From 887ecc1aaa25f1068e666e009a08a8d28f3eed75 Mon Sep 17 00:00:00 2001
From: David Williams <david@volumesoffun.com>
Date: Fri, 10 Apr 2015 16:09:35 +0200
Subject: [PATCH] Adding test to measure voxel access times when sampling the
 volume randomly.

---
 tests/testvolume.cpp | 39 +++++++++++++++++++++++++++++++++++++++
 tests/testvolume.h   |  3 +++
 2 files changed, 42 insertions(+)

diff --git a/tests/testvolume.cpp b/tests/testvolume.cpp
index 2215f933..6910abf0 100644
--- a/tests/testvolume.cpp
+++ b/tests/testvolume.cpp
@@ -219,6 +219,32 @@ int32_t testSamplersWithWrappingBackwards(VolumeType* volume, Region region)
 	return result;
 }
 
+template <typename VolumeType>
+int32_t testDirectRandomAccess(const VolumeType* volume)
+{
+	std::mt19937 rng;
+	int32_t result = 0;
+
+	for (uint32_t ct = 0; ct < 10000; ct++)
+	{
+		uint32_t rand = rng();
+
+		// Four random number between 0-255
+		uint32_t part0 = static_cast<int32_t>(rand & 0xFF);
+		int32_t part1 = static_cast<int32_t>((rand >> 8) & 0xFF);
+		int32_t part2 = static_cast<int32_t>((rand >> 16) & 0xFF);
+		int32_t part3 = static_cast<int32_t>((rand >> 24) & 0xFF);
+
+		result = cantorTupleFunction(result, volume->getVoxel(part0, part1, part2));
+		result = cantorTupleFunction(result, volume->getVoxel(part1, part2, part3));
+		result = cantorTupleFunction(result, volume->getVoxel(part2, part3, part0));
+		result = cantorTupleFunction(result, volume->getVoxel(part3, part0, part1));
+
+	}
+
+	return result;
+}
+
 TestVolume::TestVolume()
 {
 	m_regVolume = Region(-57, -31, 12, 64, 96, 131); // Deliberatly awkward size
@@ -452,6 +478,19 @@ void TestVolume::testPagedVolumeSamplersWithExternalBackwards()
 	QCOMPARE(result, static_cast<int32_t>(-993539594));
 }
 
+/*
+ * Random access tests
+ */
+void TestVolume::testPagedVolumeDirectRandomAccess()
+{
+	int32_t result = 0;
+	QBENCHMARK
+	{
+		result = testDirectRandomAccess(m_pPagedVolume);
+	}
+	QCOMPARE(result, static_cast<int32_t>(805464457));
+}
+
 int32_t TestVolume::testPagedVolumeChunkAccess(uint16_t localityMask)
 {
 	std::mt19937 rng;
diff --git a/tests/testvolume.h b/tests/testvolume.h
index 617222df..e189cbc9 100644
--- a/tests/testvolume.h
+++ b/tests/testvolume.h
@@ -57,6 +57,8 @@ private slots:
 	void testPagedVolumeDirectAccessWithExternalBackwards();
 	void testPagedVolumeSamplersWithExternalBackwards();
 
+	void testPagedVolumeDirectRandomAccess();
+
 	void testPagedVolumeChunkLocalAccess();
 	void testPagedVolumeChunkRandomAccess();
 
@@ -72,6 +74,7 @@ private:
 
 	PolyVox::RawVolume<int32_t>* m_pRawVolume;
 	PolyVox::PagedVolume<int32_t>* m_pPagedVolume;
+	PolyVox::PagedVolume<int32_t>* m_pPagedVolumeHighMem;
 
 	PolyVox::PagedVolume<uint32_t>::Chunk* m_pPagedVolumeChunk;
 };