Create C++ Apriltag example (#794)

* Create C++ Apriltag example

* Delete libphotonlibcamera.so

* Update PhotonCameraWrapper.h

* Delete extra files

Update .gitignore

photonlib-cpp-examples/aimandrange/build.gradle

@@ -1,7 +1,7 @@
 plugins {
     id "cpp"
     id "google-test-test-suite"
-    id "edu.wpi.first.GradleRIO" version "2023.2.1"
+    id "edu.wpi.first.GradleRIO" version "2023.3.2"
 
     id "com.dorongold.task-tree" version "2.1.0"
 }

photonlib-cpp-examples/aimattarget/build.gradle

@@ -1,7 +1,7 @@
 plugins {
     id "cpp"
     id "google-test-test-suite"
-    id "edu.wpi.first.GradleRIO" version "2023.2.1"
+    id "edu.wpi.first.GradleRIO" version "2023.3.2"
 
     id "com.dorongold.task-tree" version "2.1.0"
 }

photonlib-cpp-examples/apriltagExample/.gitignore

@@ -0,0 +1 @@
+vendordeps

photonlib-cpp-examples/apriltagExample/WPILib-License.md

@@ -0,0 +1,24 @@
+Copyright (c) 2009-2021 FIRST and other WPILib contributors
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+   * Redistributions of source code must retain the above copyright
+     notice, this list of conditions and the following disclaimer.
+   * Redistributions in binary form must reproduce the above copyright
+     notice, this list of conditions and the following disclaimer in the
+     documentation and/or other materials provided with the distribution.
+   * Neither the name of FIRST, WPILib, nor the names of other WPILib
+     contributors may be used to endorse or promote products derived from
+     this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY FIRST AND OTHER WPILIB CONTRIBUTORS "AS IS" AND
+ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+WARRANTIES OF MERCHANTABILITY NONINFRINGEMENT AND FITNESS FOR A PARTICULAR
+PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL FIRST OR CONTRIBUTORS BE LIABLE FOR
+ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

photonlib-cpp-examples/apriltagExample/build.gradle

@@ -0,0 +1,116 @@
+plugins {
+    id "cpp"
+    id "google-test-test-suite"
+    id "edu.wpi.first.GradleRIO" version "2023.3.2"
+
+    id "com.dorongold.task-tree" version "2.1.0"
+}
+
+repositories {
+    mavenLocal()
+    jcenter()
+}
+
+apply from: "${rootDir}/../shared/examples_common.gradle"
+
+// Define my targets (RoboRIO) and artifacts (deployable files)
+// This is added by GradleRIO's backing project DeployUtils.
+deploy {
+    targets {
+        roborio(getTargetTypeClass('RoboRIO')) {
+            // Team number is loaded either from the .wpilib/wpilib_preferences.json
+            // or from command line. If not found an exception will be thrown.
+            // You can use getTeamOrDefault(team) instead of getTeamNumber if you
+            // want to store a team number in this file.
+            team = project.frc.getTeamOrDefault(5940)
+            debug = project.frc.getDebugOrDefault(false)
+
+            artifacts {
+                // First part is artifact name, 2nd is artifact type
+                // getTargetTypeClass is a shortcut to get the class type using a string
+
+                frcCpp(getArtifactTypeClass('FRCNativeArtifact')) {
+                }
+
+                // Static files artifact
+                frcStaticFileDeploy(getArtifactTypeClass('FileTreeArtifact')) {
+                    files = project.fileTree('src/main/deploy')
+                    directory = '/home/lvuser/deploy'
+                }
+            }
+        }
+    }
+}
+
+def deployArtifact = deploy.targets.roborio.artifacts.frcCpp
+
+// Set this to true to enable desktop support.
+def includeDesktopSupport = true
+
+// Set to true to run simulation in debug mode
+wpi.cpp.debugSimulation = false
+
+// Default enable simgui
+wpi.sim.addGui().defaultEnabled = true
+// Enable DS but not by default
+wpi.sim.addDriverstation()
+
+model {
+    components {
+        frcUserProgram(NativeExecutableSpec) {
+            // We don't need to build for roborio -- if we do, we need to install
+            // a roborio toolchain every time we build in CI
+            // Ideally, we'd be able to set the roborio toolchain as optional, but
+            // I can't figure out how to set that environment variable from build.gradle
+            // (see https://github.com/wpilibsuite/native-utils/blob/2917c69fb5094e36d499c465f047dab81c68446c/ToolchainPlugin/src/main/java/edu/wpi/first/toolchain/ToolchainGraphBuildService.java#L71)
+            // for now, commented out
+
+            // targetPlatform wpi.platforms.roborio
+
+            if (includeDesktopSupport) {
+                targetPlatform wpi.platforms.desktop
+            }
+
+            sources.cpp {
+                source {
+                    srcDir 'src/main/cpp'
+                    include '**/*.cpp', '**/*.cc'
+                }
+                exportedHeaders {
+                    srcDir 'src/main/include'
+                }
+            }
+
+            // Set deploy task to deploy this component
+            deployArtifact.component = it
+
+            // Enable run tasks for this component
+            wpi.cpp.enableExternalTasks(it)
+
+            // Enable simulation for this component
+            wpi.sim.enable(it)
+            // Defining my dependencies. In this case, WPILib (+ friends), and vendor libraries.
+            wpi.cpp.vendor.cpp(it)
+            wpi.cpp.deps.wpilib(it)
+        }
+    }
+    testSuites {
+        frcUserProgramTest(GoogleTestTestSuiteSpec) {
+            testing $.components.frcUserProgram
+
+            sources.cpp {
+                source {
+                    srcDir 'src/test/cpp'
+                    include '**/*.cpp'
+                }
+            }
+
+            // Enable run tasks for this component
+            wpi.cpp.enableExternalTasks(it)
+
+            wpi.cpp.vendor.cpp(it)
+            wpi.cpp.deps.wpilib(it)
+            wpi.cpp.deps.googleTest(it)
+        }
+    }
+}

