fix gfx2 text color, added cx16 snow example

compiler/res/prog8lib/cx16/gfx2.p8

@@ -918,7 +918,7 @@ _done
                         y++
                         %asm {{
                             phx
-                            ldx  #1
+                            ldx  color
                             lda  cx16.VERA_DATA1
                             sta  P8ZP_SCRATCH_B1
                             ldy  #8

docs/source/todo.rst

@@ -3,6 +3,14 @@ TODO
 
 For next release
 ^^^^^^^^^^^^^^^^
+- fix compiler error about containment
+                    if xx[idx]==0 or xx[idx]==319 {
+                        ; nothing here, if a call is here the error doesn't trigger !??
+                        ; gfx2.plot(xx[idx], yy[idx], PILED_SNOW_COLOR)
+                    } else {
+                        ...
+                    }
+
 - 6502 codegen: make it possible to use cpu opcodes such as 'nop' as variable names by prefixing all asm vars with something such as ``p8v_``? Or not worth it (most 3 letter opcodes as variables are nonsensical anyway)
   then we can get rid of the instruction lists in the machinedefinitions as well.  This is already no problem at all in the IR codegen.
 - create BSS section in output program and put StStaticVariables in there with bss=true. Don't forget to add init code to zero out everything that was put in bss. If array in bss->only zero ONCE! So requires self-modifying code

examples/cx16/snow.p8

@@ -0,0 +1,82 @@
+%import math
+%import gfx2
+
+main {
+    sub start() {
+        gfx2.screen_mode(4)
+
+        uword[128] xx
+        uword[128] yy
+
+        ubyte @zp idx
+        for idx in 0 to 127 {
+            xx[idx] = math.rndw() % 320
+            yy[idx] = math.rndw() % 240
+        }
+
+        gfx2.text(96, 90, 2, sc:"**************")
+        gfx2.text(104, 100, 5, sc:"let it snow!")
+        gfx2.text(96, 110, 2, sc:"**************")
+
+        const ubyte FALLING_SNOW_COLOR = 1
+        const ubyte PILED_SNOW_COLOR = 15
+
+        repeat {
+            sys.waitvsync()
+            for idx in 0 to 127 {
+                gfx2.plot(xx[idx], yy[idx], FALLING_SNOW_COLOR)
+            }
+            sys.waitvsync()
+            for idx in 0 to 127 {
+                if yy[idx]==239 {
+                    ; reached the floor
+                    gfx2.plot(xx[idx], yy[idx], PILED_SNOW_COLOR)
+                    yy[idx] = 0
+                    xx[idx] = math.rndw() % 320
+                } else if gfx2.pget(xx[idx], yy[idx]+1)==PILED_SNOW_COLOR {
+                    ; pile up
+                    uword @zp snowx = xx[idx]
+                    if snowx!=0 and snowx!=319 {        ; check to avoid x coordinate under/overflow
+                        uword pilex1
+                        uword pilex2
+                        if math.rnd() & 1 {
+                            pilex1 = snowx-1
+                            pilex2 = snowx+1
+                        } else {
+                            pilex1 = snowx+1
+                            pilex2 = snowx-1
+                        }
+                        if gfx2.pget(pilex1, yy[idx]+1)==0 {
+                            gfx2.plot(snowx, yy[idx], 0)
+                            gfx2.plot(pilex1, yy[idx]+1, PILED_SNOW_COLOR)
+                        } else if gfx2.pget(pilex2, yy[idx]+1)==0 {
+                            gfx2.plot(snowx, yy[idx], 0)
+                            gfx2.plot(pilex2, yy[idx]+1, PILED_SNOW_COLOR)
+                        } else {
+                            gfx2.plot(snowx, yy[idx], PILED_SNOW_COLOR)
+                        }
+                    }
+                    yy[idx] = 0
+                    xx[idx] = math.rndw() % 320
+                } else {
+                    ; fall
+                    gfx2.plot(xx[idx], yy[idx], 0)
+                    yy[idx]++
+                    when math.rnd() & 3 {
+                        1 -> {
+                            if xx[idx]
+                                xx[idx]--
+                        }
+                        2 -> {
+                            if xx[idx] < 319
+                                xx[idx]++
+                        }
+                    }
+                }
+            }
+        }
+
+        repeat {
+        }
+    }
+}

examples/cx16/testgfx2.p8

@@ -192,7 +192,7 @@ main {
 
         ubyte tp
         for tp in 0 to 15 {
-            gfx2.text(19+tp,20+tp*11, 5, sc:"ScreenCODE text! 1234![]<>#$%&*()")
+            gfx2.text(19+tp,20+tp*11, 7, sc:"ScreenCODE text! 1234![]<>#$%&*()")
         }
 
     }