June 2018 Update

Task/Fractal-tree/BASIC/fractal-tree-1.basic

@@ -0,0 +1,45 @@
+graphsize 300,300
+
+level = 12 : len =63		# initial values
+x = 230: y = 285			
+rotation = pi/2
+
+A1 = pi/27 : A2 = pi/8		# constants which determine shape
+C1 = 0.7 : C2 = 0.85
+
+dim xs(level+1) : dim ys(level+1)	# stacks
+
+fastgraphics
+color black
+rect 0,0,graphwidth,graphheight
+refresh
+color green
+gosub tree
+refresh
+imgsave "Fractal_tree_BASIC-256.png", "PNG"
+end
+
+tree:
+	xs[level] = x : ys[level] = y
+	gosub putline
+	if level>0 then
+		level = level - 1
+		len = len*C1
+		rotation = rotation - A1
+		gosub tree
+		len = len/C1*C2
+		rotation = rotation + A1 + A2
+		gosub tree
+		rotation = rotation - A2
+		len = len/C2
+		level = level + 1
+	end if
+	x = xs[level] : y = ys[level]
+	return
+
+putline:
+	yn = -sin(rotation)*len + y
+	xn = cos(rotation)*len + x
+	line x,y,xn,yn
+	x = xn : y = yn
+	return