photonlib-cpp-examples/apriltagExample/gradlew

@@ -0,0 +1,240 @@
+#!/bin/sh
+
+#
+# Copyright © 2015-2021 the original 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
+#
+#      https://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.
+#
+
+##############################################################################
+#
+#   Gradle start up script for POSIX generated by Gradle.
+#
+#   Important for running:
+#
+#   (1) You need a POSIX-compliant shell to run this script. If your /bin/sh is
+#       noncompliant, but you have some other compliant shell such as ksh or
+#       bash, then to run this script, type that shell name before the whole
+#       command line, like:
+#
+#           ksh Gradle
+#
+#       Busybox and similar reduced shells will NOT work, because this script
+#       requires all of these POSIX shell features:
+#         * functions;
+#         * expansions «$var», «${var}», «${var:-default}», «${var+SET}»,
+#           «${var#prefix}», «${var%suffix}», and «$( cmd )»;
+#         * compound commands having a testable exit status, especially «case»;
+#         * various built-in commands including «command», «set», and «ulimit».
+#
+#   Important for patching:
+#
+#   (2) This script targets any POSIX shell, so it avoids extensions provided
+#       by Bash, Ksh, etc; in particular arrays are avoided.
+#
+#       The "traditional" practice of packing multiple parameters into a
+#       space-separated string is a well documented source of bugs and security
+#       problems, so this is (mostly) avoided, by progressively accumulating
+#       options in "$@", and eventually passing that to Java.
+#
+#       Where the inherited environment variables (DEFAULT_JVM_OPTS, JAVA_OPTS,
+#       and GRADLE_OPTS) rely on word-splitting, this is performed explicitly;
+#       see the in-line comments for details.
+#
+#       There are tweaks for specific operating systems such as AIX, CygWin,
+#       Darwin, MinGW, and NonStop.
+#
+#   (3) This script is generated from the Groovy template
+#       https://github.com/gradle/gradle/blob/master/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
+#       within the Gradle project.
+#
+#       You can find Gradle at https://github.com/gradle/gradle/.
+#
+##############################################################################
+
+# Attempt to set APP_HOME
+
+# Resolve links: $0 may be a link
+app_path=$0
+
+# Need this for daisy-chained symlinks.
+while
+    APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
+    [ -h "$app_path" ]
+do
+    ls=$( ls -ld "$app_path" )
+    link=${ls#*' -> '}
+    case $link in             #(
+      /*)   app_path=$link ;; #(
+      *)    app_path=$APP_HOME$link ;;
+    esac
+done
+
+APP_HOME=$( cd "${APP_HOME:-./}" && pwd -P ) || exit
+
+APP_NAME="Gradle"
+APP_BASE_NAME=${0##*/}
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
+
+# Use the maximum available, or set MAX_FD != -1 to use that value.
+MAX_FD=maximum
+
+warn () {
+    echo "$*"
+} >&2
+
+die () {
+    echo
+    echo "$*"
+    echo
+    exit 1
+} >&2
+
+# OS specific support (must be 'true' or 'false').
+cygwin=false
+msys=false
+darwin=false
+nonstop=false
+case "$( uname )" in                #(
+  CYGWIN* )         cygwin=true  ;; #(
+  Darwin* )         darwin=true  ;; #(
+  MSYS* | MINGW* )  msys=true    ;; #(
+  NONSTOP* )        nonstop=true ;;
+esac
+
+CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
+
+
+# Determine the Java command to use to start the JVM.
+if [ -n "$JAVA_HOME" ] ; then
+    if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
+        # IBM's JDK on AIX uses strange locations for the executables
+        JAVACMD=$JAVA_HOME/jre/sh/java
+    else
+        JAVACMD=$JAVA_HOME/bin/java
+    fi
+    if [ ! -x "$JAVACMD" ] ; then
