Questions tagged [computational-geometry]

Computer geometry is a branch of computer science devoted to the study of algorithms which can be stated in terms of geometry.

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Structuring a project that generates triangles inside triangles

Basically I made this completely useless program that generates triangles inside triangles. Its not perfect yet but my question is about the structure. I am generally happy with it but I want to know ...
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Triangle module in OpenSCAD

I've written the following module to generate arbitrary triangles based on a subset of lengths and angles, like what this provides. It works well enough but as-written it's fairly repetitive. I'm new ...
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112 views

C++ : Merging two convex hulls

I wrote a C++ program that merges two convex hulls in linear time. The algorithm is based on http://cgm.cs.mcgill.ca/~godfried/teaching/cg-projects/97/Plante/CompGeomProject-EPlante/algorithm.html ...
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1answer
84 views

Convex polygon-polygon swept collision test

Currently working on a pre-solve collision library. My goal is to have it be potentially usable in potential video game projects of mine, so time constraint is small as this should be used in a game ...
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2answers
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3D torus in Lua

I'm a total beginoob in Lua. The aim is to display a 3D Torus in dots (see Figure1), or at least compute the positions, privileging clarity over performance. Pseudocode link. Don't hesitate to be ...
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1answer
134 views

C++: k-Nearest Neighbours with Lambdas and Priority Queues

I implemented getting the \$k\$-nearest neighbours of an origin point to a set of points in C++17. I tried to use some more modern C++ lambda techniques and was looking for feedback on use of lambdas, ...
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1answer
917 views

The intersection of two polygons in C++

I implemented the intersection of two (convex) polygons in C++. It finds the polygon in the intersection like in this image. Looking for any and all feedback. I left the logic for line intersection ...
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Calculating the term of dfdeta [closed]

I am trying to improve the time running of this code. Some dummies variable is defined and it is just some part of a lot of lines of code, but I tried it with dummies variables. It takes too much in ...
6
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1answer
108 views

Find overlapping area of octagons

Here is my problem statement: There is a matrix of octagons, for example, 4 octagons in a row and 3 such rows. So 4 columns and 3 rows of octagons. But they are not arranged in a perfect rectangle ...
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Compute angular distances between data points in a matrix

I am having a hard time speeding up a function that I use to compute angular distances between data points in a matrix. More precisely, I want to compute $$\sum_{r=1}^n|\pi - \arccos\left(\frac{(X_{i}-...
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1answer
166 views

A program for fun to see how red and blue appears blended to purple due to resolution

I do some art both analog and digital. This time I did some color test digitally. To work on my programming skill so that it's shareable I'm asking for help to get some code review. How's the ...
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Generate points for smooth movement between two given points

This is one of the methods in a project for generating points between two given points. We add points of route with a 25ms delay in an array and a camera on Google Maps is always at the last point. So ...
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3answers
939 views

Counting the triangles that can be formed from segments of given lengths

Problem Statement: Given an unsorted array of positive integers. Find the number of triangles that can be formed with three different array elements as lengths of three sides of triangles. ...
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1answer
49 views

Find intersection of rectangle with itself rotated

Given \$w, h, \alpha\$ for a rectangle centered at origin with width \$w\$, height \$h\$ and itself rotated by \$\alpha\$ around origin clockwise, I wrote a code to find the intersection area. ...
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2answers
143 views

Read coordinates from many files and calculate polygon areas

My goal with this snippet is to create an array of coordinates which in turn is a tuple of 68 elements, area and modified area array for all 10k elements and assign it to the ...
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3answers
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Determine if a triangle is equilateral, isosceles, or scalene

I've been fiddling around with some easy code challenges and there's one about determining if a triangle is equilateral, isosceles, or scalene. I've come up with a working solution, but I feel this ...
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2answers
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Find 4 points which form a square with the biggest area

I have set of points on the coordinate plane. I need to find the 4 points which form a square with the biggest area. I'm new in JavaScript so I'd like to get any suggestions about code style, ...
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1answer
298 views

Choosing evenly distributed points from a million points on a sphere

I have \$10^5\$ to \$10^6\$ points on a sphere, and want to choose some points from them which are as close as uniformly distributed as possible. For that reason, I do the following: at each step I ...
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Cubic spline interpolation in Python from scratch

I implemented the cubic spline interpolation explained in https://en.wikipedia.org/wiki/Spline_interpolation as a Python class. Of course, such an interpolation should exist already in some Python ...
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2answers
582 views

Find all k points which are closest to origin

We have a list of points on the plane. Find the K closest points to the origin (0, 0). (Here, the distance between two points on a plane is the Euclidean distance.) You may return the ...
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1answer
376 views

Searching extreme points of polyhedron

In my Uni, my scientific professor asked me to make some researches about the extreme points of polyhedrals. And I did them. I found that there is still no code in public for searching extreme points ...
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2answers
288 views

Line segment intersection from [de Berg et al, 2000], computational geometry

I've implemented the following algorithm (From "Computational Geometry : Algorithms and Applications"). The code is below: (All the code actually is here: https://github.com/lukkio88/...
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1answer
233 views

Given a list of coordinates, find the rectangle with minimal area

A problem on leetcode asks the coder to write an algorithm to take a bunch of coordinates in the xy-plane and return the minimum area of a rectangle made from four of these coordinates (or return <...
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1answer
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Project Euler Problem #102 in F#: counting triangles that contain the origin

