通訊

你的程式透過每台機器人都有的兩個裝置與比賽溝通：

• 發射器（emitter）會傳送訊息給比賽。它不需要啟用。
• 接收器（receiver）會接收來自比賽的訊息。請像感測器一樣啟用它。

以下每一節都是一個適用於入門機器人的完整程式。所有訊息都列在訊息參考中。

靠牆上的標記得分

要靠字母受害者或認知目標得分，機器人必須：

1. 在標記附近停止超過 1 秒。如果機器人在最後一秒內移動過，Erebus 會忽略這次回報。
2. 傳送標記的位置和類型：X 和 Z 以公分為單位，類型則是一個字母。

牆上的標記	類型
字母受害者 Φ（受傷）	H
字母受害者 Ψ（穩定）	S
字母受害者 Ω（未受傷）	U
認知目標，總和 0（易燃氣體）	F
認知目標，總和 1（毒性物質）	P
認知目標，總和 2（腐蝕性物質）	C
認知目標，總和 3（有機過氧化物）	O

雖然從 2026 年起受害者顯示的是符號，類型仍然是字母。GPS 提供的是公尺，所以要乘以 100。

Python

from controller import Robot
import struct

robot = Robot()
timeStep = int(robot.getBasicTimeStep())

emitter = robot.getDevice("emitter")  # Always on the robot. It does not need to be enabled.
gps = robot.getDevice("gps")
gps.enable(timeStep)
leftWheel = robot.getDevice("left wheel motor")
rightWheel = robot.getDevice("right wheel motor")
leftWheel.setPosition(float("inf"))
rightWheel.setPosition(float("inf"))

def wait(seconds):
    start = robot.getTime()
    while robot.step(timeStep) != -1:
        if robot.getTime() - start >= seconds:
            break

def report(tokenType):
    # 1. Stop for more than 1 second
    leftWheel.setVelocity(0)
    rightWheel.setVelocity(0)
    wait(1.2)
    # 2. Send the position in centimeters, and the type as one letter
    x, _, z = gps.getValues()
    message = struct.pack("i i c", int(x * 100), int(z * 100), tokenType.encode())
    emitter.send(message)
    robot.step(timeStep)

report("H")  # Reports a harmed victim (Φ) where the robot is
print("Reported")

C/C++

#include <iostream>
#include <cmath>
#include <cstring>
#include <webots/Robot.hpp>
#include <webots/Emitter.hpp>
#include <webots/GPS.hpp>
#include <webots/Motor.hpp>

using namespace webots;

Robot *robot;
Emitter *emitter;
GPS *gps;
Motor *leftWheel, *rightWheel;
int timeStep;

void wait(double seconds) {
  double start = robot->getTime();
  while (robot->step(timeStep) != -1) {
    if (robot->getTime() - start >= seconds)
      break;
  }
}

void report(char tokenType) {
  // 1. Stop for more than 1 second
  leftWheel->setVelocity(0);
  rightWheel->setVelocity(0);
  wait(1.2);
  // 2. Send the position in centimeters, and the type as one letter
  int position[2] = {(int)(gps->getValues()[0] * 100), (int)(gps->getValues()[2] * 100)};
  char message[9];
  memcpy(message, position, sizeof(position));
  message[8] = tokenType;
  emitter->send(message, sizeof(message));
  robot->step(timeStep);
}

int main() {
  robot = new Robot();
  timeStep = (int)robot->getBasicTimeStep();

  emitter = robot->getEmitter("emitter"); // Always on the robot. It does not need to be enabled.
  gps = robot->getGPS("gps");
  gps->enable(timeStep);
  leftWheel = robot->getMotor("left wheel motor");
  rightWheel = robot->getMotor("right wheel motor");
  leftWheel->setPosition(INFINITY);
  rightWheel->setPosition(INFINITY);

  report('H'); // Reports a harmed victim (Φ) where the robot is
  std::cout << "Reported" << std::endl;

  delete robot;
  return 0;
}

機器人必須和標記在牆的同一側，而且機器人和你傳送的位置都必須靠近標記。規則要求最多半個地塊，所以請以此為目標。Erebus v26.1 檢查的距離是 9 cm。

在 world1.wbt 的起點執行這個程式：那裡沒有標記，所以控制視窗的歷史紀錄會顯示 Misidentification of Victim -5。錯誤的回報（包括回報假目標）會扣 5 分，而且每個標記只能得分一次。

缺乏進展

當機器人卡住時，缺乏進展（lack of progress）會把它移回最後一個檢查點，並扣 5 分。機器人 20 秒沒有移動就會自動發生，你的程式也可以傳送 L 主動宣告。每次發生時，比賽都會傳送 L 給機器人，讓你的程式知道它的位置改變了。

Python

from controller import Robot
import struct

robot = Robot()
timeStep = int(robot.getBasicTimeStep())

emitter = robot.getDevice("emitter")
receiver = robot.getDevice("receiver")
receiver.enable(timeStep)  # The receiver must be enabled

askedAt = None
while robot.step(timeStep) != -1:
    # Call a lack of progress once, after 2 seconds
    if askedAt is None and robot.getTime() > 2:
        emitter.send(struct.pack("c", b"L"))
        askedAt = robot.getTime()

