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/* ************************************************************************** */
/* */
/* ::: :::::::: */
/* helper.c :+: :+: :+: */
/* +:+ +:+ +:+ */
/* By: cacharle <marvin@42.fr> +#+ +:+ +#+ */
/* +#+#+#+#+#+ +#+ */
/* Created: 2020/01/11 07:32:20 by cacharle #+# #+# */
/* Updated: 2020/01/12 15:43:29 by cacharle ### ########.fr */
/* */
/* ************************************************************************** */
#include "cub3d.h"
t_bool helper_is_player_cell(t_cell cell)
{
return (cell == CELL_LOOK_NORTH || cell == CELL_LOOK_SOUTH ||
cell == CELL_LOOK_WEST || cell == CELL_LOOK_EAST);
}
void helper_free_splited(char **splited)
{
int i;
if (splited == NULL)
return ;
i = -1;
while (splited[++i] != NULL)
free(splited[i]);
free(splited);
}
void helper_rotate_player(t_state *state, double rotation)
{
state->dir = vector_rotate(state->dir, rotation);
state->plane = vector_rotate(state->plane, rotation);
}
void helper_init_dir_plane(t_state *state, int y, int x)
{
if (state->map[y][x] == CELL_LOOK_NORTH)
state->dir.y = 1.0;
else if (state->map[y][x] == CELL_LOOK_SOUTH)
state->dir.y = -1.0;
else if (state->map[y][x] == CELL_LOOK_WEST)
state->dir.x = -1.0;
else if (state->map[y][x] == CELL_LOOK_EAST)
state->dir.x = 1.0;
state->plane = vector_rotate(state->dir, M_PI_2);
state->plane = vector_scale(state->plane, 1.0 / vector_norm(state->plane));
state->plane = vector_scale(state->plane, 0.66);
state->plane = vector_apply(state->plane, &fabs);
}
/*
** -1 0 1 <-- camera_x
** v v v
** ################
** # | # <-- screen
** # | #
** ################
**
** camera_x is the x column from the camera percpective
** scaling the plane vector and adding it to the direction vector
** to create a vector in the *direction* of the column x.
*/
t_vector get_ray(t_state *state, int x)
{
double camera_x;
camera_x = 2 * x / (double)state->window.width - 1;
return (vector_add(state->dir, vector_scale(state->plane, camera_x)));
}
/*
** delta between each grid unit form the vector percpective
**
** if we have a vector v = [2 3]:
** dx = |v| / v_1
** = sqrt(v_1^2 + v_2^2) / v_1
** = (v_1^2 + v_2^2) / v_1^2
** = 1 + v_2^2 / v_1^2
** Same thing for dy
** dy = |v| / v_2
** = sqrt(v_1^2 + v_2^2) / v_1
** = (v_1^2 + v_2^2) / v_2^2
** = v_1^2 / v_2^2 + 1
**
** This can be simplified (for some obscure reason):
** dx = |1 / v_1|
** dy = |1 / v_2|
*/
t_vector get_delta(t_vector ray)
{
t_vector delta;
delta.x = vector_norm(ray) / ray.x;
delta.y = vector_norm(ray) / ray.y;
return (delta);
}
/*
** first delta between player position and first grid unit
**
** current x and y are the perpendicular distance to the nearest wall,
** we multiply them by their corresponding delta.
** 0 <= perpendicular distance <= 1 is a ratio, how much of the full delta we need to take.
**
** if (ray.x < 0)
** current.x = state->pos.x - map_pos.x;
** else
** current.x = fabs(state->pos.x - map_pos.x + 1.0);
** if (ray.y < 0)
** current.y = state->pos.y - map_pos.y;
** else
** current.y = fabs(state->pos.y - map_pos.y + 1.0);
** current.x *= delta.x;
** current.y *= delta.y;
*/
t_vector get_init_delta(t_state *state, t_vector *ray, t_vector *map_pos, t_vector *delta)
{
t_vector current;
current = vector_apply(&fabs, VECTOR_SUB(state->pos, *map_pos));
if (ray.x > 0)
current.x += 1.0;
if (ray.y > 0)
current.y += 1.0;
current.x *= delta.x;
current.y *= delta.y;
return (current);
}
/*
** perpendicular distance between the wall hit and the camera plane.
** We don't use euclidean distance because it would cause a fisheye effect.
**
** ====================X========== wall
** | /|
** | <------ / | -----+
** | / | |
** plane | / | <- perpendicular distance
** | | / |
** v | / |
** <-------^----/----------------- camera plane
** | /
** dir -> | /
** | / <- euclidean distance
** |/
** x <- pos
**
** In this case the perpendicular distance (p) is the difference
** of the y-coord of the hit point and the y-coord of the pos + dir vector.
** We use the y component because we hit the wall from a south/north percepective,
** if we had hit it form west/east, we would use the x component instead.
*/
double get_perp_dist(t_state *state, t_vector *hit_point, t_side side)
{
if (side == SIDE_NS)
return hit_point->y - state->pos.y + state->dir.y);
else if (side == SIDE_NS)
return hit_point->x - state->pos.x + state->dir.x);
}
/*
** 0 <= 1 / perp_dist <= 1
** height * (1 / perp_dist) is how much of the screen height do we take
*/
int get_line_height(t_state *state, double prep_dist, t_side side)
{
return ((int)((double)state->window.height / perp_wall_dist));
}
void helper_ray_next(t_vector *current, t_vector *map_pos,
t_vector delta, t_vector map_step)
{
if (current->x < current->y)
{
current->x += delta.x;
map_pos->x += map_step.x;
}
else
{
current->y += delta.y;
map_pos->y += map_step.y;
}
}
t_image *get_tex(t_state *state, t_side side)
{
if (side == SIDE_NS)
{
if (hit_point->y < state->pos.y)
return (state->textures[TEX_NORTH]);
else
return (state->textures[TEX_SOUTH]);
}
else if (side == SIDE_WE)
{
if (hit_point->x < state->pos.x)
return (state->textures[TEX_WEST]);
else
return (state->textures[TEX_EAST]);
}
return (NULL);
}
/*
** Since we're drawing each column, all the texels we want to draw on the window
** are on a single column of the texture.
** First we find the x-coord relative to the wall we hit
*/
int get_tex_x()
{
//calculate value of wall_x
double wall_x; //where exactly the wall was hit
if (side == 0) wall_x = state->pos.y + perp_dist * ray.y;
else wall_x = state->pos.x + perp_dist * ray.x;
wall_x -= floor(wall_x);
//x coordinate on the texture
int tex_x = (int)(wall_x * (double)texWidth);
if(side == 0 && ray.x > 0) tex_x = texture_width - tex_x - 1;
if(side == 1 && ray.y < 0) tex_x = texture_width - tex_x - 1;
return (tex_x);
}
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