Saturday, July 24, 2010

Lines

I played around with my nav mesh trying to get the funnel algorithm working. I had it working in most cases but now and again the part that works out if the next funnel is contained in the current one got confused and while the funnel algorithm was cool it was not getting me much closer to have a walkable-area system for an adventure game.

Thus I started a new game state. It allows the player to add a 4 point convex polygon with 'a' key. The verts can then be moved around by dragging them. In the above picture the little square in the bottom right is the currently selected polygon and you can see the four circles representing it's vertices. You can't drag the verts in such a way to make a convex poly. There's quite a lot of useful 2d math bits in the above code. The green lines represent edge normals and the little red dot is the point on the nearest line closest to the mouse cursor.

The idea is when laying out the walkable area you drop a few of these boxes down and rearrange them to cover the walkable area. More verts can be added to the polys by presing 'i' near a highlighted edge. The polygons can be linked by clicking c then drawing a line that connects two edges between two different polygons. The blue circle shows the current connections.

It's pretty much there really. I need to add a layer of A* on top and wrap it all up in a nice interface where I can call something like WalkTo(x, y). Once that's done I'll clean it up and add it as an example to google code repo.
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