Making Your First Roadrunner Program

This page will walk you through the creation of a simple Roadrunner program. If you have not yet downloaded Roadrunner, see here.

Imports

The first lines of code needed in every Roadrunner program are the import statements. These will vary based on what you are programming and generally IDEs like Android Studio will automatically add them. But, for demonstration purposes, we will import these.

import com.acmerobotics.roadrunner.Pose2d;
import com.acmerobotics.roadrunner.Vector2d;
import com.acmerobotics.roadrunner.ftc.Actions;
import com.qualcomm.robotcore.eventloop.opmode.LinearOpMode;
import org.firstinspires.ftc.teamcode.roadrunner.MecanumDrive;

Starting Pose

Next, you need to specify a starting pose. This is used in the creation of the Mecanum Drive class (next step) to tell Roadrunner where it is starting. This should be modified to your starting position in autonomous. In the following code, the starting position is set to a coordinate of (0.0, -54.0) facing forward (a heading of 90.0°).

Notice

Be careful to make sure your starting heading is specified in radians. You can do this with either a Math.toRadians() function call or by specifying the heading in radians manually like Math.PI.

Pose2d beginPose = new Pose2d(0.0, -54.0, Math.toRadians(90.0));

Mecanum Drive

After creating a starting pose, you can then create an instance of the Roadrunner Mecanum Drive class. beginPose, the variable we just created, is passed into MecanumDrive specifying the starting pose of the robot.

MecanumDrive drive = new MecanumDrive(hardwareMap, beginPose);

Variables

Next, you can create a variable to store the trajectory that the robot will follow and a variable to store the action to run this trajectory.

TrajectoryActionBuilder traj;
Action trajAction;

Trajectory Creation

We then create the trajectory itself. This consists of the following actions. Strafing to the coordinate (72.0, -54.0). Setting the start tangent for the next movement to 90.0°. Moving in a spline to the coordinate (0.0, 0.0) with an end tangent of 90.0°.

traj = drive.actionBuilder(drive.pose)
  // Put your movements here
  .strafeTo(Vector2d(72.0, -54.0))
  .setTangent(Math.toRadians(90.0))
  .splineToConstantHeading(Vector2d(0.0, 0.0), Math.toRadians(90.0))

Trajectory Action

Finally, we build the trajectory into an Action and execute that action.

trajAction = traj.build()

Actions.runBlocking(trajAction);

Putting it all together

Here is the completed code.

import com.acmerobotics.roadrunner.Pose2d;
import com.acmerobotics.roadrunner.Vector2d;
import com.acmerobotics.roadrunner.ftc.Actions;
import com.qualcomm.robotcore.eventloop.opmode.LinearOpMode;
import org.firstinspires.ftc.teamcode.roadrunner.MecanumDrive;

public class MyOpmode extends LinearOpMode {
  @Override
  public void runOpMode() {
    // Specify a starting pose
    Pose2d beginPose = new Pose2d(0.0, -54.0, Math.toRadians(90.0));

    // Create an instance of the Mecanum Drive class
    MecanumDrive drive = new MecanumDrive(hardwareMap, beginPose);

    // Create variables to store the Trajectory and Action
    TrajectoryActionBuilder traj;
    Action trajAction;

    // Create a Trajectory
    traj = drive.actionBuilder(drive.pose)
      // Put your functions here
      .strafeTo(Vector2d(72.0, -54.0))
      .setTangent(Math.toRadians(90.0))
      .splineToConstantHeading(Vector2d(0.0, 0.0), Math.toRadians(90.0))

    // Create an action that follows the created trajectory
    trajAction = traj.build()

    // Run the action
    Actions.runBlocking(trajAction);
  }
}

Demonstration

This video shows a demonstration of this program.