564 lines
15 KiB
C
564 lines
15 KiB
C
/**
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* @file mapping.h
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* @brief Map the environment using the line sensor and the ultrasonic sensor
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*
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* Reference:
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* https://stackoverflow.com/questions/37207022/flood-fill-algorithm-maze
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*
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* @author Woon Jun Wei
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*/
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#ifndef MAPPING_H
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#define MAPPING_H
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#include <stdio.h>
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#include "pico/stdlib.h"
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#include <stdlib.h>
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#include "time.h"
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#include "pico/rand.h"
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#include "FreeRTOS.h"
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#include "task.h"
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#include "message_buffer.h"
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#include "semphr.h"
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#include "car_config.h"
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// Function to generate a random number between min and max (inclusive)
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int
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generate_random(int min, int max)
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{
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int num = (get_rand_32() % (max - min + 1)) + min;
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printf("Random number generated: %d\n", num);
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return num;
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}
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// Define a queue structure for BFS
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typedef struct {
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int x;
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int y;
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} QueueNode;
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typedef struct {
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QueueNode *array;
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int front, rear, size;
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unsigned capacity;
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} Queue;
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// Function to create a new queue
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Queue* createQueue(unsigned capacity) {
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Queue* queue = (Queue*)malloc(sizeof(Queue));
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queue->capacity = capacity;
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queue->front = queue->size = 0;
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queue->rear = capacity - 1;
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queue->array = (QueueNode*)malloc(capacity * sizeof(QueueNode));
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return queue;
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}
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// Function to check if the queue is empty
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bool isEmpty(Queue* queue) {
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return (queue->size == 0);
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}
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// Function to check if the queue is full
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bool isFull(Queue* queue) {
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return (queue->size == queue->capacity);
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}
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// Function to enqueue a cell in the queue
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void enqueue(Queue* queue, int x, int y) {
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if (isFull(queue))
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return;
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queue->rear = (queue->rear + 1) % queue->capacity;
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queue->array[queue->rear].x = x;
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queue->array[queue->rear].y = y;
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queue->size = queue->size + 1;
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}
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// Function to dequeue a cell from the queue
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QueueNode dequeue(Queue* queue) {
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QueueNode cell = queue->array[queue->front];
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queue->front = (queue->front + 1) % queue->capacity;
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queue->size = queue->size - 1;
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return cell;
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}
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// Function to perform BFS and find the shortest path
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void bfs_shortest_path(maze_t *maze, int startX, int startY) {
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// Create a queue for BFS
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Queue* queue = createQueue(maze->height * maze->width);
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// Initialize visited array
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bool visited[maze->height][maze->width];
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for (int i = 0; i < maze->height; i++) {
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for (int j = 0; j < maze->width; j++) {
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visited[i][j] = false;
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}
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}
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// Mark the starting cell as visited and enqueue it
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visited[startY][startX] = true;
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enqueue(queue, startX, startY);
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// Define directions (up, down, left, right)
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int dx[] = { -1, 1, 0, 0 };
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int dy[] = { 0, 0, -1, 1 };
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// Perform BFS
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while (!isEmpty(queue)) {
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// Dequeue a cell and process it
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QueueNode current = dequeue(queue);
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int x = current.x;
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int y = current.y;
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// Process the cell (you can customize this part based on your needs)
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// Here, we mark the cell with a special character to indicate it's part of the shortest path
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maze->mazecells[y][x].type = 'P'; // 'P' for path
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// Explore adjacent cells
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for (int i = 0; i < 4; i++) {
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int newX = x + dx[i];
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int newY = y + dy[i];
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// Check if the new position is within the maze boundaries
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if (newX >= 0 && newX < maze->width && newY >= 0 && newY < maze->height) {
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// Check if the cell is not a wall and hasn't been visited
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if (maze->mazecells[newY][newX].type != 'X' && !visited[newY][newX]) {
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// Mark the new cell as visited and enqueue it
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visited[newY][newX] = true;
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enqueue(queue, newX, newY);
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}
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}
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}
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}
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// Free the allocated memory for the queue
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free(queue);
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}
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/**
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* Create a map with hardcoded walls, obstacles, and the goal
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* With the start point at the bottom left corner.
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* Ensures there is at least one clear path from start to goal.
