fb3e.c

一个简单的LINUX图象显示程序需要VGA

#include <stdio.h>
#include <fcntl.h>
#include <unistd.h>
#include <errno.h>
#include <string.h>
#include <sys/ioctl.h>
#include <sys/mman.h>
#include <linux/fb.h>
#include <linux/types.h>

#define D	5

int 	Bpp;
int 	xlen;
void*	fb_mm;
int 	scr_len;
struct 	fb_fix_screeninfo fix;
struct 	fb_var_screeninfo var;
int 	nXL;
int 	nYL;	


typedef struct _point {
	int x, y;
}point;

void draw_rect(point *pt, int w, int h)
{
	char *p;
	int i;

	p = fb_mm + (var.xres * pt->y + pt->x) * Bpp;
	
	for (i = 0; i < h; i++)
	{
		memset(p, 0x99, w * Bpp);
		p += xlen;
	}
}

void* flying(void *pstart)
{
	int dy = -D;
	int dx = -D;
	point *pt;
	char *p;
	int i;

	pt = (point *)pstart;

	while(1)
	{
		if (pt->x + nXL > var.xres)
		{
			pt->x = var.xres - nXL;
			dx = -D;
		}
		else if (pt->x < 0)
		{
			pt->x = 0;
			dx = D;
		}

		if (pt->y + nYL > var.yres)
		{
			pt->y = var.yres - nYL;
			dy = -D;
		}
		else if (pt->y < 0)
		{
			pt->y = 0;
			dy = D;
		}

		memset(fb_mm, 0, scr_len);

		draw_rect(pt, nXL, nYL);
	
		usleep(20);

		pt->x += dx;
		pt->y += dy;
	}
	
	return NULL;
}

int main()
{
	int 	fd;
	pthread_t tid0, tid1;

	point pt = {0, 0};

	fd = open("/dev/fb0", O_RDWR);

	if(fd < 0)
	{
		fprintf(stderr, "fail to open fb!\n");
		return 0;
	}

	ioctl(fd, FBIOGET_VSCREENINFO, &var);

	Bpp     = var.bits_per_pixel / 8;
	xlen    = var.xres * Bpp;
	scr_len = var.yres * xlen;
	nXL     = var.xres / 16;
	nYL     = nXL;

	ioctl(fd, FBIOGET_FSCREENINFO, &fix);

	fb_mm = mmap(NULL, 
				fix.smem_len,	
				PROT_READ | PROT_WRITE, 
				MAP_SHARED, 
				fd, 
				0
				);

	if (MAP_FAILED == fb_mm) 
	{
		fprintf(stderr, "fail to mmap\n");
		close(fd);
		return -ENOMEM;
	}


	pthread_create(&tid0, NULL, flying, &pt);

	pthread_join(tid0, NULL);

	munmap(fb_mm, fix.smem_len);

	close(fd);

	return 0;
}