void frustum_plane_corners(Vec3f out[4], float fov, float aspect, float plane)
{
const Vec2f wh = frustum_plane_wh(fov, aspect, plane);
const Vec3f up = Vec3f_Y();
const Vec3f right = Vec3f_X();
const Vec3f fc {0, 0, plane};
out[FPC_TOP_LEFT] = fc + (up * Vec3f(wh.y/2)) - (right * Vec3f(wh.x/2));
out[FPC_TOP_RIGHT] = fc + (up * Vec3f(wh.y/2)) + (right * Vec3f(wh.x/2));
out[FPC_BOTTOM_LEFT] = fc - (up * Vec3f(wh.y/2)) - (right * Vec3f(wh.x/2));
out[FPC_BOTTOM_RIGHT] = fc - (up * Vec3f(wh.y/2)) + (right * Vec3f(wh.x/2));
}
static Quat mouse_rotate(const Quat &in, float x, float y, float sensitivity)
{
const Quat xq(Vec3f_Y(), -x * sensitivity);
const Quat yq(Vec3f_X(), -y * sensitivity);
return xq * (in * yq);
}