+        die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+    fi
+else
+    JAVACMD=java
+    which java >/dev/null 2>&1 || die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+fi
+
+# Increase the maximum file descriptors if we can.
+if ! "$cygwin" && ! "$darwin" && ! "$nonstop" ; then
+    case $MAX_FD in #(
+      max*)
+        MAX_FD=$( ulimit -H -n ) ||
+            warn "Could not query maximum file descriptor limit"
+    esac
+    case $MAX_FD in  #(
+      '' | soft) :;; #(
+      *)
+        ulimit -n "$MAX_FD" ||
+            warn "Could not set maximum file descriptor limit to $MAX_FD"
+    esac
+fi
+
+# Collect all arguments for the java command, stacking in reverse order:
+#   * args from the command line
+#   * the main class name
+#   * -classpath
+#   * -D...appname settings
+#   * --module-path (only if needed)
+#   * DEFAULT_JVM_OPTS, JAVA_OPTS, and GRADLE_OPTS environment variables.
+
+# For Cygwin or MSYS, switch paths to Windows format before running java
+if "$cygwin" || "$msys" ; then
+    APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
+    CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
+
+    JAVACMD=$( cygpath --unix "$JAVACMD" )
+
+    # Now convert the arguments - kludge to limit ourselves to /bin/sh
+    for arg do
+        if
+            case $arg in                                #(
+              -*)   false ;;                            # don't mess with options #(
+              /?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
+                    [ -e "$t" ] ;;                      #(
+              *)    false ;;
+            esac
+        then
+            arg=$( cygpath --path --ignore --mixed "$arg" )
+        fi
+        # Roll the args list around exactly as many times as the number of
+        # args, so each arg winds up back in the position where it started, but
+        # possibly modified.
+        #
+        # NB: a `for` loop captures its iteration list before it begins, so
+        # changing the positional parameters here affects neither the number of
+        # iterations, nor the values presented in `arg`.
+        shift                   # remove old arg
+        set -- "$@" "$arg"      # push replacement arg
+    done
+fi
+
+# Collect all arguments for the java command;
+#   * $DEFAULT_JVM_OPTS, $JAVA_OPTS, and $GRADLE_OPTS can contain fragments of
+#     shell script including quotes and variable substitutions, so put them in
+#     double quotes to make sure that they get re-expanded; and
+#   * put everything else in single quotes, so that it's not re-expanded.
+
+set -- \
+        "-Dorg.gradle.appname=$APP_BASE_NAME" \
+        -classpath "$CLASSPATH" \
+        org.gradle.wrapper.GradleWrapperMain \
+        "$@"
+
+# Stop when "xargs" is not available.
+if ! command -v xargs >/dev/null 2>&1
+then
+    die "xargs is not available"
+fi
+
+# Use "xargs" to parse quoted args.
+#
+# With -n1 it outputs one arg per line, with the quotes and backslashes removed.
+#
+# In Bash we could simply go:
+#
+#   readarray ARGS < <( xargs -n1 <<<"$var" ) &&
+#   set -- "${ARGS[@]}" "$@"
+#
+# but POSIX shell has neither arrays nor command substitution, so instead we
+# post-process each arg (as a line of input to sed) to backslash-escape any
+# character that might be a shell metacharacter, then use eval to reverse
+# that process (while maintaining the separation between arguments), and wrap
+# the whole thing up as a single "set" statement.
+#
+# This will of course break if any of these variables contains a newline or
+# an unmatched quote.
+#
+
+eval "set -- $(
+        printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
+        xargs -n1 |
+        sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
+        tr '\n' ' '
+    )" '"$@"'
+
+exec "$JAVACMD" "$@"

