + rInner * sin((i + 1) * pAngle + radAngleOffset)
if TFfill then
triangle(x1, y1, x2, y2, x3, y3)
else
line(x1, y1, x2, y2)
line(x2, y2, x3, y3)
end if
        x1 = x3 : y1 = y3
    next
    if TFfill then
        fillcircle(x, y, rInner)
    end if
end sub

function rand(n1, n2)  ' numbers between n1, n2 inclusive, no worries first and second argument
dim hi, lo
if n1 > n2 then
hi = n1 : lo = n2
else
hi = n2 : lo = n1
end if
rand = rnd(hi - lo + 2) + lo -1
end function

function rclr() 'set a rand color fairly bright
dim test
test = rgb( rand(255, 64) * rand(0, 1), rand(255, 64) * rand(0, 1), rand(255, 64) * rand(0, 1) )
if test then
rclr = test
else
rclr = rgb(255, 255, 255)
  end if
end function

function rdir()  ' handy for dx, dy, da random directions pos or neg
if  rnd(3) = 2 then
rdir = 1
else
rdir = -1
end if
end function


sub demo1()
setcaption("Star fill demo for up to 15 point stars")
npoints = 3
while npoints < 16
cls
pAngle = 360 / nPoints : pAngle2 = pAngle/2
aDir =2:  cDir = 2
c=0 : ang = 0 : cc = 0
while c < 180
c += 1
ang += aDir
if ang > pAngle then : ang = pAngle : aDir *= -1 : end if
if ang < 0 then : ang = 0 : aDir *= -1 : end if
cc += cDir
if cc > pAngle2 then : cc=pAngle2 : cDir *= -1 : end if
if cc < 0 then : cc=0 : cDir *= -1 : end if
ccc = cc/pAngle2 * 255
ink(rgb(ccc, ccc, .5 * (255 - cc)) )
star( cx, cy, 100, 350, npoints, ang, 0 )
star( cx, cy, 40, 100, npoints, -ang + pAngle2, 1  )
ink(0x00aa88)
text(10, 10, 20, str(nPoints) + " Point Stars")
screenswap
wait(40)
wend
nPoints += 3
wend
end sub


sub demo2()

setcaption("Star seeding... move mouse around to spread seeds...")
nb = 100
dim bx[nb], by[nb], bdx[nb], bdy[nb], bc[nb]
tm = 1000
dim tx[tm], ty[tm], tir[tm], tor[tm], tnp[tm], tao[tm], tad[tm], tf[tm], tc[tm]
tstart = 1

while key(27) = 0
cls
nxt = rand(0, nb)
bx[nxt] = mouseX
by[nxt] = mouseY
bdx[nxt] = rand(-4, 4)
bdy[nxt] = rand(5, 1)
bc[nxt] = rclr()
wait(20)
for i = 0 to nb
if bdy[i] then
ink(bc[i])
fillellipse( bx[i], by[i], 9, 5)
bx[i] = bx[i] + bdx[i] + rand(0, 2)
by[i] = by[i] + bdy[i]
if bx[i] < 0 or bx[i] > xmax or by[i] < 0 or by[i] > ymax then
bdy[i] = 0
if bx[i] > 0 and bx[i] < xmax then
tx[tstart] = bx[i] - bdx[i]
ty[tstart] = ymax
tir[tstart] = rand(2, 9)
tor[tstart] = rand(1, 9) * tir[tstart] + tir[tstart]
tnp[tstart] = rand(3, 10)
tao[tstart] = rand(0, 360)
tad[tstart] = rdir()
tc[tstart] = bc[i]
tf[tstart] = rand(0, 1)
tstart += 1
if tstart > tm then : tstart = 0 : end if
end if
end if
end if
next
for i = 0 to tm
if tx[i] <> 0 or ty[i] <> 0 then
ink(tc[i])
star( tx[i], ty[i], tir[i], tor[i], tnp[i], tao[i], tf[i] )
if ty[i] > -100 then
ty[i] = ty[i] - 1
tao[i] = tao[i] + tad[i] * 3
end if
end if
next
screenswap
wait(2)
wend
end sub

demo1
demo2



[B+]

