Mass

body.Mass

The mass of an entity body, which dictates how effective applied forces and collisions are on an entity's physics body.

Since there is no in-built gravity or air resistance by default, the mass will have no direct affect on an entity's Velocity, independent of applied forces.

Type	Initialised Value	Description
float	eg. 5.0	The modifier for force calculations on the entity body.

Example:

Push an entity into an opposing 'wind' force and see how different masses change how effective the opposing force is on the entity.

-- entity.lua
local function init(self)
    self.Physics = true
    
    local mass = 10	
    local box_shape = api.physics.NewBoxShape(1, 1, 1) 
    local box = api.physics.NewBody(box_shape, mass)  
     
    self.Body = box
    self.Body:ApplyForce(api.physics.NewVector(32, 32 ,0))
	
    local mass_changes = {"decrease", "not be changed", "increase"}
    self.Data.mass_change = mass_changes[math.random(1, #mass_changes)]
    print("This entity has a mass which will "..self.Data.mass_change..".")
end

local function update(self, dt)
    local not_force_update = self.Body.Force:Dot(self.Body.Force) == 0
    if not_force_update then 
        if self.Data.mass_change == "decrease" then 
            self.Body.Mass = 1
        end
        if self.Data.mass_change == "not be changed" then
            self.Body.Mass = self.Body.Mass
        end
        if self.Data.mass_change == "increase" then 
            self.Body.Mass = 100
        end
    end
    
    local wind_force = api.physics.NewVector(-0.1, -0.1 ,0)
    self.Body:ApplyForce(wind_force)	
end 

-- Turn on physics calculations for this entity.
-- Create a box shape and a body with a mass of 10. Assign it to the entity.
-- Apply an initial force to move the entity towards the top-right of the panel map.
-- Randomly select a new mass which the entity will update to.
-- Check that the initial force has finished processing, before changing the mass.
-- Decrease (to 1), increase (to 100), or leave the entity's mass unchanged (at 10).
-- Create and apply a wind force (-0.1, -0.1, 0), to blow the entity backwards.
-- Watch the panel map to see the effect: immediately, gradually, or eventually.

-- Prints:
-- This entity has a mass which will decrease.

-- Or Prints:
-- This entity has a mass which will not be changed.

-- Or Prints:
-- This entity has a mass which will increase.