photonlib-cpp-examples/apriltagExample/gradlew.bat

@@ -0,0 +1,91 @@
+@rem
+@rem Copyright 2015 the original author or authors.
+@rem
+@rem Licensed under the Apache License, Version 2.0 (the "License");
+@rem you may not use this file except in compliance with the License.
+@rem You may obtain a copy of the License at
+@rem
+@rem      https://www.apache.org/licenses/LICENSE-2.0
+@rem
+@rem Unless required by applicable law or agreed to in writing, software
+@rem distributed under the License is distributed on an "AS IS" BASIS,
+@rem WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+@rem See the License for the specific language governing permissions and
+@rem limitations under the License.
+@rem
+
+@if "%DEBUG%"=="" @echo off
+@rem ##########################################################################
+@rem
+@rem  Gradle startup script for Windows
+@rem
+@rem ##########################################################################
+
+@rem Set local scope for the variables with windows NT shell
+if "%OS%"=="Windows_NT" setlocal
+
+set DIRNAME=%~dp0
+if "%DIRNAME%"=="" set DIRNAME=.
+set APP_BASE_NAME=%~n0
+set APP_HOME=%DIRNAME%
+
+@rem Resolve any "." and ".." in APP_HOME to make it shorter.
+for %%i in ("%APP_HOME%") do set APP_HOME=%%~fi
+
+@rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+set DEFAULT_JVM_OPTS="-Xmx64m" "-Xms64m"
+
+@rem Find java.exe
+if defined JAVA_HOME goto findJavaFromJavaHome
+
+set JAVA_EXE=java.exe
+%JAVA_EXE% -version >NUL 2>&1
+if %ERRORLEVEL% equ 0 goto execute
+
+echo.
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+echo.
+echo Please set the JAVA_HOME variable in your environment to match the
+echo location of your Java installation.
+
+goto fail
+
+:findJavaFromJavaHome
+set JAVA_HOME=%JAVA_HOME:"=%
+set JAVA_EXE=%JAVA_HOME%/bin/java.exe
+
+if exist "%JAVA_EXE%" goto execute
+
+echo.
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
+echo.
+echo Please set the JAVA_HOME variable in your environment to match the
+echo location of your Java installation.
+
+goto fail
+
+:execute
+@rem Setup the command line
+
+set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
+
+
+@rem Execute Gradle
+"%JAVA_EXE%" %DEFAULT_JVM_OPTS% %JAVA_OPTS% %GRADLE_OPTS% "-Dorg.gradle.appname=%APP_BASE_NAME%" -classpath "%CLASSPATH%" org.gradle.wrapper.GradleWrapperMain %*
+
+:end
+@rem End local scope for the variables with windows NT shell
+if %ERRORLEVEL% equ 0 goto mainEnd
+
+:fail
+rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
+rem the _cmd.exe /c_ return code!
+set EXIT_CODE=%ERRORLEVEL%
+if %EXIT_CODE% equ 0 set EXIT_CODE=1
+if not ""=="%GRADLE_EXIT_CONSOLE%" exit %EXIT_CODE%
+exit /b %EXIT_CODE%
+
+:mainEnd
+if "%OS%"=="Windows_NT" endlocal
+
+:omega