And one from SmallBASIC that can draw lines close together without as many holes:

Code: [Select]

'Star Maker another demo.bas  SmallBASIC 0.12.6 [B+=MGA] 2016-06-03

'Thanks Andy Amaya for following code
sub filltri(x1, y1, x2, y2, x3, y3)
  local x, y, length, slope1, slope2, slope3
  'triangle coordinates must be ordered: where x1 < x2 < x3
  if x2 < x1 then x = x2 : y = y2 : x2 = x1 : y2 = y1 : x1 = x : y1 = y
  'swap x1, y1, with x3, y3
  if x3 < x1 then x = x3 : y = y3 : x3 = x1 : y3 = y1 : x1 = x : y1 = y
  'swap x2, y2 with x3, y3
  if x3 < x2 then x = x3 : y = y3 : x3 = x2 : y3 = y2 : x2 = x : y2 = y
  if x1 <> x3 then slope1 = (y3 - y1) / (x3 - x1)
  'draw the first half of the triangle
  length = x2 - x1
  if length <> 0 then
    slope2 = (y2 - y1) / (x2 - x1)
    for x = 0 to length
      line int(x + x1), int(x * slope1 + y1), int(x + x1), int(x * slope2 + y1)
    next
  end if
  'draw the second half of the triangle
  y = length * slope1 + y1 : length = x3 - x2
  if length <> 0 then
    slope3 = (y3 - y2) / (x3 - x2)
    for x = 0 To length
      line int(x + x2), int(x * slope1 + y), int(x + x2), int(x * slope3 + y2)
    next
  end if
  line x1, y1, x2, y2
  line x2, y2, x1, y1
  line x2, y2, x3, y3
  line x3, y3, x2, y2
  line x1, y1, x3, y3
  line x3, y3, x1, y1
end

sub Star(x, y, rInner, rOuter, nPoints, angleOffset, TFfill)
  ' x, y are same as for circle,
  ' rInner is center circle radius
  ' rOuter is the outer most point of star
  ' nPoints is the number of points,
  ' angleOffset = angle offset IN DEGREES, it will be converted to radians in sub
  ' this is to allow us to spin the polygon of n sides
  ' TFfill filled True or False (1 or 0)
  local p_angle, rad_angle_offset, x1, y1, x2, y2, x3, y3, i
  p_angle = rad(360 / nPoints)  :  rad_angle_offset = rad(angleOffset)
  x1 = x + rInner * cos(rad_angle_offset)
  y1 = y + rInner * sin(rad_angle_offset)
  for i = 0 to nPoints - 1
    x2 = x + rOuter * cos(i * p_angle + rad_angle_offset + .5 * p_angle)
    y2 = y + rOuter * sin(i * p_angle + rad_angle_offset + .5 * p_angle)
    x3 = x + rInner * cos((i + 1) * p_angle + rad_angle_offset)
    y3 = y + rInner * sin((i + 1) * p_angle + rad_angle_offset)
    if TFfill then
      filltri x1, y1, x2, y2, x3, y3
    else
      line x1, y1, x2, y2
      line x2, y2, x3, y3
    end if
    x1 = x3 : y1 = y3
  next
  if TFfill then circle x, y, rInner filled 
end

'demo
npoints = 3
cx = xmax / 2 : cy = ymax / 2

while npoints < 17
  cls
  pAngle = 360 / nPoints
  pAngle2 = pAngle / 2
  aDir = .1
  cDir = .1
  c = 0
 
  while c<3600
    c ++
    ang += aDir
    if ang > pAngle then ang = pAngle : aDir *= -1
    if ang < 0 then ang = 0 : aDir *= -1
    cc += cDir
    if cc > pAngle2 then cc = pAngle2 : cDir *= -1
    if cc < 0 then cc=0 : cDir *= -1
    ccc = cc / pAngle2 * 255
    color rgb(ccc, ccc, .5 * (255 - cc))
    star cx, cy, 100, 350, npoints, ang, 0
    star cx, cy, 40, 100, npoints, -ang + pAngle2, 1
    showpage
    delay 1
  wend
  pause
  nPoints ++
wend

