Help with ncurses: Snake game

[Camjerlams]

#include <curses.h>
#define UP 3
#define DOWN 2
#define RIGHT 5
#define LEFT 4


int main(void){
   
  // activate the keypad to read from this terminal
  keypad(initscr(),TRUE);

  int pout = 0; //pen on/off (if even/odd)
  int xPos=1;     // initialise the x and y positions of the cursor
  int yPos=2;
  char map[1000][1000];
  char c='\0';  // input character initialise to null
  
          
  while( c!='q'){ // loop while the user has not pressed 'q'
    
        if(pout % 2 == 0){
        mvaddch(yPos,xPos,'*');
        map[yPos][xPos] = '*';
}
        if(pout % 2 != 0){
        mvaddch(yPos,xPos,' ');
}
        c=getch();    // read a single character
    
    if (c == 'p'){    //p changes even-->odd etc for toggle
        pout = pout + 1;
        noecho();
}
   
    switch(c){
    case UP: 
      yPos--;
      break;
    case DOWN:
      yPos++;
      break;
    case LEFT:
      xPos--;
      break;
    case RIGHT:
      xPos++;

}
} 

mvdelch(yPos,xPos+1);  //delete the q
xPos = 1;
yPos = 3;

while( c!='f'){
    mvaddch(yPos,xPos,'O');    //This is the start of snake, snake won't move..
    // read a single character
    c=getch();
    // move according to cursor
    switch(c){
    case UP:
      if (map[yPos-1][xPos]== ' '){
        yPos--;
    map[yPos][xPos] = 'O';
      }
      break;
    case DOWN:
      if (map[yPos+1][xPos]== ' '){
        yPos++;
    map[yPos][xPos] = 'O';
      }
      break;
    case LEFT:
      if (map[yPos][xPos-1]== ' '){
        xPos--;
    map[yPos][xPos] = 'O';
      }
      break;
    case RIGHT:
      if (map[yPos][xPos+1]== ' '){
        xPos++;
    map[yPos][xPos] = 'O';
      }
    }
  }
}

You toggle the pen on and off with 'p' to draw a map, or obstacle course. When 'q' is pressed the cursor should return to top left and print 'O', from there its a game of snake (but without the snake food)-so you cant go through the map thats been drawn or your tail.

It compiles and I can draw the map, but can't get the snake to go..

Any suggestions? Im noob so it's probably something rediculous.

I'll also add a move counter once i get the snake to move.

[tabstop]

Every other time you wanted to put a character on the screen you used mvaddch. Why not do it here too? (You never print the map, so changing map won't affect what's on the screen in any way I can see.)

[Camjerlams]

Every other time you wanted to put a character on the screen you used mvaddch. Why not do it here too? (You never print the map, so changing map won't affect what's on the screen in any way I can see.)

The seond while loop has the mvaddch operator at the top for the snake, the map never prints but the idea was to buil an array thats a mirror image of the screen and can dictate where the cursor can go. I didnt know how else to recognise the obstacles on the screen..

[Adak]

Yes, changing the values of your variables won't move the snake. You need the equivalent of putchar() to do that.

When the head has found a valid place to move to, then the entire snake body needs to move so it occupies the former position of the segment in front of it. So it's a quick "wave" action, from head to tail, as the segments of the snake move.

In a windows text game, it looks like this in a text based game. Here, the user's char is ascii 1, and d is "door", but "door" really means "room". (Don't ask, OK?)

  if (GetAsyncKeyState(VK_UP) & 0xf)  // Up! key 
   {
      t = (r - 1);
      Goto(user.x, user.y);
      switch (room[*d][t][c]) {
      case ' ':                // Space.
         //printf("room[y2][x]: %uc\n",room[y2][x]); //getchar();
         room[*d][r][c] = ' ';
         room[*d][t][c] = '\1';
         putchar(' ');
         --r;
         Goto(c, r);   putchar(1);
         break;

