lua use lcd_drawline to draw lines inside rliimages

rewrite draw_text to use new viewport buffer

set_viewport now accepts rliimage to allowe interfacing with rb. functions

fix long standing 2-bit bug with text drawing in lua
fix 2-bit img
saving bug (i'm guessing just a one off, just enabled clipping)

fix font_getstringsize bug

fix shape of numbers draw_num.lua also add auto centering

add page scrolling to printtable

add a new demo script 'stars'

Change-Id: I866905cee82ee89ebc0eb020a56a7ecdb101bf5e

apps/plugins/lua/include_lua/draw_num.lua

@@ -20,17 +20,13 @@
  *
  ****************************************************************************/
 ]]
-
 --[[ Exposed Functions
     _draw_nums.print; binary (base = 2) , octal (base = 8), hexadecimal (base = 16)
     _draw_nums.nums; table of number characters
 ]]
-
 if not rb.lcd_framebuffer then rb.splash(rb.HZ, "No Support!") return nil end
-
 local _draw_nums = {} do
     local _poly = require "draw_poly"
-
         -- every 2 elements is an x, y coord pair
         -- n[?]  = {x,y,x,y,x,y}
     local nums = {
@@ -43,11 +39,11 @@ local _draw_nums = {} do
         [2] = {1,1,3,1,4,2,4,3,3,4,1,5,1,7,4,7},
         [3] = {1,1,3,1,4,2,4,3,3,4,2,4,3,4,4,5,4,6,3,7,1,7},
         [4] = {1,1,1,3,2,4,4,4,4,1,4,7},
-        [5] = {1,1,4,1,1,1,1,4,3,4,4,5,4,7,1,7},
+        [5] = {1,1,4,1,1,1,1,4,3,4,4,5,4,6,3,7,1,7},
-        [6] = {1,2,1,4,1,6,2,7,3,7,4,6,4,4,1,4,1,2,2,1,4,1},
+        [6] = {1,2,1,4,1,6,2,7,3,7,4,6,4,5,3,4,1,4,1,2,2,1,3,1,4,2},
         [7] = {1,1,4,1,4,2,1,7},
-        [8] = {1,2,1,6,2,7,3,7,4,6,4,4,1,4,4,4,4,2,3,1,2,1,1,2},
+        [8] = {1,2,4,5,4,6,3,7,2,7,1,6,1,5,4,2,3,1,2,1,1,2},
-        [9] = {4,6,4,4,4,2,3,1,2,1,1,2,1,4,4,4,4,6,3,7,1,7},
+        [9] = {4,6,4,4,4,2,3,1,2,1,1,2,1,3,2,4,4,4,4,6,3,7,2,7,1,6},
         [10] = {1,7,1,4,4,4,4,7,4,2,3,1,2,1,1,2,1,4},
         [11] = {1,1,1,7,3,7,4,6,4,5,3,4,1,4,3,4,4,3,4,2,3,1,1,1},
         [12] = {4,2,3,1,2,1,1,2,1,6,2,7,3,7,4,6},
@@ -56,8 +52,6 @@ local _draw_nums = {} do
         [15] = {4,1,1,1,1,4,3,4,1,4,1,7},
     }
     _draw_nums.nums = nums
-
-
     _draw_nums.print = function(img, num, x, y, chrw, color, base, prefix, bClip, scale_x, scale_y, t_nums)
         scale_x = scale_x or 1
         scale_y = scale_y or 1
@@ -65,7 +59,6 @@ local _draw_nums = {} do
         prefix = (prefix == nil or prefix == true) and true or false
         t_nums = t_nums or nums
         local max_x, max_y, digits = 0, 0, {}
-
         if num <= 0 then
             if num < 0 then
                 digits[-3] = -1
@@ -74,7 +67,6 @@ local _draw_nums = {} do
                 digits[0] = 0
             end
         end
-
         if not prefix and (base == 2 or base == 8 or base == 16) then
             -- no prefix
         elseif base == 2 then
@@ -92,23 +84,20 @@ local _draw_nums = {} do
             error("unknown number base: " .. base)
             return nil
         end
-
         while num > 0 do -- get each digit (LeastSignificant)
             digits[#digits + 1] = num % base;
             num=num/base;
         end
-
         digits[#digits + 1] = digits[0]  -- zero
         digits[#digits + 1] = digits[-1] -- base prefix
         digits[#digits + 1] = digits[-2] -- base prefix (hex)
         digits[#digits + 1] = digits[-3] -- neg sign
-
         for i = #digits, 1, -1 do
                 max_x, max_y = _poly.polyline(img, x, y, t_nums[digits[i]],
                                           color, false, bClip, scale_x, scale_y)
+                if chrw == 0 then chrw = max_x end
                 x = x + chrw
         end
-
         return x, y + max_y, chrw
     end
 end

