/* ************************************************************************** */
/*                                                                            */
/*                                                        :::      ::::::::   */
/*   render.c                                           :+:      :+:    :+:   */
/*                                                    +:+ +:+         +:+     */
/*   By: cacharle <marvin@42.fr>                    +#+  +:+       +#+        */
/*                                                +#+#+#+#+#+   +#+           */
/*   Created: 2020/01/11 13:37:17 by cacharle          #+#    #+#             */
/*   Updated: 2020/01/12 15:45:03 by cacharle         ###   ########.fr       */
/*                                                                            */
/* ************************************************************************** */

#include "cub3d.h"

#define WINDOW_MID_HEIGHT(state) (state->window.height / 2)

int		render_update(void *param)
{
	t_state *state;

	state = param;
	if (!state->running)
	{
		state_destroy(state);
		exit(EXIT_SUCCESS);
	}
	render_update_window(state);
	mlx_put_image_to_window(state->mlx_ptr, state->window_ptr, state->window.id, 0, 0);
	return (0);
}

void	render_update_window(t_state *state)
{
	int x;

	x = -1;
	while (++x < state->window.width)
		render_column(state, x);
}

void	render_column(t_state *state, int x)
{
	t_vector	ray;
	t_vector	map_pos;
	t_vector	delta;
	t_side		side;
	int			line_height;

	ray = get_ray(state, x);
	map_pos = vector_new((double)((int)state->pos.x), (double)((int)state->pos.y));
	delta = get_delta(ray);
	current = get_init_delta(state, ray, map_pos, delta);
	map_step = vector_new(ray.x < 0.0 ? -1.0 : 1.0, ray.y < 0.0 ? -1.0 : 1.0));
	while (TRUE)
	{
		side = current.x < current.y ? SIDE_WE : SIDE_WE;
		helper_ray_next(&current, map_pos, delta, map_step);
		if (state->map[(int)map_pos.y][(int)map_pos.x] == CELL_WALL)
			break;
	}
	line_height = get_line_height(state, get_perp_dist(state, &current, side), side);
	render_window_column(state, x, side, WINDOW_MID_HEIGHT(state) - line_height / 2,
										WINDOW_MID_HEIGHT(state) + line_height / 2);
}

void	render_window_column(t_state *state, int x, t_side side, int start, int end)
{
	int		i;
	t_color	white;

	white.hexcode = 0x00ffffff;
	i = -1;
	while (++i < draw_start)
		((t_color*)state->window.data)[i * state->window.width + x] = state->ceilling_color;
	i = render_texture(state, side, start, end);
	while (++i < state->window_height)
		((t_color*)state->window.data)[i * state->window.width + x] = state->floor_color;
}

int		render_texture(t_state *state, t_side side, int start, int end)
{
	int i;
	int tex_x;
	double step;
	double tex_pos;
	int tex_y;
	t_image *texture;

	texture = get_tex(state, side);
	tex_x = get_tex_x();

	step = 1.0 * texture->height / line_height;
	texPos = (start - state->window.height / 2 + line_height / 2) * step;

	i = start - 1;
	while (++i < end)
	{
		tex_y = (int)tex_pos & (texture->height - 1);
		tex_pos += step;
		((t_color*)state->window.data)[i * state->window.width + x] =
			texture[texHeight * texY + texX];
	}
	return (end);
}