LCD에 점 찍기

임베디드 LCD에 점찍기 
하지만 난 안된다.... 좀더 들여다 봐야되겠다.

http://blog.naver.com/PostView.nhn?blogId=buniel1&logNo=60065575973&categoryNo=1&parentCategoryNo=1&viewDate=&currentPage=1&postListTopCurrentPage=&isAfterWrite=true&userTopListOpen=true&userTopListCount=20&userTopListManageOpen=false&userTopListCurrentPage=1


#include <unistd.h>

#include <stdio.h>

#include <fcntl.h>

#include <linux/fb.h>

#include <sys/mman.h>

#define FBDEVFILE "/dev/fb0"

typedef unsigned char ubyte;

unsigned short makepixel(ubyte r, ubyte g, ubyte b)

{

return (unsigned short)(((r>>3)<<11)|((g>>2)<<5)|(b>>3));

}

int main()

{

int fbfd = 0;

struct fb_var_screeninfo vinfo;

struct fb_fix_screeninfo finfo;

long int screensize = 0;

char *fbp = 0;

int x = 0, y = 0;

long int location = 0;

/* Open the file for reading and writing */

fbfd = open(FBDEVFILE, O_RDWR);

if(!fbfd) {

printf("Error : cannot open framebuffer device. \n");

exit(1);

}

printf("The framebuffer device was opened successfully.\n");

/* Get fixed screen information */

if(ioctl(fbfd, FBIOGET_FSCREENINFO, &finfo)){

printf("Error reading fixed information. \n");

exit(2);

}

/* Get variable screen information */

if(ioctl(fbfd, FBIOGET_VSCREENINFO, &vinfo)){

printf("Error reading variable information. \n");

exit(3);

}

/* Figure out the size of the screen in bytes */

screensize = vinfo.xres * vinfo.yres * vinfo.bits_per_pixel / 8;

/* Map the device to memory */

fbp = (char *)mmap(0, screensize, PROT_READ | PROT_WRITE, MAP_SHARED, fbfd, 0);

if((int)fbp == -1){

printf("Error : failed to map framebuffer device to memory. \n");

exit(4);

}

printf("The framebuffer device was mapped to memory successfully. \n");

x = 100; y = 100; /* Where we are going to put the pixel */

/* Figure out where in memory to put the pixel */

location = (x+vinfo.xoffset) * (vinfo.bits_per_pixel/8) +

  (y+vinfo.yoffset) * (finfo.line_length);

*(fbp + location) = 100;     /* Some blue */

*(fbp + location + 1) = 15;  /* A little green */

*(fbp + location + 2) = 200; /* A lot of red */

*(fbp + location + 3) = 0;   /* No transparency */

munmap(fbp, screensize);

close(fbfd);

return 0;

}