Improve temporal merging performance (#141)

* Double capacity if is running out

* Format PCL point cloud on CPU

* After review

src/VArray.cpp

@@ -100,6 +100,13 @@ void VArray::reserve(std::size_t newCapacity, bool preserveData)
 	current().elemCapacity = newCapacity;
 }
 
+void VArray::doubleCapacityIfRunningOut(float runningOutThreshold)
+{
+	if (getElemCapacity() * runningOutThreshold < getElemCount()) {
+		reserve(getElemCapacity() * 2, true);
+	}
+}
+
 VArray::~VArray()
 {
 	for (auto&& [location, state] : instance) {

src/VArray.hpp

@@ -82,6 +82,7 @@ struct VArray : std::enable_shared_from_this<VArray>
 	void insertData(const void *src, std::size_t elements, std::size_t offset);
 	void resize(std::size_t newCount, bool zeroInit=true, bool preserveData=true);
 	void reserve(std::size_t newCapacity, bool preserveData=true);
+	void doubleCapacityIfRunningOut(float runningOutThreshold=0.9);
 	std::size_t getElemSize() const { return sizeOfType; }
 	std::size_t getElemCount() const { return current().elemCount; }
 	std::size_t getElemCapacity() const { return current().elemCapacity; }

src/api/apiPcl.cpp

@@ -42,16 +42,18 @@ rgl_graph_write_pcd_file(rgl_node_t node, const char* file_path)
 			throw InvalidAPIObject(fmt::format("Saving PCD file {} failed - requested node does not have field XYZ.", file_path));
 		}
 
-		// Get formatted data
-		VArray::Ptr rglCloud = VArray::create<char>();
-		// TODO(msz-rai): CudaStream for formatAsync: nullptr or pointCloudNode->getGraph()->getStream()?
-		FormatPointsNode::formatAsync(rglCloud, pointCloudNode, {XYZ_F32, PADDING_32}, nullptr);
+		// We are not using format node to avoid transferring huge point cloud to GPU (risk of cuda out of memory error)
+		// We are formatting manually on the CPU instead.
+		// TODO(msz-rai): CudaStream for getFieldDataTyped: nullptr or pointCloudNode->getGraph()->getStream()?
+		auto xyzTypedArray = pointCloudNode->getFieldDataTyped<XYZ_F32>(nullptr);
+		auto xyzData = xyzTypedArray->getReadPtr(MemLoc::Host);
 
 		// Convert to PCL cloud
 		pcl::PointCloud<pcl::PointXYZ> pclCloud;
-		const pcl::PointXYZ* data = reinterpret_cast<const pcl::PointXYZ*>(rglCloud->getReadPtr(MemLoc::Host));
 		pclCloud.resize(pointCloudNode->getWidth(), pointCloudNode->getHeight());
-		pclCloud.assign(data, data + pclCloud.size(), pointCloudNode->getWidth());
+		for (int i = 0; i < xyzTypedArray->getCount(); ++i) {
+			pclCloud[i] = pcl::PointXYZ(xyzData[i].x(), xyzData[i].y(), xyzData[i].z());
+		}
 		pclCloud.is_dense = pointCloudNode->isDense();
 
 		// Save to PCD file

src/graph/TemporalMergePointsNode.cpp

@@ -61,6 +61,8 @@ void TemporalMergePointsNode::schedule(cudaStream_t stream)
 		size_t pointCount = input->getPointCount();
 		const auto toMergeData = input->getFieldData(field, stream);
 		data->insertData(toMergeData->getReadPtr(MemLoc::Device), pointCount, width);
+		// Double capacity of VArray if is close to run out. It prevents reallocating memory every insertion.
+		data->doubleCapacityIfRunningOut();
 	}
 	width += input->getWidth();
 }