The next post steering behaviors series is unaligned collision avoidance. We will be using the Vector2D.as and Vehicle.as classes for this. You will need these classes for the this post. This post is based on Craig Reynold’s article Steering Behaviors For Autonomous Characters. Flocking is created by combining several steering behaviors: Separation, Cohesion and Alignment. ...

The Sierpinski Triangle is a famous fractal named after the mathematician who discovered it. It is made up of nested triangles that get smaller and smaller. If you were to zoom in, you would see the same image (though it may be translated) and you could zoom forever and never find the end. So, how do you create the Sierpinski Triangle in AS3? First you have to know how to do recursion. Recursion is...

In the last three posts, we explored the how A* works, then we put A-star into code, then we looked at different heuristics for A*. Now we will combine A* pathfinding with the path following steering behavior. We have already done most of the work to do this. But we'll do a quick review in case you missed those posts. A* Pathfinding In A* we take a grid of cells and find a path from start to finish. Each...

Ray casting is a technique usually used in 3D worlds (often for rendering). Ray casting is exactly what it implies a ray is cast from a start point until it hits something (or a max length, so the computer doesn't die). Ray casting in 2D is great for collision detections, especially fast-moving objects (bullets). In this post, we will learn the basics of ray casting in 2D, then we will apply it to bullets in a...

Metaballs came around in the 90s with the Demo Effect. What made metaballs so cool was their squishy look and melding into other nearby metaballs. First I found a nice article and stuck it into as3. It turned out really slow (even after the suggested optimizations), but it worked and made some cool pictures. A metaball, according to that article, is defined by the function: F(x,y) = R / sqrt( (x-x0)^2 +...

The Separation of Axis Theorem(SAT) is a technique to test whether two convex polygons are colliding. The SAT theorem: "given two convex shapes, there exists a line onto which their projections will be separate if and only if they are not intersecting." The line where the shapes have disjoint projections is called the separating axis. A separating line is the line that can be drawn between the two shapes,...

The Sierpinski Triangle is a famous fractal named after the mathematician who discovered it. It is made up of nested triangles that get smaller and smaller. If you were to zoom in, you would see the same image (though it may be translated) and you could zoom forever and never find the end. So, how do you create the Sierpinski Triangle in AS3? First you have to know how to do recursion. Recursion is...