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* @param maze
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*/
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void
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create_map(maze_t *maze)
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{
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// Create the map based on maze height and width
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for (int i = 0; i < maze->height; i++)
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{
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for (int j = 0; j < maze->width; j++)
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{
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if (i == 0 || i == maze->height - 1 || j == 0
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|| j == maze->width - 1)
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{
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maze->mazecells[i][j].type = 'X'; // Walls at the border
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}
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else
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{
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// Randomly place walls and obstacles
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if (generate_random(0, 9)
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< 2) // Adjust the threshold for more or fewer obstacles
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{
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maze->mazecells[i][j].type = 'X'; // Obstacle
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}
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else
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{
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maze->mazecells[i][j].type = ' '; // Empty space
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}
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}
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maze->mazecells[i][j].reachable = 0;
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maze->mazecells[i][j].visited = 0;
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}
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}
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// Set the start point
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maze->mazecells[0][0].type = 'S';
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maze->mazecells[0][0].reachable = 1;
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maze->mazecells[0][0].visited = 1;
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// Set the goal (assuming it's at the top-right corner)
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maze->mazecells[maze->height - 1][maze->width - 1].type = 'G';
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// Ensure there is a clear path from start to goal
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for (int i = 1; i < maze->height - 1; i++)
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{
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maze->mazecells[i][maze->width / 2].type = ' '; // Clear path
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}
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}
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/**
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* Create a hardcoded map with a clear path from start to goal
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* @param maze
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*/
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void
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create_hardcoded_map(maze_t *maze)
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{
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// Set fixed height and width during initialization
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maze->height = 5;
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maze->width = 5;
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// Create the map with a clear path
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char hardcoded_map[5][5] = {
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{ 'S', ' ', ' ', ' ', 'G' }, { ' ', ' ', 'X', ' ', ' ' },
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{ ' ', ' ', ' ', ' ', ' ' }, { ' ', 'X', ' ', ' ', ' ' },
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{ 'C', ' ', 'X', ' ', ' ' },
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};
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// Copy the hardcoded map to the maze structure
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for (int i = 0; i < maze->height; i++)
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{
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for (int j = 0; j < maze->width; j++)
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{
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maze->mazecells[i][j].type = hardcoded_map[i][j];
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maze->mazecells[i][j].reachable = 0;
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maze->mazecells[i][j].visited = 0;
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}
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}
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}
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/**
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* @brief Mapping Initialization
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*/
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void
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mapping_init(maze_t *p_maze)
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{
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printf("Initializing mapping\n");
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// Set fixed height and width during initialization
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p_maze->height = MAX_HEIGHT / 2;
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p_maze->width = MAX_WIDTH / 2;
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// Create the maze
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printf("Creating maze\n");
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create_hardcoded_map(p_maze);
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printf("Maze created\n");
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}
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/**
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* @brief Print the map
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* @param maze
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*/
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void
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print_map(maze_t *maze)
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{
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for (int i = maze->height - 1; i >= 0; i--)
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{
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for (int j = 0; j < maze->width; j++)
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{
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char cellType = maze->mazecells[j][i].type;
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switch (cellType)
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{
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case 'X':
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printf("X "); // Wall
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break;
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case 'O':
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printf("O "); // Obstacle
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break;
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case 'S':
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printf("S "); // Start
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break;
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case 'G':
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printf("G "); // Goal
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break;
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case 'C':
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printf("C "); // Car
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break;
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case 'V':
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printf("V "); // Visited
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break;
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default:
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printf(" "); // Empty space
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break;
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}
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}
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printf("\n");
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}
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}
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/**
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* @brief Print the map with the reachable cells
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* @param maze
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*/
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void
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print_map_reachable(maze_t *maze)
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{
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for (int i = maze->height - 1; i >= 0; i--)
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{
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for (int j = 0; j < maze->width; j++)
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{
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printf("%d ", maze->mazecells[j][i].reachable);
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}
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printf("\n");
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}
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}
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/**
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* @brief Perform floodfill on the maze
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* @param maze
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* @param x starting position x-coordinate
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* @param y starting position y-coordinate
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* @param value value to fill
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*/
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void
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floodfill(maze_t *maze, int x, int y, int value)
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{
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// Check if the current position is within the maze boundaries and not
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// visited
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if (x >= 0 && x < maze->width && y >= 0 && y < maze->height
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&& maze->mazecells[x][y].visited == 0)
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{
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maze->mazecells[x][y].reachable = value;
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maze->mazecells[x][y].visited = 1;
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// Recursive floodfill for neighboring cells
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floodfill(maze, x + 1, y, value + 1); // right
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floodfill(maze, x - 1, y, value + 1); // left
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floodfill(maze, x, y + 1, value + 1); // up
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floodfill(maze, x, y - 1, value + 1); // down
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}
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}
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/**
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* @brief Function to check if the entire maze has been explored
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* @param maze
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* @return true if all cells are visited, false otherwise
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*/
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bool
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maze_explored(const maze_t *maze)
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{
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for (int i = 0; i < maze->height; i++)
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{
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for (int j = 0; j < maze->width; j++)
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{
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if (maze->mazecells[j][i].type != 'X'
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&& maze->mazecells[j][i].type != 'V')
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{
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return false;
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}
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}
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}
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return true;
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}
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// Update the find_shortest_path function with the newly created bfs_shortest_path function
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void find_shortest_path(maze_t *maze) {
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// Assuming the starting point is the bottom-left corner (0, 0)
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int startX = 0;
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int startY = 0;
