starfield use the setoffset func

.gitignore

@@ -7,4 +7,5 @@
 !picz/*.png
 
 spirale
+starfield
 

Makefile

@@ -8,6 +8,11 @@ genplotting.o:	genplotting.f90 Makefile
 
 # -----------------------------------------------
 
+starfield:	starfield.f90 Makefile genplotting.o
+	gfortran -Wall $< genplotting.o -o $@
+
+# -----------------------------------------------
+
 spirale:	spirale.f90 Makefile genplotting.o
 	gfortran -Wall $< genplotting.o -o $@
 

genplotting.f90

@@ -1,4 +1,5 @@
-!                    SPIRALING...
+!              THE GENPLOTTING MODULE
+!
 ! new Thu Apr 23 01:13.37 PM UTC 2026
 !
 module genplotting
@@ -31,23 +32,36 @@ subroutine genp_init (foo, fname)
   xscale  = 0.0    ;       yscale  = 0.0
 end subroutine
 ! ---------------------------------------------------------
+subroutine genp_set_offset(ox, oy)
+  real, intent(in)     :: ox, oy
+  xoffset = ox      ;      yoffset = oy
+end subroutine
+subroutine genp_get_offset(ox, oy)
+  real, intent(out)     :: ox, oy
+  ox = xoffset      ;      oy = yoffset
+end subroutine
+! ---------------------------------------------------------
 subroutine genp_move (px, py)
   real, intent(in)        :: px, py
-  write (outunit, '(2F12.5, I5)') px, py, -1
+  real                    :: lx, ly
-  if (px .lt. xmin)      xmin = px
+  lx = px + xoffset     ;     ly = py + yoffset
-  if (px .gt. xmax)      xmax = px
+  write (outunit, '(2F12.5, I5)') lx, ly, -1
-  if (py .lt. ymin)      ymin = py
+  if (lx .lt. xmin)      xmin = lx
-  if (py .gt. ymax)      ymax = py
+  if (lx .gt. xmax)      xmax = lx
+  if (ly .lt. ymin)      ymin = ly
+  if (ly .gt. ymax)      ymax = ly
 end subroutine
 ! ---------------------------------------------------------
 subroutine genp_draw (px, py, color)
   real, intent(in)        :: px, py
   integer, intent(in)     :: color
-  write (outunit, '(2F12.5, I5)') px, py, color
+  real                    :: lx, ly
-  if (px .lt. xmin)      xmin = px
+  lx = px + xoffset     ;     ly = py + yoffset
-  if (px .gt. xmax)      xmax = px
+  write (outunit, '(2F12.5, I5)') lx, ly, color
-  if (py .lt. ymin)      ymin = py
+  if (lx .lt. xmin)      xmin = lx
-  if (py .gt. ymax)      ymax = py
+  if (lx .gt. xmax)      xmax = lx
+  if (ly .lt. ymin)      ymin = ly
+  if (ly .gt. ymax)      ymax = ly
 end subroutine
 ! ---------------------------------------------------------
 ! ---------------------------------------------------------

starfield.f90

@@ -0,0 +1,47 @@
+program starfield
+  use genplotting
+  implicit none
+
+  write (0, '(A)') "----[ genplotting starfield ]----"
+
+  call genp_init (0, 'starfield.scratch')
+  call do_starfield (105)
+  call genp_end (0)
+
+contains
+! ---------------------------------------------------------
+subroutine plot_a_star(at_x, at_y, sz, col)
+  real, intent(in)        :: at_x, at_y, sz
+  integer, intent(in)     :: col
+  integer                 :: idx
+  real                    :: rad, xv, yv
+
+  write(0, '("plot a star ", 2F8.3)') at_x, at_y
+  call genp_set_offset(at_x, at_y)
+
+  do idx=0, 360, 30
+    rad = 0.04 + (real(idx) * (3.14159 / 180))
+    xv = sz * sin(rad)    ;    yv = sz * cos(rad)
+    call genp_move(0.0, 0.0)
+    call genp_draw(xv, yv, col)
+  enddo
+
+end subroutine
+! ---------------------------------------------------------
+subroutine do_starfield (nbstar)
+  integer, intent(in)     :: nbstar
+
+  integer         idx, color
+  real            px, py, sz
+
+  do idx=0, nbstar
+    px = (rand(0) * 10.00) - 5.00
+    py = (rand(0) * 10.00) - 5.00
+    sz = (rand(0) *  0.16) + 0.19
+    color = 1 + mod(idx, 7)
+    call plot_a_star(px, py, sz, color)
+  end do
+end subroutine
+! ---------------------------------------------------------
+! ---------------------------------------------------------
+end program