From 5f8aa3cf6cb5f628c7131f2ddf710562e10ad32e Mon Sep 17 00:00:00 2001
From: Sam Moore <matches@ucc.asn.au>
Date: Tue, 17 Jun 2014 17:25:47 +0800
Subject: [PATCH] Python script for plotting data using Gnuplot

---
 tools/stream_plot.py | 89 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 89 insertions(+)
 create mode 100755 tools/stream_plot.py

diff --git a/tools/stream_plot.py b/tools/stream_plot.py
new file mode 100755
index 0000000..0b7bb58
--- /dev/null
+++ b/tools/stream_plot.py
@@ -0,0 +1,89 @@
+#!/usr/bin/python -u
+
+# Script to plot data in real(ish) time
+# Naive approach is to just read from stdin and plot each point as it arrives
+# This isn't so great if you have a fast data rate, the plot window flashes and gets out of sync
+# Improvement is to use a thread to read from stdin, and a thread (main thread) that periodically plots the data (set the time interval to be sufficiently slow)
+
+import os
+import sys
+import select
+import threading
+import time
+import Gnuplot, Gnuplot.funcutils
+
+plt = Gnuplot.Gnuplot(persist=1)
+data = []
+semaphore = threading.Semaphore()
+running = True
+
+def ProcessData(points):
+	#TODO: Alter to change data as it is read
+	global data
+	if len(data) > 0:
+		# Store finite differences
+		points += [points[i]-data[-1][i] for i in xrange(len(points))]
+	else:
+		points += [0 for _ in xrange(len(points))]
+	return points
+
+def PlotData():
+	#TODO: Alter to change plotting of data
+	global data
+	data = data[-100:]
+
+	plt.plot(Gnuplot.Data(data, with_="lp",using="2:($8/$9)", title="[Real] clock_gettime()"))
+	plt.replot(Gnuplot.Data(data, with_="lp",using="2:($8/$10)", title="[CPU] SDL_GetPerformanceCounter()"))
+	plt.replot(Gnuplot.Data(data, with_="lp",using="2:($8/$11)", title="[GPU] OpenGL Query (GL_TIME_ELAPSED)"))
+
+# Produces data points by reading from stdin
+def Producer():
+	global data
+	global running
+	while running:
+		line = sys.stdin.readline()
+		line = line.strip(" \t\r\n")
+		if line == "":
+			continue
+		semaphore.acquire()
+		try:
+			data.append(ProcessData(map(float, line.split())))
+		except:
+			pass
+		semaphore.release()
+
+# "Consumes" data points by plotting them. Not really a consumer because it doesn't actually clear any but whatever
+def Consumer():
+	global data
+	global running
+	data_size = len(data)
+	while running:
+		prev_size = data_size
+		data_size = len(data)
+		if data_size != prev_size and data_size >= 2:
+			semaphore.acquire()
+			PlotData()
+			data_size = len(data)
+			semaphore.release()
+			
+		time.sleep(1)
+	
+# Setup plot and start threads
+def main(argv):
+	global running
+	plt.title("Performance Graph")
+	plt.xlabel("Real Time (s)")
+	plt.ylabel("Average FPS (since last data point)")
+	producer = threading.Thread(target=Producer)
+	producer.start()
+	try:
+		Consumer() # Can run plot in main thread, easier that way
+	except KeyboardInterrupt:
+		sys.stderr.write("Press enter to exit.\n")
+		pass
+	running = False
+	producer.join()
+
+if __name__ == "__main__":
+	main(sys.argv)
+	
-- 
2.20.1