apps/plugins/lua/include_lua/draw_text.lua

@@ -23,7 +23,6 @@
 -- draw text onto image if width/height are supplied text is centered
 
 if not rb.lcd_framebuffer then rb.splash(rb.HZ, "No Support!") return nil end
-
 do
     -- Internal Constants
     local rocklib_image = getmetatable(rb.lcd_framebuffer())
@@ -40,16 +39,15 @@ do
     return function(img, x, y, width, height, font, color, text)
         font = font or rb.FONT_UI
 
-        local opts = {x = 0, y = 0, width = LCD_W - 1, height = LCD_H - 1,
-               font = font, drawmode = 3, fg_pattern = 0x1, bg_pattern = 0}
 
-        if rb.LCD_DEPTH  == 2 then -- invert 2-bit screens
+        if rb.lcd_rgbpack ~= _NIL then -- Color target 
-            --vp.drawmode = bit.bxor(vp.drawmode, 4)
+            rb.set_viewport(img, {fg_pattern = color, font = font, drawmode = 2})--DRMODE_FG
-            opts.fg_pattern = 3 - opts.fg_pattern
+        else
-            opts.bg_pattern = 3 - opts.bg_pattern
+            if color ~= 0 then color = 3 end--DRMODE_SOLID
+            rb.set_viewport(img, {font = font, drawmode = color})
         end
-        rb.set_viewport(opts)
 
+        if width or height then
             local res, w, h = rb.font_getstringsize(text, font)       
 
             if not width then
@@ -63,58 +61,13 @@ do
             else
                 height = (height - h) / 2
             end
+            x = width + x
+            y = height + y
 
-        -- make a copy of the current screen for later
-        --local screen_img = _newimg(LCD_W, LCD_H)
-        local screen_img = _newimg(LCD_W, h * 2)
-        _copy(screen_img, _LCD)
-
-        -- check if the screen buffer is supplied image if so set img to the copy
-        if img == _LCD then
-            img = screen_img
         end
 
-        -- we will be printing the text to the screen then blitting into img
+        rb.lcd_putsxy(x, y, text)
-        --rb.lcd_clear_display()
-        _clear(_LCD, opts.bg_pattern or 0, 1, 1, LCD_W, h * 2)
 
-        if w > LCD_W then -- text is too long for the screen do it in chunks
-            local l = 1
-            local resp, wp, hp
-            local lenr = text:len()
-
-            while lenr > 1 do
-                l = lenr
-                resp, wp, hp = rb.font_getstringsize(text:sub(1, l), font)
-
-                while wp >= LCD_W and l > 1 do
-                    l = l - 1
-                    resp, wp, hp = rb.font_getstringsize(text:sub( 1, l), font)
-                end
-
-                rb.lcd_putsxy(0, 0, text:sub(1, l))
-                text = text:sub(l)
-
-                if x + width > img:width() or y + height > img:height() then
-                    break
-                end
-
-                -- using the mask we made blit color into img
-                _copy(img, _LCD, x + width, y + height, _NIL, _NIL, _NIL, _NIL, false, BSAND, color)
-                x = x + wp
-                --rb.lcd_clear_display()
-                _clear(_LCD, opts.bg_pattern or 0, 1, 1, LCD_W, h * 2)
-
-                lenr = text:len()
-            end
-        else --w <= LCD_W
-            rb.lcd_putsxy(0, 0, text)
-
-            -- using the mask we made blit color into img
-            _copy(img, _LCD, x + width, y + height, _NIL, _NIL, _NIL, _NIL, false, BSAND, color)
-        end
-
-        _copy(_LCD, screen_img) -- restore screen
         rb.set_viewport() -- set viewport default
         return res, w, h
     end

