Add a tool for checking localizations

Allows us to put a non-field april tag on the field and see where the
robot thinks it is relative to the field origin.

Signed-off-by: milind-u <milind.upadhyay@gmail.com>
Change-Id: I194c2ca988500b5073f4f375d5e6a8f91be892bd
diff --git a/y2023/vision/localization_verifier.cc b/y2023/vision/localization_verifier.cc
new file mode 100644
index 0000000..7a5f792
--- /dev/null
+++ b/y2023/vision/localization_verifier.cc
@@ -0,0 +1,103 @@
+#include "aos/init.h"
+#include "frc971/constants/constants_sender_lib.h"
+#include "frc971/control_loops/drivetrain/localization/localizer_output_generated.h"
+#include "frc971/vision/vision_generated.h"
+#include "glog/logging.h"
+#include "y2023/localizer/localizer.h"
+
+DEFINE_string(config, "aos_config.json", "Path to the config file to use.");
+
+DEFINE_uint64(min_april_id, 1,
+              "Minimum april id to consider as part of the field and ignore");
+DEFINE_uint64(max_april_id, 8,
+              "Maximum april id to consider as part of the field and ignore");
+
+// This binary allows us to place extra april tags on the field and verify
+// that we can compute their field pose correctly
+
+namespace y2023::vision {
+
+using localizer::Localizer;
+
+Localizer::Transform LocalizerOutputToTransform(
+    const frc971::controls::LocalizerOutput &localizer) {
+  const auto T_field_robot =
+      Eigen::Translation3d(localizer.x(), localizer.y(), 0.0);
+
+  Eigen::AngleAxisd robot_yaw_angle(localizer.theta(),
+                                    Eigen::Vector3d::UnitZ());
+  const auto R_field_robot = Eigen::Quaterniond(robot_yaw_angle);
+  const Localizer::Transform H_field_robot =
+      (T_field_robot * R_field_robot).matrix();
+  return H_field_robot;
+}
+
+void HandleDetections(
+    const frc971::vision::TargetMap &detections,
+    const Localizer::Transform &H_robot_camera,
+    aos::Fetcher<frc971::controls::LocalizerOutput> *localizer_fetcher) {
+  localizer_fetcher->Fetch();
+  CHECK(localizer_fetcher->get());
+
+  for (const auto *target_pose : *detections.target_poses()) {
+    // Only look at april tags not part of the field
+    if (target_pose->id() >= FLAGS_min_april_id &&
+        target_pose->id() <= FLAGS_max_april_id) {
+      continue;
+    }
+
+    const Localizer::Transform H_camera_target =
+        localizer::PoseToTransform(target_pose);
+    const Localizer::Transform H_field_robot =
+        LocalizerOutputToTransform(*localizer_fetcher->get());
+
+    // Get the field-based target pose using the detection, extrinsics, and
+    // localizer output
+    const Localizer::Transform H_field_target =
+        H_field_robot * H_robot_camera * H_camera_target;
+
+    LOG(INFO) << "Field to target " << target_pose->id();
+    LOG(INFO) << "Transform: " << H_field_target;
+    LOG(INFO) << "Translation: "
+              << Eigen::Affine3d(H_field_target).translation();
+    LOG(INFO);
+  }
+}
+
+void LocalizationVerifierMain() {
+  aos::FlatbufferDetachedBuffer<aos::Configuration> config =
+      aos::configuration::ReadConfig(FLAGS_config);
+
+  frc971::constants::WaitForConstants<Constants>(&config.message());
+
+  aos::ShmEventLoop event_loop(&config.message());
+
+  frc971::constants::ConstantsFetcher<Constants> constants_fetcher(&event_loop);
+
+  aos::Fetcher<frc971::controls::LocalizerOutput> localizer_fetcher =
+      event_loop.MakeFetcher<frc971::controls::LocalizerOutput>("/localizer");
+
+  for (const auto *camera : *constants_fetcher.constants().cameras()) {
+    CHECK(camera->has_calibration());
+    Localizer::Transform H_robot_camera =
+        frc971::control_loops::drivetrain::FlatbufferToTransformationMatrix(
+            *camera->calibration()->fixed_extrinsics());
+
+    const std::string_view pi_name =
+        camera->calibration()->node_name()->string_view();
+    event_loop.MakeWatcher(absl::StrCat("/", pi_name, "/camera"),
+                           [&](const frc971::vision::TargetMap &target_map) {
+                             HandleDetections(target_map, H_robot_camera,
+                                              &localizer_fetcher);
+                           });
+
+    event_loop.Run();
+  }
+}
+
+}  // namespace y2023::vision
+
+int main(int argc, char **argv) {
+  aos::InitGoogle(&argc, &argv);
+  y2023::vision::LocalizationVerifierMain();
+}