photonlib-cpp-examples/apriltagExample/settings.gradle

@@ -0,0 +1,30 @@
+import org.gradle.internal.os.OperatingSystem
+
+rootProject.name = 'aimattarget'
+
+pluginManagement {
+    repositories {
+        mavenLocal()
+        jcenter()
+        gradlePluginPortal()
+        String frcYear = '2023'
+        File frcHome
+        if (OperatingSystem.current().isWindows()) {
+            String publicFolder = System.getenv('PUBLIC')
+            if (publicFolder == null) {
+                publicFolder = "C:\\Users\\Public"
+            }
+            def homeRoot = new File(publicFolder, "wpilib")
+            frcHome = new File(homeRoot, frcYear)
+        } else {
+            def userFolder = System.getProperty("user.home")
+            def homeRoot = new File(userFolder, "wpilib")
+            frcHome = new File(homeRoot, frcYear)
+        }
+        def frcHomeMaven = new File(frcHome, 'maven')
+        maven {
+            name 'frcHome'
+            url frcHomeMaven
+        }
+    }
+}

photonlib-cpp-examples/apriltagExample/simgui-ds.json

@@ -0,0 +1,102 @@
+{
+  "Keyboard 0 Settings": {
+    "window": {
+      "visible": true
+    }
+  },
+  "keyboardJoysticks": [
+    {
+      "axisConfig": [
+        {},
+        {
+          "decKey": 87,
+          "incKey": 83
+        },
+        {
+          "decayRate": 0.0,
+          "keyRate": 0.009999999776482582
+        },
+        {},
+        {
+          "decKey": 65,
+          "incKey": 68
+        }
+      ],
+      "axisCount": 6,
+      "buttonCount": 4,
+      "buttonKeys": [
+        90,
+        88,
+        67,
+        86
+      ],
+      "povConfig": [
+        {
+          "key0": 328,
+          "key135": 323,
+          "key180": 322,
+          "key225": 321,
+          "key270": 324,
+          "key315": 327,
+          "key45": 329,
+          "key90": 326
+        }
+      ],
+      "povCount": 1
+    },
+    {
+      "axisConfig": [
+        {
+          "decKey": 74,
+          "incKey": 76
+        },
+        {
+          "decKey": 73,
+          "incKey": 75
+        }
+      ],
+      "axisCount": 2,
+      "buttonCount": 4,
+      "buttonKeys": [
+        77,
+        44,
+        46,
+        47
+      ],
+      "povCount": 0
+    },
+    {
+      "axisConfig": [
+        {
+          "decKey": 263,
+          "incKey": 262
+        },
+        {
+          "decKey": 265,
+          "incKey": 264
+        }
+      ],
+      "axisCount": 2,
+      "buttonCount": 6,
+      "buttonKeys": [
+        260,
+        268,
+        266,
+        261,
+        269,
+        267
+      ],
+      "povCount": 0
+    },
+    {
+      "axisCount": 0,
+      "buttonCount": 0,
+      "povCount": 0
+    }
+  ],
+  "robotJoysticks": [
+    {
+      "guid": "Keyboard0"
+    }
+  ]
+}

