love2d first steps

g_imgTable = {
    ["tank"] = nil,
    ['bullet'] = nil
}

g_fired = {
}

g_enems = {

}

cords = {['x'] = nil, ['y'] = nil}
selfcords = {['x'] = 0, ['y'] = 0, ['dx'] = 0, ['dy'] = 0}
screen = {['w'] = nil, ['h'] = nil}
moveState = {up = nil, down = nil, left = nil, right = nil}


step = 100
speed = 300
bulletCount = 0
oldState = false

function addEnemy() --todo

end

function setParent() --todo
end

function love.load()
    love.graphics.setBackgroundColor(255, 255, 255)
    screen.w = love.graphics.getWidth()
    screen.h = love.graphics.getHeight()
    selfcords.x = screen.w / 2
    selfcords.y = screen.h / 2
    g_imgTable["tank"] = love.graphics.newImage('tank.png')
    g_imgTable["bullet"] = love.graphics.newImage('bullet.png')
end

function love.update(dt)
    cords.x, cords.y = love.mouse.getPosition()
    interceptInput()
    for k, v in pairs(g_fired) do
        v.x = v.x + math.cos(v.ang) * speed * dt;
        v.y = v.y + math.sin(v.ang) * speed * dt;

        if v.x > screen.w or v.x < 0 or v.y > screen.h or v.y < 0 then
            releaseBullet(v)
        end
    end

    if selfcords.dx ~= 0 or selfcords.dy ~= 0 then
        selfcords.x = selfcords.x + selfcords.dx * dt
        selfcords.y = selfcords.y + selfcords.dy * dt

        if selfcords.dx < 0 then
            selfcords.dx = selfcords.dx + step
        elseif selfcords.dx > 0 then
            selfcords.dx = selfcords.dx - step
        end

        if selfcords.dy < 0 then
            selfcords.dy = selfcords.dy + step
        elseif selfcords.dy > 0 then
            selfcords.dy = selfcords.dy - step
        end
    end

    local curState = love.keyboard.isDown(' ')

    if curState and not oldState  then
        createBullet()
    end
    bulletCount = bulletCount > 64 and 0 or bulletCount
    oldState = love.keyboard.isDown(' ')
end

function interceptInput()
    moveState.up = love.keyboard.isDown('w')
    moveState.down = love.keyboard.isDown('s')
    moveState.left = love.keyboard.isDown('a')
    moveState.right = love.keyboard.isDown('d')

    if moveState.up then
        selfcords.dy = selfcords.dy - step
    end
    if moveState.down then
        selfcords.dy = selfcords.dy + step
    end
    if moveState.left then
        selfcords.dx = selfcords.dx - step
    end
    if moveState.right then
        selfcords.dx = selfcords.dx + step
    end
end

function combineBullet(num, x, y, ang)
    return {['num'] = num, ['x'] = x, ['y'] = y, ['ang'] = ang}
end

function createBullet()
    local x, y = selfcords.x, selfcords.y
    local w, h = x - cords.x, y - cords.y
    local ang = math.atan2(h, w) + math.pi
    bulletCount = bulletCount + 1
    table.insert(g_fired, combineBullet(bulletCount, x + math.cos(ang) * 16, y + math.sin(ang) * 16, ang))
end

function releaseBullet(bullet)
    for k, v in ipairs(g_fired) do
        if v.num == bullet.num then
            table.remove(g_fired, k)
        end
    end
end

function love.draw()
    local x, y = selfcords.x, selfcords.y
    local w, h = x - cords.x, y - cords.y
    love.graphics.draw(g_imgTable["tank"], x, y, math.atan2(h, w) - math.pi / 2, 1, 1, 16, 16)

    for k, v in pairs(g_fired) do
        love.graphics.draw(g_imgTable["bullet"], v.x, v.y, 0, 1, 1, 8, 8)
    end

    love.graphics.setColor(0, 0, 0)
    love.graphics.print(#g_fired, 100, 100)
    love.graphics.setColor(255, 255, 255)
end