Atomics Emulator

-- [ Charged Particles/Atoms Simulation Source Code Basics ] --
-- For archived versions, visit my pastebin: https://pastebin.com/u/1m1m0

local particle = script.Parent
local attractionPower = 5 -- Attraction strength between attracting particles
local halfLife = 60 -- Time for a particle to flip it's charge
local radiateThreshold = {1, 2, 3} -- Amount/s of particles a particle with an opposite charge is touching to eject itself

--[ VELOCITY PRESET ]
-- Function to apply electromagnetic force
function ApplyElectromagneticForce(object1, object2)
    local direction = object1.Position - object2.Position
    local distance = direction.Magnitude

    -- Do not apply the force if the objects are too close to each other
    if distance <= 0.9 * object1.Size.X then
        return -- This prevents velocities from approaching infinity
    end

    local forceMagnitude = (attractionPower * object1.Size.X * object2.Size.X) / (distance * distance)
    local force = direction.Unit * forceMagnitude

    -- Check the charges of the objects
    local charge1 = object1:FindFirstChild("Charge") and object1.Charge.Value
    local charge2 = object2:FindFirstChild("Charge") and object2.Charge.Value

    -- If the charges are the same, they attract eachother (I know, it violeates real world laws)
    if charge1 == charge2 then
        object1.Velocity = object1.Velocity - force
        object2.Velocity = object2.Velocity + force
        -- If the charges are different, they repel each other
    else
        object1.Velocity = object1.Velocity + force
        object2.Velocity = object2.Velocity - force
    end
end

--]]
--[[ [ BODYFORCE PRESET ]

-- Function to apply electromagnetic force using BodyForce
function ApplyElectromagneticForce(object1, object2)
    local direction = object1.Position - object2.Position
    local distance = direction.Magnitude

    -- Do not apply the force if the objects are too close to each other
    if distance <= 0.9 * object1.Size.X then
        return
    end

    local forceMagnitude = (attractionPower * object1.Size.X * object2.Size.X) / (distance * distance)
    local force = direction.Unit * forceMagnitude

    -- Check the charges of the objects
    local charge1 = object1:FindFirstChild("Charge") and object1.Charge.Value
    local charge2 = object2:FindFirstChild("Charge") and object2.Charge.Value

    -- If the charges are the same, they repel each other
    if charge1 == charge2 then
        force = -force -- Reverse the direction of the force
    end

    -- Apply the force using a BodyForce instance
    local bodyForce = object1:FindFirstChild("ElectromagneticBodyForce")
    if not bodyForce then
        bodyForce = Instance.new("BodyForce")
        bodyForce.Name = "ElectromagneticBodyForce"
        bodyForce.Force = force
        bodyForce.Parent = object1
    else
        bodyForce.Force = force
    end
end

--]]

-- Function to check and apply electromagnetic force
local function CheckAndApplyElectromagneticForce(obj)
    if not obj:IsA("BasePart") or obj:IsA("Model") or obj:IsA("Union") or obj:IsA("Tool") or obj:IsA("MeshPart") or obj:IsA("Mesh") then
        return   -- BasePart means everything in Workspace, some may not be included and you may need to add "obj:IsA("")" with their classname in the list above.
    end
    if obj == particle or obj == obj:IsA("Player") then
        return -- Excludes the players and particle itself from electromagnetic force, feel free to add more.
    end
    if obj.Anchored then
        return -- Prevents particle from applying force to the anchored objects. (Saves resources and computation power)
    end

    -- Randomly assign a charge to the object if it doesn't have one
    if not obj:FindFirstChild("Charge") then
        local boolValue = Instance.new("BoolValue")
        boolValue.Name = "Charge"
        boolValue.Value = math.random() > 0.5 -- Get rid of this line for identical xharges if you want
        boolValue.Parent = obj

        -- Start a coroutine to flip the charge at a random interval
        coroutine.wrap(function()
            while obj do
                wait(math.random() * halfLife) -- Wait for a random time up to 60 seconds (Default half life)
                boolValue.Value = not boolValue.Value -- Flip the charge

                -- Break any existing constraints when the charge flips
                for _, child in pairs(obj:GetChildren()) do
                    if child:IsA("RodConstraint") then
                        child:Destroy()
                    end
                end
            end
        end)()
    end

    ApplyElectromagneticForce(particle, obj)
end

game:GetService("RunService").Heartbeat:Connect(function()
    for _, object in pairs(game.Workspace:GetDescendants()) do
        CheckAndApplyElectromagneticForce(object)
    end
end)

-- Function to create a RodConstraint between particles with the same charge
local function CreateConstraint(part)
    local otherPart = part:GetTouchingParts()[radiateThreshold] -- Get the first 1, 2 or 3 parts that is touching the current part
    if otherPart then
        local charge1 = part:FindFirstChild("Charge") and part.Charge.Value
        local charge2 = otherPart:FindFirstChild("Charge") and otherPart.Charge.Value
        if charge1 == charge2 then
            local attachment0 = Instance.new("Attachment", part)
            local attachment1 = Instance.new("Attachment", otherPart)
            local constraint = Instance.new("RodConstraint")
            constraint.Attachment0 = attachment0
            constraint.Attachment1 = attachment1
            constraint.Length = part.Size.X/2 + otherPart.Size.X/2 -- Set the length to the sum of the radii of the parts
            constraint.Parent = part
        end
    end
end

particle.Touched:Connect(CreateConstraint)