Today I want to introduce a very different piece of software I have been putting together lately. It is a RTS (real time strategy) engine. I started playing with the idea as a time killer some years ago, kicking off the development with a fast version of the A* pathfinding algorithm backed not by a grid (as usual) but by a quadtree. Quadtrees make pathfinding super-fast because of their hierarchical division of space and their adaptive partition sizes. Even though I used visibility graphs to store the navigable nodes from one given point, quadtrees are also fast for checking the properties/elements of a position’s surroundings, for child nodes are always spatially contained in parent nodes.

The new version 3.6 of the Particle Physics Simulator is now out with customizable star sprites and fading tails. The new tail graphics have an impact on performance with older devices (just like mine), but should be handled with minor fps drops by newer processors. However, if you encounter problems you can disable tails or set them to “short length” in the preferences screen.

I just published the latest version (3.5) of the Particle Physics Simulator, with a fancy new feature that allows for different-sized particles to be shot into the simulation. You’ll notice a frame with a size-changing particle when you hold your touch down for a shoot. The size of that particle at the moment you take the shot is the size of the particle being created. Easy, ain’t it?

The new version of the Particle Physics Simulator (v3.4) is now out. This version brings us the capability to load and save simulations to XML files. Now you can export your simulation to a file and load it later on.

In order to save the current simulation, just open the menu and then tap the “Save file” entry. In the file dialog that pops up select the folder you want to save your simulation and the name of your new file if you want to create one, or the file to overwrite, and tap “select”. It is done, your simulation has been exported to an XML file!

New friction feature has been added to the Particle Physics Simulator v3.3 for Android. Now, particles can be set to have friction so that their velocity will decrease over time at a steady rate. You can make them behave like snooker balls! Also, this version tunes particle tail lengths and adds some interesting performance tweaks that should make it run smoother in handicapped devices.

I just released the new bugfix version (3.2.4) which fixes the following bugs (all of them reported by Keith):

• Repel touches were off in big simulation area mode.
• Zooming multitouch acted as a single touch when first finger was lifted.
• Particles got stuck on wall ends.
• Additionally, the maximum number of walls has been increased from ten to fifteen.