/**
* @file			alg_debayer_bilinear.h
* @brief		bilinear demosaicing algorithm
* @author		Patrick Roth - roth@stettbacher.ch
* @copyright	Stettbacher Signal Processing AG
* 
* @remarks
*
* <PRE>
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
* </PRE>
*
*/



/*
 * This code inplements a bilinear demosaicing algorithm and is pixel size independent. Including this code at the
 * C-Source file will define the pixel-bit-depth (see debayer.c).
 */
// static void bilinear8(uint8_t *img_rgb, const uint8_t *img_bayer, const int height, const int width, const enum enumBayerPattern_t bayer_pattern)
// static void bilinear16(uint16_t *img_rgb, const uint16_t *img_bayer, const int height, const int width, const enum enumBayerPattern_t bayer_pattern)
{
	int x, y, red, green, blue;
	int index_rgb, index_upper, index_center, index_lower;
	enum enumBayerPattern_t pattern, pattern_nextline;


	red = 0;
	green = 0;
	blue = 0;
	pattern_nextline = bayer_pattern;
	pattern = bayer_pattern;

	/*
	* figure out pattern color with coordinate 1/1 (second line / second row)
	*/
	switch(bayer_pattern) {
		case BP_GR:		// green-red-green-red-...
			pattern = BP_GB;
			pattern_nextline = BP_RG;
			break;
			
		case BP_RG:		// red-green-red-green-...
			pattern = BP_BG;
			pattern_nextline = BP_GR;
			break;
			
		case BP_BG:		// blue-green-blue-green-...
			pattern = BP_RG;
			pattern_nextline = BP_GB;
			break;
			
		case BP_GB:		// green-blue-green-blue-...
			pattern = BP_GR;
			pattern_nextline = BP_BG;
			break;
	}

	/*
	 * loop through image without border area
	 */
	for(y = 1; y < (height-1); y++) {
		
		// initialize line indices used to reference pixel at 3x3 kernel
		index_upper = (y-1)*width;
		index_center = y*width;
		index_lower = (y+1)*width;
		
		// initialize index used to reference pixel at RGB image
		index_rgb = y*width*3+3;
		
		
		for(x = 1; x < (width-1); x++) {
			
			calc_bilinear(img_bayer[index_upper], img_bayer[index_upper+1], img_bayer[index_upper+2],
						  img_bayer[index_center], img_bayer[index_center+1], img_bayer[index_center+2],
						  img_bayer[index_lower], img_bayer[index_lower+1], img_bayer[index_lower+2],
						  &pattern, &red, &green, &blue);
			
			img_rgb[index_rgb] = red;
			img_rgb[index_rgb+1] = green;
			img_rgb[index_rgb+2] = blue;
			
			index_rgb += 3;
			index_upper++;
			index_center++;
			index_lower++;
		}
		
		pattern = pattern_nextline;
		pattern_nextline = getBayerType(pattern, 1, 0);
	}
	
	/*
	 * handle pixels at horizontal upper border line
	 */
	pattern = getBayerType(bayer_pattern, 0, 1);
	index_center = 0;
	index_upper = width;
	index_lower = width;
	index_rgb = 3;
	for(x = 1; x < (width-1); x++) {
		
		calc_bilinear(img_bayer[index_upper], img_bayer[index_upper+1], img_bayer[index_upper+2],
					  img_bayer[index_center], img_bayer[index_center+1], img_bayer[index_center+2],
					  img_bayer[index_lower], img_bayer[index_lower+1], img_bayer[index_lower+2],
					  &pattern, &red, &green, &blue);
		
		img_rgb[index_rgb] = red;
		img_rgb[index_rgb+1] = green;
		img_rgb[index_rgb+2] = blue;
		
		index_rgb += 3;
		index_upper++;
		index_center++;
		index_lower++;
	}
	
	/*
	 * handle pixels at horizontal lower border line
	 */
	pattern = getBayerType(bayer_pattern, height-1, 1);
	index_center = (height-1)*width;
	index_upper = index_center-width;
	index_lower = index_center-width;
	index_rgb = ((height-1)*width*3)+3;
	for(x = 1; x < (width-1); x++) {
		
		calc_bilinear(img_bayer[index_upper], img_bayer[index_upper+1], img_bayer[index_upper+2],
					  img_bayer[index_center], img_bayer[index_center+1], img_bayer[index_center+2],
					  img_bayer[index_lower], img_bayer[index_lower+1], img_bayer[index_lower+2],
					  &pattern, &red, &green, &blue);
		
		img_rgb[index_rgb] = red;
		img_rgb[index_rgb+1] = green;
		img_rgb[index_rgb+2] = blue;
		
