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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4
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2answers
848 views

Find the largest area polygon built from a given list of vertices

This is code that gets a list of polygon vertices, non-ordered, and finds the order in which they should be arranged in order to create the polygon with the largest area. There are two key elements ...
10
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3answers
539 views

Check if 2 rectangles fit in another one, given their length and height

I was very intrigued with the manner to solve this problem. The program needs to know if 2 rectangles fit in another one, considering the lines of the 2 rectangles are always parallel to the other one'...
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2answers
522 views

Rectangle-segment collision detection

I am working with C++ and SDL, hoping to create a game later. I am implementing the collision detection between rectangles and segments. I found this (NateS user's solution) about line-rectangle ...
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2answers
391 views

Grouping rectangles horizontally and vertically

As you can see the below code for each method is that same, except for the properties it uses. For example X vs Y and ...
6
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1answer
1k views

High performance triangle - axis aligned bounding box clipping

Implementation of a Robust (i.e. with a finite plane thickness) Sutherland–Hodgman algorithm for clipping polygons against an axis-aligned bounding box. I use the following code only for clipping ...
2
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0answers
305 views

Shortest bitonic tour

This a solution to the shortest bitonic tour using dynamic programming. Bitonic tour starts at the leftmost point then goes strictly rightward to the rightmost point and finally strictly leftward to ...
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0answers
352 views

Get vertical acceleration from rotation vector and accelerometer values

My goal here is to calculate the acceleration towards the ground, which I call "vertical acceleration". This seems to be working OK for the most part, except when there is a lot of rotation going on ...
2
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2answers
73 views

Find the best path amongst N random points

For an application with a graphical canvas, I want to generate N points. But then I want to link those points, and I want to find the best path through those points. I wanted to use a dynamic ...
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0answers
783 views

Computing intersection of 2D infinite lines

I wrote a small program to compute intersection of 2D infinite lines using Boost Geometry A line is defined by two points in Line class. The ...
2
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1answer
57 views

Find cells crossed by a line

This method find cells that are crossed by line A-B and adds them to one vector. I have got some duplicates here and some lines of code are very similiar but they differ in one variable. Should this ...
5
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1answer
4k views

Perimeter of a polygon given its vertices

I recently completed this code challenge so just looking for some feedback on my code. The task is to read polygon coordinates from a file and calculate the perimeter, I was provided with a script ...
3
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2answers
564 views

Convex envelope algorithm of random set of points

This is my "naive" implementation of a convex hull algorithm. By naive I mean that I am not using any of the advanced algorithms that exist to solve this problem. ...
10
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1answer
513 views

Template class for Andrew's Monotone Chain Algorithm Convex Hull

This is my first attempt at writing a template class. I am implementing Andrew's Monotone Chain algorithm, as described here to calculate a 2D Convex Hull. Since this is my first try at templates, I ...
9
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2answers
13k views

Point inside Polygon check

I have written a method to determine whether a Vector2 lies inside a polygon or outside of it. The polygon is defined by an array of clockwise vertices, p[]. It returns true if the point is inside, ...
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4answers
669 views

Striped closed poly-line

I'm working on class Striped_polyline which represents a closed poly-line filled with equidistant horizontal lines1: stripedpoly.cpp: ...
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2answers
4k views

Calculate the area of rectangles union

I've been given the following task: Given N rectangles with edges parallel to axis, calculate the area of the union of all rectangles. The input and output are files specified in program arguments. ...
8
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3answers
1k views

Given a set of points and pairs of lines, count the number of points that are between the pairs of lines

This is a contest problem. The entire description is here. In resume: The question gives a point simulating a light explosion that always has a negative x coordinate, a set of pairs line segments on ...
9
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1answer
719 views

Count number of isosceles triangles in a set of points

Given a set of points, what is the number of isosceles triangles that can be formed with the combinations of all points in the set? It is certain that 3 collinear points never exists in the set. <...
4
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1answer
405 views

Project Euler 91 (via HackerRank): Right triangles with integer coordinates

This is my code to solve HackerRank's version of Project Euler Problem 91: on an N × N grid, find the number of possible right triangles where one vertex is (0, 0) and the other two vertices are ...
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3answers
7k views

Checking if the point is on the line segment [closed]

Previously, I wrote the following code: ...
7
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2answers
544 views

Finding the maximum pairwise difference in a collection of colors

Note that this problem is equivalent to finding the longest line segment defined by any two points in a collection of 3D coordinates, which may be an easier way to visualize the problem, and is almost ...
7
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1answer
355 views

Graham scan implementation in Haskell

It looks like this is a really classical question, but I'd like to ask it one more time as all those solutions look quite long and complicated for me (maybe because I am dumb :) ) So this is a ...
8
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1answer
2k views

Drawing circles with triangles

As pyglet has no in-built method to return a vertex list of circle, I had to build one myself. This is a critical piece of code that I will use very frequently. I need it to be of very fine ...
3
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1answer
83 views

Remove “lines” from a 2D vec

I have some code here that I am very unhappy with. The task I am trying to accomplish is this. Given a 2d vec like this: [[0 2 0] [1 3 5] [3 3 0]] which can ...
6
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2answers
4k views

