EME

Engineering|Media|Electronics

[engineeringandmedia-blog1]

Node js and data fetching

So here we are at Week2 in a little more server-side Javascript via node js.. As usual, we assume these commands are being executed on AWS on a EC2 t1.micro instance running Ubuntu 12.04.2 LTS. So what we have is to pull data from Yahoo API. Now instead of parsing complete html pages for, let's say, financial data in our case, we use a (hidden) fetch command. 

In a nutshell, if I need data for some stocks(in a csv), I use -

//http://finance.yahoo.com/d/quotes.csv?s=GE+PTR+MSFT&f=snd1l1yr

 (where sysmbols used in this URL means something, like d stands for Dividend/Share; s for Symbol etc). Find it here.

After this let's implement the node js script[using node modules such as restler, csv and accounting]:

 # Download and make executable

wget https://spark-public.s3.amazonaws.com/startup/code/market-research.js wget https://spark-public.s3.amazonaws.com/startup/code/market-research-wrapper.js # Install npm dependencies. This will create a node_modules directory in # the current working directory. Don't cd into other directories right # now; later we'll show how to install modules globally. npm install restler csv accounting # As a script node market-research.js node market-research.js FB ORCL # As an executable chmod 777 market-research.js ./market-research.js ./market-research.js GOOG CRM # As a module, through another program invoked as a script node market-research-wrapper.js # As a module, through another program being invoked as an executable chmod 777 market-research-wrapper.js ./market-research-wrapper.js # Also as a module - but with the external code being input at the command line # via the -e flag node -e "require('./market-research.js')" node -e "var mr = require('./market-research.js'); mr.marketResearch();" node -e "var mr = require('./market-research.js'); mr.marketResearch([\"FB\",\"ORCL\"]);"

[engineeringandmedia-blog1]

Part of fragment processing.

[engineeringandmedia-blog1]

Graphics pipeline and Rasterization overview

As we discussed, Rasterization is just a process of converting a 3d world into 2d image(pixels) of that world, and apparently there is a great deal of fakery involved in the computer graphics hardware. 

Let's look at Rasterization Overview(in brief): [in order of phases]:

1. Clip space Transformation - The first phase of rasterization is to transform the vertices of each triangle into a certain region of space. Everything within this volume will be rendered to the output image, and everything that falls outside of this region will not be. This region corresponds to the view of the world that the user wants to render.

2. Normalized coordinates - The X, Y, and Z of each vertex's position is divided by W to get normalized device coordinates. That is all. Range of X, Y, Z is [-1,1]. The division by W is an important part of projecting 3D triangles onto 2D images.

3.Window Transformation - This time transformation from Normalized coordinates to Window coordinates. As the name suggests, window coordinates are relative to the window that OpenGL is running within.

4. Scan Conversion - This process takes the triangle and breaks it up based on the arrangement of window pixels over the output image that the triangle covers.

5. Fragment Processing - This phase takes a fragment from a scan converted triangle and transforms it into one or more color values and a single depth value.

6. Fragment Writing - After generating one or more colors and a depth value, the fragment is written to the destination image. This step involves more than simply writing to the destination image. 

[engineeringandmedia-blog1]

OpenGL basics

openGL is rather interesting the way it is programmed at the low level. Everything is based on a system of triangles. 

3D graphics is thus a system of producing colors for pixels that convince you that the scene you are looking at is a 3D world rather than a 2D image. The process of converting a 3D world into a 2D image of that world is called rendering.

There are several methods for rendering a 3D world. The process used by real-time graphics hardware, such as that found in your computer, involves a very great deal of fakery. This process is called rasterization, and a rendering system that uses rasterization is called a rasterizer.

In rasterizers, all objects that you see are empty shells. There are techniques that are used to allow you to cut open these empty shells, but this simply replaces part of the shell with another shell that shows what the inside looks like. Everything is a shell.

All of these shells are made of triangles. Even surfaces that appear to be round are merely triangles if you look closely enough. There are techniques that generate more triangles for objects that appear closer or larger, so that the viewer can almost never see the faceted silhouette of the object. But they are always made of triangles.

Source.

[engineeringandmedia-blog1]

CS184.1x Foundations of Computer Graphics

3D Graphics. OpenGL. GLSL. Raytracing(offline). Transformation. Lighting. UC Berkeley Ravi Ramamoorthi

[engineeringandmedia-blog1]

Maxim

This was initially frustrating to know about the course using Maxim, instead of Minim, which we all have been using for so long..  The reason I got from the staff was, Maxim is designed to work cross platforms(JAVA, Andriod and JavaScript(iOS)) compared to Minim which is designed only for Java! Meh.. You can find the documentation for Maxim here.

[engineeringandmedia-blog1]

Audio and Music Engineering: Part 1 Musical Sound & Electronics by Mark Bocko, Robert Clark

Amplifier. Electronics. KVL. KCL. Op-amp. Audio. Theory. #comingup

[engineeringandmedia-blog1]

void setup()  { maxim = new Maxim; player = maxim.loadFile("ping.wav"); player.setLooping(false); player.speed(ratio); }

[engineeringandmedia-blog1]

Creative Programming for Digital Media and Mobile Apps

Processing. Sound. Maxim. iOS. Android.  #comingup

[engineeringandmedia-blog1]

The basics. Of what I am dealing with. UNIX.

[engineeringandmedia-blog1]

http://infinite-gorge-1280.herokuapp.com/

First Web app! With node.js on AWS(Amazon web services)! 

Hello World! on AWS t1 micro instance hosted on heroku via cygwin.. Woop.

[engineeringandmedia-blog1]

Hiya!

Personal blog where I am planning to document for the coursework and certified courses I am currently taking primarily in the field of Web, Engineering, Media, Visual Communication and such. I'm sure someone out there would find it helpful. Cheers..