apps/plugins/lua/include_lua/image_save.lua

@@ -198,7 +198,7 @@ do
         end
 
         -- Bitmap lines start at bottom unless biHeight is negative
-        for point in _points(img, 1, h, w + bytesleft, 1) do
+        for point in _points(img, 1, h, w + bytesleft, 1, 1, 1, true) do
             imgdata[#imgdata + 1] = fs_bytes_E(bpp, point or 0)
 
             if #fbuffer >= 31 then -- buffered write, increase # for performance

apps/plugins/lua/include_lua/printtable.lua

@@ -145,13 +145,14 @@ function print_table(t, t_count, settings)
 
     local wrap, justify, start, curpos, co_routine, hasheader, m_sel
     local header_fgc, header_bgc, item_fgc, item_bgc, item_selc
-    local table_linedesc, drawsep, overflow, dpad_fn
+    local table_linedesc, drawsep, overflow, dpad_fn, pagescroll
     do
         local s = settings or _print.get_settings()
         wrap, justify  = s.wrap, s.justify
         start, curpos  = s.start, s.curpos
         co_routine     = s.co_routine
         hasheader      = s.hasheader
+        pagescroll     = s.pagescroll
         drawsep        = s.drawsep
         sb_width       = s.sb_width or sb_width
         m_sel          = false
@@ -234,8 +235,13 @@ function print_table(t, t_count, settings)
                           dpad_fn(t_p.col, -1, -t_p.col_scrl, t_p.row, -1, -t_p.row_scrl,
                                   nil, overflow, (t_p.row + t_p.vcursor - 1))
 
+
+        if pagescroll == true then
+            t_p.row = t_p.row + y_chg * maxline - 1
+        end
         t_p.vcursor = t_p.vcursor + y_chg
 
+
         if t_p.vcursor > maxline or t_p.vcursor < t_p.vcursor_min then
             t_p.row = yi
         end
@@ -268,6 +274,7 @@ function print_table(t, t_count, settings)
         elseif y_chg ~= 0 then
             --t_p.col = 0 -- reset column to the beginning
             _print.clear()
+
             _print.opt.sel_line(t_p.vcursor)
 
             t_p.row_scrl = set_accel(timeb, t_p.row_scrl, t_p)

apps/plugins/lua/rocklib_img.c

@@ -81,6 +81,57 @@ struct rli_iter_d
     struct rocklua_image *img;
 };
 
+/* viewport for rliimages to use rb functions */
+static struct viewport img_vp =
+{
+    .x        = 0,
+    .y        = 0,
+    .width    = 0,
+    .height   = 0,
+    .font     = FONT_UI,
+    .drawmode = DRMODE_SOLID,
+#if LCD_DEPTH > 1
+    .fg_pattern = LCD_WHITE,
+    .bg_pattern = LCD_BLACK,
+#endif
+};
+
+static void *img_address_fn(int x, int y)
+{
+/* Address lookup function
+ * core will use this to get an address from x/y coord
+ * depending on the lcd function core sometimes uses this for
+ * only the first and last address
+ * and handles subsequent address based on stride */
+
+    struct frame_buffer_t *fb = img_vp.buffer;
+/* LCD_STRIDEFORMAT & LCD_NATIVE_STRIDE macros allow Horiz screens to work with RB */
+#if LCD_STRIDEFORMAT == VERTICAL_STRIDE
+    size_t element = (x * LCD_NATIVE_STRIDE(fb->stride)) + y;
+#else
+    size_t element = (y * LCD_NATIVE_STRIDE(fb->stride)) + x;
+#endif
+    /* use mod fb->elems to protect from buffer ovfl */
+    return fb->fb_ptr + (element % fb->elems);
+}
+/* sets an image into a vp to be used by rockbox image functions */
+static void img_set_as_vp(struct rocklua_image *img, struct viewport *vp)
+{
+    int w = img->width;
+    int h = img->height;
+    vp->x = 0;
+    vp->y = 0;
+    vp->width  = w;
+    vp->height = h;
+
+    static struct frame_buffer_t fb;/* warning passed to external fns */
+    fb.elems = LCD_NBELEMS(w, h); /* recalculate these rb expects num pixels */
+    fb.stride = STRIDE_MAIN(w, h); /* recalculate these */
+    fb.data = img->data;
+    fb.get_address_fn = &img_address_fn;
+    rb->viewport_set_buffer(vp, &fb, SCREEN_MAIN); /* not multiscreen aware yet */
+}
+
 /* __tostring information enums */
 enum rli_info {RLI_INFO_ALL = 0, RLI_INFO_TYPE, RLI_INFO_WIDTH,
                RLI_INFO_HEIGHT, RLI_INFO_ELEMS, RLI_INFO_BYTES,
@@ -261,7 +312,7 @@ static void bounds_check_xy(lua_State *L, struct rocklua_image *img,
     luaL_argerror(L, narg, ERR_IDX_RANGE);
 } /* bounds_check_xy */
 
