/* 	This code saves the contents of an OpenGL window into a TIFF file.
	It requires libtiff!
*/	

void	DumpWindowTIFF(int win_width, int win_height, char *basename, int step) 
{
	TIFF		*file;
	GLubyte		*image, *p;
	int			i;
	char		filename[MAX_BUFFER_SIZE];

	/* Compose the name of the TIFF file: basename_step#.tif */
	sprintf(filename,"%s_%.4d.tif", basename, step);

	/* Open TIFF file */
	file = TIFFOpen(filename, "w");
	if (file == NULL) {
		return;
	}

	/* Allocate space for the image */
	image = (GLubyte *) malloc(win_width * win_height * sizeof(GLubyte) * 3);

	/* OpenGL's default 4 byte pack alignment would leave extra bytes at the
	 end of each image row so that each full row contained a number of bytes
	 divisible by 4.  Ie, an RGB row with 3 pixels and 8-bit componets would
	 be laid out like "RGBRGBRGBxxx" where the last three "xxx" bytes exist
	 just to pad the row out to 12 bytes (12 is divisible by 4). To make sure
	 the rows are packed as tight as possible (no row padding), set the pack
	 alignment to 1. */
	glPixelStorei(GL_PACK_ALIGNMENT, 1);

	/* Read framebuffer into image */
	glReadPixels(0, 0, win_width, win_height, GL_RGB, GL_UNSIGNED_BYTE, image);

	/* Set TIFF tags */
	TIFFSetField(file, TIFFTAG_IMAGEWIDTH, (uint32) win_width);
	TIFFSetField(file, TIFFTAG_IMAGELENGTH, (uint32) win_height);
	TIFFSetField(file, TIFFTAG_BITSPERSAMPLE, 8);
	/* This uses LZW compression */
	TIFFSetField(file, TIFFTAG_COMPRESSION, COMPRESSION_LZW);
	/* This uses no compression */
	/* TIFFSetField(file, TIFFTAG_COMPRESSION, COMPRESSION_NONE); */
	TIFFSetField(file, TIFFTAG_PHOTOMETRIC, PHOTOMETRIC_RGB);
	TIFFSetField(file, TIFFTAG_SAMPLESPERPIXEL, 3);
	TIFFSetField(file, TIFFTAG_PLANARCONFIG, PLANARCONFIG_CONTIG);
	TIFFSetField(file, TIFFTAG_ROWSPERSTRIP, 1);

	/* Write image to TIFF file scanline by scanline */
	p = image;
	for (i = win_height - 1; i >= 0; i--) {
		if (TIFFWriteScanline(file, p, i, 0) < 0) {
			free(image);
			TIFFClose(file);
			return;
		}
		p += win_width * sizeof(GLubyte) * 3;
	}

	/* Close TIFF file */
	TIFFClose(file);
}