Hello, Im trying to do a simple astroids game but I got some problems with the anti aliasing, as you can see on the screenshot below. It doesnt show clear on the picture below but it surely isnt anti-aliased

http://img59.imageshack.us/my.php?image=screengb9.png

I make random "comets" in GDI+ on bitmaps and loads them in textures as streams and then renders them with Spritebatch.

The initializing code:

graphics.PreferMultiSampling = true;
graphics.ApplyChanges();

You're saying that that red line is a bitmap / texture?

If so: there's no way that the graphics device can anti-alias the contents of a texture... it can anti-alias the edges of one, but not the "stuff" in it. Antialiasing is for smoothing out edges, edges of polygons, not what is "in" them.

If not: How are you drawing those red lines? Also, when are you calling those two lines in listed above, in the constructor for your Game? If so, you don't need the ApplyChanges().