[B+]

Star maker fed some plasma:

Code: [Select]

'Star Maker on plasma.bas  SmallBASIC 0.12.6 [B+=MGA] 2016-06-04

'Thanks Andy Amaya for following code
sub filltri(x1, y1, x2, y2, x3, y3)
  local x, y, length, slope1, slope2, slope3
  'triangle coordinates must be ordered: where x1 < x2 < x3
  if x2 < x1 then x = x2 : y = y2 : x2 = x1 : y2 = y1 : x1 = x : y1 = y
  'swap x1, y1, with x3, y3
  if x3 < x1 then x = x3 : y = y3 : x3 = x1 : y3 = y1 : x1 = x : y1 = y
  'swap x2, y2 with x3, y3
  if x3 < x2 then x = x3 : y = y3 : x3 = x2 : y3 = y2 : x2 = x : y2 = y
  if x1 <> x3 then slope1 = (y3 - y1) / (x3 - x1)
  'draw the first half of the triangle
  length = x2 - x1
  if length <> 0 then
    slope2 = (y2 - y1) / (x2 - x1)
    for x = 0 to length
      line int(x + x1), int(x * slope1 + y1), int(x + x1), int(x * slope2 + y1)
    next
  end if
  'draw the second half of the triangle
  y = length * slope1 + y1 : length = x3 - x2
  if length <> 0 then
    slope3 = (y3 - y2) / (x3 - x2)
    for x = 0 To length
      line int(x + x2), int(x * slope1 + y), int(x + x2), int(x * slope3 + y2)
    next
  end if
  line x1, y1, x2, y2
  line x2, y2, x1, y1
  line x2, y2, x3, y3
  line x3, y3, x2, y2
  line x1, y1, x3, y3
  line x3, y3, x1, y1
end

sub Star(x, y, rInner, rOuter, nPoints, angleOffset, TFfill)
  ' x, y are same as for circle,
  ' rInner is center circle radius
  ' rOuter is the outer most point of star
  ' nPoints is the number of points,
  ' angleOffset = angle offset IN DEGREES, it will be converted to radians in sub
  ' this is to allow us to spin the polygon of n sides
  ' TFfill filled True or False (1 or 0)
  local p_angle, rad_angle_offset, x1, y1, x2, y2, x3, y3, i
  p_angle = rad(360 / nPoints)  :  rad_angle_offset = rad(angleOffset)
  x1 = x + rInner * cos(rad_angle_offset)
  y1 = y + rInner * sin(rad_angle_offset)
  for i = 0 to nPoints - 1
    x2 = x + rOuter * cos(i * p_angle + rad_angle_offset + .5 * p_angle)
    y2 = y + rOuter * sin(i * p_angle + rad_angle_offset + .5 * p_angle)
    x3 = x + rInner * cos((i + 1) * p_angle + rad_angle_offset)
    y3 = y + rInner * sin((i + 1) * p_angle + rad_angle_offset)
    if TFfill then
      filltri x1, y1, x2, y2, x3, y3
    else
      line x1, y1, x2, y2
      line x2, y2, x3, y3
    end if
    x1 = x3 : y1 = y3
  next
  if TFfill then circle x, y, rInner filled 
end

'demo
npoints = 3
cx = xmax / 2 : cy = ymax / 2
const a=127
while npoints < 18
  cls
  b = rnd ^ 2 : c = rnd ^ 2 : d = rnd ^ 2
  for r = 1 to 100
    color RGB(a + a * sin(b * r), a + a * sin(c * r), a + a * sin(d * r))
    star cx, cy, r, r * 3.5, npoints, ang, 0
  next
  showpage
  delay 3000
  npoints ++
  if npoints > 17 then npoints = 3
wend

[Rick3137]

 Very impressive.