		index_rgb += 3;
		index_upper++;
		index_center++;
		index_lower++;
	}
	
	/*
	 * handle pixels at vertical left border line
	 */
	index_upper = 0;
	index_center = width;
	index_lower = 2*width;
	index_rgb = width*3;
	for(y = 1; y < (height-1); y++) {
		pattern = getBayerType(bayer_pattern, y, 0);
		calc_bilinear(img_bayer[index_upper+1], img_bayer[index_upper], img_bayer[index_upper+1],
					  img_bayer[index_center+1], img_bayer[index_center], img_bayer[index_center+1],
					  img_bayer[index_lower+1], img_bayer[index_lower], img_bayer[index_lower+1],
					  &pattern, &red, &green, &blue);
		
		img_rgb[index_rgb] = red;
		img_rgb[index_rgb+1] = green;
		img_rgb[index_rgb+2] = blue;
		
		index_rgb += 3*width;
		index_upper += width;
		index_center += width;
		index_lower += width;
	}
	
	/*
	 * handle pixels at vertical right border line
	 */
	index_upper = width-2;
	index_center = index_upper+width;
	index_lower = index_upper+2*width;
	index_rgb = width*3*2-3;
	for(y = 1; y < (height-1); y++) {
		pattern = getBayerType(bayer_pattern, y, width-1);
		calc_bilinear(img_bayer[index_upper], img_bayer[index_upper+1], img_bayer[index_upper],
					  img_bayer[index_center], img_bayer[index_center+1], img_bayer[index_center],
					  img_bayer[index_lower], img_bayer[index_lower+1], img_bayer[index_lower],
					  &pattern, &red, &green, &blue);
		
		img_rgb[index_rgb] = red;
		img_rgb[index_rgb+1] = green;
		img_rgb[index_rgb+2] = blue;
		
		index_rgb += 3*width;
		index_upper += width;
		index_center += width;
		index_lower += width;
	}
	
	
	/*
	 * Handle upper left corner
	 */
	pattern = getBayerType(bayer_pattern, 0, 0);
	index_upper = width;
	index_lower = width;
	calc_bilinear(img_bayer[index_upper+1], img_bayer[index_upper], img_bayer[index_upper+1],
				  img_bayer[1], img_bayer[0], img_bayer[1],
				  img_bayer[index_lower+1], img_bayer[index_lower], img_bayer[index_lower+1],
				  &pattern, &red, &green, &blue);
	img_rgb[0] = red;
	img_rgb[1] = green;
	img_rgb[2] = blue;
	
	/*
	 * Handle upper right corner
	 */
	pattern = getBayerType(bayer_pattern, 0, width-1);
	index_upper = 2*width-2;
	index_center = width-2;
	index_lower = 2*width-2;
	calc_bilinear(img_bayer[index_upper], img_bayer[index_upper+1], img_bayer[index_upper],
				  img_bayer[index_center], img_bayer[index_center+1], img_bayer[index_center],
				  img_bayer[index_lower], img_bayer[index_lower+1], img_bayer[index_lower],
				  &pattern, &red, &green, &blue);
	index_rgb = 3*width-3;
	img_rgb[index_rgb] = red;
	img_rgb[index_rgb+1] = green;
	img_rgb[index_rgb+2] = blue;
	
	/*
	 * Handle lower left corner
	 */
	pattern = getBayerType(bayer_pattern, height-1, 0);
	index_upper = (height-2)*width;
	index_center = (height-1)*width;
	index_lower = (height-2)*width;
	calc_bilinear(img_bayer[index_upper+1], img_bayer[index_upper], img_bayer[index_upper+1],
				  img_bayer[index_center+1], img_bayer[index_center], img_bayer[index_center+1],
				  img_bayer[index_lower+1], img_bayer[index_lower], img_bayer[index_lower+1],
				  &pattern, &red, &green, &blue);
	index_rgb = ((height-1)*width)*3;
	img_rgb[index_rgb] = red;
	img_rgb[index_rgb+1] = green;
	img_rgb[index_rgb+2] = blue;
	
	/*
	 * Handle lower right corner
	 */
	pattern = getBayerType(bayer_pattern, height-1, width-1);
	index_upper = (height-2)*width-2;
	index_center = (height-1)*width-2;
	index_lower = (height-2)*width-2;
	calc_bilinear(img_bayer[index_upper], img_bayer[index_upper+1], img_bayer[index_upper],
				  img_bayer[index_center], img_bayer[index_center+1], img_bayer[index_center],
				  img_bayer[index_lower], img_bayer[index_lower+1], img_bayer[index_lower],
				  &pattern, &red, &green, &blue);
	index_rgb = height*width*3-3;
	img_rgb[index_rgb] = red;
	img_rgb[index_rgb+1] = green;
	img_rgb[index_rgb+2] = blue;
	
	
}