    # Listen for messages from the game
    while receiver.getQueueLength() > 0:
        data = receiver.getBytes()
        if len(data) == 1 and data == b"L":
            print("Lack of progress! The robot is back at the last checkpoint.")
        receiver.nextPacket()

C/C++

#include <iostream>
#include <webots/Robot.hpp>
#include <webots/Emitter.hpp>
#include <webots/Receiver.hpp>

using namespace webots;
using namespace std;

int main() {
  Robot *robot = new Robot();
  int timeStep = (int)robot->getBasicTimeStep();

  Emitter *emitter = robot->getEmitter("emitter");
  Receiver *receiver = robot->getReceiver("receiver");
  receiver->enable(timeStep); // The receiver must be enabled

  bool asked = false;
  while (robot->step(timeStep) != -1) {
    // Call a lack of progress once, after 2 seconds
    if (!asked && robot->getTime() > 2) {
      char message = 'L';
      emitter->send(&message, 1);
      asked = true;
    }

    // Listen for messages from the game
    while (receiver->getQueueLength() > 0) {
      const char *data = (const char *)receiver->getData();
      if (receiver->getDataSize() == 1 && data[0] == 'L')
        cout << "Lack of progress! The robot is back at the last checkpoint." << endl;
      receiver->nextPacket();
    }
  }

  delete robot;
  return 0;
}

接收器可能收到不同的訊息，所以請像範例一樣，在讀取之前先檢查每則訊息的長度。

比賽資訊

傳送 G 可以取得分數和剩餘時間。比賽會回覆一則 16 位元組的訊息：字母 G、分數、剩餘比賽時間和剩餘實際時間，單位是秒。

Python

from controller import Robot
import struct

robot = Robot()
timeStep = int(robot.getBasicTimeStep())

emitter = robot.getDevice("emitter")
receiver = robot.getDevice("receiver")
receiver.enable(timeStep)

lastAsked = 0
while robot.step(timeStep) != -1:
    # Ask for the game information once a second
    if robot.getTime() - lastAsked > 1:
        emitter.send(struct.pack("c", b"G"))
        lastAsked = robot.getTime()

    while receiver.getQueueLength() > 0:
        data = receiver.getBytes()
        if len(data) == 16:  # The game information is 16 bytes long
            _, score, timeLeft, realTimeLeft = struct.unpack("c f i i", data)
            print("Score:", round(score, 2), "Time left:", timeLeft, "s", "Real time left:", realTimeLeft, "s")
        receiver.nextPacket()

C/C++

#include <iostream>
#include <cstring>
#include <webots/Robot.hpp>
#include <webots/Emitter.hpp>
#include <webots/Receiver.hpp>

using namespace webots;
using namespace std;

int main() {
  Robot *robot = new Robot();
  int timeStep = (int)robot->getBasicTimeStep();

  Emitter *emitter = robot->getEmitter("emitter");
  Receiver *receiver = robot->getReceiver("receiver");
  receiver->enable(timeStep);

  double lastAsked = 0;
  while (robot->step(timeStep) != -1) {
    // Ask for the game information once a second
    if (robot->getTime() - lastAsked > 1) {
      char message = 'G';
      emitter->send(&message, 1);
      lastAsked = robot->getTime();
    }

    while (receiver->getQueueLength() > 0) {
      const char *data = (const char *)receiver->getData();
      if (receiver->getDataSize() == 16 && data[0] == 'G') { // The game information is 16 bytes long
        float score;
        int timeLeft, realTimeLeft;
        memcpy(&score, data + 4, 4);
        memcpy(&timeLeft, data + 8, 4);
        memcpy(&realTimeLeft, data + 12, 4);
        cout << "Score: " << score << " Time left: " << timeLeft << " s Real time left: " << realTimeLeft << " s" << endl;
      }
      receiver->nextPacket();
    }
  }

  delete robot;
  return 0;
}

比賽時間在沼澤中會流逝得更快，只要任一種時間用完，比賽就會結束。請同時利用兩者來判斷何時該返回起點。

結束比賽

傳送 E 可以結束比賽。如果機器人在起始地塊上，且已辨識出至少一個牆上的標記，就會獲得 10% 的出口加成。

Python

from controller import Robot
import struct

robot = Robot()
timeStep = int(robot.getBasicTimeStep())
emitter = robot.getDevice("emitter")

robot.step(timeStep)
print("Ending the game")
# Ends the game. Send it on the starting tile, after identifying a token, to get the exit bonus.
# The game stops your program right after this message.
emitter.send(struct.pack("c", b"E"))
robot.step(timeStep)

C/C++

#include <iostream>
#include <webots/Robot.hpp>
#include <webots/Emitter.hpp>

using namespace webots;

int main() {
  Robot *robot = new Robot();
  int timeStep = (int)robot->getBasicTimeStep();
  Emitter *emitter = robot->getEmitter("emitter");

  robot->step(timeStep);
  std::cout << "Ending the game" << std::endl;
  // Ends the game. Send it on the starting tile, after identifying a token, to get the exit bonus.
  // The game stops your program right after this message.
  char message = 'E';
  emitter->send(&message, 1);
  robot->step(timeStep);

  delete robot;
  return 0;
}

警告

機器人傳送 E 時，無論它在哪裡比賽都會結束，而且機器人無法繼續。請先確認它已經回到起始地塊，並且已經提交地圖。

接下來，在牆上的標記中學習如何分辨各種標記。