Script for simulating snowfall

snowflakes.py

@@ -0,0 +1,161 @@
+#!/usr/bin/env python
+
+import sk6812_multistrip as sk6812
+import time
+import math
+import sys
+import random
+
+s = sk6812.SK6812(sys.argv[1], 2703)
+
+phase = 0
+nled = 16
+nstrip = 8
+
+interval = 1.0/60
+
+#scale = 0.15
+scale = 0.5
+
+strip = 0
+
+tiltphase = 0
+
+#phase_speeds = [13, 23, 42, 5]
+#phase_speeds = [37, 41, 43, 47]
+phase_speeds = [701, 709, 719, 727]
+
+class Framebuffer:
+	def __init__(self):
+		self.clear()
+
+	def clear(self):
+		self.r = [0] * (nstrip * nled)
+		self.g = [0] * (nstrip * nled)
+		self.b = [0] * (nstrip * nled)
+		self.w = [0] * (nstrip * nled)
+
+	def setpixel(self, strip, led, r, g, b, w):
+		idx = strip * nled + led
+		self.r[idx] = r
+		self.g[idx] = g
+		self.b[idx] = b
+		self.w[idx] = w
+
+	def addtopixel(self, strip, led, r, g, b, w):
+		idx = strip * nled + led
+		self.r[idx] += r
+		self.g[idx] += g
+		self.b[idx] += b
+		self.w[idx] += w
+
+	def render(self):
+		for strip in range(nstrip):
+			for led in range(nled):
+				idx = strip * nled + led
+				s.set_color(strip, led,
+						self.r[idx],
+						self.g[idx],
+						self.b[idx],
+						self.w[idx])
+
+class Snowflake:
+	def __init__(self):
+		self.phase = random.random() * 2 * math.pi
+		self.frequency = 2*math.pi * 1
+		self.speed = random.random() * 0.1 + 0.05
+
+		self.radius = 1.1
+		self.radiussq = self.radius**2
+
+		self.pos_strip = self.base_pos_strip = random.randint(0, nstrip-1)
+		self.pos_led = nled-1+self.radius
+
+	def move(self):
+		self.phase += self.frequency * interval
+		self.pos_strip = self.base_pos_strip + 1 * math.sin(self.phase)
+
+		self.pos_led -= 0.1
+
+	def render(self, framebuffer):
+		for strip in range(int(math.floor(self.pos_strip-self.radius)), int(math.ceil(self.pos_strip+self.radius))):
+			for led in range(int(math.floor(self.pos_led-self.radius)), int(math.ceil(self.pos_led+self.radius))):
+				if led < 0 or led >= nled:
+					continue
+
+				distsq = (strip - self.pos_strip)**2 + (led - self.pos_led)**2
+
+				brightness = 1 - distsq / self.radiussq
+				if brightness < 0:
+					continue # brightness 0 -> no effect -> save some calculations
+
+				norm_strip = strip
+				while norm_strip < 0:
+					norm_strip += nstrip
+				while norm_strip >= nstrip:
+					norm_strip -= nstrip
+
+				framebuffer.addtopixel(norm_strip, led, 0, 0, int(32*brightness), int(48*brightness))
+
+	def has_fallen(self):
+		return self.pos_led < -self.radius
+
+snowflakes = []
+framebuffer = Framebuffer()
+
+frame = 0
+
+snowlevel = [0] * nstrip
+
+while True:
+	# garbage collection
+	if True: #frame % 10 == 0:
+		visible_snowflakes = []
+		for flake in snowflakes:
+			if not flake.has_fallen():
+				visible_snowflakes.append(flake)
+			else:
+				idx = int(flake.base_pos_strip)
+				if idx < 0:
+					idx += nstrip
+				elif idx >= nstrip:
+					idx -= nstrip
+
+				snowlevel[idx] += 0.2
+
+		snowflakes = visible_snowflakes
+
+	# spawn new flakes
+	if random.random() < 0.1:
+		snowflakes.append(Snowflake())
+	
+	framebuffer.clear()
+
+	# move and render the flakes
+	for flake in snowflakes:
+		flake.move()
+		flake.render(framebuffer)
+
+	# add snow on the ground
+	for strip in range(nstrip):
+		led = 0
+		level = snowlevel[strip]
+		while level > 0:
+			if level >= 1:
+				brightness = 1
+			else:
+				brightness = level
+
+			framebuffer.addtopixel(strip, led, 0, int(8*brightness), int(32*brightness), int(12*brightness))
+
+			level -= 1
+			led += 1
+
+		snowlevel[strip] *= 0.999
+
+	framebuffer.render()
+
+	s.commit()
+
+	time.sleep(interval)
+	frame += 1