Package frc.spectrumLib.vision

Class Limelight

java.lang.Object
frc.spectrumLib.vision.Limelight
public class Limelight extends Object
Provides a high-level interface to a single Limelight camera for AprilTag-based pose estimation and basic targeting.

All methods are safe to call when the camera is not attached (isAttached() returns false); they return zero / false / empty values in that case.

Two pose estimation flavors are supported:

  • MegaTag1 — full 3-D pose estimation using one or more AprilTags.
  • MegaTag2 — fused estimate that incorporates the robot heading supplied via setRobotOrientation(double).

  • Constructor Details

    • Limelight

      public Limelight(Limelight.LimelightConfig config)
      Constructs a Limelight wrapper from a fully populated Limelight.LimelightConfig.
      Parameters:
      config - the camera configuration

    • Limelight

      public Limelight(String name)
      Constructs a Limelight wrapper with a default configuration for the given camera name.
      Parameters:
      name - the network-table name of the camera

    • Limelight

      public Limelight(String name, boolean attached)
      Constructs a Limelight wrapper, explicitly setting whether the camera is attached.
      Parameters:
      name - the network-table name of the camera
      attached - true if the camera is physically present on the robot

    • Limelight

      public Limelight(String name, int pipeline)
      Constructs a Limelight wrapper and immediately sets its active pipeline.
      Parameters:
      name - the network-table name of the camera
      pipeline - the pipeline index to activate (refer to robot vision configuration for pipeline indexes)

    • Limelight

      public Limelight(String name, int pipeline, Limelight.LimelightConfig config)
      Constructs a Limelight wrapper with an explicit configuration and immediately sets its active pipeline.
      Parameters:
      name - the network-table name of the camera
      pipeline - the pipeline index to activate
      config - the fully populated Limelight.LimelightConfig to use

  • Method Details

    • getName

      public String getName()
      Returns the network-table name of this camera.
      Returns:
      the camera name as configured in the LL dashboard

    • isAttached

      public boolean isAttached()
      Returns whether this camera is physically connected to the robot.
      Returns:
      true if attached

    • getHorizontalOffset

      public double getHorizontalOffset()
      Get the horizontal offset from crosshair to target
      Returns:
      Horizontal Offset From Crosshair To Target (LL1: -27 degrees to 27 degrees / LL2: -29.8 to 29.8 degrees)

    • getVerticalOffset

      public double getVerticalOffset()
      Get the vertical offset from crosshair to target
      Returns:
      Vertical Offset From Crosshair To Target in degrees (LL1: -20.5 degrees to 20.5 degrees / LL2: -24.85 to 24.85 degrees)

    • targetInView

      public boolean targetInView()
      Returns whether the LL has any valid targets (April tags or other vision targets)
      Returns:
      Whether the LL has any valid targets (April tags or other vision targets)

    • multipleTagsInView

      public boolean multipleTagsInView()
      Checks if the LL sees multiple tags
      Returns:
      whether the LL sees multiple tags or not

    • getTagCountInView

      public double getTagCountInView()
      Returns the number of AprilTags included in the current MegaTag1 pose estimate.
      Returns:
      number of tags contributing to the current pose estimate, or 0 if not attached or no estimate is available

    • getClosestTagID

      public double getClosestTagID()
      Gets the ID of the apriltag most centered in the LL's view (or based on different
      Returns:
      the tag ID of the apriltag most centered in the LL's view (or based on different criteria set in LL dasbhoard)

    • getTargetSize

      public double getTargetSize()
      Returns the area of the primary target as a percentage of the camera image (0–100).
      Returns:
      target area percentage, or 0 if not attached

    • getMegaTag1_Pose3d

      public Pose3d getMegaTag1_Pose3d()
      Get the corresponding LL Pose3d (MEGATAG1) for the alliance in DriverStation.java
      Returns:
      the corresponding LL Pose3d (MEGATAG1) for the alliance in DriverStation.java

    • getMegaTag2_Pose2d

      public Pose2d getMegaTag2_Pose2d()
      Get the corresponding LL Pose2d (MEGATAG1) for the alliance in DriverStation.java
      Returns:
      the corresponding LL Pose3d (MEGATAG2) for the alliance in DriverStation.java

    • getMegaTag1_PoseEstimate

      public LimelightHelpers.PoseEstimate getMegaTag1_PoseEstimate()
      Returns the full MegaTag1 LimelightHelpers.PoseEstimate, including timestamp, tag count, and raw fiducials. Returns an empty estimate when not attached or when no estimate is available.
      Returns:
      the MegaTag1 pose estimate in the WPILib Blue origin frame

    • getMegaTag2_PoseEstimate

      public LimelightHelpers.PoseEstimate getMegaTag2_PoseEstimate()
      Returns the full MegaTag2 LimelightHelpers.PoseEstimate (heading-fused), including timestamp and tag count. Returns an empty estimate when not attached or when no estimate is available.
      Returns:
      the MegaTag2 pose estimate in the WPILib Blue origin frame

