changed cx16/rotating-stars example to starszoom instead.

compiler/test/TestCompilerOnExamples.kt

@@ -136,10 +136,10 @@ class TestCompilerOnExamplesCx16: FunSpec({
             "multi-irq-new",
             "plasma",
             "rasterbars",
-            "rotating-stars",
             "showbmx",
             "snow",
             "spotlight",
+            "starszoom",
             "tehtriz",
             "testgfx2",
             "testmonogfx",

docs/source/todo.rst

@@ -1,11 +1,13 @@
 TODO
 ====
 
+fix the  ubyte[<space>] parser error.
+
+crash:   speeds[star] = msb(r[star])    speeds and r are uword arrays
+
 word starw
 for starw in 50 downto 0        -> compiler error word loop variable can only loop over bytes or words
 
-fix the  ubyte[<space>] parser error.
-
 Regenerate skeleton doc files.
 
 Improve register load order in subroutine call args assignments:

examples/cx16/rotating-stars.p8

@@ -1,57 +0,0 @@
-; Animate a rotating and zooming sprite field.
-; Rather than doing complicated 3d stuff, this simply uses polar coordinates.
-; Every star lies along the circle and just has a radius R.
-
-%import math
-%import palette
-%import gfx_lores
-%option no_sysinit
-
-main {
-    %option verafxmuls
-
-    sub start() {
-        const ubyte NUM_STARS = 128         ; must be 128 to evenly distribute (angle goes from 0..255 in steps of 2)
-
-        ubyte[NUM_STARS] r
-        ubyte[NUM_STARS] speeds
-        uword[NUM_STARS]  prev_x
-        ubyte[NUM_STARS]  prev_y
-        uword angle
-
-        gfx_lores.set_screen_mode()
-
-        ; init the star positions
-        ubyte star
-        for star in 0 to NUM_STARS-1 {
-            r[star] = 4 + math.rnd()/4
-            speeds[star] = (math.rnd() & 3) + 1
-        }
-
-        repeat {
-            sys.waitvsync()
-            ;; palette.set_color(0, $400)
-            for star in NUM_STARS-1 downto 0 {
-                gfx_lores.plot(prev_x[star], prev_y[star], 0)
-                cx16.r2L = star*2 + msb(angle)
-                uword sx = (msb(math.sin8(cx16.r2L) as word * r[star]) + 128) as uword + 32
-                ubyte sy = (msb(math.cos8(cx16.r2L) as word * r[star]) + 120)
-                prev_x[star] = sx
-                if sy<240 {
-                    prev_y[star] = sy
-                    gfx_lores.plot(sx, sy, star)
-                } else
-                    prev_y[star] = 0
-
-                r[star] += speeds[star]
-                if r[star] >= 255-3 {
-                    r[star] = 4
-                    speeds[star] = (math.rnd() & 3) + 1
-                }
-            }
-            angle += $0040
-            ;; palette.set_color(0, $000)
-        }
-    }
-}
-

examples/cx16/starszoom.p8

@@ -0,0 +1,75 @@
+; Animate a zooming star field.
+; Rather than doing complicated 3d stuff, this simply uses polar coordinates.
+; Every star lies along the circle and has a radius.
+; Movement is dictated by a random accelleration, which increases the speed, which increases the radius.
+
+; TODO extend the radius to a larger maximum (0-319 or perhaps 0-511, instead of 0-255) so that we can fill the whole screen.
+; TODO do something with the colors palette: make stars darker in the distance
+
+%import math
+%import palette
+%import gfx_lores
+%option no_sysinit
+
+main {
+    %option verafxmuls
+
+    sub start() {
+        const ubyte NUM_STARS = 128                 ; maximum is 128.
+        const ubyte CIRCLE_SKIP = 256/NUM_STARS
+
+        ubyte[NUM_STARS] color
+        uword[NUM_STARS] @split radius
+        uword[NUM_STARS] @split accel
+        uword[NUM_STARS] @split speed
+        uword[NUM_STARS] @split prev_x
+        ubyte[NUM_STARS] prev_y
+
+        gfx_lores.set_screen_mode()
+
+        ; init the star positions
+        ubyte star
+        for star in 0 to NUM_STARS-1 {
+            color[star] = star
+            accel[star] = (math.rnd() & 15) | 1
+            radius[star] = mkword(math.rnd() & %11111000, 0)
+            speed[star] = 0   ; radius[star] >> 6           ;  a slow buildup of movement at the start is kinda nice I think, so we start with speed zero
+        }
+
+        const uword angle = 0       ; if you make this a variable and increase it, the stars rotate.
+
+        repeat {
+            sys.waitvsync()
+            ;;palette.set_color(0, $400)
+            for star in NUM_STARS-1 downto 0 {
+
+                gfx_lores.plot(prev_x[star], prev_y[star], 0)
+
+                cx16.r2L = star*CIRCLE_SKIP + msb(angle)
+                uword sx = (msb(math.sin8(cx16.r2L) as word * msb(radius[star])) + 128) as uword + 32
+                ubyte sy = (msb(math.cos8(cx16.r2L) as word * msb(radius[star])) + 120)
+
+                prev_x[star] = sx
+                if sy<240 {
+                    prev_y[star] = sy
+                    gfx_lores.plot(sx, sy, color[star])
+                } else
+                    prev_y[star] = 0
+
+                if radius[star] > $fffe - speed[star] {
+                    ; reset star to center
+                    accel[star] = (math.rnd() & 15) | 1
+                    radius[star] = $0400 + accel[star] * 128
+                    speed[star] = 0  ; radius[star] >> 6
+                    color[star] = math.rnd()
+                } else {
+                    ; can still move more.
+                    radius[star] += speed[star]
+                    speed[star] += accel[star]
+                }
+            }
+            ;; angle += $0040
+            ;;palette.set_color(0, $000)
+        }
+    }
+}

examples/test.p8

@@ -1,22 +1,15 @@
 %import textio
-%import floats
 %zeropage basicsafe
 %option no_sysinit
 
 main {
     sub start() {
-        word @shared x1 = -118
+        ubyte[] stuff1=[1,2,3]
-        floats.print(x1 as float)
+        ubyte [] stuff2=[1,2,3]
-        txt.nl()
+        ubyte[ ] stuff3=[1,2,3]     ; TODO fix parse error
-        floats.print(x1 as float/1.9)
+        stuff1[1]++
-        txt.nl()
+        stuff2[1]++
-        xf1 = x1/1.9
+        stuff3[1]++
-        floats.print(xf1)
-        txt.nl()
-
-        float @shared xf1 = -118
-        floats.print(xf1/1.9)
-        txt.nl()
     }
 }