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

#ifdef UNIX
#include <unistd.h>
#include <sys/wait.h>
#endif

#ifdef WIN32
#define M_PI	3.14159265
#include <windows.h>
#endif


#include <GL/gl.h>
#include <GL/glu.h>
#include "glut.h"



void			DumpAndWriteWholeWindow( char * );
unsigned char *		DumpPixels( int, int, int, int );
void			WritePpm( char *, unsigned char *, int, int );


/**
 ** dump and write the whole window:
 **/

void
DumpAndWriteWholeWindow( char *filename )
{
	unsigned char *array;
	int xdim, ydim;

	xdim = glutGet( GLUT_WINDOW_WIDTH );
	ydim = glutGet( GLUT_WINDOW_HEIGHT );
	array = DumpPixels( 0, 0, xdim, ydim );
	WritePpm( filename, array, xdim, ydim );
	delete [] array;
}




/**
 ** Perform an OpenGL window dump:
 **/


unsigned char *
DumpPixels( int xl, int yb, int xdim, int ydim )
{
	unsigned char *array;		/* array to hold the RGB dump	*/


	/* allocate the array to hold the RGB pixel values:		*/

	array = new unsigned char[ 3*xdim*ydim ];
	if( array == NULL )
	{
		fprintf( stderr, "DumpPpm() cannot malloc the temporary array!\n" );
		return NULL;
	}


	/* setup and do the dump:					*/

	glPixelStorei( GL_PACK_ALIGNMENT, 1 );
	glPixelStorei( GL_PACK_ROW_LENGTH, xdim );
	glReadBuffer( GL_FRONT );
	glReadPixels( xl, yb, xdim, ydim, GL_RGB, GL_UNSIGNED_BYTE, array );

	return array;
}



/**
 ** Write a PPM image file:
 **/

void
WritePpm( char *filename, unsigned char *array, int xdim, int ydim )
{
	FILE *fp;			/* pointer to PPM file	*/
	unsigned char *p;		/* pointer into array[]		*/
	int i, j;			/* counters			*/
	int ipix;			/* hex pixel count		*/


	/* open the file for this image:				*/

	fp = fopen( filename, "w" );
	if( fp == NULL)
	{
		fprintf( stderr, "DumpPpm() cannot create the PPM file '%s'\n", filename );
		return;
	}


	/* write the PPM header:					*/

	fprintf( fp, "P3\n%d %d\n255\n", xdim, ydim );


	/* write the pixels:						*/

	for( i = 0; i < ydim; i++ )
	{
		fprintf( fp, "\n\n" );
		p = &array[ 3*xdim*(ydim-1-i) ];
		for( j = 0, ipix = 0; j < xdim; j++, p += 3 )
		{
			fprintf( fp, "%03d %03d %03d  ", (int)*(p+0), (int)*(p+1), (int)*(p+2) );
			if( ++ipix >= 5 )
			{
				putc( '\n', fp );
				ipix = 0;
			}
		}
	}


	/* end game:							*/

	fflush( fp );
	fclose( fp );
}