Just uploaded the next version of Guardian for playtesting (you’ll need to be an XNA Creators Club member and signed in to follow the link successfully). There were lots of changes this time around. Over 250 items checked off of the todo list, many of them polish type things, but also some very major changes and additions.
When developing the iPhone version of Guardian I manually created my sprite sheets. I used individual sprites up until the end so everything was pretty much set in stone by the time I created the the sprite sheet. Even then I ended up having to recreate the sprite sheet two or three times, and let me tell you, manually figuring out the texture coordinates isn’t a particularly pleasant experience. In this case I believe I made the right choice. There were few enough sprites that I would have spent more time creating the tool than I would have saved.
Things are coming along nicely with Guardian. The Dream Build Play entry deadline is fast approaching, but I think I’m in pretty good shape to get my entry completed. The video shows most of the functionality. Pretty much all that’s left now is fleshing out some of the graphics, and adding a few more weapons. Then I can start getting some sleep.
Here’s a video of the XNA game I’ve been working on. It’s a port of the iPhone version with some additional functionality planned.
Someone over in the XNA forums asked a question about how to make sprite explosions like those in the old Defender arcade game, where the sprite is broken into pieces and exploded everywhere.
So we finally come to the last post in the horizon culling series. Previously we’ve discussed what horizon culling is and some reasons for using it. Then we went through the math involved in determining the angle between a line from the camera to the planet center and a line from the center to the point on the horizon.
In my previous post on horizon culling we talked about what horizon culling is, the reasons one might want to do it, and went over a simple C# vector class. In this post we’ll take a look at the math we’ll need to use.
In 3D graphics, a technique that’s often used to improve performance is called culling. Culling means to reduce the population of a wild animal by selective slaughter. It also means, and this is the definition we’ll be using here, to select from a large quantity. For Horizon Culling, the large quantity we’ll be selecting from is the tens of thousands of triangles used to draw a spherical planet. And we’ll be using the horizon to determine which triangles to cull.