Player Initialization

Player initialization converts the spawn symbol from the map (N/S/E/W) into a world position and a raycasting-ready camera basis. This state is required before the first rendered frame.

Camera basis setup

From spawn tile to raycasting vectors

The map stores only `N/S/E/W`. Startup converts that symbol into a centered world position, a direction vector, and a perpendicular camera plane.

01

find_player(app, lines, map_start)

Runs during validation setup and locates the single spawn tile.

// tile found at (col, row)
player.x = col + 0.5
player.y = row + 0.5
player.orientation = tile_char

`+0.5` centers the player in the cell and avoids wall-boundary ambiguity.

02

init_player_vectors(app)

Converts orientation into `dir` and `plane`, which must stay perpendicular.

North N

dir

(0, -1)

plane

(+FOV_FACTOR, 0)

looks upward in map rows

South S

dir

(0, +1)

plane

(-FOV_FACTOR, 0)

looks downward in map rows

West W

dir

(-1, 0)

plane

(0, -FOV_FACTOR)

looks toward lower x

East E

dir

(+1, 0)

plane

(0, +FOV_FACTOR)

looks toward higher x

03 camera basis visualization

Next orientation

North — dir(0, -1) plane(+FOV_FACTOR, 0)

✓

render loop can start

`player.x/y` are centered, `dir ⟂ plane`, and camera vectors are non-zero.

Runtime Order

The current startup sequence is:

1. parse_file(...)
2. validation locates the single spawn tile
3. init_player_vectors(app)
4. init_mlx(app)
5. frame loop starts

Validation guarantees that there is exactly one valid spawn before vector setup runs.

Spawn Extraction

The spawn is found during validation setup with find_player(...).

When the spawn tile is found at (col, row), the player position is centered:

player.x = col + 0.5;
player.y = row + 0.5;
player.orientation = tile_char;

The +0.5 offset matters because movement and raycasting operate in continuous world coordinates, not tile indexes. Starting in the center avoids immediate boundary ambiguity.

Vector Initialization

init_player_vectors(app) converts orientation into:

• direction vector: dir_x, dir_y
• camera plane vector: plane_x, plane_y

The direction vector points where the player looks. The camera plane is perpendicular to it and controls the horizontal field of view used by raycasting.

Orientation Table

Spawn	Direction	Camera plane
N	(0, -1)	(+FOV_FACTOR, 0)
S	(0, +1)	(-FOV_FACTOR, 0)
W	(-1, 0)	(0, -FOV_FACTOR)
E	(+1, 0)	(0, +FOV_FACTOR)

Invariants

After player initialization:

• player position is centered in the spawn tile
• orientation is one of N/S/E/W
• direction vector is non-zero
• camera plane is perpendicular to direction
• rendering can safely cast rays from the player position

Code References

• srcs/validation/validate_bfs.c (find_player)
• srcs/validation/validate_map_player.c
• srcs/core/init_app.c (init_player_vectors)
• srcs/core/main.c