Tuesday, May 18, 2010

Auto balancing Decision trees aka Resource Trees II

Just continuing from last time.

So after we called Act on the economy node it checks that it isn't a leaf node and therefore it checks it resources.

Monday, May 10, 2010

Auto balancing Decision trees aka Resource Trees I

Today were gonna talk about a process for decision making that you can use for higher level Ai functions in games. Basically this method can handle purchases, tech level up. In some case even goal selection for a computer opponent. I will discuss this in the context of trying to make an Ai for an RTS game but the same principles will hold for a turn based strategy game and depending on context in a lot of other games too.
So the basic idea here is the following. Computers are really good at managing tree structures we have tons of efficient algorithms that works well with them and we can search in them easily. This however is not just limited to existing algorithms, basically any kinda of data is normally easy to analyze if you can represent it as a tree.

This comes from the fact that when you represent data as a tree you have already performed a divide and conquer on that data to divide it into smaller parts. Those making the code to crunch the data for each node of the tree a lot simpler than if you had to crunch all that data in one piece.

Monday, May 3, 2010

Still alive here


Shadow Maps
This is pretty much the standards for doing shadows in games nowdays, and the dafacto standard for doing them for movies, Shadow buffers in difference form shadow volumes is image based and can therefore handle alpha masked polygons like a fence, It also allows techniques for blurring or otherwise distorting the shadows.

Percentage Closer Filtering 
A problem with shadow maps is that they easily get pixelized even with the best intentions. Percentage closer filtering is a technique to combat those jaggies and making your shadow edges soft, We will look at different implementations for example randomised kernel rotation with a poisson disc.

Percentage Closer Soft Shadows
In the real world shadows become softer and softer the further they come from the object casting the shadow. This is how to do the same in games using a technique that builds on the Percentage Closer Filtering technique.