#include <stdio.h>
#include <linux/fb.h>
#include <asm/fcntl.h>
#include <asm/mman.h>

int main(int argc, char** argv)
{
	int i, fbfd = 0;
	char *fbp, buf[60];
	struct fb_var_screeninfo vinfo;
	struct fb_fix_screeninfo finfo;
	long int screensize = 0;

	/* open device */
	fbfd = open("/dev/fb0", O_RDWR);

	/* get screen info */
	ioctl(fbfd, FBIOGET_FSCREENINFO, &finfo);
	ioctl(fbfd, FBIOGET_VSCREENINFO, &vinfo);

	/* cauclate screen size */
	screensize = vinfo.xres * vinfo.yres * vinfo.bits_per_pixel / 8;

	/* map screen buffer to memory */
	buf[0]= 0;
	fbp= (char*)mmap(0,screensize,PROT_READ|PROT_WRITE,0, fbfd, 0);
	
	/* draw */
	vinfo.yres >>= 1;
	for(i=0; i<vinfo.yres; i++)
	{
		*(fbp + i*vinfo.xres + i) = 0xFF;
		*(fbp + i*vinfo.xres + (vinfo.yres - i)) = 0x88;
	}

	close(fbfd);
	return 0;
}