#include <stdio.h>#include <fcntl.h>#include <stdlib.h>#include <errno.h>#include <sys/mman.h>#include <linux/fb.h>#define FBDEV "/dev/fb0"static char * default_framebuffer = FBDEV;struct fb_dev{	int fb;	void * fb_mem;	int fb_width,fb_height,fb_line_len,fb_size;	int fb_bpp;};static struct fb_dev fbdev;#if 0static void draw(int color){	int i,j;	unsigned short int *p = (unsigned short int*)fbdev.fb_mem;	for(i=0;i<fbdev.fb_height;i++,p+=fbdev.fb_line_len/2)	{		for(j=0;j<fbdev.fb_width;j++)			p[j] = color;	}}#endifstatic void draw(void){	int i,j;	unsigned short int *p = (unsigned short int *)fbdev.fb_mem;		for(i=0;i<fbdev.fb_height;i++)	{		if(i<fbdev.fb_height/2)			for(j=0;j<fbdev.fb_width;j++)				*p++ = 0xf800;		else			for(j=1;j<fbdev.fb_width;j++)				*p++ = 0x1f;	}				}			int framebuffer_open(void){	int fb;	struct fb_var_screeninfo fb_vinfo;	struct fb_fix_screeninfo fb_finfo;	char * fb_dev_name = NULL;	if(!(fb_dev_name = getenv("FRAMEBUFFER")))		fb_dev_name = default_framebuffer;	fb = open(fb_dev_name,O_RDWR);	if(fb<0)	{		printf("device %s open failed\n",fb_dev_name);		return -1;	}	if(ioctl(fb,FBIOGET_VSCREENINFO,&fb_vinfo))	{		printf("Can't get VSCREENINFO:%s\n",strerror(errno));		close(fb);		return -1;	}	ioctl(fb, FBIOPUT_VSCREENINFO, &fb_vinfo);	if(ioctl(fb,FBIOGET_FSCREENINFO,&fb_finfo))	{		printf("Can't get FSCREENINFO:%s\n",strerror(errno));		return -1;	}	fbdev.fb_bpp = fb_vinfo.red.length + fb_vinfo.green.length + fb_vinfo.blue.length + fb_vinfo.transp.length;	fbdev.fb_width = fb_vinfo.xres;	fbdev.fb_height = fb_vinfo.yres;	fbdev.fb_line_len = fb_finfo.line_length;	fbdev.fb_size = fb_finfo.smem_len;	printf("frame buffer:%d(%d)x%d,%dbpp,0x%xbyte\n",fbdev.fb_width,fbdev.fb_line_len,fbdev.fb_height,fbdev.fb_bpp,fbdev.fb_size);	if(fbdev.fb_bpp !=16)	{		printf("frame buffer must be 16bpp mode\n");		exit(0);	}	fbdev.fb_mem = mmap(NULL,fbdev.fb_size,PROT_READ|PROT_WRITE,MAP_SHARED,fb,0);	if(fbdev.fb_mem == NULL || (int)fbdev.fb_mem == -1)	{		fbdev.fb_mem = NULL;		printf("mmap failed\n");		close(fb);		return -1;	}	fbdev.fb = fb;	memset(fbdev.fb_mem,0x0,fbdev.fb_size);	return 0;}void framebuffer_close(){	if(fbdev.fb_mem)	{		munmap(fbdev.fb_mem,fbdev.fb_size);		fbdev.fb_mem = NULL;	}	if(fbdev.fb)	{		close(fbdev.fb);		fbdev.fb =0;	}}int main(void){//	int i;	framebuffer_open();#if 0	for(i=0;i<16;i++)	{		printf("%d,color=0x%x",i,i<<i);		draw(1<<i);		getchar();		}#endif	draw();	framebuffer_close();	return 0;}