DCEL | C Library for Doubly Connected Edge List | Graphics library

I have an array of items, and for each of the item in the array, I need to do some check against the rest of the items in the same array.

Here is the code I am using:

I am using a HalfEdge data structure to represent the connectivity between the faces on my mesh.

I am importing an external model, and I am constructing the HalfEdge structure during the import process. However, with meshes with many triangles, the construction process takes up too much time.

Specifically, it appears that the process of linking the half-edges take up the most time. I would like to get some advice on how to improve my algorithm.

Below is the code I am using to initialize my data structure. The first for-loop creates a Face with the vertices data, while pushing the HalfEdges that compose the Face into a separate array to be used momentarily after.

The second for-loop is reponsible for looking into the array of all HalfEdges, and finding matching pairs (i.e., the two that are twins of one another).

I logged out the time before and after each process, and noticed that the second loop is what slows everything down.

Here are the time stamps

start constructing DCEL 14:55:22

start making faces 14:55:22

end making faces 14:55:22

/* this is where it takes long.. almost 6 seconds on a mesh with 13000 triangles */

start linking halfEdges 14:55:22

end linking halfEdges 14:55:28

end constructing DCEL 14:55:28

And here is the actual code

For one of the preprocessing steps of a GPU renderer for Scalable Vector Graphics, I am dealing with SVG curves (of the four types: lines, quadratic and cubic Bézier curves, and ellipse arcs). One of the steps is curve subdivision on intersections, as a prestep algorithm to populate a doubly-connected edge list.

Previously, I went to store each type of curve in a separate struct (Line, QuadraticBezier, CubicBezier and EllipticArc), which means that, to operate on them, I needed to write the same (similar) code to each of those combinations (leading to a whopping 10-ication of the code). Now, I want to try something different. I have two options: using an interface ICurve, or use a struct Curve that has a Type and reunite all the operations.

The code that operates on the curve looks (bar the duplication) like this:

I am writing 12,000 records with 46 columns, as a production report, to an excel file. The worksheet is not displayed while it is filled with data.

Previous StackOverflow information taught me to use arrays of objects to put values in ranges for speed. I had hoped this worked for formatting the values as well.

Code snip:

For my thesis I am using some CGAL code written by another student a year ago. I cannot get it to build, however.

The function that is giving errors is the following:

For my thesis project I am dependent on a bunch of CGAL code written by another student a year ago. Unfortunately, I can't get the code to compile due to errors. These errors were probably not experienced by the previous student, so they probably are more related to my setup than the code itself, but I have no idea what the direct cause is.

The errors are in the file CCBSegmentCalculator.h. The code is as follows: