直接操作Framebuffer测试液晶屏

自己写的一个液晶屏测试小程序，直接写frambuffer，总共四幅画面，如下所示：

程序很简单，就是进行内存映射之后写frambuffer。这个程序是在华清远见的一个程序上改的，目前只支持16BPP的液晶屏。代码如下：

#include <unistd.h>
#include <stdlib.h>
#include <stdio.h>
#include <fcntl.h>
#include <linux/fb.h>
#include <sys/mman.h>

int main(int argc, char *argv[])
{
	int fbfd = 0;
	struct fb_var_screeninfo vinfo;
	unsigned long screensize = 0;
	unsigned long location = 0;
	char *fbp = 0;
	int x = 0, y = 0;
	int seg_len = 0;
	int tmp_seg_len = 0;
	int seg_num = 0;
	unsigned short rgb = 0;
	unsigned int r = 0, g = 0, b = 0;

	// Open the file for reading and writing
	fbfd = open("/dev/fb0", O_RDWR);
	if (!fbfd) {
		printf("Error: cannot open framebuffer device.\n");
		exit(1);
	}
	printf("The framebuffer device was opened successfully.\n");

	// Get variable screen information
	if (ioctl(fbfd, FBIOGET_VSCREENINFO, &vinfo)) {
		printf("Error reading variable information.\n");
		exit(1);
	}

	printf("%dx%d, %dbpp\n", vinfo.xres, vinfo.yres, vinfo.bits_per_pixel);
	if (vinfo.bits_per_pixel != 16) {
		printf("Error: not supported bits_per_pixel, it only supports 16 bit color\n");
		exit(1);
	}

	// Figure out the size of the screen in bytes
	screensize = vinfo.xres * vinfo.yres * 2;

	// 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");

	seg_len = vinfo.yres/6;
#if 1
	seg_len = vinfo.yres/6;
	for (seg_num = 0; seg_num < 6; seg_num++) {
		if (seg_num == 5) 
			tmp_seg_len = vinfo.yres - seg_len*5;
		else 
			tmp_seg_len = seg_len;
		
		for (y = 0; y < tmp_seg_len; y++) {
			for (x = 0; x < vinfo.xres; x++) {
				location = seg_num*seg_len*vinfo.xres*2 + (y*vinfo.xres+ x)*2;
				switch (seg_num) {
					case 0:
					r = 0xff;
					g = (0xff/seg_len)*y;
					b = 0;
					break;
					case 1:
					r = (0xff/seg_len)*(seg_len-y);
					g = 0xff;
					b = 0;
					break;
					case 2:
					r = 0;
					g = 0xff;
					b = (0xff/seg_len)*y; 
					break;
					case 3:
					r = 0;
					g = (0xff/seg_len)*(seg_len-y);
					b = 0xff;
					break;
					case 4:
					r =  (0xff/seg_len)*y; 	
					g = 0;
					b = 0xff;
					break;
					case 5:
					r = 0xff;
					b = (0xff/seg_len)*(seg_len-y); 
					g = 0;
					break;
					default:
					printf("%s--%d:unknown seg_num %d\n", __FILE__, __LINE__);
					break;
				}

				r = (r*0x1f)/0xff;
				g = (g*0x3f)/0xff;
				b = (b*0x1f)/0xff;
				rgb = (r << 11) | (g << 5) | b;
				*((unsigned short*)(fbp + location)) = rgb;
			}
		}
	}
	
	sleep(2);
	
	seg_len = vinfo.yres/6;
	for (seg_num = 0; seg_num < 6; seg_num++) {
		if (seg_num == 5) 
			tmp_seg_len = vinfo.yres - seg_len*5;
		else 
			tmp_seg_len = seg_len;

