File:world raycast callback example.png

function worldRayCastCallback(fixture, x, y, xn, yn, fraction)
	local hit = {}
	hit.fixture = fixture
	hit.x, hit.y = x, y
	hit.xn, hit.yn = xn, yn
	hit.fraction = fraction

	table.insert(Ray.hitList, hit)

	return 1 -- Continues with ray cast through all shapes.
end

function createStuff()
	-- Cleaning up the previous stuff.
	for i = 1, #Terrain.Stuff do
		Terrain.Stuff[i].Fixture:destroy()
		Terrain.Stuff[i] = nil
	end

	-- Generates some random shapes.
	for i = 1, 30 do
		local p = {}

		p.x, p.y = math.random(100, 700), math.random(100, 500)
		local shapetype = math.random(3)
		if shapetype == 1 then
			local w, h, r = math.random() * 10 + 40, math.random() * 10 + 40, math.random() * math.pi * 2
			p.Shape = love.physics.newRectangleShape(p.x, p.y, w, h, r)
		elseif shapetype == 2 then
			local a = math.random() * math.pi * 2
			local x2, y2 = p.x + math.cos(a) * (math.random() * 30 + 20), p.y + math.sin(a) * (math.random() * 30 + 20)
			p.Shape = love.physics.newEdgeShape(p.x, p.y, x2, y2)
		else
			local r = math.random() * 40 + 10
			p.Shape = love.physics.newCircleShape(p.x, p.y, r)
		end

		p.Fixture = love.physics.newFixture(Terrain.Body, p.Shape)

		Terrain.Stuff[i] = p
	end
end

function love.keypressed()
	createStuff()
end

function love.load()
	-- Setting this to 1 to avoid all current scaling bugs.
	love.physics.setMeter(1)

	-- Start out with the same random stuff each start.
	math.randomseed(0xfacef00d)

	World = love.physics.newWorld()

	Terrain = {}
	Terrain.Body = love.physics.newBody(World, 0, 0, "static")
	Terrain.Stuff = {}
	createStuff()

	Ray = {
		x1 = 0,
		y1 = 0,
		x2 = 0,
		y2 = 0,
		hitList = {}
	}
end

function love.update(dt)
	local now = love.timer.getMicroTime()

	World:update(dt)

	-- Clear fixture hit list.
	Ray.hitList = {}
	
	-- Calculate ray position.
	local pos = (math.sin(now/4) + 1.2) * 0.4
	Ray.x2, Ray.y2 = math.cos(pos * (math.pi/2)) * 1000, math.sin(pos * (math.pi/2)) * 1000
	
	-- Cast the ray and populate the hitList table.
	World:rayCast(Ray.x1, Ray.y1, Ray.x2, Ray.y2, worldRayCastCallback)
end

function love.draw()
	-- Drawing the terrain.
	love.graphics.setColor(255, 255, 255)
	for i = 1, #Terrain.Stuff do
		if Terrain.Stuff[i].Shape:getType() == "polygon" then
			love.graphics.polygon("line", Terrain.Body:getWorldPoints( Terrain.Stuff[i].Shape:getPoints() ))
		elseif Terrain.Stuff[i].Shape:getType() == "edge" then
			love.graphics.line(Terrain.Body:getWorldPoints( Terrain.Stuff[i].Shape:getPoints() ))
		else
			local x, y = Terrain.Body:getWorldPoints(Terrain.Stuff[i].x, Terrain.Stuff[i].y)
			love.graphics.circle("line", x, y, Terrain.Stuff[i].Shape:getRadius())
		end
	end

	-- Drawing the ray.
	love.graphics.setLineWidth(3)
	love.graphics.setColor(255, 255, 255, 100)
	love.graphics.line(Ray.x1, Ray.y1, Ray.x2, Ray.y2)
	love.graphics.setLineWidth(1)

	-- Drawing the intersection points and normal vectors if there were any.
	for i = 1, #Ray.hitList do
		local hit = Ray.hitList[i]
		love.graphics.setColor(255, 0, 0)
		love.graphics.circle("line", hit.x, hit.y, 3)
		love.graphics.setColor(0, 255, 0)
		love.graphics.line(hit.x, hit.y, hit.x + hit.xn * 25, hit.y + hit.yn * 25)
	end
end