-static struct rocklua_image* rli_checktype(lua_State *L, int arg)
+static struct rocklua_image* rli_checktype_opt(lua_State *L, int arg)
 {
 #if 0
     return (struct rocklua_image*) luaL_checkudata(L, arg, ROCKLUA_IMAGE);
@@ -284,10 +335,17 @@ static struct rocklua_image* rli_checktype(lua_State *L, int arg)
             }
         }
     }
-
+    /* Not a ROCKLUA IMAGE */
-    luaL_typerror(L, arg, ROCKLUA_IMAGE);  /* else error */
+    return NULL;
-    return NULL;  /* to avoid warnings */
 #endif
+} /* rli_checktype_opt*/
+
+static struct rocklua_image* rli_checktype(lua_State *L, int arg)
+{
+    struct rocklua_image *img = rli_checktype_opt(L, arg);
+    if (img == NULL)
+        luaL_typerror(L, arg, ROCKLUA_IMAGE);
+    return img;
 } /* rli_checktype */
 
 static struct rocklua_image * alloc_rlimage(lua_State *L, bool alloc_data,
@@ -519,6 +577,7 @@ static bool next_rli_iter(struct rli_iter_d *d)
     return true;
 } /* next_rli_iter */
 
+#if 0
 static void d_line(struct rocklua_image *img,
                    int x1, int y1,
                    int x2, int y2,
@@ -574,6 +633,38 @@ static void d_line(struct rocklua_image *img,
         *a1 += s_a; /* whichever axis is in 'a' stepped(-1 or +1) */
     }
 
+} /* d_line */
+#endif
+
+
+static void d_line(struct rocklua_image *img,
+                   int x1, int y1,
+                   int x2, int y2,
+                   fb_data *clr)
+{
+    /* NOTE! clr passed as pointer */
+#if LCD_DEPTH == 2
+    img_vp.fg_pattern = 0x55 * (~(*clr) & 3);
+    img_vp.drawmode = DRMODE_FG;
+#elif LCD_DEPTH > 1
+    img_vp.fg_pattern = *clr;
+    img_vp.drawmode = DRMODE_FG;
+#else /* bit of a hack to make sure lines show properly from lua */
+      /* use rb.lcd_drawline if you want full control */
+
+    img_vp.drawmode = *clr & (DRMODE_SOLID|DRMODE_INVERSEVID);
+    if (img_vp.drawmode != (DRMODE_SOLID|DRMODE_INVERSEVID))
+        img_vp.drawmode = DRMODE_SOLID;
+#endif
+
+    img_set_as_vp(img, &img_vp);
+
+    struct viewport *oldvp = rb->screens[SCREEN_MAIN]->set_viewport(&img_vp);
+
+    rb->lcd_drawline(x1 - 1, y1 - 1 , x2 - 1, y2 - 1);
+
+    rb->screens[SCREEN_MAIN]->set_viewport(oldvp);
+
 } /* d_line */
 
 /* ellipse worker function */
@@ -1266,9 +1357,21 @@ RB_WRAP(lcd_clear_display)
 
