Computer geometry is a branch of computer science devoted to the study of algorithms which can be stated in terms of geometry.
7
votes
3answers
146 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 ...
8
votes
1answer
114 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
votes
1answer
67 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 ...
1
vote
3answers
224 views
0
votes
0answers
29 views
Scale geometry based on distance between 2 vertices - follow-up
Edit: Changes I made from previous script:
Reformatted lines of code to be more readable and correct for Python
Created individual functions for items that were previously crammed into singe ...
7
votes
2answers
109 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 ...
6
votes
0answers
75 views
Just another 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 Graham ...
8
votes
1answer
147 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
votes
1answer
66 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 ...
5
votes
2answers
237 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 ...
0
votes
2answers
125 views
11
votes
5answers
223 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
votes
1answer
85 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. ...
7
votes
1answer
402 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
votes
2answers
112 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
votes
1answer
68 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
votes
1answer
99 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
137 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?
...
2
votes
0answers
239 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?
...
1
vote
2answers
48 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
votes
1answer
76 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
votes
2answers
97 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
votes
2answers
146 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
votes
2answers
100 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
votes
3answers
116 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?
...
4
votes
1answer
87 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
votes
1answer
91 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
votes
2answers
140 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
votes
0answers
106 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 ...
3
votes
1answer
109 views
Ray→plane and ray→quad intersection
This checks the intersection between a Ray and a Plane and between a Ray and a ...
2
votes
2answers
159 views
Haversine formula in SQL
This is an implementation of the Haversine formula in Microsoft Transact SQL.
How can I simplify the function?
...
6
votes
2answers
129 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
votes
1answer
52 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
votes
3answers
124 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
votes
1answer
957 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 ...
4
votes
1answer
162 views
Generate sample coordinates inside a Polygon
I have a Polygon named as poly. I attempted to randomly select 5 coordinate points that lies inside the polygon.
...
7
votes
1answer
107 views
2D Convex hull exercise
I'm reading Real World Haskell, and this is my first try with the language.
This is the result of the exercises of chapter 3:
Consider three two-dimensional points a, b, and c. If we look at ...
1
vote
0answers
163 views
Optimize QuadTree to find K Nearest Neighbors
I'm looking a way to make my k nearest neighbors search more efficient. The context of the question is that I'm given a list of topics that have a unique ID (integer) and a (x,y) coordinate (floats) ...
3
votes
1answer
118 views
Calculating the distance squared between all vertex-pairs of a number of 2D polygons
I have implemented my code using Cython. It is the current bottleneck in my computations.
There are two non-numpy functions involved:
calculate_2D_dist_squared ...
11
votes
2answers
572 views
CodeEval's SkyScrapers challenge
This is a solution to CodeEval's SkyScrapers challenge.
You are given a list of triples \$(l, h, r)\$. Each triple represents an axis-aligned rectangle, with top-left corner at \$(l, h)\$ and ...
14
votes
7answers
1k views
Custom mathematical vector class
My first bigger C++ project: a vector class for personal use and statistical computation.
...
-1
votes
1answer
263 views
Custom 2D/3D Graphics Vector Classes vs SFML's
I don't really like SFML's Vector Classes so I tried making my own. Any criticism is welcome.
...
8
votes
6answers
3k views
C++ 3D Vector Implementation
I have been learning C++ now for 2 months and this week I started reading a book on 3D graphics. I like coding whatever mathematical stuff I learn so I can understand it better, so when I learnt about ...
6
votes
1answer
150 views
3D matrix rotation in homogeneous coordinate space
Assuming that the framework is in place to handle the difference between row and column major matrices, I am curious to know if in a header based library such implementation is semantically and ...
2
votes
1answer
158 views
Neighbours from point connections
I am working with a mesh of triangles (in 3D, although I doubt it makes a difference). The mesh is given as list of lists, each list containing the indices of the three vertices of a triangle in said ...
7
votes
2answers
69 views
Isometric Projection and Culling
I'm working on a small isometric drawing system in JavaScript. After much help from the Gamedev section, reading old questions, I've got something working. However, it's still a little hacky. I need ...
13
votes
2answers
645 views
Detecting two intersecting circles with editable x, y, and radius in JavaFX
I was actually pretty proud of this programming project that I came across in this book I'm working through. I only really had problems figuring out the formula for detecting whether or not the two ...
8
votes
1answer
406 views
Finding largest subset of line segments that don't intersect
I completed a challenge of codeeval called BayBridges. It can be found here. I have uploaded my code on GitHub here.
In summary, the challenge is to take a list of line segments, each specified by ...
8
votes
2answers
163 views
Finding the nearest polygon
Finding the nearest polygon out of a list of polygons seems to be quite a challenge on performance, due to lack of optimization.
Consider the following image:
I'll give the concept behind this. ...
3
votes
1answer
752 views
Calculating the distance between one point, and many others
In my program, I have entities that I call "blobs", because they have a blobby shape. Blobs are polygons. If I have two blobs, then their information array would look like:
...
