/* ************************************************************************** */
/*                                                                            */
/*                                                        :::      ::::::::   */
/*   render.c                                           :+:      :+:    :+:   */
/*                                                    +:+ +:+         +:+     */
/*   By: greg <greg@student.42.fr>                  +#+  +:+       +#+        */
/*                                                +#+#+#+#+#+   +#+           */
/*   Created: 2024/10/14 14:55:05 by greg              #+#    #+#             */
/*   Updated: 2024/10/14 16:53:21 by greg             ###   ########.fr       */
/*                                                                            */
/* ************************************************************************** */

#include "algo.h"


static int	init_step(t_ray *ray)
{
		if (ray->raydirX < 0)
		{
			ray->stepX = -1;
			ray->sidedistX = (ray->posX - ray->mapX) * ray->deltadistX;
		}
		else
		{
			ray->stepX = 1;
			ray->sidedistX = (ray->mapX + 1.0 - ray->posX) * ray->deltadistX;
		}
		if (ray->raydirY < 0)
		{
			ray->stepY = -1;
			ray->sidedistY = (ray->posY - ray->mapY) * ray->deltadistY;
		}
		else
		{
			ray->stepY = 1;
			ray->sidedistY = (ray->mapY + 1.0 - ray->posY) * ray->deltadistY;
		}
		return (0);
}

static int ray_pos(t_ray *ray, int x)
{
			// position et direction du rayon
		ray->cameraX = 2 * x / ray->width - 1;
		ray->raydirX = ray->dirX + ray->planeX * ray->cameraX;
		ray->raydirY = ray->dirY + ray->planeY * ray->cameraX;

		ray->mapX = (int)ray->posX;
		ray->mapY = (int)ray->posY;

		ray->deltadistX = (ray->raydirX == 0) ? 1e30 : fabs(1 / ray->raydirX);
		ray->deltadistY = (ray->raydirY == 0) ? 1e30 : fabs(1 / ray->raydirY);
		return (0);
}
int	draw_img(t_ray *ray, int drawStart, int *img_data, int drawEnd, int x)
{
	// draw vertical line
	int y = 0;
	while (y <= drawStart)
	{
		img_data[y * (int)ray->width + x] = 0x29f8ff;;
		y++;
	}
	y = drawStart;
	while (y <= drawEnd)
	{
		img_data[y * (int)ray->width + x] = 0xFF0000;
		y++;
	}
	y++;
	while (y <= ray->height)
	{
		img_data[y * (int)ray->width + x] = 0xFF985C;
		y++;
	}
	return (0);
}

void	find_wall(t_ray *ray)
{
	int side;
	int hit;

	hit = 0;
	while(hit == 0)
	{
		if(ray->sidedistX < ray->sidedistY) //jump to next map square, either in x-direction, or in y-direction
		{
			ray->sidedistX += ray->deltadistX;
			ray->mapX += ray->stepX;
			side = 0;
		}
		else
		{
			ray->sidedistY += ray->deltadistY;
			ray->mapY += ray->stepY;
			side = 1;
		}
		if(worldMap[ray->mapX][ray->mapY] == 1)		//Check if ray has hit a wall
			hit = 1;
	}
	if(side == 0) 
		ray->perpwalldist = (ray->sidedistX - ray->deltadistX);
	else
		ray->perpwalldist = (ray->sidedistY - ray->deltadistY);
}

int	render(t_ray *ray)
{
	int x;
	int lineHeight;
	int *img_data;
	int	drawStart;
	int drawEnd;
	
	img_data = (int *)mlx_get_data_addr(ray->img_ptr, &(int){32}, &(int){ray->width * 4}, &(int){0}); 
	ft_bzero(img_data, ray->width * ray->height * sizeof(int)); 	// clear image data
	x = 0;
	while (x++ < ray->width)
	{
		ray_pos(ray, x);
		init_step(ray); 	//calculate step and initial sideDist
		find_wall(ray);
		lineHeight = (int)(ray->height / ray->perpwalldist); 		//Calculate height of line to draw on screen
		drawStart = -lineHeight / 2 + ray->height / 2; 		//calculate lowest and highest pixel to fill in current stripe
		if(drawStart < 0)
			drawStart = 0;
		drawEnd = lineHeight / 2 + ray->height / 2;
		if(drawEnd >= ray->height)
			drawEnd = ray->height - 1;
		draw_img(ray, drawStart, img_data, drawEnd, x);
	}
	mlx_put_image_to_window(ray->mlx_ptr, ray->win_ptr, ray->img_ptr, 0, 0);
	return (0);
}