OpenGL cube vertex and indices explained

Submitted by Dickens A S on Wed, 10/26/2022 - 16:18

Understanding the vertex coordinates and corresponding indices slightly complicated. 
Sometimes the developer gets carried away due to too many numbers needs to be maintained in the VBO array

This article gives a typical approach to number in counter clockwise and group indices same way

Let us go by step by step

Front face

3 ---- -----2
|           |
|           |
0 ----------1

From bottom left you can count 0,1,2,3 counter clock wise

Back Face

Install Oracle Client with SQL Loader in RHEL / CentOS

Submitted by Dickens A S on Sat, 04/23/2022 - 02:49

This article explains how to install oracle client using RPM files

which ever version you want to choose you can choose for example 21.6


Download all these and issue the below RPM command lines

Windows 10 Docker Engine Installation with Minikube

Submitted by Dickens A S on Fri, 04/22/2022 - 05:01

Docker Engine is available as open source

Docker is licensed under the Apache License, Version 2.0

To make the docker engine work properly in windows 10 there are few features we need to enable

To do that, launch "Turn Windows features on or off" from control panel

And enable the below features

  • Containers
  • Hyper-V
  • Virtual Machine Platform
  • Windows Hypervisor Platform
  • Windows Subsystem for Linux

Then go to docker exe download site for windows

Selenium JavaScript element to WebElement conversion

Submitted by Dickens A S on Sun, 04/10/2022 - 09:04

This article explains sometimes the HTML element of a browser will be beyond the visible rendered region.

In that case Selenium XPath which got by the findElement or findElements will less in number

Therefore we can combine javascript code and find those elements and cast it to WebElement

Node modules from a different path using NODE_PATH

Submitted by Dickens A S on Sat, 04/09/2022 - 15:41

This article explains how to use node.js modules from different folder, for example you have installed "express" in a different folder and want to use it another application without installing inside local node_modules

How to do it

1.) Install express in a different folder

Example c:\dev\test1

npm install express

Now you have c:\dev\test1\node_modules created

2.) Go to another folder and create your index.js

Example c:\dev\test2

Android Concurrent Executor Interface

Submitted by Dickens A S on Sat, 03/26/2022 - 14:33

This article demonstrates how to use Core Java in android for concurrent Executor,

Question: Why we should use Core Java Executor? why not AsyncTask?

Answer: The reason is android based SDK announced AsyncTask is Deprecated

Question: So simple core java Runnable is good?

Answer: Not really, But in combination with java.util.concurrent.Executor Runnable is good

Question: Is this told by android SDK documentation

Answer: Yes, As shown below

Convert SVG to PNG using R programming

Submitted by Dickens A S on Sun, 10/03/2021 - 08:39
cygwin tools

cygwin libraries

Then within cygwin terminal type "R" in the terminal it will give you a prompt and issue the below commands

Plotting graph in R with X11 window system using Cygwin

Submitted by Dickens A S on Tue, 09/07/2021 - 03:02

This article demonstrates how to show a simple graph with help X11 system available in Cygwin/X

1.) How to install X11 in Cygwin

Double click the setup and launch the list of software shown in the previous article

choose the below two softwares



Compete the installation 

2.) How to start the X11

Go to Start Menu

Click on "XWin Server"

Wait for 30 seconds

in your taskbar you will see two icons as below

Compile/Install GTK4 on Ubuntu Focal 20.04 or Bionic 18.04

Submitted by Dickens A S on Thu, 08/12/2021 - 12:36

This article explains how compile GTK4 on Lower LTS versions of Ubuntu

Compiling GTK4 on a older version of linux is very difficult and identifying the corresponding dependency libraries alos very difficult, unfortunately the online build tools only uses the long time table version likke bionic or focal

Therefore I have managed to get the sequence of install command to install all pre-requested libraries to make the GTK4 compile with best possible facilities without leaving any minor facility in GTK4.

Reading MIDI Port from Kotlin Native using rtmidi in Windows

Submitted by Dickens A S on Sun, 08/08/2021 - 01:48

This article demonstrates how a MIDI port can be read from Kotlin native code via rtmidi library


This C function/api offers identifying the port of the MIDI which needs to be monitored/watched


This C function/api offers receiving the byte which is the key pressed in the MIDI keyboard or MIDI simulator, the message: CArrayPointer<UByteVar> parameter contains the numeric of the key pressed

Kotlin Code