photonlib-cpp-examples/apriltagExample/src/main/cpp/Drivetrain.cpp

@@ -0,0 +1,92 @@
+/*
+ * MIT License
+ *
+ * Copyright (c) 2022 PhotonVision
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+#include "Drivetrain.h"
+
+#include <frc/RobotController.h>
+#include <frc/smartdashboard/Field2d.h>
+
+void Drivetrain::SetSpeeds(const frc::DifferentialDriveWheelSpeeds& speeds) {
+  auto leftFeedforward = m_feedforward.Calculate(speeds.left);
+  auto rightFeedforward = m_feedforward.Calculate(speeds.right);
+  double leftOutput = m_leftPIDController.Calculate(m_leftEncoder.GetRate(),
+                                                    speeds.left.value());
+  double rightOutput = m_rightPIDController.Calculate(m_rightEncoder.GetRate(),
+                                                      speeds.right.value());
+
+  m_leftGroup.SetVoltage(units::volt_t{leftOutput} + leftFeedforward);
+  m_rightGroup.SetVoltage(units::volt_t{rightOutput} + rightFeedforward);
+}
+
+void Drivetrain::Drive(units::meters_per_second_t xSpeed,
+                       units::radians_per_second_t rot) {
+  SetSpeeds(m_kinematics.ToWheelSpeeds({xSpeed, 0_mps, rot}));
+}
+
+void Drivetrain::UpdateOdometry() {
+  m_poseEstimator.Update(m_gyro.GetRotation2d(),
+                         units::meter_t{m_leftEncoder.GetDistance()},
+                         units::meter_t{m_rightEncoder.GetDistance()});
+}
+
+void Drivetrain::ResetOdometry(const frc::Pose2d& pose) {
+  m_leftEncoder.Reset();
+  m_rightEncoder.Reset();
+  m_drivetrainSimulator.SetPose(pose);
+  m_poseEstimator.ResetPosition(
+      m_gyro.GetRotation2d(), units::meter_t{m_leftEncoder.GetDistance()},
+      units::meter_t{m_rightEncoder.GetDistance()}, pose);
+}
+
+void Drivetrain::SimulationPeriodic() {
+  // To update our simulation, we set motor voltage inputs, update the
+  // simulation, and write the simulated positions and velocities to our
+  // simulated encoder and gyro. We negate the right side so that positive
+  // voltages make the right side move forward.
+
+  m_drivetrainSimulator.SetInputs(units::volt_t{m_leftGroup.Get()} *
+                                      frc::RobotController::GetInputVoltage(),
+                                  units::volt_t{m_rightGroup.Get()} *
+                                      frc::RobotController::GetInputVoltage());
+  m_drivetrainSimulator.Update(20_ms);
+
+  m_leftEncoderSim.SetDistance(m_drivetrainSimulator.GetLeftPosition().value());
+  m_leftEncoderSim.SetRate(m_drivetrainSimulator.GetLeftVelocity().value());
+  m_rightEncoderSim.SetDistance(
+      m_drivetrainSimulator.GetRightPosition().value());
+  m_rightEncoderSim.SetRate(m_drivetrainSimulator.GetRightVelocity().value());
+  m_gyroSim.SetAngle(-m_drivetrainSimulator.GetHeading().Degrees().value());
+}
+
+void Drivetrain::Periodic() {
+  UpdateOdometry();
+
+  auto result = m_pcw.Update(m_poseEstimator.GetEstimatedPosition());
+  if (result) {
+    m_poseEstimator.AddVisionMeasurement(
+        result.value().estimatedPose.ToPose2d(), result.value().timestamp);
+  }
+
+  m_fieldSim.SetRobotPose(m_poseEstimator.GetEstimatedPosition());
+}

photonlib-cpp-examples/apriltagExample/src/main/cpp/Robot.cpp

@@ -0,0 +1,61 @@
+/*
+ * MIT License
+ *
+ * Copyright (c) 2022 PhotonVision
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+#include "Robot.h"
+
+#include <frc/RobotBase.h>
+#include <networktables/NetworkTable.h>
+
+void Robot::RobotInit() {
+  if constexpr (frc::RobotBase::IsSimulation()) {
+    auto inst = nt::NetworkTableInstance::GetDefault();
+    inst.StopServer();
+    // set the NT server if simulating this code.
+    // "localhost" for photon on desktop, or "photonvision.local" or
+    // "[ip-address]" for coprocessor
+    inst.SetServer("localhost");
+    inst.StartClient4("Robot Simulation");
+  }
+}
+
+void Robot::TeleopPeriodic() {
+  // Get the x speed. We are inverting this because Xbox controllers return
+  // negative values when we push forward.
+  const auto xSpeed = -m_controller.GetLeftY() * Drivetrain::kMaxSpeed;
+
+  // Get the rate of angular rotation. We are inverting this because we want a
+  // positive value when we pull to the left (remember, CCW is positive in
+  // mathematics). Xbox controllers return positive values when you pull to
+  // the right by default.
+  auto rot = -m_controller.GetRightX() * Drivetrain::kMaxAngularSpeed;
+
+  m_drive.Drive(xSpeed, rot);
+}
+
+void Robot::RobotPeriodic() { m_drive.Periodic(); }
+void Robot::SimulationPeriodic() { m_drive.SimulationPeriodic(); }
+
+#ifndef RUNNING_FRC_TESTS
+int main() { return frc::StartRobot<Robot>(); }
+#endif

