Adds a PLY writing points processor. (#80)

cartographer/io/CMakeLists.txt

@@ -21,6 +21,16 @@ google_library(io_null_points_processor
     io_points_processor
 )
 
+google_library(io_ply_writing_points_processor
+  USES_GLOG
+  SRCS
+    ply_writing_points_processor.cc
+  HDRS
+    ply_writing_points_processor.h
+  DEPENDS
+    io_points_processor
+)
+
 google_library(io_points_batch
   USES_EIGEN
   SRCS

cartographer/io/ply_writing_points_processor.cc

@@ -0,0 +1,112 @@
+/*
+ * Copyright 2016 The Cartographer Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "cartographer/io/ply_writing_points_processor.h"
+
+#include <iomanip>
+
+#include "glog/logging.h"
+
+namespace cartographer {
+namespace io {
+
+namespace {
+
+// Writes the PLY header claiming 'num_points' will follow it into
+// 'output_file'.
+void WriteBinaryPlyHeader(const bool has_color, const int64 num_points,
+                          std::ofstream* stream) {
+  string color_header = !has_color ? "" : "property uchar red\n"
+                                          "property uchar green\n"
+                                          "property uchar blue\n";
+
+  (*stream) << "ply\n"
+            << "format binary_little_endian 1.0\n"
+            << "comment generated by Cartographer\n"
+            << "element vertex " << std::setw(15) << std::setfill('0')
+            << num_points << "\n"
+            << "property float x\n"
+            << "property float y\n"
+            << "property float z\n"
+            << color_header << "end_header\n";
+}
+
+void WriteBinaryPlyPointCoordinate(const Eigen::Vector3f& point,
+                                   std::ofstream* stream) {
+  char buffer[12];
+  memcpy(buffer, &point[0], sizeof(float));
+  memcpy(buffer + 4, &point[1], sizeof(float));
+  memcpy(buffer + 8, &point[2], sizeof(float));
+  for (int i = 0; i < 12; ++i) {
+    stream->put(buffer[i]);
+  }
+}
+
+void WriteBinaryPlyPointColor(const Color& color, std::ostream* stream) {
+  stream->put(color[0]);
+  stream->put(color[1]);
+  stream->put(color[2]);
+}
+
+}  // namespace
+
+PlyWritingPointsProcessor::PlyWritingPointsProcessor(const string& filename,
+                                                     PointsProcessor* next)
+    : next_(next),
+      num_points_(0),
+      has_colors_(false),
+      file_(filename, std::ios_base::out | std::ios_base::binary) {}
+
+PointsProcessor::FlushResult PlyWritingPointsProcessor::Flush() {
+  file_.flush();
+  file_.seekp(0);
+
+  WriteBinaryPlyHeader(has_colors_, num_points_, &file_);
+  file_.flush();
+
+  switch (next_->Flush()) {
+    case FlushResult::kFinished:
+      return FlushResult::kFinished;
+
+    case FlushResult::kRestartStream:
+      LOG(FATAL) << "PLY generation must be configured to occur after any "
+                    "stages that require multiple passes.";
+  }
+  LOG(FATAL);
+}
+
+void PlyWritingPointsProcessor::Process(std::unique_ptr<PointsBatch> batch) {
+  if (batch->points.empty()) {
+    next_->Process(std::move(batch));
+    return;
+  }
+
+  if (num_points_ == 0) {
+    has_colors_ = !batch->colors.empty();
+    WriteBinaryPlyHeader(has_colors_, 0, &file_);
+  }
+  for (size_t i = 0; i < batch->points.size(); ++i) {
+    WriteBinaryPlyPointCoordinate(batch->points[i], &file_);
+    if (!batch->colors.empty()) {
+      WriteBinaryPlyPointColor(batch->colors[i], &file_);
+    }
+    ++num_points_;
+  }
+  next_->Process(std::move(batch));
+}
+
+}  // namespace io
+}  // namespace cartographer

cartographer/io/ply_writing_points_processor.h

@@ -0,0 +1,46 @@
+/*
+ * Copyright 2016 The Cartographer Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <fstream>
+
+#include "cartographer/io/points_processor.h"
+
+namespace cartographer {
+namespace io {
+
+// Streams a PLY file to disk. The header is written in 'Flush'.
+class PlyWritingPointsProcessor : public PointsProcessor {
+ public:
+  PlyWritingPointsProcessor(const string& filename, PointsProcessor* next);
+  ~PlyWritingPointsProcessor() override {}
+
+  PlyWritingPointsProcessor(const PlyWritingPointsProcessor&) = delete;
+  PlyWritingPointsProcessor& operator=(const PlyWritingPointsProcessor&) =
+      delete;
+
+  void Process(std::unique_ptr<PointsBatch> batch) override;
+  FlushResult Flush() override;
+
+ private:
+  PointsProcessor* const next_;
+
+  int64 num_points_;
+  bool has_colors_;
+  std::ofstream file_;
+};
+
+}  // namespace io
+}  // namespace cartographer

cartographer/io/xray_points_processor.cc

@@ -96,7 +96,7 @@ PointsProcessor::FlushResult XRayPointsProcessor::Flush() {
   switch (next_->Flush()) {
     case FlushResult::kRestartStream:
       LOG(FATAL) << "X-Ray generation must be configured to occur after any "
-                    "stages that require multiple passes";
+                    "stages that require multiple passes.";
 
     case FlushResult::kFinished:
       return FlushResult::kFinished;