Friday, December 07, 2007

Background loading of assets

Before I wanted to start out with the actual networking part, I wanted a way to load the assets from disk in the background, and before the game was actually running. This to prevent slowdowns in the network simulation when a new building/unit was constructed and the asset had to be loaded from disk.

In order to do this, I wanted a nice front-end(A progressbar to display the loading progress) and a back-end: A background thread which did the loading and put each asset into the TextureManager.

I started out with the ProgressBar, as the asset pre-loader was half done. It just needed to be modified to be able to work in a thread.

The progressbar is just another Control for my game. It basically draws it's outline, and based on a Value it shows a nice (blue) bar. I initially had a problem with the outlines not showing up. But, this is related to the way how D3DSprite and D3DXLine render. I solved the issue by doing a Sprite.End() RenderLine Sprite.Begin(), but that cuts down on performance, so I need a better way. I reported it as a 'tweak' in mantis, so I don't forget about it.

Loading, please wait...

The background asset loader was also heavily modified. I initially wanted to try and run it while performing my normal gamestate functionality, but I found out it's way too slow for that. The change was that when I constructed the Preloader, it would parse the list of assets to load and store these, and then with a call to LoadNext() it would take the next asset from the list and load it. So, I shoved that into my BackgroundLoader class, and all was done. The BackgroundLoader is a thread that keeps running until all loading is done, and once it loads the next asset, it will increase a counter, so I can poll how many assets are done and then update the progress bar.

However, I was quite shocked when I tested out the background loading process. It's slow as hell! It took 94 seconds in debug build and 87 seconds in release build to load all 58 assets in just 2 colors. Image how long it'll take when you're playing with 6 friends...

Slowpoke is slow :(

So yea, background loading is in, except it's terribly slow. In fact, it's so slow, it's unusable to develop the network play with, because having to wait ~1.5 minute before being able to test something out is too much for me.

For the coming tests(The actual network gameplay), I'll be testing with a reduced preload set, just a handfull of units / buildings.


Mindy said...

Awesome! Loving these posts! Keep up the great work

Your Greatest Fan said...


In this day and age who cares about performance. I have a ton of ram and a top of the range hardware so im sure this loading wont be an issue.
Focus on making the networking stuff lean and mean by writing it custom.

You 'Woot' Greatest Fan