shader_type spatial;

void vertex() {
    vec3 right = normalize(cross(vec3(0.0, 1.0, 0.0), to_camera));
    vec3 up = vec3(0.0, 1.0, 0.0);
    vec3 forward = normalize(cross(right, up));
    mat4 billboard_matrix = mat4(
        vec4(right, 0.0),
        vec4(up, 0.0),
        vec4(forward, 0.0),
        vec4(model_pos, 1.0)
    );
    MODELVIEW_MATRIX = VIEW_MATRIX * billboard_matrix;
}