## Resolved: How to add a diagonal to a doubly-connected edge list in constant time?

Question: I’m working through the polygon triangulation algorithm in Computational Geometry: Algorithms and Applications, 3rd edition, by Mark de Berg and others. The data structure used to represent the polygon is called a “doubly-connected edge list”. As the book describes, ...

## Resolved: Given a simple polygon P, consisting of n vertices, and Set S Of k points, determine if each of the polygon vertices are covered by some point from S

Question: Given a simple polygon P, consisting of n vertices, and Set S Of k points, determine if each of the polygon vertices are covered by some point from S. My best solution was to check for every P vertex ...

## Resolved: get coordinate of points where a line crosses a polygon

Question: I would like to find the points where a line intersects with a polygon. I obtain this polygon using a concave outline calculation from this thread. so far I tried defining a line with: but inters.xy returns a NotImplemented ...

## Resolved: Find common tangents of two convex polygons

Question: Given two convex polygons P, Q separated by a line, how can I find their common tangents? There should be 4 total. Geometry isn’t my strong side so any help will be appreciated ðŸ™‚ Answer: Any tangent will be ...

## Resolved: Rotating Line around Point in p5.js

Question: Goal: I’m trying to create a triangle given two angles (a0,b0). To do so, I’m trying to rotate a vector r0 by some angle a0 around one of the vertices of r0. Here’s a diagram illustrating my idea. Problem: ...

## Resolved: Location of Rotated Point

Question: Question: How do I get the location of a point after rotation? Goal: I want to create a triangle given two angles. The user can manipulate two angles (a0,b0) and the program will determine the third vertex based on ...

## Resolved: Algorithm for cutting mesh with the plane

Question: I’m trying to write an algorithm for cutting tessellated mesh with the given plane (plane defined with the point on the plane and unit normal vector). Also, this algorithm should triangulate all polygons and fill the hole after split. ...

## Resolved: Finding a hierarchy of polygons

Question: I need an algorithm to determine a hierarchy of polygons. For example, I have only closed loops of vertices, where polygons have CCW vertices order and holes have CW vertices order. I want to create a structure to contain ...

## Resolved: openGL 3D Rectangle not overlapping properly in C++

Question: You are given 3 rectangular strips whose vertex coordinates are as given below. Rectangle A (RED COLOR) (-0.5,0.6,-0.8), (-0.2,0.9,-0.8), (0.8,-0.1, 0.8), (0.5, -0.4, 0.8) Rectangle B (GREEN COLOR) (0.0, 0.8, 0.8), (0.3, 0.5, 0.8), (-0.7, -0.5, -0.8), (-1.0, -0.2, ...

## Resolved: Fitting an ellipsoid given 2D contours

Question: I have coordinates corresponding to a set of 2D contours, each corresponding to different heights. These contours do not draw out a perfect ellipsoid in 3D, and instead what I would like to do is to find the best ...