Add python sample for fetching counters

docs/python_api/examples/renderdoc/fetch_counters.py

@@ -0,0 +1,92 @@
+import renderdoc as rd
+
+draws = {}
+
+# Define a recursive function for iterating over draws
+def iterDraw(d, indent = ''):
+	global draws
+
+	# save the drawcall by eventId
+	draws[d.eventId] = d
+
+	# Iterate over the draw's children
+	for d in d.children:
+		iterDraw(d, indent + '    ')
+
+def sampleCode(controller):
+	# Iterate over all of the root drawcalls, so we have names for each
+	# eventId
+	for d in controller.GetDrawcalls():
+		iterDraw(d)
+
+	# Enumerate the available counters
+	counters = controller.EnumerateCounters()
+
+	if not (rd.GPUCounter.SamplesPassed in counters):
+		raise RuntimeError("Implementation doesn't support Samples Passed counter")
+
+	# Now we fetch the counter data, this is a good time to batch requests of as many
+	# counters as possible, the implementation handles any book keeping.
+	results = controller.FetchCounters([rd.GPUCounter.SamplesPassed])
+
+	# Get the description for the counter we want
+	samplesPassedDesc = controller.DescribeCounter(rd.GPUCounter.SamplesPassed)
+
+	# Describe each counter
+	for c in counters:
+		desc = controller.DescribeCounter(c)
+
+		print("Counter %d (%s):" % (c, desc.name))
+		print("    %s" % desc.description)
+		print("    Returns %d byte %s, representing %s" % (desc.resultByteWidth, desc.resultType, desc.unit))
+
+	# Look in the results for any draws with 0 samples written - this is an indication
+	# that if a lot of draws appear then culling could be better.
+	for r in results:
+		draw = draws[r.eventId]
+
+		# Only care about draws, not about clears and other misc events
+		if not (draw.flags & rd.DrawFlags.Drawcall):
+			continue
+
+		if samplesPassedDesc.resultByteWidth == 4:
+			val = r.value.u32
+		else:
+			val = r.value.u64
+
+		if val == 0:
+			print("EID %d '%s' had no samples pass depth/stencil test!" % (r.eventId, draw.name))
+
+def loadCapture(filename):
+	# Open a capture file handle
+	cap = rd.OpenCaptureFile()
+
+	# Open a particular file - see also OpenBuffer to load from memory
+	status = cap.OpenFile(filename, '', None)
+
+	# Make sure the file opened successfully
+	if status != rd.ReplayStatus.Succeeded:
+		raise RuntimeError("Couldn't open file: " + str(status))
+
+	# Make sure we can replay
+	if not cap.LocalReplaySupport():
+		raise RuntimeError("Capture cannot be replayed")
+
+	# Initialise the replay
+	status,controller = cap.OpenCapture(None)
+
+	if status != rd.ReplayStatus.Succeeded:
+		raise RuntimeError("Couldn't initialise replay: " + str(status))
+
+	return cap,controller
+
+if 'pyrenderdoc' in globals():
+	pyrenderdoc.Replay().BlockInvoke(sampleCode)
+else:
+	cap,controller = loadCapture('test.rdc')
+
+	sampleCode(controller)
+
+	controller.Shutdown()
+	cap.Shutdown()
+