Merge pull request #14 from casten/casten-sierpenski-add

added a new example for Sierpenski Triangle

Author: greenbreakfast

examples/sierpenski-1306.py

@@ -0,0 +1,54 @@
+#! /usr/bin/python
+#Sierpenski Triangle Example for ssd1306 OLED board (and Omega2 of course!)
+#by Casten Riepling
+#Thanks to greenbreakfast for the nice i2c-exp-driver library + examples!
+
+from OmegaExpansion import oledExp as oled
+import random
+import time
+
+#since we can only write a byte at a time, we need to keep
+#the previous state in memory to OR it with
+state = [[0 for x in range(16)] for y in range(128)]
+
+
+#init all the 1306 driver stuff
+oled.driverInit()
+oled.setImageColumns()
+oled.setDisplayMode(0)
+
+#init our positional state and boundary vertices
+currX = currY = 0
+vertices = [{'x':0,'y':0}, {'x':63,'y':63}, {'x':0,'y':127}]
+
+#To make it a little more fun, we'll use a diminishing wait so one can
+#get an idea of the algorithm at work
+sleepTime = 1.0
+
+#The algorithm works as follows.  Start with 3 vertices of a triangle and begin at
+#one of them.  Randomly choose a vertex.  Go half way to that vertex and draw a point.
+#Repeat until you are happy.
+
+while True:
+        #pick a vertex
+        i = random.randint(0,2)
+        vert = vertices[i]
+
+        #find the point halfway between
+        currX = int((vert['x']+currX) / 2)
+        currY = int((vert['y']+currY) / 2)
+
+        #convert to columns and bit patterns
+        col = int(currX/8)
+        bitX = 1<<(currX%8)
+
+        #OR the info into the existing data
+        state[currY][col] |= int(state[currY][col] | bitX)
+
+        #write the data to the display
+        oled.setCursorByPixel(col,currY)
+        oled.writeByte(state[currY][col])
+
+        #and do some sleeping for dramatic effect
+        time.sleep(sleepTime)
+        sleepTime = sleepTime - (sleepTime/20)