function love.load()

------------------------------
    gravintensity = 4000
    playerspeed = 8000
    numberofballs = 4
    planetrestitution = 0.75
    lineardamping = 0.75
    planetdensity = 0.75
------------------------------

    love.physics.setMeter(64)
    world = love.physics.newWorld(0, 0, true)
    world:setCallbacks(beginContact, endContact, preSolve, postSolve)

    love.graphics.setBackgroundColor(104, 136, 248)
    love.graphics.setMode(650, 650, false, true, 0)

    dynamicobjects = {}
    sceneobjects = {}

    GenerateBalls(numberofballs)

    sceneobjects.block1 = {}
    sceneobjects.block1.body = love.physics.newBody(world, 0, 650/2, "static")
    sceneobjects.block1.shape = love.physics.newRectangleShape(10, 650)
    sceneobjects.block1.fixture = love.physics.newFixture(sceneobjects.block1.body, sceneobjects.block1.shape, 0)


    sceneobjects.block2 = {}
    sceneobjects.block2.body = love.physics.newBody(world, 650, 650/2, "static")
    sceneobjects.block2.shape = love.physics.newRectangleShape(10, 650)
    sceneobjects.block2.fixture = love.physics.newFixture(sceneobjects.block2.body, sceneobjects.block2.shape, 0)

    sceneobjects.block3 = {}
    sceneobjects.block3.body = love.physics.newBody(world, 650/2, 0, "static")
    sceneobjects.block3.shape = love.physics.newRectangleShape(650, 10)
    sceneobjects.block3.fixture = love.physics.newFixture(sceneobjects.block3.body, sceneobjects.block3.shape, 0)

    sceneobjects.block4 = {}
    sceneobjects.block4.body = love.physics.newBody(world, 650/2, 650, "static")
    sceneobjects.block4.shape = love.physics.newRectangleShape(650, 10)
    sceneobjects.block4.fixture = love.physics.newFixture(sceneobjects.block4.body, sceneobjects.block4.shape, 0)
end


function love.update(dt)
    world:update(dt)

    for i, ball in ipairs(dynamicobjects) do
        for j, well in ipairs(dynamicobjects) do
            if ball ~= well then
                dy = ball.body:getY() - well.body:getY()
                dx = ball.body:getX() - well.body:getX()

                angle = math.atan2(dy, dx)
                dist = math.sqrt(dx * dx + dy * dy)

                ball.body:applyForce(ball.body:getMass() * ((-gravintensity / math.pow(dist, 1.25)) * math.cos(angle)), well.body:getMass() * ((-gravintensity / math.pow(dist, 1.25)) * math.sin(angle)))
            end
        end
    end

    if love.keyboard.isDown("r") then
        for k, ball in ipairs(dynamicobjects) do
            ball.body:destroy()
        end
        dynamicobjects = {}
        GenerateBalls(numberofballs)
    end

    if love.keyboard.isDown("right") then
        dynamicobjects[1].body:applyForce(playerspeed, 0)
    end
    if love.keyboard.isDown("left") then
        dynamicobjects[1].body:applyForce(-playerspeed, 0)
    end
    if love.keyboard.isDown("up") then
        dynamicobjects[1].body:applyForce(0, -playerspeed)
    end
    if love.keyboard.isDown("down") then
        dynamicobjects[1].body:applyForce(0, playerspeed)
    end
end

function love.draw()
    for i, ball in ipairs(dynamicobjects) do
        love.graphics.setColor(ball.r, ball.g, ball.b)
        love.graphics.circle("fill", ball.body:getX(), ball.body:getY(), ball.shape:getRadius())
    end

    love.graphics.setColor(50, 50, 50)
    love.graphics.polygon("fill", sceneobjects.block1.body:getWorldPoints(sceneobjects.block1.shape:getPoints()))
    love.graphics.polygon("fill", sceneobjects.block2.body:getWorldPoints(sceneobjects.block2.shape:getPoints()))
    love.graphics.polygon("fill", sceneobjects.block3.body:getWorldPoints(sceneobjects.block3.shape:getPoints()))
    love.graphics.polygon("fill", sceneobjects.block4.body:getWorldPoints(sceneobjects.block4.shape:getPoints()))
end

function GenerateBalls(count)
    for i=0,count - 1 do
        ball = {}
        ball.body = love.physics.newBody(world, math.random(650), math.random(650), "dynamic")
        ball.shape = love.physics.newCircleShape(math.random(5, 60))
        ball.fixture = love.physics.newFixture(ball.body, ball.shape, planetdensity)
        ball.fixture:setRestitution(planetrestitution)
        ball.r = math.random(255)
        ball.g = math.random(255)
        ball.b = math.random(255)
        ball.body:setMass(ball.shape:getRadius() * ball.fixture:getDensity())
        ball.body:setLinearDamping(0.75)
        ball.fixture:setUserData("ball")
        table.insert(dynamicobjects, ball)
    end
end

function JoinBalls(fixa, fixb)
    if fixa:getShape():getRadius() > fixb:getShape():getRadius() then
        largef = fixa
        smallf = fixb
    else
        largef = fixb
        smallf = fixa
    end

    largef:getShape():setRadius(fixa:getShape():getRadius() + fixb:getShape():getRadius())

    smallf:getBody():destroy()

    for i, ball in ipairs(dynamicobjects) do
        if ball.fixture == smallf then
            table.remove(dynamicobjects, i)
            return
        end
    end

end

function beginContact(a, b, coll)
    if a:getUserData() == "ball" and b:getUserData() == "ball" then
        JoinBalls(a, b)
    end
end

function endContact(a, b, coll)

end

function preSolve(a, b, coll)

end

function postSolve(a, b, coll)

end