cub3D

1. For each screen column, build a camera ray from player direction + camera plane.
2. Run DDA grid stepping until the ray hits a wall tile.
3. Compute perpendicular wall distance to avoid fish-eye distortion.
4. Project wall stripe height on screen and sample texture coordinates.
5. Draw floor/ceiling and apply distance-based shading.

for (int x = 0; x < render_w; ++x) {
    ray_setup(&ray, player, camera, x);
    dda_cast(&ray, map);
    wall_project(&ray, render_h);
    wall_draw_stripe(&ray, x);
    floor_draw_column(&ray, x);
}

Core files: fn_game_ray.c, fn_game_wall_loop.c, fn_game_wall_draw.c, fn_game_floor_draw.c.

• Built with emcc and MLX42 via GLFW-on-web path.
• Graphics flags: USE_GLFW=3, USE_WEBGL2=1, FULL_ES3=1.
• Runtime flags: NO_EXIT_RUNTIME=1, ALLOW_MEMORY_GROWTH.
• Stability: raised stack to STACK_SIZE=8388608.
• Assets/maps bundled with --preload-file.

• Desktop uses blocking mlx_loop.
• Browser uses emscripten_set_main_loop_arg to hook into browser frame scheduling.
• The same C game loop logic is reused through MLX loop hooks.

emscripten_set_main_loop_arg(
    (em_arg_callback_func)mlx_loop,
    g->mlx, 0, 1
);

• Native path recenters cursor each frame and reads center delta.
• Web path uses relative-like delta from previous mouse sample.
• Spike filtering drops abnormal jumps; tiny deltas are ignored.
• Sensitivity is slightly scaled for browser control stability.

• Bonus mode always enabled for web build.
• Map fixed to /maps/default.cub.
• Keys, doors, minimap, sprites, lava, and checkpoints active.
• On key pickup, nearest checkpoint selected for lava respawn.
• Respawn keeps last look direction and pitch for continuity.

source ~/emsdk/emsdk_env.sh
make -f Makefile.web
make -f Makefile.web serve

If emcmake or emcc is missing, emsdk environment is not loaded in the current shell.