		for (y = 0; y < tmp_seg_len; y++) {
			for (x = 0; x < vinfo.xres; x++) {
				location = seg_num*seg_len*vinfo.xres*2 + (y*vinfo.xres+ x)*2;
				switch (seg_num) {
					case 0://grey
					r = 100;
					g = 100;
					b = 100; 
					break;
					case 1: //black
					r = 0x00;
					g = 0x00;
					b = 0x00;
					break;
					case 2://white
					r = 0xff;
					g = 0xff;
					b = 0xff;
					break;
					case 3://red
					r = 0xff;
					g = 0;
					b = 0;
					break;
					case 4: //green
					r =  0; 	
					g = 0xff;
					b = 0;
					break;
					case 5: //blue
					r = 0;
					g = 0;
					b = 0xff; 
					break;
					default:
					printf("%s--%d:unknown seg_num %d\n", __FILE__, __LINE__);
					break;	
				}

				r = (r*0x1f)/0xff;
				g = (g*0x3f)/0xff;
				b = (b*0x1f)/0xff;
				rgb = (r << 11) | (g << 5) | b;
				*((unsigned short*)(fbp + location)) = rgb;
			}
		}
	}
#endif

#if 1
	sleep(2);

	seg_len = vinfo.xres/6;
	for (seg_num = 0; seg_num < 6; seg_num++) {	
		if (seg_num == 5) 
			tmp_seg_len = vinfo.xres - seg_len*5;
		else 
			tmp_seg_len = seg_len;

		for (x = 0; x < tmp_seg_len; x++) {
			for (y = 0; y < vinfo.yres; y++) {
				location = y*vinfo.xres*2 + (seg_num*seg_len + x)*2;
				
				switch (seg_num) {
					case 0:
					r = 0xff;
					g = (0xff/seg_len)*x;
					b = 0;
					break;
					case 1:
					r = (0xff/seg_len)*(seg_len-x);
					g = 0xff;
					b = 0;
					break;
					case 2:
					r = 0;
					g = 0xff;
					b = (0xff/seg_len)*x; 
					break;
					case 3:
					r = 0;
					g = (0xff/seg_len)*(seg_len-x);
					b = 0xff;
					break;
					case 4:
					r =  (0xff/seg_len)*x; 	
					g = 0;
					b = 0xff;
					break;
					case 5:
					r = 0xff;
					g = 0;
					b = (0xff/seg_len)*(seg_len-x); 
					break;
					default:
					printf("%s--%d:unknown seg_num %d\n", __FILE__, __LINE__);
					break;
				}

				r = (r*0x1f)/0xff;
				g = (g*0x3f)/0xff;
				b = (b*0x1f)/0xff;
				rgb = (r << 11) | (g << 5) | b;
				*((unsigned short*)(fbp + location)) = rgb;
			}
		}
	}

	sleep(2);

	seg_len = vinfo.xres/6;
	/* white black gray red green blue */
	for (seg_num = 0; seg_num < 6; seg_num++) {
		if (seg_num == 5) 
			tmp_seg_len = vinfo.xres - seg_len*5;
		else 
			tmp_seg_len = seg_len;

		for (x = 0; x < tmp_seg_len; x++) {
			for (y = 0; y < vinfo.yres; y++) {
				location = y*vinfo.xres*2 + (seg_num*seg_len + x)*2;
				
				switch (seg_num) {
					case 0://grey
					r = 100;
					g = 100;
					b = 100; 
					break;
					case 1://black
					r = 0;
					g = 0;
					b = 0;
					break;
					case 2: //white
					r = 0xff;
					g = 0xff;
					b = 0xff;
					break;
					case 3://red
					r = 0xff;
					g = 0;
					b = 0;
					break;
					case 4: //green
					r =  0; 	
					g = 0xff;
					b = 0;
					break;
					case 5: //blue
					r = 0;
					g = 0;
					b = 0xff; 
					break;
					default:
					printf("%s--%d:unknown seg_num %d\n", __FILE__, __LINE__);
					break;
				}
				
				r = (r*0x1f)/0xff;
				g = (g*0x3f)/0xff;
				b = (b*0x1f)/0xff;
				rgb = (r << 11) | (g << 5) | b;
				*((unsigned short*)(fbp + location)) = rgb;
			}
		}
	}
#endif

	munmap(fbp, screensize);
	close(fbfd);
	return 0;
}