SDL tile collision

//http://www.youtube.com/user/thecplusplusguy
//SDL tile collision
#include <iostream>
#include <vector>
#include <SDL/SDL.h>
#include <cmath>
#include <fstream>

const int WIDTH=640;
const int HEIGHT=480;

int map[15][20]={
{0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0},
{0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0},
{0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0},
{0,0,0,0,0,0,1,0,0,0,1,0,0,0,0,0,0,0,0,0},
{0,0,0,0,0,0,1,0,0,0,1,0,0,0,0,0,0,0,0,0},
{0,0,0,0,0,0,1,0,0,0,1,0,0,0,0,0,0,0,0,0},
{0,0,0,0,0,0,1,0,0,0,1,0,0,0,0,0,0,0,0,0},
{0,0,0,0,0,0,1,1,1,1,1,0,0,0,0,0,0,0,0,0},
{0,0,0,0,0,0,1,0,1,0,0,0,0,0,0,0,0,0,0,0},
{0,0,0,0,0,0,1,0,1,0,0,0,0,0,0,0,0,0,0,0},
{0,0,0,0,0,0,1,0,1,0,0,0,0,0,0,0,0,0,0,0},
{0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0},
{0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0},
{0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0},
{0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}
};

bool collision(SDL_Rect* player,int direction)
{

        if(direction == 1 && (map[(player->y/32)+1][player->x/32] == 1 || map[(player->y/32)+1][(int)ceil(player->x/32.0)] == 1)) return true;
        if(direction == 2 && (map[(int)ceil(player->y/32.)-1][player->x/32] == 1 || map[(int)ceil(player->y/32.)-1][(int)ceil(player->x/32.)] == 1)) return true;
        if(direction == 3 && (map[player->y/32][(int)ceil(player->x/32.)-1] == 1 || map[(int)ceil(player->y/32.)][(int)ceil(player->x/32.)-1] == 1)) return true;
        if(direction == 4 && (map[player->y/32][(player->x/32)+1] == 1 || map[(int)ceil(player->y/32.)][(player->x/32)+1] == 1)) return true;
        return false;


}

int main(int argc,char** argv)
{
    SDL_Init(SDL_INIT_EVERYTHING);
    SDL_Surface* screen=SDL_SetVideoMode(640,480,32,SDL_SWSURFACE);
    bool running=true;
    SDL_Event event;
    Uint32 start;
    SDL_Rect player={32,32,32,32};
    bool b[4]={0,0,0,0};
    int direction=0;
    while(running)
    {
        start=SDL_GetTicks();
        while(SDL_PollEvent(&event))
        {
            switch(event.type)
            {
                case SDL_QUIT:
                    running=false;
                    break;
                case SDL_KEYDOWN:
                    switch(event.key.keysym.sym)
                    {
                        case SDLK_ESCAPE:
                            running=false;
                            break;
                    }
                    break;
                case SDL_MOUSEMOTION:
                    break;

            }
        }
        for(int i=0;i<15;i++)
            for(int j=0;j<20;j++)
            {
                SDL_Rect rec={j*32,i*32,32,32};
                SDL_FillRect(screen,&rec,SDL_MapRGB(screen->format,0,0,map[i][j]*255));
            }
        SDL_FillRect(screen,&player,SDL_MapRGB(screen->format,255,0,0));
        direction=0;
        Uint8* keys=SDL_GetKeyState(0);
        if(keys[SDLK_w])
        {
            direction=2;
            if(!collision(&player,direction))
                player.y-=2;
        }
        if(keys[SDLK_s])
        {
            direction=1;
            if(!collision(&player,direction))
                player.y+=2;
        }
        if(keys[SDLK_a])
        {
            direction=3;
            if(!collision(&player,direction))
                player.x-=2;
        }
        if(keys[SDLK_d])
        {
            direction=4;
            if(!collision(&player,direction))
                player.x+=2;
        }


        SDL_Flip(screen);
        if(1000.0/30>(SDL_GetTicks()-start))
            SDL_Delay(1000.0/30-(SDL_GetTicks()-start));
    }
    SDL_Quit();
}