(C# Monogame) When adding objects to a list, keyboard input lags for a frame

Question

Basically, I have a list of enemy objects and timed events using gameTime.TotalGameTime.TotalSeconds. Every 0.1 seconds it calls upon a method to check for enemy spawns, and if we're at second 2.5 we add an enemy to the enemy list.

Now what happens is that keyboard input lags for a second, for example, if i'm moving continuously to the left, my character will stop for a short period (like 0.1 secs i think) before resuming moving.

I'm using gameTime to check for keyboard input every millisecond, but i've tried not using it too and it still happens. It's also weird because I have code that creates bullet objects every 0.5 seconds if i hold down Z the same way it does with enemies (through adding the object to a list), but that doesn't make it lagg the input

if (elapsedMs > oldElapsedMs + 0.001) //Millisecond update, for movement
        {
            oldElapsedMs = elapsedMs;

            //Keys to be held down.
            newState = Keyboard.GetState();
            Keys[] pressed_Key = Keyboard.GetState().GetPressedKeys();
            for (int i = 0; i < pressed_Key.Length; i++)
            {
                switch (pressed_Key[i])
                {
                    case Keys.Escape:
                        this.Exit();
                        break;
                    case Keys.Left:
                        player.tryMoveLeft();
                        break;
                    case Keys.Right:
                        player.tryMoveRight();
                        break;
                    case Keys.Up:
                        player.tryMoveUp();
                        break;
                    case Keys.Down:
                        player.tryMoveDown();
                        break;

                    default:
                        break;
                }
            }
        }

Spawn check code:

//0.1sec Update, spawning code
        if (elapsedSpawnTime > oldElapsedSpawnTime + 0.1)
        {
            oldElapsedSpawnTime = elapsedSpawnTime;
            spawnTimer += 1; //Every 0.1 sec add one to spawnTimer. The spawn timer int is what stage.Spawn() uses to check for spawns.
            stage.Spawn();


        }

my spawning method in my stage class:

public void Spawn()
    {
        switch (game.spawnTimer) //Each int is 0.1sec
        {
            //10 spawnTimer = 1 Second

            case 40:
            case 42:
            case 44:
            case 46:
                game.enemyList.Add(new Enemy(game.enemySprite, 500, 500, 1, true));
                break;

            default:
                break;
        }
    }

Thanks. If you want to help me but need more info you can add my skype @ emil1000123

Answer 1

The code in the screenshot says

( elapsedMs > oldElapsedMs + 0.001 )

The variable names tell that those values are in milliseconds, so are you are checking every 0.001 milliseconds?

Answer 2

It seems that the issue lies in the millisecond update:

if (elapsedMs > oldElapsedMs + 0.001)

So, what happens if it gets at this statement, but havn't passed 1 millisecond yet?

A computer looks at code in ticks, those are way faster than milliseconds, and thus it'll ignore that statement at all, which can result in a tiny lag, depending on your PC's performance and file size (which will increase by adding arrays or lists)

Now, I don't know what you've used in the TryMoveLeft() (ect.) methodes. But I think you're better of my getting rid of the said if-statement. and try to rework the way how you player walks.

Maybe I might give a few tips if I can see how the player.TryMoveRight method looks like.