Physics

I just recently got picking working using the Bullet Physics Engine. Picking is a way to “pick” an object via a primitive (triangle) using a cursor from the camera’s perspective. Hovering your mouse cursor over an object and clicking on it is obviously a very intuitive way to interact with a scene. However, it’s not as intuitive to program, because the location selected is in 2D screen coordinates, and not 3D world coordinates. The difficulty in picking really lies in somehow determining the 3D coordinate space of the object to select. First, lets see what I’m talking about.

I saw a video online recently of several cubes flying into the scene and stacking up to form a larger cube. I thought it was a pretty simple yet powerful effect. The effect was achieved using Particle Flow, so the movement of the particles are entirely animated and not in real time. After seeing this, I immediately wanted to try it, but with a more general solution. So, off I went to write a physics system for my particle engine.