42_cube3D/game/dda.c

/* ************************************************************************** */
/*                                                                            */
/*                                                        :::      ::::::::   */
/*   dda.c                                              :+:      :+:    :+:   */
/*                                                    +:+ +:+         +:+     */
/*   By: erey-bet <marvin@42.fr>                    +#+  +:+       +#+        */
/*                                                +#+#+#+#+#+   +#+           */
/*   Created: 2023/05/02 15:49:00 by erey-bet          #+#    #+#             */
/*   Updated: 2023/05/11 16:22:58 by erey-bet         ###   ########.fr       */
/*                                                                            */
/* ************************************************************************** */

#include "game.h"

void	init_dda(t_dda *dda, t_ply *ply, t_ray *ray)
{
	dda->map_x = (int)ply->pos_x;
	dda->map_y = (int)ply->pos_y;
	if (ray->dir_x == 0)
		dda->delta_dist_x = 1e30;
	else
		dda->delta_dist_x = ft_abs(1 / ray->dir_x);
	if (ray->dir_y == 0)
		dda->delta_dist_y = 1e30;
	else
		dda->delta_dist_y = ft_abs(1 / ray->dir_y);
	dda->step_x = 1;
	dda->step_y = 1;
	if (ray->dir_x < 0)
		dda->step_x = -1;
	if (ray->dir_y < 0)
		dda->step_y = -1;
	if (ray->dir_x < 0)
		dda->side_dist_x = (ply->pos_x - dda->map_x) * dda->delta_dist_x;
	else
		dda->side_dist_x = (dda->map_x + 1.0 - ply->pos_x) * dda->delta_dist_x;
	if (ray->dir_y < 0)
		dda->side_dist_y = (ply->pos_y - dda->map_y) * dda->delta_dist_y;
	else
		dda->side_dist_y = (dda->map_y + 1.0 - ply->pos_y) * dda->delta_dist_y;
	dda->hit = 0;
}

void	loop_dda(t_game *game, t_dda *dda)
{
	while (dda->hit == 0)
	{
		if (dda->side_dist_x < dda->side_dist_y)
		{
			dda->side_dist_x += dda->delta_dist_x;
			dda->map_x += dda->step_x;
			dda->side = 0;
		}
		else
		{
			dda->side_dist_y += dda->delta_dist_y;
			dda->map_y += dda->step_y;
			dda->side = 1;
		}
		if (dda->map_x < 0 || dda->map_y < 0 || dda->map_y >= game->map.size_y
			|| dda->map_x >= (int)ft_strlen(game->map.map[dda->map_y]))
		{
			dda->perp_wall_dist = 1e30;
			return ;
		}
		else
			dda->perp_wall_dist = 0;
		if (game->map.map[dda->map_y][dda->map_x] == '1')
			dda->hit = 1;
	}
}

void	ray_dda(t_dda *dda)
{
	if (dda->perp_wall_dist != 1e30)
	{
		if (dda->side == 0)
			dda->perp_wall_dist = dda->side_dist_x - dda->delta_dist_x;
		else
			dda->perp_wall_dist = dda->side_dist_y - dda->delta_dist_y;
		if (dda->perp_wall_dist == 0)
			dda->perp_wall_dist = 1e30;
	}
	dda->line_height = (int)(HEIGHT / dda->perp_wall_dist);
	dda->draw_start = -(dda->line_height) / 2 + HEIGHT / 2;
	if (dda->draw_start < 0)
		dda->draw_start = 0;
	dda->draw_end = dda->line_height / 2 + HEIGHT / 2;
	if (dda->draw_end >= HEIGHT)
		dda->draw_end = HEIGHT - 1;
}

void	dda(t_game *game, int x)
{
	t_dda	dda;
	t_ray	*ray;
	t_ply	*ply;

	ray = &game->ray;
	ply = &game->ply;
	init_dda(&dda, ply, ray);
	loop_dda(game, &dda);
	ray_dda(&dda);
	draw(game, &dda, x);
}