update

function update(self, dt)

Performs the continuous processing of this entity instance, each tick.

The dt parameter is the interval between each tick, (approximately 1 / Target Tick Rate). Repeating incremental processes, like movement, can be standardised by being multiplied by dt. This reduces the variation caused by differing hardware processing speeds.

As a necessary entity method, this function should be returned by the entity.lua file. It must be in a table under the key update.

Parameters:

Name	Type	Description
self	Entity	This entity itself.
dt	float	The time elapsed in seconds between this tick and the previous one.

Example:

Update an entity's position each tick, to move it towards a location.

-- entity.lua
local function update(self, dt)
    local x, y = self:GetPosition()
    local target = {x = 100, y = 100}
    local drag = 100
	
    local differential_in_x = (target.x - x)/drag
    local differential_in_y = (target.y - y)/drag

    self:Move(
        differential_in_x * dt, 
        differential_in_y * dt, 
        0)
    
    print("This entity is gradually moving towards position (100,100,0)."
end

return { init = function (self) end,
         update = update,
         message = function (self, msg) end }

-- Get the current position of the entity, each tick.
-- Set the XY location for the entity to move to.
-- Calculate the total distance left each tick, between the entity and (100,100,0).
-- Apply a drag, to only move a small percentage of the total distance at a time.
-- Move the entity by a small amount each tick.
-- Return the 'update' function as a value in a table.

-- Prints (every tick):
-- This entity is gradually moving towards position (100,100,0).