 RB_WRAP(lcd_set_drawmode)
 {
+    int previous;
     int mode = (int) luaL_checkint(L, 1);
+    if (rli_checktype_opt(L, 2) != NULL) /* is rliimage? */
+    {
+        previous = img_vp.drawmode;
+        img_vp.drawmode = mode;
+    }
+    else
+    {
+        struct viewport *vp = *(RB_SCREEN_STRUCT(L, 2)->current_viewport);
+        previous = vp->drawmode;
         RB_SCREENS(L, 2, set_drawmode, mode);
-    return 0;
+    }
+    lua_pushinteger(L, previous);
+    return 1;
 }
 
 /* helper function for lcd_puts functions */
@@ -1443,6 +1546,7 @@ RB_WRAP(lcd_scroll_stop)
 
 static inline struct viewport* opt_viewport(lua_State *L,
                                      int narg,
+                                     bool set_coords,
                                      struct viewport* vp,
                                      struct viewport* alt)
 {
@@ -1450,14 +1554,23 @@ static inline struct viewport* opt_viewport(lua_State *L,
         return alt;
 
     luaL_checktype(L, narg, LUA_TTABLE);
-
+    if (set_coords)
+    {
         vp->x = check_tablevalue(L, "x", narg);
         vp->y = check_tablevalue(L, "y", narg);
         vp->width = check_tablevalue(L, "width", narg);
         vp->height = check_tablevalue(L, "height", narg);
-    vp->font = check_tablevalue(L, "font", narg);
+    }
+    vp->font = check_tablevalue_def(L, "font", narg, FONT_UI);
     vp->drawmode = check_tablevalue_def(L, "drawmode", narg, DRMODE_SOLID);
-#if LCD_DEPTH > 1
+
+#if LCD_DEPTH == 2
+    unsigned int fg = check_tablevalue(L, "fg_pattern", narg);
+    unsigned int bg = check_tablevalue(L, "bg_pattern", narg);
+    /*invert fg and bg patterns (3-)*/
+    vp->fg_pattern = 0x55 * (3 - (~(fg) & 3));
+    vp->bg_pattern = 0x55 * (3 - (~(bg) & 3));
+#elif LCD_DEPTH > 1
     vp->fg_pattern = (unsigned int) check_tablevalue(L, "fg_pattern", narg);
     vp->bg_pattern = (unsigned int) check_tablevalue(L, "bg_pattern", narg);
 #endif
@@ -1467,8 +1580,15 @@ static inline struct viewport* opt_viewport(lua_State *L,
 
 RB_WRAP(set_viewport)
 {
+    void *ud = rli_checktype_opt(L, 1);
+    if (ud != NULL)
+    {
+            img_set_as_vp((struct rocklua_image*) ud, &img_vp);
+            RB_SCREENS(L, 3, set_viewport, opt_viewport(L, 2, false, &img_vp, &img_vp));
+            return 0;
+    }
     static struct viewport vp;
-    RB_SCREENS(L, 2, set_viewport, opt_viewport(L, 1, &vp, NULL));
+    RB_SCREENS(L, 2, set_viewport, opt_viewport(L, 1, true, &vp, NULL));
     return 0;
 }
 
@@ -1489,7 +1609,7 @@ RB_WRAP(font_getstringsize)
     else
         fontnumber = FONT_SYSFIXED;
 
-    if lua_isnil(L, 2)
+    if lua_isnoneornil(L, 2)
         result = RB_SCREENS(L, 3, getstringsize, str, &w, &h);
     else
         result = rb->font_getstringsize(str, &w, &h, fontnumber);

apps/plugins/lua_scripts/rlimg.lua

@@ -76,7 +76,7 @@ local BLUE  = _clr.set(WHITE, 0, 0, 255)
 -------------------------------------------
 local clrs
 local CANCEL_BUTTON = rb.actions.PLA_CANCEL
-
+local LCD_DEPTH = rb.LCD_DEPTH
 -- EXAMPLES ---------------------------------------------------------------------- EXAMPLES---------------------------------------------------------------------
 function my_blit(dst_val, dx, dy, src_val, sx, sy)
     -- user defined blit operation
@@ -84,7 +84,7 @@ function my_blit(dst_val, dx, dy, src_val, sx, sy)
     --you may change pixels in both the source and dest image
     --return nil to stop early
 
