/* ************************************************************************** */
/*                                                                            */
/*                                                        :::      ::::::::   */
/*   raycast.c                                          :+:      :+:    :+:   */
/*                                                    +:+ +:+         +:+     */
/*   By: cyrillefrouin <cyrillefrouin@student.42.fr>+#+  +:+       +#+        */
/*                                                +#+#+#+#+#+   +#+           */
/*   Created: 2018/06/25 15:47:43 by cyrillefrouin     #+#    #+#             */
/*   Updated: 2018/06/25 15:47:57 by cyrillefrouin    ###   ########.fr       */
/*                                                                            */
/* ************************************************************************** */

#include "wolf3d.h"

int					draw_ray(t_data *data)
{
	for (int x = 0; x < data->width; x++)
	{
		double cameraX = 2 * x / (double)data->width - 1;
		double rayDirX = data->dir.x + data->plane.x * cameraX;
		double rayDirY = data->dir.y + data->dir.y * cameraX;

		int mapX = (int)data->dir.x;
		int mapY = (int)data->dir.y;

		double sideDistX;
		double sideDistY;

		double deltaDistX = fabs(1 / rayDirX);
		double deltaDistY = fabs(1 / rayDirY);
		double perpWallDist;

		int stepX;
		int stepY;

		int hit = 0;
		int side;

		if (rayDirX < 0)
		{
			stepX = -1;
			sideDistX = (data->dir.x - mapX) * deltaDistX;
		}
		else
		{
			stepX = 1;
			sideDistX = (mapX + 1.0 - data->dir.x) * deltaDistX;
		}
		if (rayDirY < 0)
		{
			stepY = -1;
			sideDistY = (data->dir.y - mapY) * deltaDistY;
		}
		else
		{
			stepY = 1;
			sideDistY = (mapY + 1.0 - data->dir.y) * deltaDistY;
		}

		int iter = 0;
		while (hit == 0 && iter < 50)
		{
			if (sideDistX < sideDistY)
			{
				sideDistX += deltaDistX;
				mapX += stepX;
				side = 0;
			}
			else
			{
				sideDistY += deltaDistY;
				mapY += stepY;
				side = 1;
			}
			if (mapX >= 0 && mapY >= 0 && data->map.map[mapX][mapY] > 0) hit = 1;
			iter++;
		}
		if (side == 0) perpWallDist = (mapX - data->pos.x + (1 - stepX) / 2) / rayDirX;
		else           perpWallDist = (mapY - data->pos.y + (1 - stepY) / 2) / rayDirY;

		int lineHeight = (int)(data->height / perpWallDist);

		int drawStart = -lineHeight / 2 + data->height / 2;
		if (drawStart < 0) drawStart = 0;
		int drawEnd = lineHeight / 2 + data->height / 2;
		if (drawEnd >= data->height) drawEnd = data->height - 1;

		unsigned int color = 0xAAAA00;
		if (side == 1)
			color /= 2;

		t_vector_i start = {x, drawStart};
		t_vector_i end = {x, drawEnd};
		put_line_in_image(data, start, end, color);
		// ft_printf("Finished drawing line %d\n", x);
	}

	mlx_put_image_to_window(data->mlx, data->win, data->img, 0, 0);
	return (1);
}