I've recently decided to get into functional programming with F#, and decided to learn the language through Project Euler. The following is my implementation of problem 102: Problem: Three ...
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1answer
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Optimal algorithm to move a a rope from one position to another

I'm an engineer working with a deformable membrane that is attached to actuators. The goal is to move the membrane from one shape to another, without ripping the membrane. This imposes "neighbor ...
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2answers
237 views

Computing bezier curves of degree n with recursive functions

I have been looking at homemade CNC and have been wondering how curves are drawn, so I looked into it and found this cool article. I then decided to try coming up with a bezier curve algorithm in C. ...
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519 views

Implementing Cyrus Beck algorithm for convex polygons

I have found the coordinates of the centroid for finding the direction of the normal vectors of the edges of the convex polygons. This method seems to work in the cases I tested. Is this fool proof ? ...
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Get directions for unit movement with conditions

I am developing a bot for Starcraft II. In my code for unit movement, I often find myself doing this: Calculate points around the current position of the unit Check if these points are valid and can ...
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2answers
219 views

AI to avoid obstacle

The AI I'm making is really simple, however it might be a bit too inefficient for what it is doing. The chart below shows speed differences between various arithmetic and math operations. ...
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1answer
204 views

Graham Scan Algorithm in Haskell

I have just begun learning functional programming and Haskell. This is my attempt to implement a solution to Graham Scan Algorithm in Haskell. Note that I am not even sure if this is indeed Graham ...
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2answers
73 views

Determine whether path A→B→C on a plane constitutes a left or right turn

I have recently started learning functional programming and Haskell. I have encountered this problem: Consider three two-dimensional points a, b, and c. If we look at the angle formed by the line ...
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189 views

Where is the most desolate place in Colorado?

The Story While flying a plane over the forests of Wisconsin a couple years ago, I thought to myself "If I lost an engine, I would be awfully long way from an emergency landing airport. I wonder ...
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1answer
481 views

Drawing concentric circles to console

This prints out a triple layer circle with 12 points per circle and finds the points across a grid. I had a really hard time with this and I'm planning to implement a lot more code but I don't want ...
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2answers
9k views

Intersection over Union for rotated rectangles

Problem Statement I am trying to find the intersection over union (IoU) metric for one to several rotated rectangles compared to many different rotated rectangles. Here are some images to help ...
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Function to calculate distances and nearest points between 2 GeoPandas dataframes

I have 2 geoPandas frames and want to calculate the distance and the nearest point (see functions below) from the geoSeries geometry from dataframe 1 (containing ...
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3answers
1k views

Program to see how many points lie strictly inside a convex polygon

The program takes in a set of coordinates that defines the polygon. It then takes in a set of points. The idea is to find out how many of these points lie strictly inside the convex polygon (not on ...
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1answer
117 views

Curvature data to coordinates

I want to determine a path (x and y coordinates) by using curvature data (radius, with constant distance (length_of_arc) travelled between data points. I want to ...
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2answers
2k views

Given a list of coordinates check if 4 points make a line

I was doing some preparation for coding interviews and I came across the following question: Given a list of coordinates "x y" return True if there exists a line ...
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2answers
66 views

Checking where/if another creature lies in a creature's field of view

Note: this is a more specific form of this I am working on a simulation of some virtual creatures. They all have vision that lets them see other creatures. To do this, I calculate the difference ...
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2answers
312 views

Finding the closest pair of points divide-and-conquer speed improvement

This is a follow up to a previously asked Finding the closest pair of points divide-and-conquer question . The original code changed significantly based on answers from @AJNeufeld therefore I created ...
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2answers
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Finding the closest pair of points divide-and-conquer

Here is my code for the famous "finding the closest pair of points" problem from CLRS book section 33.4 using a divide-and-conquer approach (this code returns the minimum distance between pair of ...
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1answer
851 views
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1answer
498 views

Lagrange Interpolation over quadrilateral points

I've been working on a program which calculates, given a point and 4 surrounding points, the Lagrange polynomial, in order to interpolate a value. Consider that I'm not a mathematician and I better ...
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2answers
263 views

Math matrix, mainly for graphics

I wrote a matrix library to replace my old matrix library. I was using my old matrix library to do basic operations for 3D rendering but that library grew old and now I'm seeking to replace it. I'm ...
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1answer
358 views

Draw common tangents to two circles interactively in MATLAB

Requirement After a user draws two circles with their mouse successively, the program should draw all common tangents, if any, to them. Here is my implementation ...
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4answers
123 views

Solving for <45 degree angles of a multi-vector system

I'm working on a problem from codechef.com. The goals are: Solve for whether or not the driver took a "sharp turn", meaning for some angle θ, θ > 45°. Test each point \$ (x_i, y_i) \$ in the system ...
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2answers
1k views

Given points on a 2D plane, find line that passes through the most points

Could someone give some feedbacks from perspective of oo design and coding style on the following codes: Question: Given n points on a 2D plane, find the Line with maximum number of points that lie ...
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2answers
531 views

Angle reflection function

I've developed a function to calculate the exit angle of a projectile after it collides with a boundary/edge inside a rectangular space, based on the entry angle and the axis it is colliding with. ...
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1answer
126 views

Finding angle and direction between line segments

I'm putting together a short demo on two things: Finding the angle between two line segments and direction (right or left) as you travel counterclockwise around a shape Using newer ecmascript syntax (...
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1answer
50 views

Calculating minimum size of rectangle that contains two smaller ones [closed]

My Rectangle class contains one vertex (x,y), its width a, and its height b; the opposite ...

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