var on_ground = place_meeting(x, y + 1, obj_wall);
if (on_ground) coyote = 6; else coyote--;

if (keyboard_check_pressed(vk_space)) buffer = 6; else buffer--;

if (buffer > 0 && coyote > 0) {
    vsp = jump_force;
    coyote = 0;
    buffer = 0;
}