Update PhotonCamera error messages to be more specific (#697)

Closes #692

photon-core/src/main/java/org/photonvision/vision/pipe/impl/Draw3dTargetsPipe.java

@@ -114,7 +114,6 @@ public class Draw3dTargetsPipe
                     // Distort the points so they match the image they're being overlaid on
                     distortPoints(tempMat, tempMat);
                 }
-
                 var topPoints = tempMat.toList();
 
                 dividePointList(bottomPoints);

photon-lib/src/main/java/org/photonvision/PhotonCamera.java

@@ -31,18 +31,23 @@ import edu.wpi.first.networktables.DoubleArrayPublisher;
 import edu.wpi.first.networktables.DoublePublisher;
 import edu.wpi.first.networktables.IntegerEntry;
 import edu.wpi.first.networktables.IntegerSubscriber;
+import edu.wpi.first.networktables.MultiSubscriber;
 import edu.wpi.first.networktables.NetworkTable;
 import edu.wpi.first.networktables.NetworkTableInstance;
+import edu.wpi.first.networktables.PubSubOption;
 import edu.wpi.first.networktables.RawSubscriber;
 import edu.wpi.first.networktables.StringSubscriber;
 import edu.wpi.first.wpilibj.DriverStation;
 import edu.wpi.first.wpilibj.Timer;
+import java.util.Set;
 import org.photonvision.common.dataflow.structures.Packet;
 import org.photonvision.common.hardware.VisionLEDMode;
 import org.photonvision.targeting.PhotonPipelineResult;
 
 /** Represents a camera that is connected to PhotonVision. */
 public class PhotonCamera {
+    static final String kTableName = "photonvision";
+
     protected final NetworkTable rootTable;
     RawSubscriber rawBytesEntry;
     BooleanEntry driverModeEntry;
@@ -96,6 +101,8 @@ public class PhotonCamera {
 
     Packet packet = new Packet(1);
 
+    private final MultiSubscriber m_topicNameSubscriber;
+
     /**
      * Constructs a PhotonCamera from a root table.
      *
@@ -106,7 +113,7 @@ public class PhotonCamera {
      */
     public PhotonCamera(NetworkTableInstance instance, String cameraName) {
         name = cameraName;
-        var mainTable = instance.getTable("photonvision");
+        var mainTable = instance.getTable(kTableName);
         this.rootTable = mainTable.getSubTable(cameraName);
         path = rootTable.getPath();
         rawBytesEntry = rootTable.getRawTopic("rawBytes").subscribe("rawBytes", new byte[] {});
@@ -117,6 +124,12 @@ public class PhotonCamera {
         heartbeatEntry = rootTable.getIntegerTopic("heartbeat").subscribe(-1);
         ledModeEntry = mainTable.getIntegerTopic("ledMode").getEntry(-1);
         versionEntry = mainTable.getStringTopic("version").subscribe("");
+
+        m_topicNameSubscriber =
+                new MultiSubscriber(
+                        instance,
+                        new String[] {"/photonvision/"},
+                        new PubSubOption[] {PubSubOption.topicsOnly(true)});
     }
 
     /**
@@ -280,7 +293,7 @@ public class PhotonCamera {
             prevHeartbeatValue = curHeartbeat;
         }
 
-        return ((now - prevHeartbeatChangeTime) < HEARBEAT_DEBOUNCE_SEC);
+        return (now - prevHeartbeatChangeTime) < HEARBEAT_DEBOUNCE_SEC;
     }
 
     private void verifyVersion() {
@@ -292,12 +305,25 @@ public class PhotonCamera {
         // Heartbeat entry is assumed to always be present. If it's not present, we
         // assume that a camera with that name was never connected in the first place.
         if (!heartbeatEntry.exists()) {
-            DriverStation.reportError(
-                    "PhotonVision coprocessor at path " + path + " not found on NetworkTables!", true);
+            Set<String> cameraNames = rootTable.getInstance().getTable(kTableName).getSubTables();
+            if (cameraNames.isEmpty()) {
+                DriverStation.reportError(
+                        "Could not find any PhotonVision coprocessors on NetworkTables. Double check that PhotonVision is running, and that your camera is connected!",
+                        false);
+            } else {
+                DriverStation.reportError(
+                        "PhotonVision coprocessor at path "
+                                + path
+                                + " not found on NetworkTables. Double check that your camera names match!",
+                        true);
+                DriverStation.reportError(
+                        "Found the following PhotonVision cameras on NetworkTables:\n"
+                                + String.join("\n", cameraNames),
+                        false);
+            }
         }
-
         // Check for connection status. Warn if disconnected.
-        if (!isConnected()) {
+        else if (!isConnected()) {
             DriverStation.reportWarning(
                     "PhotonVision coprocessor at path " + path + " is not sending new data.", true);
         }

photon-lib/src/main/java/org/photonvision/SimPhotonCamera.java

@@ -48,7 +48,7 @@ public class SimPhotonCamera {
      */
     public SimPhotonCamera(NetworkTableInstance instance, String cameraName) {
         ts.removeEntries();
-        ts.subTable = instance.getTable("/photonvision").getSubTable(cameraName);
+        ts.subTable = instance.getTable(PhotonCamera.kTableName).getSubTable(cameraName);
         ts.updateEntries();
     }
 

photon-lib/src/main/native/cpp/photonlib/PhotonCamera.cpp

@@ -33,10 +33,11 @@
 namespace photonlib {
 
 constexpr const units::second_t VERSION_CHECK_INTERVAL = 5_s;
+static const std::vector<std::string_view> PHOTON_PREFIX = {"/photonvision/"};
 