photonlib-cpp-examples/apriltagExample/src/main/include/Drivetrain.h

@@ -0,0 +1,140 @@
+/*
+ * MIT License
+ *
+ * Copyright (c) 2022 PhotonVision
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+#pragma once
+
+#include <numbers>
+
+#include <frc/AnalogGyro.h>
+#include <frc/Encoder.h>
+#include <frc/controller/PIDController.h>
+#include <frc/controller/SimpleMotorFeedforward.h>
+#include <frc/estimator/DifferentialDrivePoseEstimator.h>
+#include <frc/kinematics/DifferentialDriveKinematics.h>
+#include <frc/kinematics/DifferentialDriveOdometry.h>
+#include <frc/motorcontrol/MotorControllerGroup.h>
+#include <frc/motorcontrol/PWMSparkMax.h>
+#include <frc/simulation/AnalogGyroSim.h>
+#include <frc/simulation/DifferentialDrivetrainSim.h>
+#include <frc/simulation/EncoderSim.h>
+#include <frc/smartdashboard/Field2d.h>
+#include <frc/smartdashboard/SmartDashboard.h>
+#include <frc/system/plant/LinearSystemId.h>
+#include <units/angle.h>
+#include <units/angular_velocity.h>
+#include <units/length.h>
+#include <units/velocity.h>
+
+#include "PhotonCameraWrapper.h"
+
+/**
+ * Represents a differential drive style drivetrain.
+ */
+class Drivetrain {
+ public:
+  Drivetrain() {
+    m_gyro.Reset();
+
+    // We need to invert one side of the drivetrain so that positive voltages
+    // result in both sides moving forward. Depending on how your robot's
+    // gearbox is constructed, you might have to invert the left side instead.
+    m_rightGroup.SetInverted(true);
+
+    // Set the distance per pulse for the drive encoders. We can simply use the
+    // distance traveled for one rotation of the wheel divided by the encoder
+    // resolution.
+    m_leftEncoder.SetDistancePerPulse(2 * std::numbers::pi * kWheelRadius /
+                                      kEncoderResolution);
+    m_rightEncoder.SetDistancePerPulse(2 * std::numbers::pi * kWheelRadius /
+                                       kEncoderResolution);
+
+    m_leftEncoder.Reset();
+    m_rightEncoder.Reset();
+
+    m_rightGroup.SetInverted(true);
+
+    frc::SmartDashboard::PutData("Field", &m_fieldSim);
+  }
+
+  static constexpr units::meters_per_second_t kMaxSpeed =
+      3.0_mps;  // 3 meters per second
+  static constexpr units::radians_per_second_t kMaxAngularSpeed{
+      std::numbers::pi};  // 1/2 rotation per second
+
+  void SetSpeeds(const frc::DifferentialDriveWheelSpeeds& speeds);
+  void Drive(units::meters_per_second_t xSpeed,
+             units::radians_per_second_t rot);
+  void UpdateOdometry();
+  void ResetOdometry(const frc::Pose2d& pose);
+
+  frc::Pose2d GetPose() const { return m_poseEstimator.GetEstimatedPosition(); }
+
+  void SimulationPeriodic();
+  void Periodic();
+
+ private:
+  static constexpr units::meter_t kTrackWidth = 0.381_m * 2;
+  static constexpr double kWheelRadius = 0.0508;  // meters
+  static constexpr int kEncoderResolution = 4096;
+
+  frc::PWMSparkMax m_leftLeader{1};
+  frc::PWMSparkMax m_leftFollower{2};
+  frc::PWMSparkMax m_rightLeader{3};
+  frc::PWMSparkMax m_rightFollower{4};
+
+  frc::MotorControllerGroup m_leftGroup{m_leftLeader, m_leftFollower};
+  frc::MotorControllerGroup m_rightGroup{m_rightLeader, m_rightFollower};
+
+  frc::Encoder m_leftEncoder{0, 1};
+  frc::Encoder m_rightEncoder{2, 3};
+
+  frc2::PIDController m_leftPIDController{8.5, 0.0, 0.0};
+  frc2::PIDController m_rightPIDController{8.5, 0.0, 0.0};
+
+  frc::AnalogGyro m_gyro{0};
+
+  frc::DifferentialDriveKinematics m_kinematics{kTrackWidth};
+
+  frc::DifferentialDrivePoseEstimator m_poseEstimator{
+      m_kinematics, m_gyro.GetRotation2d(),
+      units::meter_t{m_leftEncoder.GetDistance()},
+      units::meter_t{m_rightEncoder.GetDistance()}, frc::Pose2d{}};
+
+  PhotonCameraWrapper m_pcw;
+
+  // Gains are for example purposes only - must be determined for your own
+  // robot!
+  frc::SimpleMotorFeedforward<units::meters> m_feedforward{1_V, 3_V / 1_mps};
+
+  // Simulation classes help us simulate our robot
+  frc::sim::AnalogGyroSim m_gyroSim{m_gyro};
+  frc::sim::EncoderSim m_leftEncoderSim{m_leftEncoder};
+  frc::sim::EncoderSim m_rightEncoderSim{m_rightEncoder};
+  frc::Field2d m_fieldSim;
+  frc::LinearSystem<2, 2, 2> m_drivetrainSystem =
+      frc::LinearSystemId::IdentifyDrivetrainSystem(
+          1.98_V / 1_mps, 0.2_V / 1_mps_sq, 1.5_V / 1_mps, 0.3_V / 1_mps_sq);
+  frc::sim::DifferentialDrivetrainSim m_drivetrainSimulator{
+      m_drivetrainSystem, kTrackWidth, frc::DCMotor::CIM(2), 8, 2_in};
+};

