Pulsing Shapes using the LÖVE framework

main.lua

local lg, lt = love.graphics, love.timer
local pi, cos, sin = math.pi, math.cos, math.sin
local centerX, centerY = 400, 300
local wave = 0

-- rotate x,y around xRef,yRef by r
function rotateAround(x, y, xRef, yRef, r)
	local c, s = cos(r), sin(r)
	return c * (x - xRef) - s * (y - yRef) + xRef, s * (x - xRef) + c * (y - yRef) + yRef 
end

-- draw an isotopy shape
function drawShape(corners, radius, x, y, r, color)
	local cornerRot = 2 * pi / corners

	lg.push()

		lg.translate(x, y)
		lg.rotate(math.rad(-45))
		lg.setColor(color)

		x, y = rotateAround(0, 0 - radius, 0, 0, r)

		for i=1, corners do
			local nx, ny = rotateAround(x, y, 0, 0, cornerRot)
			lg.line(x, y, nx, ny)
			x, y = nx, ny
		end

	lg.pop()

end

function love.update()
	wave = sin(2 * math.pi * 1.041 * lt.getTime())
end

function love.draw()
	local x, y, t = centerX, centerY, lt.getTime()
	drawShape(3, 15 + 5 * wave, x, y, t, { 1, 0, 0, 1 })
	drawShape(6, 15 + 5 * wave, x, y, t + pi, { 1, 0, 0, 1 })
	local pulse = ((wave + 1) / 2) * 30
	for i=1, 30 do
		drawShape(4, 50 + (i * 5) + 20 * wave ^ 2, x, y, t * ((i - 10) * 0.025), { 0, 1, 0, 0.5 + (pulse - i) * 0.01 })
	end
	drawShape(6, 200 + 10 * -wave ^ 3 / wave, x, y, t / 5, { 1, 1, 0, 1 })
	drawShape(6, 200 + 10 * -wave ^ 3 / wave, x, y, t / 5 - pi / 2, { 1, 1, 0, 1 })
end