/** Returns the view matrix, used to transform coordinates from world space
to eye space. */
const Matrix &get_view_matrix() const { return view_matrix; }
/** Returns the object matrix, used to transform coordinates from eye space
to world space. */
/** Returns the view matrix, used to transform coordinates from world space
to eye space. */
const Matrix &get_view_matrix() const { return view_matrix; }
/** Returns the object matrix, used to transform coordinates from eye space
to world space. */