/* color test image generator
 *
 * (C) 2019 by Andreas Eversberg <jolly@eversberg.eu>
 * All Rights Reserved
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#include <math.h>
#include <stdlib.h>
#include <stdint.h>
#include "../libsample/sample.h"
#include "color.h"

#define RAMP_WIDTH	0.0000002

static struct color_bar {
	double amplitude, phase;
} color_bar[8] = {
	{0.0, 0.0},
	{0.336, 167.1},
	{0.474, 283.5},
	{0.443, 240.7},
	{0.443, 60.7},
	{0.474, 103.5},
	{0.336, 347.1},
	{0.0, 0.0},
};

int color_gen_line(sample_t *sample, double x, double samplerate, sample_t *color_u, sample_t *color_v, int v_polarity, double line_start, double line_end)
{
	int b = 5;
	double step = 1.0 / samplerate;
	int i = 0;
	double amplitude, Y, U, V, colorphase;

	/* skip x to line_start */
	while (x < line_start && x < line_end) {
		i++;
		x += step;
	}
	if (x >= line_end)
		return i;

	/* color */
	Y = (1.0 - (double)b / 7.0) * 0.75;
	amplitude = color_bar[b].amplitude;
	if (v_polarity < 0)
		colorphase = (360.0 - color_bar[b].phase) / 180.0 * M_PI;
	else
		colorphase = color_bar[b].phase / 180.0 * M_PI;
	U = cos(colorphase) * amplitude;
	V = sin(colorphase) * amplitude;
	while (x < line_end) {
		color_u[i] = U;
		color_v[i] = V;
		sample[i++] = Y;
		x += step;
	}

	return i;
}