' Christmas Greetings 2020 from vegipete
' Required firmware version 5.06.00 or greater
'
mode 1,8
cls

middle = 250  ' tree center line

' 5 point star coords
dim xs(5) = (0,59,-95,95,-59,0)
dim ys(5) = (-100,81,-31,-31,81,-100)

nflakes = 1000
dim fl(nflakes,1)
dim drift(2) = (0,-1,1)

' draw trunk
box 0,576,MM.HRES,25,0,rgb(gray),rgb(gray)
line middle,575,middle-10,575,3,rgb(brown)
line middle-10,575,middle-10,500,3,rgb(brown)

' draw 1/2 tree
y = 100
for i = 0 to 3
 x = 55+i*50
 arc middle-x,y,50+i*50,55+i*50, 98,170,rgb(green)
 arc middle-x/2,y+i*3,50+i*50,55+i*50,150,199,rgb(green)
 y = y + i * 40 + 30
next i

' mirror half tree
blit read 1,middle-200,50,200,550
blit write 1,middle,50,1

' draw star
math scale xs(),0.25,xs()
math scale ys(),0.25,ys()
math add xs(),middle,xs()
math add ys(), 95,ys()
polygon 5,xs(),ys(),rgb(yellow),rgb(yellow)

' fill in colours
pixel fill middle,125,rgb(green)
pixel fill middle,175,rgb(green)
pixel fill middle,275,rgb(green)
pixel fill middle,375,rgb(green)
pixel fill middle,555,rgb(brown)
pixel fill middle, 95,rgb(yellow)

' Draw greeting - vertical stack to make thicker
text 550,150,"H a p p y","CM",5,1,rgb(blue)
text 550,151,"H a p p y","CM",5,1,rgb(blue),-1
text 550,200,"H o l i d a y s !","CM",5,1,rgb(blue)
text 550,201,"H o l i d a y s !","CM",5,1,rgb(blue),-1

' make it snow
' slip angle is 2 in 1
do
 for i = 1 to nflakes
   if fl(i,1) then
     if pixel(fl(i,0),fl(i,1)+1) then  'blocked?
       x1 = fl(i,0) : y1 = fl(i,1)
       ' check for sideways drift
       c = (pixel(fl(i,0)-1,fl(i,1)+1)=0) and (pixel(fl(i,0)-1,fl(i,1)+2)=0)
       c = c + 2*((pixel(fl(i,0)+1,fl(i,1)+1)=0) and (pixel(fl(i,0)+1,fl(i,1)+2)=0))
       if c = 3 then c = cint(1 + rnd)
       if c then
         pixel fl(i,0),fl(i,1),0   ' erase old
         fl(i,1) = fl(i,1) + 1
         fl(i,0) = fl(i,0) + drift(c)
         pixel fl(i,0),fl(i,1)     ' draw new
       else
         fl(i,1) = 0   ' snow flake has stuck in place
       endif
     else
       pixel fl(i,0),fl(i,1),0 ' erase old
       fl(i,1) = fl(i,1) + 1
       pixel fl(i,0),fl(i,1)     ' draw new
     endif
   else  ' maybe make new flake
     if rnd > .975 then
       fl(i,1) = 1
       fl(i,0) = int(rnd * MM.HRES)
     endif
   endif
 next i
loop