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// Perform BFS to find the shortest path
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bfs_shortest_path(maze, startX, startY);
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}
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void
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backtrack_to_start(maze_t *maze, int *currentX, int *currentY)
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{
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// Get the current cell type
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char currentCellType = maze->mazecells[*currentX][*currentY].type;
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// Base case: Stop if the current cell is the start
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if (currentCellType == 'S')
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{
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printf("Backtracking completed. Reached the start!\n");
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return;
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}
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// Update the current cell as part of the backtracking path
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maze->mazecells[*currentX][*currentY].type = 'P'; // 'P' for path
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// Initialize newX and newY
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int newX = *currentX;
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int newY = *currentY;
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// Explore adjacent cells in all directions
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for (int i = 0; i < 4; i++)
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{
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// Adjust the new position based on the movement direction
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switch ((mapping_direction_t)i)
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{
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case up:
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newY++;
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break;
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case down:
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newY--;
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break;
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case left:
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newX--;
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break;
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case right:
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newX++;
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break;
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}
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// Check if the new position is within the maze boundaries
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if (newX >= 0 && newX < maze->width && newY >= 0 && newY < maze->height)
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{
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// Check if the new cell is part of the backtracking path
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if (maze->mazecells[newX][newY].type == 'V'
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|| maze->mazecells[newX][newY].type == 'P')
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{
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// Move to the new position
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*currentX = newX;
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*currentY = newY;
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// Recursively backtrack from the new position
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backtrack_to_start(maze, currentX, currentY);
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// If backtracking is successful, stop exploring other
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// directions
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return;
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}
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}
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// Reset newX and newY to the original values
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newX = *currentX;
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newY = *currentY;
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}
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// If no valid adjacent cells are found, backtrack to the previous position
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switch (currentCellType)
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{
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case 'C':
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maze->mazecells[*currentX][*currentY].type
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= ' '; // Clear the car's position
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break;
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default:
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maze->mazecells[*currentX][*currentY].type
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= 'V'; // Mark as visited during backtracking
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break;
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}
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// Print the map during backtracking
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printf("Map during backtracking:\n");
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print_map(maze);
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// Move back to the previous position (if not at the start)
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if (currentCellType != 'S')
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{
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// Update the current position to the previous position
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*currentX = newX;
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*currentY = newY;
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}
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// Print the map after moving back during backtracking
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printf("Map after moving back during backtracking:\n");
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print_map(maze);
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}
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/**
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* @brief Task to explore the maze, find the shortest path, and reach the goal
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* @param pvParameters
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*/
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void
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combined_task(void *pvParameters)
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{
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maze_t *maze = (maze_t *)pvParameters;
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int currentX = 0; // Initial X position
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int currentY = 0; // Initial Y position
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// Reset maze before floodfill
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for (int i = 0; i < maze->height; i++)
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{
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for (int j = 0; j < maze->width; j++)
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{
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maze->mazecells[j][i].visited = 0;
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}
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}
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// Explore the maze and perform floodfill
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for (;;)
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{
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// Simulate car movement (you can replace this logic with your actual
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// movement algorithm)
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mapping_direction_t moveDirection
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= (mapping_direction_t)(get_rand_32() % 4);
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// Update the previously visited position before moving
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if (maze->mazecells[currentX][currentY].type
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!= 'S') // Check if it's not the start position
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{
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maze->mazecells[currentX][currentY].type = 'V'; // 'V' for visited
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}
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switch (moveDirection)
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{
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case up:
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if (currentY < maze->height - 1
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&& maze->mazecells[currentX][currentY + 1].type != 'X')
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{
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currentY++;
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}
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break;
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case down:
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if (currentY > 0
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&& maze->mazecells[currentX][currentY - 1].type != 'X')
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{
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currentY--;
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}
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break;
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case left:
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if (currentX > 0
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&& maze->mazecells[currentX - 1][currentY].type != 'X')
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{
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currentX--;
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}
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break;
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case right:
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if (currentX < maze->width - 1
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&& maze->mazecells[currentX + 1][currentY].type != 'X')
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{
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currentX++;
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}
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break;
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}
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// Update the car's position in the maze
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if (maze->mazecells[currentX][currentY].type
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!= 'S') // Check if it's not the start position
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{
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maze->mazecells[currentX][currentY].type = 'C'; // 'C' for car
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}
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// Print the map with the car's position
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printf("Map with the car's position:\n");
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print_map(maze);
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// Floodfill the maze after each movement
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floodfill(maze, maze->width - 1, 0, 0);
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// Check if the car has explored the entire maze
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if (maze_explored(maze))
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{
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printf("Entire maze explored! Now finding the shortest path.\n");
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backtrack_to_start(maze, ¤tX, ¤tY);
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find_shortest_path(maze);
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}
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vTaskDelay(
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pdMS_TO_TICKS(100)); // Delay to simulate time between movements
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}
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}
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/**
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* @brief Initialise tasks for the Maze
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* @param maze
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*/
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void
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mapping_tasks_init(maze_t *maze)
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{
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TaskHandle_t combined_task_handle = NULL;
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xTaskCreate(combined_task,
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"combined_task",
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configMINIMAL_STACK_SIZE,
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(void *)maze,
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PRIO,
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&combined_task_handle);
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}
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#endif /* MAPPING_H */
|