(
  msl_pipeline: (
    allow_and_force_point_size: false,
    vertex_pulling_transform: true,
    vertex_buffer_mappings: [(
      id: 1,
      stride: 20,
      indexed_by_vertex: true,
      attributes: [(
        shader_location: 0, // position
        offset: 0,
        format: Float32,    // too small, inflated to a vec4
      ),
      (
        shader_location: 1, // normal
        offset: 4,
        format: Float32x4,  // too big, truncated to a vec3
      )],
    ),
    (
      id: 2,
      stride: 16,
      indexed_by_vertex: false,
      attributes: [(
        shader_location: 2, // texcoord
        offset: 0,
        format: Float32x2,
      )],
    )],
  ),
)