added cx16 bubbleuniverse example

examples/cx16/bubbleuniverse.p8

@@ -0,0 +1,50 @@
+%import graphics
+%import floats
+%import math
+%option no_sysinit
+
+; Bubble Universe
+; see: https://stardot.org.uk/forums/viewtopic.php?f=54&t=25833
+
+main {
+    sub start() {
+        graphics.enable_bitmap_mode()
+
+        const ubyte n = 200
+        const float r = floats.TWOPI/235
+        const ubyte s = 60
+        float t
+
+        uword[] palette = [$000, $000, $00f, $f0f, $0ff, $fff]
+        cx16.FB_set_palette(palette, 0, len(palette))
+
+        repeat {
+            graphics.clear_screen(1,0)
+            ubyte i
+            for i in 0 to n {
+                ubyte j
+                float ang1_start = i+t
+                float ang2_start = r*i+t
+                float v=0
+                float u=0
+                for j in 0 to n {
+                    float ang1 = ang1_start+v
+                    float ang2 = ang2_start+u
+                    u=floats.sin(ang1)+floats.sin(ang2)
+                    v=floats.cos(ang1)+floats.cos(ang2)
+                    ubyte c=2
+                    if i>=100
+                        c++
+                    if j>=100
+                        c+=2
+                    graphics.colors(c,0)
+                    ; TODO nice rgb color?:  GCOL i%/num_curves%*255,j%/iteration_length%*255,255-(i%/num_curves%+j%/iteration_length%)*128
+                    uword a = 40 + ((2+u) * s) as uword
+                    uword b = ((v+2)*s) as uword
+                    graphics.plot(a,b)
+                }
+            }
+            t+=0.025
+        }
+    }
+}