-    if _lcd.DEPTH < 2 then
+    if LCD_DEPTH < 2 then
         return src_val
     end
 
@@ -518,7 +518,7 @@ function twist(img)
             for ix = 1, _lcd.W, w do
                 y_col = y_col + 1
                 y = ims.y_pos[(y_col % 2) + 1]
-                if _lcd.DEPTH > 1 then
+                if LCD_DEPTH > 1 then
                     _lcd:copy(ims.strip, ix, 1, 1, y, w, h, false, _blit.BDEQC, colors[1])
                 else
                     _lcd:copy(ims.strip, ix, 1, 1, y, w, h, false, _blit.BSAND)
@@ -767,10 +767,10 @@ function long_text()
     local wait = 0
     w = w + wp * 3
     h = h + 4
-    local img = _img.new(w + 1, h)
+    local img = _img.new(w + 1, h + 1)
     img:clear(BLACK)
     _draw.rounded_rect_filled(img, 1, 1, w, h, 15, WHITE)
-    _draw_text(img, 1, 2, nil, nil, nil, BLACK, txt)
+    _draw_text(img, 1, 1, nil, nil, nil, BLACK, txt)
 
     for p = -w + 1, w - 1 do
         wait = 0
@@ -858,7 +858,7 @@ function main_menu()
                 [14] = function(EXIT_) return true end
                 }
 
-    if _lcd.DEPTH < 2 then
+    if LCD_DEPTH < 2 then
         table.remove(mt, 10)
         table.remove(ft, 10)
     end
@@ -880,7 +880,7 @@ _timer("main") -- keep track of how long the program ran
 -- Clear the screen
 _lcd:clear(BLACK)
 
-if _lcd.DEPTH > 1 then
+if LCD_DEPTH > 1 then
 --draw a gradient using available colors
 if IS_COLOR_TARGET == true then
     clrs = {