photonlib-cpp-examples/apriltagExample/src/main/include/PhotonCameraWrapper.h

@@ -0,0 +1,46 @@
+/*
+ * MIT License
+ *
+ * Copyright (c) 2022 PhotonVision
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+#pragma once
+#include <photonlib/PhotonCamera.h>
+#include <photonlib/PhotonPoseEstimator.h>
+
+#include <utility>
+
+#include <frc/apriltag/AprilTagFieldLayout.h>
+#include <frc/apriltag/AprilTagFields.h>
+
+class PhotonCameraWrapper {
+ public:
+  photonlib::PhotonPoseEstimator m_poseEstimator{
+      frc::LoadAprilTagLayoutField(frc::AprilTagField::k2023ChargedUp),
+      photonlib::LOWEST_AMBIGUITY,
+      std::move(photonlib::PhotonCamera{"WPI2023"}), frc::Transform3d{}};
+
+  inline std::optional<photonlib::EstimatedRobotPose> Update(
+      frc::Pose2d estimatedPose) {
+    m_poseEstimator.SetReferencePose(frc::Pose3d(estimatedPose));
+    return m_poseEstimator.Update();
+  }
+};

photonlib-cpp-examples/apriltagExample/src/main/include/Robot.h

@@ -0,0 +1,50 @@
+/*
+ * MIT License
+ *
+ * Copyright (c) 2022 PhotonVision
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+#pragma once
+
+#include <photonlib/PhotonCamera.h>
+
+#include <frc/TimedRobot.h>
+#include <frc/XboxController.h>
+#include <frc/controller/PIDController.h>
+#include <frc/drive/DifferentialDrive.h>
+#include <frc/motorcontrol/PWMVictorSPX.h>
+#include <units/angle.h>
+#include <units/length.h>
+
+#include "Drivetrain.h"
+
+class Robot : public frc::TimedRobot {
+ public:
+  void RobotInit() override;
+  void RobotPeriodic() override;
+  void TeleopPeriodic() override;
+  void SimulationPeriodic() override;
+
+ private:
+  frc::XboxController m_controller{0};
+
+  Drivetrain m_drive;
+};

photonlib-cpp-examples/apriltagExample/src/test/cpp/main.cpp

@@ -0,0 +1,34 @@
+/*
+ * MIT License
+ *
+ * Copyright (c) 2022 PhotonVision
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+#include <hal/HAL.h>
+
+#include "gtest/gtest.h"
+
+int main(int argc, char** argv) {
+  HAL_Initialize(500, 0);
+  ::testing::InitGoogleTest(&argc, argv);
+  int ret = RUN_ALL_TESTS();
+  return ret;
+}

photonlib-cpp-examples/examples.txt

@@ -1,3 +1,4 @@
 aimandrange
 getinrange
 aimattarget
+apriltagExample

photonlib-cpp-examples/getinrange/build.gradle

@@ -1,7 +1,7 @@
 plugins {
     id "cpp"
     id "google-test-test-suite"
-    id "edu.wpi.first.GradleRIO" version "2023.2.1"
+    id "edu.wpi.first.GradleRIO" version "2023.3.2"
 
     id "com.dorongold.task-tree" version "2.1.0"
 }