-PhotonCamera::PhotonCamera(std::shared_ptr<nt::NetworkTableInstance> instance,
+PhotonCamera::PhotonCamera(nt::NetworkTableInstance instance,
                            const std::string_view cameraName)
-    : mainTable(instance->GetTable("photonvision")),
+    : mainTable(instance.GetTable("photonvision")),
       rootTable(mainTable->GetSubTable(cameraName)),
       rawBytesEntry(rootTable->GetRawTopic("rawBytes").Subscribe("raw", {})),
       driverModeEntry(rootTable->GetBooleanTopic("driverMode").Publish()),
@@ -56,13 +57,12 @@ PhotonCamera::PhotonCamera(std::shared_ptr<nt::NetworkTableInstance> instance,
       pipelineIndexSubscriber(
           rootTable->GetIntegerTopic("pipelineIndex").Subscribe(-1)),
       ledModeSubscriber(mainTable->GetIntegerTopic("ledMode").Subscribe(0)),
+      m_topicNameSubscriber(instance, PHOTON_PREFIX, {.topicsOnly = true}),
       path(rootTable->GetPath()),
       m_cameraName(cameraName) {}
 
 PhotonCamera::PhotonCamera(const std::string_view cameraName)
-    : PhotonCamera(std::make_shared<nt::NetworkTableInstance>(
-                       nt::NetworkTableInstance::GetDefault()),
-                   cameraName) {}
+    : PhotonCamera(nt::NetworkTableInstance::GetDefault(), cameraName) {}
 
 PhotonPipelineResult PhotonCamera::GetLatestResult() {
   if (test) return testResult;
@@ -134,10 +134,29 @@ void PhotonCamera::VerifyVersion() {
   const std::string& versionString = versionEntry.Get("");
   if (versionString.empty()) {
     std::string path_ = path;
-    FRC_ReportError(
-        frc::warn::Warning,
-        "PhotonVision coprocessor at path {} not found on NetworkTables!",
-        path_);
+    std::vector<std::string> cameraNames =
+        rootTable->GetInstance().GetTable("photonvision")->GetSubTables();
+    if (cameraNames.empty()) {
+      FRC_ReportError(frc::warn::Warning,
+                      "Could not find any PhotonVision coprocessors on "
+                      "NetworkTables. Double check that PhotonVision is "
+                      "running, and that your camera is connected!");
+    } else {
+      FRC_ReportError(
+          frc::warn::Warning,
+          "PhotonVision coprocessor at path {} not found on NetworkTables. "
+          "Double check that your camera names match!",
+          path_);
+
+      std::string cameraNameOutString;
+      for (unsigned int i = 0; i < cameraNames.size(); i++) {
+        cameraNameOutString += "\n" + cameraNames[i];
+      }
+      FRC_ReportError(
+          frc::warn::Warning,
+          "Found the following PhotonVision cameras on NetworkTables:{}",
+          cameraNameOutString);
+    }
   } else if (!VersionMatches(versionString)) {
     FRC_ReportError(frc::warn::Warning,
                     "Photon version {} does not match coprocessor version {}!",

photon-lib/src/main/native/include/photonlib/PhotonCamera.h

@@ -30,6 +30,7 @@
 #include <networktables/BooleanTopic.h>
 #include <networktables/DoubleTopic.h>
 #include <networktables/IntegerTopic.h>
+#include <networktables/MultiSubscriber.h>
 #include <networktables/NetworkTable.h>
 #include <networktables/NetworkTableInstance.h>
 #include <networktables/RawTopic.h>
@@ -57,7 +58,7 @@ class PhotonCamera {
    * @param cameraName The name of the camera, as seen in the UI.
    * over.
    */
-  explicit PhotonCamera(std::shared_ptr<nt::NetworkTableInstance> instance,
+  explicit PhotonCamera(nt::NetworkTableInstance instance,
                         const std::string_view cameraName);
 
   /**
@@ -178,6 +179,8 @@ class PhotonCamera {
   nt::IntegerSubscriber pipelineIndexSubscriber;
   nt::IntegerSubscriber ledModeSubscriber;
 
+  nt::MultiSubscriber m_topicNameSubscriber;
+
   std::string path;
   std::string m_cameraName;
 

photon-lib/src/main/native/include/photonlib/SimPhotonCamera.h

@@ -37,7 +37,7 @@
 namespace photonlib {
 class SimPhotonCamera : public PhotonCamera {
  public:
-  SimPhotonCamera(std::shared_ptr<nt::NetworkTableInstance> instance,
+  SimPhotonCamera(nt::NetworkTableInstance instance,
                   const std::string& cameraName)
       : PhotonCamera(instance, cameraName) {
     latencyMillisEntry = rootTable->GetEntry("latencyMillis");
@@ -48,14 +48,12 @@ class SimPhotonCamera : public PhotonCamera {
     targetSkewEntry = rootTable->GetEntry("targetSkewEntry");
     targetPoseEntry = rootTable->GetEntry("targetPoseEntry");
     rawBytesPublisher = rootTable->GetRawTopic("rawBytes").Publish("raw");
-    versionEntry = instance->GetTable("photonvision")->GetEntry("version");
+    versionEntry = instance.GetTable("photonvision")->GetEntry("version");
     // versionEntry.SetString(PhotonVersion.versionString);
   }
 
   explicit SimPhotonCamera(const std::string& cameraName)
-      : SimPhotonCamera(std::make_shared<nt::NetworkTableInstance>(
-                            nt::NetworkTableInstance::GetDefault()),
-                        cameraName) {}
+      : SimPhotonCamera(nt::NetworkTableInstance::GetDefault(), cameraName) {}
 
   virtual ~SimPhotonCamera() = default;