apps/plugins/lua_scripts/stars.lua

@@ -0,0 +1,256 @@
+--[[
+             __________               __   ___.
+   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
+   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
+   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
+   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
+                     \/            \/     \/    \/            \/
+ $Id$
+
+ Copyright (C) 2024 William Wilgus
+ This program is free software; you can redistribute it and/or
+ modify it under the terms of the GNU General Public License
+ as published by the Free Software Foundation; either version 2
+ of the License, or (at your option) any later version.
+ This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
+ KIND, either express or implied.
+]]--
+--https://nullprogram.com/blog/2011/06/13/ [Infinite Parallax Starfield]
+
+-- Imports 
+local _clr   = require("color") -- clrset, clrinc provides device independent colors
+local _lcd   = require("lcd")   -- lcd helper functions
+local _draw  = require("draw")  -- draw all the things (primitives)
+local _poly  = require("draw_poly") -- vector drawing with tables of coords
+require("actions")
+--'CONSTANTS' (in lua there really is no such thing as all vars are mutable)
+--------------------------------------------------------
+--colors for fg/bg ------------------------
+--first number of each quad is fallback for monochrome devices, excluded columns default to 0
+local WHITE = _clr.set(-1, 255, 255, 255)
+local BLACK = _clr.set(0, 0, 0, 0)
+local RED   = _clr.set(WHITE, 100)
+local GREEN = _clr.set(WHITE, 0, 100)
+local BGREEN = _clr.set(WHITE, 0, 255)
+local BLUE  = _clr.set(WHITE, 0, 0, 100)
+
+local STAR_SEED = 0x9d2c5680;
+local STAR_TILE_SIZE = math.max(rb.LCD_WIDTH, rb.LCD_HEIGHT) * 4;
+local bxor, band, rshift, lshift, arshift = bit.bxor, bit.band, bit.rshift, bit.lshift, bit.arshift
+local random, randomseed = math.random, math.randomseed
+local start_x, start_y, start_z
+
+-- load users coords from file if it exists
+local fname = rb.PLUGIN_DATA_DIR .. "/stars.pos"
+file = io.open(fname, "r")
+if file then
+   local v = 0
+   for line in file:lines() do
+       v = v + 1
+       if v == 1 then
+           start_x = tonumber(line) or 0
+       elseif v == 2 then
+           start_y = tonumber(line) or 0
+       elseif v == 3 then
+           start_z = tonumber(line) or 0
+       else
+           break;
+       end
+   end
+   io.close( file )
+end
+
+-- Robert Jenkins' 96 bit Mix Function.
+local function mix (a, b, c)
+    a=a-b;  a=a-c;  a=bxor(a, (rshift(c, 13)));
+    b=b-c;  b=b-a;  b=bxor(b, (lshift(a, 8)));
+    c=c-a;  c=c-b;  c=bxor(c, (rshift(b, 13)));
+    a=a-b;  a=a-c;  a=bxor(a, (rshift(c, 12)));
+    b=b-c;  b=b-a;  b=bxor(b, (lshift(a, 16)));
+    c=c-a;  c=c-b;  c=bxor(c, (rshift(b, 5)));
+    a=a-b;  a=a-c;  a=bxor(a, (rshift(c, 3)));
+    b=b-c;  b=b-a;  b=bxor(b, (lshift(a, 10)));
+    c=c-a;  c=c-b;  c=bxor(c, (rshift(b, 15)));
+
+    return c
+end
+
+-- given 32 bit number returns a table of 8 nibbles (4 bits)
+local function s_bytes_nib(bits, value)
+    -- bits must be multiples of 8 (sizeof byte)
+    local bbuffer = {}
+    local byte
+    local nbytes = bit.rshift(bits, 3)
+    for b = 1, nbytes do
+        if value > 0 then
+            byte  = value % 256
+            value = (value - byte) / 256
+        else
+            byte = 0
+        end
+        bbuffer[#bbuffer + 1] = band(byte,0xF)
+        bbuffer[#bbuffer + 1] = band(rshift(byte, 2), 0xF)
+    end
+    return bbuffer
+end
+
+--[[ given table t and total elems desired uses random elems of t 
+   and random numbers between 1 and max_v if #t < total_elems]]
+function randomize_table(t, total_elems, max_v)
+    local rand_t = {}
+    local i = 1
+    repeat
+        local v = t[random(1, total_elems)]
+        if v then
+            rand_t[i] = v
+        else
+            rand_t[i] = random(1, max_v)
+        end
+        i = i + 1
+    until i > total_elems
+    return rand_t
+end
+
+local function drawship(img, x, y, color, ship_t)
+    --_poly.polyline(img, x, y, ship_t, color, true, true)
+   _poly.polygon(img, x, y, ship_t, color, BLACK, true)
+end
+
+local function draw_astroid(img, x, y, size, shape, color, scale_x, scale_y)
+    --the random number generator gets seeded with the hash so we get the same figure each time
+    randomseed(shape)
+    -- we also use the 4 bytes of the hash as 4 coord pairs and randomly generate 8 more (16) half the size (8)
+    local uniq_t = randomize_table(s_bytes_nib(32, shape), 16, 8)
