Sequence::Step &step = sequence.add_step(i->tag, *renderable);
step.set_blend(i->blend.get());
step.set_depth_test(i->depth_test.get());
Sequence::Step &step = sequence.add_step(i->tag, *renderable);
step.set_blend(i->blend.get());
step.set_depth_test(i->depth_test.get());