/* ************************************************************************** */
/*                                                                            */
/*                                                        :::      ::::::::   */
/*   ft_raycasting.c                                    :+:      :+:    :+:   */
/*                                                    +:+ +:+         +:+     */
/*   By: rbousset <marvin@42.fr>                    +#+  +:+       +#+        */
/*                                                +#+#+#+#+#+   +#+           */
/*   Created: 2020/02/14 17:22:57 by rbousset          #+#    #+#             */
/*   Updated: 2020/02/14 17:23:42 by rbousset         ###   ########lyon.fr   */
/*                                                                            */
/* ************************************************************************** */

#include <cub3d.h>
#include <stdint.h>

static void
	ft_draw_plain_horizontal(t_rgb rgb, t_cub *cl, int32_t y, int32_t x)
{
	*(int*)(cl->img.ptr +
			(x * 4 + (y * cl->img.sizeline)))
		= ft_darken(rgb, cl);
}

static void
	ft_draw_extra_tex(uint8_t tid, uint16_t y, uint16_t x, t_cub *cl)
{
	float		dist;
	float		calc;

	if ((dist = cl->rlist.row_dist) <= 0)
		dist = 0.0001;
	calc = (dist * 0.4);
	calc = (calc >= 255) ? (255) : (calc);
	calc = (calc < 1) ? (1) : (calc);
	cl->img.ptr[x * 4 + (cl->img.sizeline * y)] =
		(uint8_t)cl->tlist[tid].ptr[cl->tlist[tid].tex_x * 4 + 4 *
		cl->tlist[tid].img_h * cl->tlist[tid].tex_y] / calc;
	cl->img.ptr[x * 4 + (cl->img.sizeline * y) + 1] =
		(uint8_t)cl->tlist[tid].ptr[cl->tlist[tid].tex_x * 4 + 4 *
		cl->tlist[tid].img_h * cl->tlist[tid].tex_y + 1] / calc;
	cl->img.ptr[x * 4 + (cl->img.sizeline * y) + 2] =
		(uint8_t)cl->tlist[tid].ptr[cl->tlist[tid].tex_x * 4 + 4 *
		cl->tlist[tid].img_h * cl->tlist[tid].tex_y + 2] / calc;
	cl->img.ptr[x * 4 + cl->wlist.x_size * y + 3] = (char)0;
}

static void
	ft_set_tex_xy(uint8_t tid, t_ray *rl, t_cub *cl)
{
		cl->tlist[tid].tex_y = (int32_t)(cl->tlist[tid].img_w
			* (rl->x_floor - rl->x_cell)) % (cl->tlist[tid].img_w);
		cl->tlist[tid].tex_x = (int32_t)(cl->tlist[tid].img_h
			* (rl->y_floor - rl->y_cell)) % (cl->tlist[tid].img_h);
}

static void
	ft_floor_cast_loop(uint16_t y, uint16_t x, t_ray *rl, t_cub *cl)
{
	rl->x_cell = (int32_t)(rl->x_floor);
	rl->y_cell = (int32_t)(rl->y_floor);
	if (cl->mlist.isftex)
	{
		ft_set_tex_xy(6, rl, cl);
	}
	if (cl->mlist.isctex)
	{
		ft_set_tex_xy(7, rl, cl);
	}
	rl->x_floor += cl->mlist.x_floor_step;
	rl->y_floor += cl->mlist.y_floor_step;
	if (cl->mlist.isftex)
		ft_draw_extra_tex(6, y, x, cl);
	else
		ft_draw_plain_horizontal(cl->f_rgb, cl, y, x);
	if (cl->mlist.isctex)
		ft_draw_extra_tex(7, cl->wlist.y_size - y - 1, x, cl);
	else
		ft_draw_plain_horizontal(cl->c_rgb, cl, cl->wlist.y_size - y - 1, x);
}

void
	ft_floor_cast(uint16_t y, t_cub *cl)
{
	t_ray		*rl;
	uint16_t	x;

	rl = &cl->rlist;
	rl->x_f_ray_dir = cl->plist.dir_x - cl->plist.plane_x;
	rl->y_f_ray_dir = cl->plist.dir_y - cl->plist.plane_y;
	rl->x_f_ray_dir_bis = cl->plist.dir_x + cl->plist.plane_x;
	rl->y_f_ray_dir_bis = cl->plist.dir_y + cl->plist.plane_y;
	rl->p = y - cl->wlist.y_size / 2;
	cl->plist.pos_z = 0.5 * cl->wlist.y_size;
	rl->row_dist = cl->plist.pos_z / rl->p;
	cl->mlist.x_floor_step = rl->row_dist *
		(rl->x_f_ray_dir_bis - rl->x_f_ray_dir) / cl->wlist.x_size;
	cl->mlist.y_floor_step = rl->row_dist *
		(rl->y_f_ray_dir_bis - rl->y_f_ray_dir) / cl->wlist.x_size;
	rl->x_floor = cl->plist.pos_y + rl->row_dist * rl->x_f_ray_dir;
	rl->y_floor = cl->plist.pos_x + rl->row_dist * rl->y_f_ray_dir;
	x = 0;
	while (++x < cl->wlist.x_size)
	{
		ft_floor_cast_loop(y, x, rl, cl);
	}
}