+    _poly.polyline(img, x, y, uniq_t, color, true, true, scale_x or 1, scale_y or 1)
+    --_poly.polygon(img, x, y, uniq_t, color, color, true, scale_x or 1, scale_y or 1) --filled figures
+end
+
+local function drawStars (img, xoff, yoff, starscale, color, scale_x, scale_y)
+    local size = STAR_TILE_SIZE / starscale
+    local s_x, s_y = scale_x, scale_y
+    local w, h = rb.LCD_WIDTH, rb.LCD_HEIGHT
+
+    -- Top-left tile's top-left position
+    local sx = ((xoff - w/2) / size) * size - size;
+    local sy = ((yoff - h/2) / size) * size - size;
+
+    --Draw each tile currently in view.
+    for i = sx, w + sx + size*3, size do
+        for j = sy, h + sy + size*3, size do
+            local hash = mix(STAR_SEED, (i / size), (j / size))
+            for n = 0, 2 do
+                local px = (hash % size) + (i - xoff);
+                hash = arshift(hash, 3)
+
+                local py = (hash % size) + (j - yoff);
+                hash = arshift(hash, 3)
+
+                if px > 0 and px < w and py > 0 and py < h then
+                    if n > 0 and starscale < 5 then
+                        draw_astroid(img, px, py, n, hash, color, s_x, s_y)
+                    else
+                        if scale_x > 1 then
+                            img:set(px, py, color)
+                            img:set(px + 1, py, color)
+                        elseif scale_y > 1 then
+                            img:set(px, py, color)
+                            img:set(px, py + 1, color)
+                        else
+                            img:set(px, py, color)
+                        end
+                    end
+                end
+            end
+        end
+    end
+end
+
+do
+    local act = rb.actions
+    local quit = false
+    local last_action = 0
+    local x,y,z = start_x or 0, start_y or 0, start_z or 8
+    local x_fast = rb.LCD_WIDTH / 4
+    local y_fast = rb.LCD_HEIGHT / 4
+    local ship_x = (rb.LCD_WIDTH - 0xF) / 2
+    local ship_y = rb.LCD_HEIGHT - (rb.LCD_HEIGHT / 3)
+    local scale_x, scale_y = 1, 1
+    -- vector draw the ship points for each direction (<>^v)
+    local ship_lt_t = {0,7, 15,0, 9,7, 15,15, 0,7}
+    local ship_rt_t = {0,0, 5,7, 0,15, 15,7, 0,0}
+    local ship_up_t = {0,15, 7,0, 15,15, 7,9, 0,15}
+    local ship_dn_t = {0,0, 7,15, 15,0, 7,5, 0,0}
+    local ship_t = ship_up_t
+
+    function action_event(action)
+        if action == act.PLA_EXIT or action == act.PLA_CANCEL then
+            quit = true
+            start_x, start_y, start_z = x, y, z
+        elseif action == act.PLA_RIGHT_REPEAT then
+            x = x + x_fast
+            scale_x = scale_x + 1
+            scale_y = 1
+        elseif action == act.PLA_LEFT_REPEAT then
+            x = x - x_fast
+            scale_x = scale_x + 1
+            scale_y = 1
+        elseif action == act.PLA_UP_REPEAT then
+            y = y - y_fast
+            scale_y = scale_y + 1
+            scale_x = 1
+        elseif action == act.PLA_DOWN_REPEAT then
+            y = y + y_fast
+            scale_y = scale_y + 1
+            scale_x = 1
+        elseif action == act.PLA_RIGHT then
+            x = x + 1
+            ship_t = ship_rt_t
+        elseif action == act.PLA_LEFT then
+            x = x - 1
+            ship_t = ship_lt_t
+        elseif action == act.PLA_UP then
+            y = y - 1
+            ship_t = ship_up_t
+        elseif action == act.PLA_DOWN then
+            y = y + 1
+            ship_t = ship_dn_t
+        elseif action == act.PLA_SELECT then
+            z = z + 4
+            if z > 16 then z = 0 end
+        elseif action == act.ACTION_NONE then
+            scale_x = 1
+            scale_y = 1
+        end
+
+        _lcd:clear(BLACK)
+        for i = 0, z, 4 do
+            drawStars(_LCD, x, y, i+1, RED, scale_x, scale_y)
+            drawStars(_LCD, x, y, i+2, GREEN, scale_x, scale_y)
+            drawStars(_LCD, x, y, i+3, BLUE, scale_x, scale_y)
+            drawStars(_LCD, x, y, i+4, WHITE, scale_x, scale_y)
+        end
+        drawship(_LCD, ship_x, ship_y, BGREEN, ship_t)
+        _lcd:update()
+
+        last_action = action
+    end
+
+    function action_set_quit(bQuit)
+        quit = bQuit
+    end
+
+    function action_quit()
+        return quit
+    end
+end
+
+action_event(rb.actions.ACTION_NONE) -- we can call this now but not after registering..
+local eva = rockev.register("action", action_event)
+
+while not action_quit() do rb.sleep(rb.HZ) end
+
+if start_x and start_y then
+    file = io.open(fname, "w")
+    file:write(start_x, "\n", start_y, "\n", start_z, "\n")
+    io.close( file )
+end