SolidusCode Blog

If you ever run into a problem on Ubuntu where by your system update, software center, or synaptic fail to run properly and you get the following bug report: E: Encountered a section with no Package: header E: Problem with MergeList /var/lib/apt/lists/mx.archive.ubuntu.com_ubuntu_dists_precise-updates_restricted_binary-i386_Packages E: The package lists or status file could not be parsed or opened. You can type the following terminal commands to fix the problem: sudo rm -r /var/lib/apt/lists/* sudo apt-get update The problem was caused by previous attempts to update but your internet network failing to retrieve needed files, which results in Ubuntu getting confused.

In this collision tutorial, we will take more in detail with how exact we get the normals and how we get the intervals.  However, I will not be going in detail regarding vector math needed to understand this, although it is simple and I will eventually post blogs regarding them. Down to business.  Our shape is composed of vertices.  In the case of this rectangle, there is four vertices, in red, and four normals, in brown.  The vertices are self explanatory and the normals describe the orientation or the way a side of the triangle is facing.  Take note that the vertices are defined such that the center of the triangle, not indicated in the picture, is at position(0,0) and all vertices defining the vertex is relative to this location; just like in a normal coordinate system. Now, to get the normal for a side of the rectangle we take two vertices defining an edge of the rectangle and subtract them.  Further, we swap the x, and y components and negate the new y component.  Then we norma