    • hasAccuratePose

      public boolean hasAccuratePose()
      Returns true when the pose estimate is considered accurate — i.e., multiple tags are visible and the combined target area exceeds a minimum threshold.
      Returns:
      true if the pose estimate meets the accuracy criteria

    • getDistanceToTagFromCamera

      public double getDistanceToTagFromCamera()
      Get the distance of the 2d vector from the camera to closest apriltag
      Returns:
      the distance of the 2d vector from the camera to closest apriltag

    • getRawFiducial

      public LimelightHelpers.RawFiducial[] getRawFiducial()
      Returns the raw fiducial data for all currently detected AprilTags.
      Returns:
      array of LimelightHelpers.RawFiducial entries from the MegaTag1 estimate; empty array if not attached or no estimate is available

    • getMegaTag1PoseTimestamp

      public double getMegaTag1PoseTimestamp()
      Returns the timestamp of the MEGATAG1 pose estimation from the Limelight camera.
      Returns:
      The timestamp of the pose estimation in seconds.

    • getMegaTag2PoseTimestamp

      public double getMegaTag2PoseTimestamp()
      Returns the timestamp of the MEGATAG2 pose estimation from the Limelight camera.
      Returns:
      The timestamp of the pose estimation in seconds.

    • getPoseLatency

      @Deprecated(forRemoval=true) public double getPoseLatency()
      Deprecated, for removal: This API element is subject to removal in a future version.
      Returns the latency of the pose estimation from the Limelight camera.
      Returns:
      The latency of the pose estimation in seconds.

    • getDistanceToTarget

      public double getDistanceToTarget(double targetHeight)
      get distance in meters to a target
      Parameters:
      targetHeight - meters
      Returns:
      distance in meters to a target

    • sendValidStatus

      public void sendValidStatus(String message)
      Marks this camera as actively integrating and updates the log status message.
      Parameters:
      message - a human-readable description of why integration is valid

    • sendInvalidStatus

      public void sendInvalidStatus(String message)
      Marks this camera as not integrating and updates the log status message.
      Parameters:
      message - a human-readable description of why integration is invalid

    • setLimelightPipeline

      public void setLimelightPipeline(int pipelineIndex)
      Sets the LL pipeline to the given index.
      Parameters:
      pipelineIndex - the pipeline index (refer to robot vision configuration for pipeline indexes)

    • setRobotOrientation

      public void setRobotOrientation(double degrees)
      Sets the robot orientation in degrees for the Limelight's internal IMU.

    • setRobotOrientation

      public void setRobotOrientation(double degrees, double angularRate)
      Sets the robot orientation and yaw rate for the Limelight's internal IMU fusion (MegaTag2).
      Parameters:
      degrees - robot heading in degrees (positive counter-clockwise)
      angularRate - current yaw rate in degrees per second

    • setIMUmode

      public void setIMUmode(int mode)
      Sets the IMU mode on the Limelight.
      Parameters:
      mode - the IMU mode index (refer to the LL documentation for valid values)

    • getTagTx

      public double getTagTx()
      Returns the X offset of the primary target in robot space (meters along the robot's left/right axis).
      Returns:
      target X translation in meters, or -99999 if not attached or no target in view

    • getTagTA

      public double getTagTA()
      Returns the area of the primary target as a percentage of the camera image.
      Returns:
      target area (0–100 %), or -99999 if not attached or no target in view

    • getTagRotationDegrees

      public double getTagRotationDegrees()
      Returns the Z-axis rotation of the primary target in robot space (yaw in radians, converted to degrees).
      Returns:
      target yaw rotation in degrees, or -99999 if not attached or no target in view

    • setLEDMode

      public void setLEDMode(boolean enabled)
      Sets the LED mode of the LL.
      Parameters:
      enabled - true to enable the LED mode, false to disable it

    • blinkLEDs

      public void blinkLEDs()
      Set LL LED's to blink

    • isCameraConnected

      public boolean isCameraConnected()
      Checks if the camera is connected by looking for an empty botpose array from camera.

    • printDebug

      public void printDebug()
      Prints the vision, estimated, and odometry pose to SmartDashboard

    • isIntegrating

      public boolean isIntegrating()
      Whether pose measurements from this camera are currently being integrated.

    • setIntegrating

      public void setIntegrating(boolean isIntegrating)
      Whether pose measurements from this camera are currently being integrated.

    • getCameraName

      public String getCameraName()
      Network-table name of this camera (mirrors Limelight.LimelightConfig.getName()).

    • getLogStatus

      public String getLogStatus()
      Human-readable string describing the current integration status, logged for diagnostics.

    • setLogStatus

      public void setLogStatus(String logStatus)
      Human-readable string describing the current integration status, logged for diagnostics.

    • getTagStatus

      public String getTagStatus()
      Human-readable string describing the currently visible tag(s), logged for diagnostics.

    • setTagStatus

      public void setTagStatus(String tagStatus)
      Human-readable string describing the currently visible tag(s), logged for diagnostics.