Python Trig Calculator

It's big, it's ugly, but it should work. My question is: how could I have implemented the "typeselection" function so it is less repetitive? Any tips on other improvements in coding style are welcomed ...
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2answers
5k views

Area of an irregular polygon

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5answers
806 views

Segment Intersection — Failing on Unknown Edge Cases

I was recently at a programming competition. One of the problems was to determine whether two line segments are parallel, intersect, or do not intersect. For all of the test cases I ran, my solution ...
4
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1answer
685 views

Implementing Mitchell's best candidate algorithm

I have written an implementation of Mitchell's best candidate algorithm. Mitchell’s best-candidate algorithm generates a new random sample by creating k candidate samples and picking the best of k. ...
9
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1answer
7k views

Line segment to circle collision algorithm

I've written a function (in Python 3) which computes if a line segment (constraint) and a circle (body) collide, and returns the point of intersection (closest point to the centre of the circle): <...
2
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2answers
235 views

Find non duplicate Triangle Triplets from a list of given numbers- version 3

It is a continuation of my previous question: Find non duplicateTriangle Triplets from a list of given numbers After I realized triplet structure using less space than ...
4
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1answer
122 views

Distance between angles as points

This code calculates the distance between angles, particularly for n-tuples of angles. One example where this situation occurs is as follows: I'm using a 2 arms, one 6 degree of freedom and the other ...
2
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1answer
137 views

Find non duplicateTriangle Triplets from a list of given numbers

I implemented an O(N^2) algorithmic solution but not sure it is better than my previous implementation Find Triangle Triplets from a list of given numbers in case of performance. I adapted almost ...
4
votes
1answer
384 views

Find Triangle Triplets from a list of given numbers

If a triplet of segments A, B and C are triangle triplets if and only if A + B > C A + C > B B + C > A Is there a better implementation for this problem? ...
3
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1answer
2k views

fftshift implementation for OpenCV

I'm trying to implement fftshift from matlab for OpenCV. Can you please review the correctness of my algorithm? Have I missed something? Also, is there a better and faster way to do it? ...
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2answers
143 views

Lazy properties for the angle and length of a line segment

The code below shows the pattern I use to manage properties in my classes when I have the following requirements: Some properties are slow to calculate and are rarely used, so I want them to be lazy ...
3
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1answer
433 views

Scale object based on distance between 2 vertices

I made this script so that I can scale objects for 3D printing from Maya. I had fun making it and I'm sure it could be cleaned up or improved. If it can be cleaned up please let me know. ...
2
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2answers
218 views

Comparing triangles using Java 8 streams

I'm trying to get more familiar with Java 8 streams as they seem to be very powerful (and shorter), so I rewrote a method to use streams. However I'm not very satisfied with it and would like some ...
6
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2answers
875 views

Speeding up 2D shadow algorithm

I wrote a class to represent a set of lights in a 2D game that raycast in order to find shadows. The draw method does a lot of calculations and takes a lot of time. Mainly, the adding of areas and ...
4
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2answers
219 views

Implementation of Graham Scan algorithm in Haskell

Here is an implementation of Graham Scan algorithm for computing the convex hull of a finite set of points: ...
5
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3answers
284 views

Line passing the most number of points

Given points on a two dimensional graph, find a line that passes the most number of points. Any comments please? ...
6
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1answer
198 views

Use of static factory methods for vectors and matrices library

I've been working on a Java-based mathematics library focusing on vectors and matrices. I plan to use it for an important upcoming project, so the classes are analogous to data types available in GLSL ...
4
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1answer
432 views

Tested cartesian plane utility

I am starting to explore automated testing of code, so I decided to write some trivial code about the cartesian plane and test it. I am particularly interested in automated testing conventions and ...
4
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2answers
1k views

Cubic “bezier” curve of grade n

This is code I wrote for calculating bezier curves as quickly and RAM efficiently as possible. I would like to know if there are faster ways to optimize anything, because I am very new to C++ and ...
3
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0answers
172 views

Graphical editor with geometric intersection

If it is possible I would like some comments on the overall style of the program. It feels like I am writing the whole program as one big script and I'm not sure how to break it down into several ...
4
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1answer
317 views

Ray→plane and ray→quad intersection

This checks the intersection between a Ray and a Plane and between a Ray and a ...
2
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2answers
2k views

Haversine formula in SQL

This is an implementation of the Haversine formula in Microsoft Transact SQL. How can I simplify the function? ...
6
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2answers
261 views

Quaternion rotations and preparing matrices for a shader

I am implementing an OpenGL ES 2.0 renderer in c. I want to use quaternions for rotations. Please take a look at the way I am implementing the rotation math. Everything looks as expected when the ...
6
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1answer
94 views

'Tis the season for gift-wrapping

When reviewing a Graham scan convex hull algorithm implementation, I wrote the following function in an answer: ...
7
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3answers
2k views

Checking for intersection points

The aim of the program is to find those points which comes under the intersection of at least 2 circles.(space is a 1000x1000 matrix) ...
8
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1answer
4k views

Jarvis's March Convex Hull

I'm more concerned about the coding best practices and how it's written here than the actual algorithm and math. I'm concerned about stack constraints, passing arguments,..etc. If there is anything ...