XNA: My bullets lag the game the first time they're fired, but not after

Question

I'm working on a SpaceWar-esque project to get comfortable with XNA. I have a Ship DrawableGameComponent and a Bullet DrawableGameComponent. The player's Ship is created at the start of the game, and the Bullets are created for each Ship as part of its constructor.

In my Ship constructor, I have the following code:

for (int i = 0; i < 5; i++)
{
    activeBullets[i] = new Bullet(game);
}

The relevant part of my Ship's shoot() function is as follows:

activeBullets[bullet].Visible = true;
activeBullets[bullet].Enabled = true;
activeBullets[bullet].position = this.position;

The first five times I shoot() (that is, once for each bullet object that the ship is allotted), there is lag that I think is due to the bullet sprite being loaded. I've tried setting Visible and Enabled to true in the ship constructor loop where the Bullets are instantiated, but the first-five-shots lag persists. Any shots beyond the first five are completely lag-free.

How do I load the Bullets properly ahead of time so that there is no lag on the first shots?

Answer 1

DrawableGameComponent's come with a certain amount of overhead - aside from the memory, every time you add a component to the collection it must be resorted (because components have a DrawOrder). You don't want to be constantly adding and removing components.

For this reason, you don't want Bullet to be a DrawableGameComponent. Instead, you should make something like a ProjectileManager, which loads all the projectiles (including their textures), and manages creating/destroying/updating/drawing them. This simultaneously solves your texture-loading problem, as the textures can (and should) be loaded only once, in LoadContent().

If this does not work, then the textures are not your problem, and we'll need more information to help you further.

Answer 2

It appears that my Update function was being called at least twice before anything was being displayed, and that even though the bullets were part of the collection they were becoming disabled before being drawn and thus textures not loaded (?!?).

By setting the lifetime (which is decremented once per Update, and when lifetime = 0 the bullets are no longer Visible/Enabled) of each Bullet to 3 or greater (this may vary depending on CPU speed?) when I instantiate the Bullets as part of the ship class, the textures are properly loaded at the beginning of the game.

I'm still not sure why manually setting them to Enabled/Visible at creation doesn't force the texture to be loaded.