Love2D:ゲームエンジンその6

player = {
    x = 100,
    y = 100,
    speed = 200,
    heat = 0,
    heatp = 0.1
}
bullets = { }

function love.update(dt)
    if love.keyboard.isDown('a') then player.x = player.x - dt * player.speed end
    if love.keyboard.isDown('d') then player.x = player.x + dt * player.speed end
    if love.keyboard.isDown('w') then player.y = player.y - dt * player.speed end
    if love.keyboard.isDown('s') then player.y = player.y + dt * player.speed end
    player.heat = math.max(0, player.heat - dt)
    if love.mouse.isDown('l') and player.heat <= 0 then
        local direction = math.atan2(love.mouse.getY() - player.y, love.mouse.getX() - player.x)
        table.insert(bullets, {
            x = player.x,
            y = player.y,
            dir = direction,
            speed = 400
        })
        player.heat = player.heatp
    end
    -- update bullets:
    local i, o
    for i, o in ipairs(bullets) do
        o.x = o.x + math.cos(o.dir) * o.speed * dt
        o.y = o.y + math.sin(o.dir) * o.speed * dt
        if (o.x < -10) or (o.x > love.graphics.getWidth() + 10)
        or (o.y < -10) or (o.y > love.graphics.getHeight() + 10) then
            table.remove(bullets, i)
        end
    end
end

function love.draw()
    -- draw player:
    love.graphics.setColor(0, 255, 0, 255)
    love.graphics.circle('fill', player.x, player.y, 15, 8)
    -- draw bullets:
    love.graphics.setColor(0, 0, 255, 255)
    local i, o
    for i, o in ipairs(bullets) do
        love.graphics.circle('fill', o.x, o.y, 10, 8)
    end
end

function love.load()
    love.graphics.setBackgroundColor(0, 0, 0)
end