Add Photonlib (#231)

Merges Photonlib into Photonvision, along with the Photonlib code examples. Also creates a new PhotonTargeting library teams can depend on.

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

@@ -0,0 +1,100 @@
+/*
+ * Copyright (C) Photon Vision.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#pragma once
+
+#include <string>
+
+#include <frc/DriverStation.h>
+#include <units/time.h>
+#include <wpi/ArrayRef.h>
+#include <wpi/SmallVector.h>
+
+#include "photonlib/Packet.h"
+#include "photonlib/PhotonTrackedTarget.h"
+
+namespace photonlib {
+/**
+ * Represents a pipeline result from a PhotonCamera.
+ */
+class PhotonPipelineResult {
+ public:
+  /**
+   * Constructs an empty pipeline result.
+   */
+  PhotonPipelineResult() = default;
+
+  /**
+   * Constructs a pipeline result.
+   * @param latency The latency in the pipeline.
+   * @param targets The list of targets identified by the pipeline.
+   */
+  PhotonPipelineResult(units::second_t latency,
+                       wpi::ArrayRef<PhotonTrackedTarget> targets);
+
+  /**
+   * Returns the best target in this pipeline result. If there are no targets,
+   * this method will return an empty target with all values set to zero. The
+   * best target is determined by the target sort mode in the PhotonVision UI.
+   *
+   * @return The best target of the pipeline result.
+   */
+  PhotonTrackedTarget GetBestTarget() const {
+    if (!HasTargets() && !HAS_WARNED) {
+      ::frc::DriverStation::ReportError(
+          "This PhotonPipelineResult object has no targets associated with it! "
+          "Please check hasTargets() before calling this method. For more "
+          "information, please review the PhotonLib documentation at "
+          "http://docs.photonvision.org");
+      HAS_WARNED = true;
+    }
+    return hasTargets ? targets[0] : PhotonTrackedTarget();
+  }
+
+  /**
+   * Returns the latency in the pipeline.
+   * @return The latency in the pipeline.
+   */
+  units::second_t GetLatency() const { return latency; }
+
+  /**
+   * Returns whether the pipeline has targets.
+   * @return Whether the pipeline has targets.
+   */
+  bool HasTargets() const { return hasTargets; }
+
+  /**
+   * Returns a reference to the vector of targets.
+   * @return A reference to the vector of targets.
+   */
+  const wpi::ArrayRef<PhotonTrackedTarget> GetTargets() const {
+    return targets;
+  }
+
+  bool operator==(const PhotonPipelineResult& other) const;
+  bool operator!=(const PhotonPipelineResult& other) const;
+
+  friend Packet& operator<<(Packet& packet, const PhotonPipelineResult& result);
+  friend Packet& operator>>(Packet& packet, PhotonPipelineResult& result);
+
+ private:
+  units::second_t latency;
+  bool hasTargets;
+  wpi::SmallVector<PhotonTrackedTarget, 10> targets;
+  inline static bool HAS_WARNED = false;
+};
+}  // namespace photonlib