/* ************************************************************************** */
/*                                                                            */
/*                                                        :::      ::::::::   */
/*   fdf_drawing.c                                      :+:      :+:    :+:   */
/*                                                    +:+ +:+         +:+     */
/*   By: narnaud <narnaud@student.42.fr>            +#+  +:+       +#+        */
/*                                                +#+#+#+#+#+   +#+           */
/*   Created: 2021/11/05 14:44:08 by narnaud           #+#    #+#             */
/*   Updated: 2022/02/24 13:45:03 by narnaud          ###   ########.fr       */
/*                                                                            */
/* ************************************************************************** */

#include "fdf.h"

/* Function : get_color
 * --------------------
 *  return color as decimal value depending of altitude.
 *  point with an altitude of zero are green,
 *  points with negativ altitude tend  to the blue
 *  points with positiv altitude tend to the red.
 *
 *  db : map datas,
 *  x, y : points coordinates,
 *  coef : the position of the point through the line,
 *  	negativ for vertical lines,
 *  	positiv for horizontal lines,
 *
 * return : integer which give the color of the point formated as :
 * 			Red * 256^2 + Green * 256 + Blue
 * 			Red, Green and Blue beeing between 0 and 255.
 */

int	get_color(t_datas *db, t_2di coord, float coef)
{
	int		z0;
	float	dz;
	int		height;
	int		color_coef;

	if (coord.x > 0 && coef <= 0)
	{
		z0 = db->map->altitude[coord.y][coord.x - 1];
		dz = (float)db->map->altitude[coord.y][coord.x] - (float)z0;
		height = z0 - (int)round(coef * dz);
		color_coef = (height * 254) / db->map->hightest + 1;
	}
	else
	{
		z0 = db->map->altitude[coord.y - 1][coord.x];
		dz = (float)db->map->altitude[coord.y][coord.x] - (float)z0;
		height = z0 + (int)round(coef * dz);
		color_coef = (height * 254) / db->map->hightest + 1;
	}
	if (height >= 0)
		return (256 * 255 + color_coef * 256 * 255);
	else
		return (256 * 255 - color_coef);
}

/* Function : draw_line
 * --------------------
 *  datas :
 *  start :
 *  end :
 *  buffer :
 *
 *  return :
 *
 */

void	draw_horiz_line(t_datas *datas, t_2di coord, int *buffer)
{
	size_t		i;
	t_2df		dp;
	t_2df		pos;
	size_t		len;

	i = 0;
	pos.x = (float)datas->cam->render[coord.y][coord.x - 1].x;
	pos.y = (float)datas->cam->render[coord.y][coord.x - 1].y;
	dp.x = (float)datas->cam->render[coord.y][coord.x].x - pos.x;
	dp.y = (float)datas->cam->render[coord.y][coord.x].y - pos.y;
	len = sqrt(dp.x * dp.x + dp.y * dp.y);
	dp.x /= len;
	dp.y /= len;
	while (i < len)
	{
		pos.x += dp.x;
		pos.y += dp.y;
		if (pos.x >= 0 && pos.y >= 0 && \
				pos.x < WIN_X_SZ && pos.y < WIN_Y_SZ)
			buffer[datas->line_bytes * (int)floor(pos.y) + (int)floor(pos.x)] \
				= get_color(datas, coord, -(float)i / (float)len);
		i++;
	}
}

void	draw_vert_line(t_datas *datas, t_2di coord, int *buffer)
{
	size_t		i;
	t_2df		dp;
	t_2df		pos;
	size_t		len;

	i = 0;
	pos.x = (float)datas->cam->render[coord.y - 1][coord.x].x;
	pos.y = (float)datas->cam->render[coord.y - 1][coord.x].y;
	dp.x = (float)datas->cam->render[coord.y][coord.x].x - pos.x;
	dp.y = (float)datas->cam->render[coord.y][coord.x].y - pos.y;
	len = sqrt(dp.x * dp.x + dp.y * dp.y);
	dp.x /= len;
	dp.y /= len;
	while (i < len)
	{
		pos.x += dp.x;
		pos.y += dp.y;
		if (pos.x >= 0 && pos.y >= 0 && \
			pos.x < WIN_X_SZ && pos.y < WIN_Y_SZ)
			buffer[datas->line_bytes * (int)floor(pos.y) + (int)floor(pos.x)] \
				= get_color(datas, coord, (float)i / (float)len);
		i++;
	}
}

void	get_coords(t_2di coord, t_datas *datas)
{
	t_2df	vars;
	t_3d	pt;

	pt.x = coord.x - datas->map->width / 2;
	pt.y = coord.y - datas->map->depth / 2;
	pt.z = datas->map->altitude[coord.y][coord.x] * datas->map->z_mult;
	pt.yaw.cos = datas->cam->ang.yaw.cos;
	pt.yaw.sin = datas->cam->ang.yaw.sin;
	pt.pitch.cos = datas->cam->ang.pitch.cos;
	pt.pitch.sin = datas->cam->ang.pitch.sin;
	vars.x = pt.yaw.cos * pt.x + pt.yaw.sin * pt.y;
	vars.y = pt.pitch.sin * (pt.yaw.sin * pt.x - pt.yaw.cos * pt.y) - \
				pt.pitch.cos * pt.z;
	datas->cam->render[coord.y][coord.x].x = datas->cam->center.x + \
									round(datas->cam->zoom * vars.x);
	datas->cam->render[coord.y][coord.x].y = datas->cam->center.y + \
									round(datas->cam->zoom * vars.y);
}

void	draw_map(t_datas *datas)
{
	t_2di	coord;
	int		*buffer;

	datas->img = mlx_new_image(datas->mlx, WIN_X_SZ, WIN_Y_SZ);
	buffer = (int *)mlx_get_data_addr(datas->img, \
		&datas->pixel_bits, &datas->line_bytes, &datas->endian);
	datas->line_bytes /= 4;
	coord.y = 0;
	while (coord.y < datas->map->depth)
	{
		coord.x = 0;
		while (coord.x < datas->map->width)
		{
			get_coords(coord, datas);
			if (coord.x > 0)
				draw_horiz_line(datas, coord, buffer);
			if (coord.y > 0)
				draw_vert_line(datas, coord, buffer);
			coord.x++;
		}
		coord.y++;
	}
	mlx_put_image_to_window(datas->mlx, datas->win, datas->img, 0, 0);
	draw_infos(datas);
	mlx_destroy_image(datas->mlx, datas->img);
}