      case TMD:                // Health Pack.
         room[*d][r][c] = ' ';
         room[*d][t][c] = '\1';
         putchar(' ');
         --r;
         Goto(user.x, r);   putchar(1);
         user.life += 5; 
         break;
      case GOLD:               // Gold!  //bags of gold dust
         room[*d][r][c] = ' ';
         room[*d][t][c] = '\1';
         putchar(' ');
         --r;
         Goto(user.x, r);   putchar(1);
         user.gold++;
         break;
      case '-':
         room[*d][r][c] = ' ';
         putchar(' ');
         if (r == 1)
            r = MAXROW - 2;
         else
            r = r - 2;
         Goto(c, r); putchar(1);
         room[*d][r][c] = 1;
      }
   } else if (GetAsyncKeyState(VK_DOWN) & 0xf)  // Down!
   {
      t = (r + 1);
      Goto(user.x, user.y);
      switch (room[*d][t][c]) {
      case ' ':                // Space.
         room[*d][r][c] = ' ';
         room[*d][t][c] = '\1';
         putchar(' ');
         ++r;
         Goto(c, r);  putchar(1);
         break;
      case TMD:                // Health Pack
         room[*d][r][c] = ' ';
         room[*d][t][c] = '\1';
         putchar(' ');
         ++r;
         Goto(c, r); putchar(1);
         user.life += 5;
         break;
      case GOLD:               // Gold!
         room[*d][r][c] = ' ';
         room[*d][t][c] = '\1';
         putchar(' ');
         ++r;
         Goto(c, r); putchar(1);
         user.gold++;
         break;
      case '-':                // Door
         room[*d][r][c] = ' ';
         putchar(' ');
         if (r == MAXROW - 2)
            r = 1;
         else
            r = r + 2;
         Goto(c, r);
         putchar(1);
         room[*d][r][c] = 1;
      }
   } else if (GetAsyncKeyState(VK_LEFT) & 0xf)  // Left!
   {
      t = (c - 1);
      Goto(user.x, user.y);
      switch (room[*d][r][t]) {
      case ' ':                // Space
         room[*d][r][c] = ' ';
         room[*d][r][t] = '\1';
         putchar(' ');
         --c;
         Goto(c, r);
         putchar(1); //1
         break;
      case TMD:                // Health Pack
         room[*d][r][c] = ' ';
         room[*d][r][t] = '\1';
         putchar(' ');
         --c;
         Goto(c, r);
         putchar(1);
         user.life += 5;
         break;
      case GOLD:               //Gold!
         room[*d][r][c] = ' ';
         room[*d][r][t] = '\1';
         putchar(' ');
         --c;
         Goto(c, r);
         putchar(1);
         user.gold++;
         break;
      case '|':                // Door 
         room[*d][r][c] = ' ';
         putchar(' ');
         if (c == 1) {
            c = MAXCOL - 3;
            (*d)--;              // to a lower door  
            room[*d][r][c] = 1;  // put user into the array
            user.x=c; user.y=r;
            printRoom(*d);
            SetConsoleTextAttribute(hConsole, 0x0E);
         }else
            c -= 2;
         
         room[*d][r][c] = 1;
         Goto(c, r);
         putchar(1);
         break;
      }
   }else if (GetAsyncKeyState(VK_RIGHT) & 0xf)   // Right!
   {
      t = (c + 1);
      Goto(user.x, user.y);
      switch (room[*d][r][t]) {
      case ' ':                // Space
         room[*d][r][c] = ' ';
         room[*d][r][t] = '\1';
         putchar(' ');
         ++c;
         Goto(c, r);
         putchar(1);
         break;
      case TMD:                // Health Pack
         room[*d][r][c] = ' ';
         room[*d][r][t] = '\1';
         putchar(' ');
         ++c;
         Goto(c, r);
         putchar(1);
         user.life += 5;
         break;
      case GOLD:               //Gold!
         room[*d][r][c] = ' ';
         room[*d][r][t] = '\1';
         putchar(' ');
         ++c;
         Goto(c, r);
         putchar(1);
         user.gold++;
         break;
      case '|':                // Door
         room[*d][r][c] = ' ';
         putchar(' ');
         if (c == MAXCOL - 3) {
            c = 2;
            (*d)++;
            room[*d][r][c]= 1;
            user.x=c; user.y=r;
            printRoom(*d);
            SetConsoleTextAttribute(hConsole, 0x0E);
         }else
            c += 2;

         room[*d][r][c] = 1;
         Goto(c, r);
         putchar(1);
         break;
      }
   }else if (GetAsyncKeyState(VK_ESCAPE) & 0xf) {
      exit(1);
   }
   user.x = c;
   user.y = r;
}

Goto is not like goto in programming - it's like goto(x,y), in text based cursor movement, on the console window.

[Camjerlams]

Yes, changing the values of your variables won't move the snake. You need the equivalent of putchar() to do that.

When the head has found a valid place to move to, then the entire snake body needs to move so it occupies the former position of the segment in front of it. So it's a quick "wave" action, from head to tail, as the segments of the snake move.

I wasn't going to do that at this stage, because i don't have 'snake food' to make it grow the snake's tail will stay at the start position while the head stretches away and that's how its going to grow. I may change this later but for now id just like to get it running like this. So itll be the same as the map drawing bit only you wont be able to pass through anything on the scren.

[Hodor]

What's stopping the snake "moving" is that your array (char map[1000][1000]) is not initialized as containing all space (' ') characters. So, in the snake "movement" code the if (... = ' ') checks are evaluating to false[1]. I.e. you need to initialize the map

[1] More precisely the value of the cell, for example, [yPos-1][xPos] is undefined unless it got inititialized by your maze/obstacle part of the code (and for the majority of cells this won't be the case).

[Camjerlams]

OK- I found that in the seond switch group when checking the map for free space to move to: ' ' should be \0 as the empty array slots are null spaces not ' ' spaces... Thanks for your help guys!

[Camjerlams]

What's stopping the snake "moving" is that your array (char map[1000][1000]) is not initialized as containing all space (' ') characters. So, in the snake "movement" code the if (... = ' ') checks are evaluating to false. I.e. you need to initialize them map

You got it straight away Hodor! Thanks!

[Hodor]

You got it straight away Hodor! Thanks!

hodor

[Camjerlams]

hodor

Such wisdom..