/**
* @file			alg_rgb_to_yuv.h
* @brief		color space conversion definitions
* @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 RGB to YUV color space conversion and is pixel size independent. Including this code at the
 * C-Source file will define the pixel-bit-depth (see color.c).
 */
// static void rgb8_to_yuv(int32_t *img_yuv, const uint8_t *img_rgb, const int height, const int width)
// static void rgb16_to_yuv(int32_t *img_yuv, const uint16_t *img_rgb, const int height, const int width)
{
	
	int x, y, index;
	int blue, green, red;
	int pixel_y, pixel_u, pixel_v;
	const int scale_fact = 10;
	
	const int y_r = (int)roundf(RGB2YUV_COEFF_Y_RED*(1<<scale_fact));
	const int y_g = (int)roundf(RGB2YUV_COEFF_Y_GREEN*(1<<scale_fact));
	const int y_b = (int)roundf(RGB2YUV_COEFF_Y_BLUE*(1<<scale_fact));
	
	const int u_r = (int)roundf(RGB2YUV_COEFF_U_RED*(1<<scale_fact));
	const int u_g = (int)roundf(RGB2YUV_COEFF_U_GREEN*(1<<scale_fact));
	const int u_b = (int)roundf(RGB2YUV_COEFF_U_BLUE*(1<<scale_fact));
	
	const int v_r = (int)roundf(RGB2YUV_COEFF_V_RED*(1<<scale_fact));
	const int v_g = (int)roundf(RGB2YUV_COEFF_V_GREEN*(1<<scale_fact));
	const int v_b = (int)roundf(RGB2YUV_COEFF_V_BLUE*(1<<scale_fact));
	
	
	
	index = 0;
	for(y = 0; y < height; y++) {
		for(x = 0; x < width; x++) {
			
			// put each RGB color on stack
			red = img_rgb[index];
			green = img_rgb[index + 1];
			blue = img_rgb[index + 2];
			
			// color space conversion from  RGB to YUV
			pixel_y = (y_r*red + y_g*green + y_b*blue) >> scale_fact;
			pixel_u = (u_r*red + u_g*green + u_b*blue) >> scale_fact;
			pixel_v = (v_r*red + v_g*green + v_b*blue) >> scale_fact;
			
			img_yuv[index] = pixel_y;
			img_yuv[index+1] = pixel_u;
			img_yuv[index+2] = pixel_v;
			
			index += 3;
		}
	}
}