Ellipse animation in LÖVE lua

main.lua

function love.load()
	-- Comet, is going to move around the Sun
	comet = {}
	comet.x = 0
	comet.y = 0
	-- These are 'a' and 'b' in the ellipse formula, think aphelion and perihelion
	comet.trajectoryHeight = 40
	comet.trajectoryWidth = 120
	comet.timeItTakesToGoAroundTheSun = 3 -- 3 seconds, pretty fast
	comet.timeSinceBeginning = 0
	
	-- Origin (Sun)
	sun = {}
	sun.x = love.graphics.getWidth()/2
	sun.y = love.graphics.getHeight()/2
end

function love.update(dt)
	-- Increment the time since beginning variable, this is used to know how long it has been since the animation/movement started
	comet.timeSinceBeginning = comet.timeSinceBeginning + dt

	-- Calculate and assign the position of the comet
	positionInEllipse = LerpEllipse(comet.trajectoryWidth, comet.trajectoryHeight, comet.timeSinceBeginning, sun, comet.timeItTakesToGoAroundTheSun )
	comet.x = positionInEllipse.x
	comet.y = positionInEllipse.y
end

function love.draw()
	-- Draw yellow point (Sun)
	love.graphics.setColor(255, 155, 0, 255)
	love.graphics.circle("fill", sun.x, sun.y, 4, 4)

	-- Draw blue point (comet)
	love.graphics.setColor(60, 60, 255, 255)
	love.graphics.circle("fill", comet.x, comet.y, 1, 4)
end



--- AUXILLIARY FUNCTIONS ---

-- Lerp Ellipse gives you the x and y position for something moving along an ellipse
-- 'a' and 'b' are the 2 axis of the ellipse
-- t is the time that has passed since the animation/movement has started
-- o is the central point around which the ellipse is centered, needs to have x and y
-- d is the duration of the whole movement/animation
function LerpEllipse(a,b,t,o,d)
	position = {}
	position.x = o.x + (a*math.cos((t/d) * math.pi*2))
	position.y = o.y + (b*math.sin((t/d) * math.pi*2))
	return position
end

-- To draw ellipses with rotation we need more math
-- x = a*cos(t)*cos(angle) - b*sin(t)*sin(angle)
-- y = a*cos(t)*sin(angle) + b*sin(t)*cos(angle)
--
-- To try out in wolfram alpha:
-- having a = 20; b = 120; rotation angle = pi/8
-- put the line bellow in wolfram alpha and you will see a rotated ellipse
-- x= 20*cos(t)*cos(pi/8)-120*sin(t)*sin(pi/8), y=20*cos(t)*sin(pi/8)+120*sin(t)*cos(pi/8)

Unity C# version:
https://gist.github.com/abeldantas/9a301f622b995e471693615515cd6a73