/* Simple Video4Linux image grabber. */
/*
 *	Video4Linux Driver Test/Example Framegrabbing Program
 *
 *	Compile with:
 *		gcc -s -Wall -Wstrict-prototypes v4lgrab.c -o v4lgrab
 *      Use as:
 *              v4lgrab >image.ppm
 *
 *	Copyright (C) 1998-05-03, Phil Blundell <philb@gnu.org>
 *      Copied from http://www.tazenda.demon.co.uk/phil/vgrabber.c
 *      with minor modifications (Dave Forrest, drf5n@virginia.edu).
 *
 */

#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <stdio.h>
#include <sys/ioctl.h>
#include <stdlib.h>

#include <linux/types.h>
#include <linux/videodev.h>

#define FILE "/dev/video0"

/* Stole this from tvset.c */

#define READ_VIDEO_PIXEL(buf, format, depth, r, g, b)                   \
{                                                                       \
	switch (format)                                                 \
	{                                                               \
		case VIDEO_PALETTE_GREY:                                \
			switch (depth)                                  \
			{                                               \
				case 4:                                 \
				case 6:                                 \
				case 8:                                 \
					(r) = (g) = (b) = (*buf++ << 8);\
					break;                          \
									\
				case 16:                                \
					(r) = (g) = (b) =               \
					*((unsigned short *) buf);      \
					buf += 2;                       \
					break;                          \
			}                                               \
			break;                                          \
									\
									\
		case VIDEO_PALETTE_RGB565:                              \
		{                                                       \
			unsigned short tmp = *(unsigned short *)buf;    \
			(r) = tmp&0xF800;                               \
			(g) = (tmp<<5)&0xFC00;                          \
			(b) = (tmp<<11)&0xF800;                         \
			buf += 2;                                       \
		}                                                       \
		break;                                                  \
									\
		case VIDEO_PALETTE_RGB555:                              \
			(r) = (buf[0]&0xF8)<<8;                         \
			(g) = ((buf[0] << 5 | buf[1] >> 3)&0xF8)<<8;    \
			(b) = ((buf[1] << 2 ) & 0xF8)<<8;               \
			buf += 2;                                       \
			break;                                          \
									\
		case VIDEO_PALETTE_RGB24:                               \
			(r) = buf[0] << 8; (g) = buf[1] << 8;           \
			(b) = buf[2] << 8;                              \
			buf += 3;                                       \
			break;                                          \
									\
		default:                                                \
			fprintf(stderr,                                 \
				"Format %d not yet supported\n",        \
				format);                                \
	}                                                               \
}

static int get_brightness_adj(unsigned char *image, long size, int *brightness)
{
	long i, tot = 0;
	for (i=0;i<size*3;i++)
		tot += image[i];
	*brightness = (128 - tot/(size*3))/3;
	return !((tot/(size*3)) >= 126 && (tot/(size*3)) <= 130);
}

int main(int argc, char **argv)
{
#ifdef CONFIG_VIDEO_V4L1_COMPAT
	int fd = open(FILE, O_RDONLY), f;
	struct video_capability cap;
	struct video_window win;
	struct video_picture vpic;

	unsigned char *buffer, *src;
	int bpp = 24, r, g, b;
	unsigned int i, src_depth;

	if (fd < 0) {
		perror(FILE);
		exit(1);
	}

	if (ioctl(fd, VIDIOCGCAP, &cap) < 0) {
		perror("VIDIOGCAP");
		fprintf(stderr, "(" FILE " not a video4linux device?)\n");
		close(fd);
		exit(1);
	}

	if (ioctl(fd, VIDIOCGWIN, &win) < 0) {
		perror("VIDIOCGWIN");
		close(fd);
		exit(1);
	}

	if (ioctl(fd, VIDIOCGPICT, &vpic) < 0) {
		perror("VIDIOCGPICT");
		close(fd);
		exit(1);
	}

	if (cap.type & VID_TYPE_MONOCHROME) {
		vpic.depth=8;
		vpic.palette=VIDEO_PALETTE_GREY;    /* 8bit grey */
		if(ioctl(fd, VIDIOCSPICT, &vpic) < 0) {
			vpic.depth=6;
			if(ioctl(fd, VIDIOCSPICT, &vpic) < 0) {
				vpic.depth=4;
				if(ioctl(fd, VIDIOCSPICT, &vpic) < 0) {
					fprintf(stderr, "Unable to find a supported capture format.\n");
					close(fd);
					exit(1);
				}
			}
		}
	}
	else {
		vpic.depth=24;
		vpic.palette=VIDEO_PALETTE_RGB24;

		if(ioctl(fd, VIDIOCSPICT, &vpic) < 0) {
			vpic.palette=VIDEO_PALETTE_RGB565;
			vpic.depth=16;

			if(ioctl(fd, VIDIOCSPICT, &vpic)==-1) {
				vpic.palette=VIDEO_PALETTE_RGB555;
				vpic.depth=15;

				if(ioctl(fd, VIDIOCSPICT, &vpic)==-1) {
					fprintf(stderr, "Unable to find a supported capture format.\n");
					return -1;
				}
			}
		}
	}

	buffer = malloc(win.width * win.height * bpp);
	if (!buffer) {
		fprintf(stderr, "Out of memory.\n");
		exit(1);
	}

	do {
		int newbright;
		read(fd, buffer, win.width * win.height * bpp);
		f = get_brightness_adj(buffer, win.width * win.height, &newbright);
		if (f) {
			vpic.brightness += (newbright << 8);
			if(ioctl(fd, VIDIOCSPICT, &vpic)==-1) {
				perror("VIDIOSPICT");
				break;
			}
		}
	} while (f);

	fprintf(stdout, "P6\n%d %d 255\n", win.width, win.height);

	src = buffer;

	for (i = 0; i < win.width * win.height; i++) {
		READ_VIDEO_PIXEL(src, vpic.palette, src_depth, r, g, b);
		fputc(r>>8, stdout);
		fputc(g>>8, stdout);
		fputc(b>>8, stdout);
	}

	close(fd);
#else
	fprintf(stderr, "V4L1 API is not configured!\n");
#endif
	return 0;
}
