Mine

#include "SDL.h"

#define TILE_SIZE       32
#define WORLD_SIZEX     20
#define WORLD_SIZEY     20
#define SCREEN_SIZEX    12
#define SCREEN_SIZEY    12



int gameover;
int speedplayer1 = 1;


int world_camerax = 0;
int world_cameray = 0;


/* source and destination rectangles */
SDL_Rect rcSrc, rcSprite;

SDL_Surface * map[WORLD_SIZEY][WORLD_SIZEX]  = {
     {2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2},
     {2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2},
     {2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2},
     {2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2},
     {2, 1, 1, 2, 1, 1, 1, 1, 2, 1, 1, 1, 2, 1, 1, 1, 2, 1, 1, 2},
     {2, 1, 1, 2, 1, 1, 1, 1, 2, 1, 1, 1, 2, 1, 1, 1, 2, 1, 1, 2},
     {2, 1, 1, 2, 1, 1, 1, 1, 2, 1, 1, 1, 2, 1, 1, 1, 2, 1, 1, 2},
     {2, 1, 1, 2, 1, 1, 1, 1, 2, 1, 1, 1, 2, 1, 1, 1, 2, 1, 1, 2},
     {2, 1, 1, 2, 2, 2, 2, 2, 2, 1, 1, 1, 2, 1, 1, 1, 2, 1, 1, 2},
     {2, 1, 1, 2, 1, 1, 1, 1, 2, 1, 1, 1, 2, 1, 1, 1, 1, 1, 1, 2},
     {2, 1, 1, 2, 1, 1, 1, 1, 2, 1, 1, 1, 2, 1, 1, 1, 1, 1, 1, 2},
     {2, 1, 1, 2, 1, 1, 1, 1, 2, 1, 1, 1, 2, 1, 1, 1, 2, 1, 1, 2},
     {2, 1, 1, 2, 1, 1, 1, 1, 2, 1, 1, 1, 2, 1, 1, 1, 2, 1, 1, 2},
     {2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2},
     {2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2},
     {2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2},
     {2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2},
     {2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2},
     {2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2},
     {2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2}, } ;


void draw_tiles(SDL_Surface *screen){
SDL_Surface *tile;
   int x, y;
     int scroll_x, scroll_y;   // (NEW) 
  int offset_x, offset_y;   // (NEW) 


SDL_Rect rect; 

   SDL_Rect srcRect;

   for (y = 0; y < SCREEN_SIZEY; y++) 
  {
    for (x = 0; x < SCREEN_SIZEX; x++) 
    {
             scroll_x = (world_camerax / TILE_SIZE);  
      scroll_y = (world_cameray / TILE_SIZE);

      // (NEW)
      offset_x = scroll_x & (TILE_SIZE - 1);
      offset_y = scroll_y & (TILE_SIZE - 1);
         
          tile = map[scroll_y][scroll_x];

          
      rect.x = x * TILE_SIZE; rect.y = y * TILE_SIZE; rect.w = rect.h = TILE_SIZE;

SDL_BlitSurface( tile, &srcRect, screen, &rect ); 
}
   }
}