/*
 * writeimage.c -- By Nathan Folkert -- 06/15/10
 * 
 * Creates a bmp image from the video device
 *
 */

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

/*
 * Structures for the bmp file header
 */
struct header {
  unsigned char type[2];
  unsigned char size[4];
  unsigned char res1[2];
  unsigned char res2[2];
  unsigned char offset[4];
};
struct information {
  unsigned char size[4];
  unsigned char width[4];
  unsigned char height[4];
  unsigned char planes[2];
  unsigned char bitcount[2];
  unsigned char compression[4];
  unsigned char sizeimage[4];
  unsigned char meter[4];
  unsigned char meter2[4];
  unsigned char colors[4];
  unsigned char important[4];
};

struct header head;
struct information info;

/* Height and Width of image in pixels */
#define WIDTH 512
#define HEIGHT 480

/*
 * Helper functions to simplify code
 */
void initStructs(void);
void initBuf(char* buf);
void writePicture(char* buf , char* buffer);

int fdwrite;

int main()
{
  int fd;
  
  /* Open the two needed files */
  /* Output file */
  fdwrite = open ("pic.bmp" , O_RDWR | O_CREAT);
  if( ! fdwrite )
    {
      printf("Error Opening Output File\n" );
      return -1;
    }
  /* Video Device File */
  fd = open ("/dev/video0" , O_RDWR );
  if( ! fd )
    {
      printf("Error opening video0\n" );
      return -1;
    }

  /* Buffer that is mapped to the device memory */
  char* vidbuf;

  /* Buffer that is written to the output file */
  char* buf;

  /* Allocated output buffer */
  buf = (char *) calloc(HEIGHT*WIDTH*3+54 , 1);

  /* Map vidbuf to the memory on the device */
  vidbuf = mmap(NULL , getpagesize()*4, PROT_READ | PROT_WRITE , MAP_SHARED , fd , 0);

  initStructs();
  
  initBuf(buf);
  
  writePicture(buf , vidbuf);
 
  /* Cleanup */
  free(buf);
  close( fd );
  close( fdwrite );
  return 0;
 
}

/*
 * void writePicture(char* buf , char* buffer)
 * Write the picture out to the file opened by fdwrite
 */
void writePicture(char* buf , char* vidbuf)
{
  int j = 0;
  int i = 0;  
  int x = 54;
  
  vidbuf[8195] = 0;
  for( j = 0; j < HEIGHT; j++ )
    {
      /* Increment the HRT_Y_LOW_REG */
      vidbuf[8194] = j;
      for( i =WIDTH-1 ; i >= 0 ; i-- ) {
	/* Each pixel needs to be written three times */
	buf[x++] = vidbuf[i];
	buf[x++] = vidbuf[i];
	buf[x++] = vidbuf[i];
      }
      /* Increment the HRT_Y_HIGH_REG when needed */
      if( j == 255 )
	vidbuf[8195] = 1;
    }
   
  write( fdwrite , buf ,HEIGHT*WIDTH*3+54 );
}

/*
 * void initStructs(void)
 * Initialize the structures for the bmp header
 */
void initStructs(void)
{
  head.type[0] = 0x42;
  head.type[1] = 0x4D;

  head.size[0] = 0x0;
  head.size[1] = 0x3;
  head.size[2] = 0xAD;
  head.size[3] = 0xD4;

  head.res1[0] = 0x0;
  head.res1[1] = 0x0;
  head.res2[0] = 0x0;
  head.res2[1] = 0x0;

  head.offset[0] = 0x36;
  head.offset[1] = 0x0;
  head.offset[2] = 0x0;
  head.offset[3] = 0x0;

  info.size[0] = 0x28;
  info.size[1] = 0x0;
  info.size[2] = 0x0;
  info.size[3] = 0x0;

  //512 0x200
  info.width[0] = 0x0; 
  info.width[1] = 0x02;
  info.width[2] = 0x0;
  info.width[3] = 0x0;

  //480
  info.height[0] = 0xE0;
  info.height[1] = 0x1;
  info.height[2] = 0x0;
  info.height[3] = 0x0;

  info.planes[0] = 0x1;
  info.planes[1] = 0x0;
  
  info.bitcount[0] = 0x18;
  info.bitcount[1] = 0x0;

  info.compression[0] = 0x0;
  info.compression[1] = 0x0;
  info.compression[2] = 0x0;
  info.compression[3] = 0x0;
 
  info.sizeimage[0] = 0x0;
  info.sizeimage[1] = 0x0;
  info.sizeimage[2] = 0x0;
  info.sizeimage[3] = 0x0;

  info.meter[0] = 0x20;
  info.meter[1] = 0x2e;
  info.meter[2] = 0x0;
  info.meter[3] = 0x0;
 
  info.meter2[0] = 0x20;
  info.meter2[1] = 0x2e;
  info.meter2[2] = 0x0;
  info.meter2[3] = 0x0;

  info.colors[0] = 0x0;
  info.colors[1] = 0x0;
  info.colors[2] = 0x0;
  info.colors[3] = 0x0;

  info.important[0] = 0x0;
  info.important[1] = 0x0;
  info.important[2] = 0x0;
  info.important[3] = 0x0;

}

/*
 * void initBuf(char *buf)
 * Initialize the buffer with the bmp header
 */
void initBuf(char* buf)
{
  buf[0] = head.type[0];
  buf[1] = head.type[1];
  buf[2] = head.size[0];
  buf[3] = head.size[1];
  buf[4] = head.size[2];
  buf[5] = head.size[3];
  buf[6] = head.res1[0];
  buf[7] = head.res1[1];
  buf[8] = head.res2[0];
  buf[9] = head.res2[1];
  buf[10] = head.offset[0];
  buf[11] = head.offset[1];
  buf[12] = head.offset[2];
  buf[13] = head.offset[3];

  buf[14] = info.size[0];
  buf[15] = info.size[1];
  buf[16] = info.size[2];
  buf[17] = info.size[3];

  buf[18] = info.width[0];
  buf[19] = info.width[1];
  buf[20] = info.width[2];
  buf[21] = info.width[3];

  buf[22] = info.height[0];
  buf[23] = info.height[1];
  buf[24] = info.height[2];
  buf[25] = info.height[3];

  buf[26] = info.planes[0];
  buf[27] = info.planes[1];

  buf[28] = info.bitcount[0];
  buf[29] = info.bitcount[1];

  buf[30] = info.compression[0];
  buf[31] = info.compression[1];
  buf[32] = info.compression[2];
  buf[33] = info.compression[3];

  buf[34] = info.sizeimage[0];
  buf[35] = info.sizeimage[1];
  buf[36] = info.sizeimage[2];
  buf[37] = info.sizeimage[3];

  buf[38] = info.meter[0];
  buf[39] = info.meter[1];
  buf[40] = info.meter[2];
  buf[41] = info.meter[3];
 
  buf[42] = info.meter2[0];
  buf[43] = info.meter2[1];
  buf[44] = info.meter2[2];
  buf[45] = info.meter2[3];

  buf[46] = info.colors[0];
  buf[47] = info.colors[1];
  buf[48] = info.colors[2];
  buf[49] = info.colors[3];

  buf[50] = info.important[0];
  buf[51] = info.important[1];
  buf[52] = info.important[2];
  buf[53] = info.important[3];
}