crystal.DrawOrder

A Component that determines in what order entities are drawn. For more information on draw order, see Drawable:drawable_set_draw_order_modifier.

This base class is of little use without overriding the draw_order() method.

Constructor

Like all other components, DrawOrder components are created by calling Entity:add_component.

The constructor for DrawOrder expects no arguments.

Methods

Name	Description
draw_order	Returns the unmodified draw order (number) for drawable components on this entity.

Examples

This example defines a component class inheriting from DrawOrder to sort entities according to their Y position on the screen. This would be useful in a game using top-down perspective.

local YDrawOrder = Class("YDrawOrder", crystal.DrawOrder);
YDrawOrder.draw_order = function(self)
  local x, y = self:entity():position();
  return y;
end

local ecs = crystal.ECS:new();
local entity = ecs:spawn(crystal.Entity);
entity:add_component(crystal.Body);
entity:add_component(crystal.Sprite);
entity:add_component(YDrawOrder);