Generative Graphics with openFrameworks on the Raspberry Pi

Session 1

RPi Setup

Requirements

• Raspberry Pi model B
• Charger 5V 1-2A with Micro USB B
• At least 4 GB SD card
• SD card reader
• Ethernet cable
• Raspbian image file
• Follow the instructions here
  to set up your Raspberry Pi

Session 2

openFrameworks intro

Install openFrameworks

Follow the instructions available here to install openFrameworks on the Raspberry Pi.

Get a text editor

If you don't have your favorite text editor yet, download Sublime Text - it is available for Mac, Linux and Windows

It looks and works the same way in all three platforms.

Download examples

There is a Git repository here. Click on Download ZIP or clone it with Git if you have it installed by using the following commands in the Terminal:

cd /Users/your/workshop/directory
git clone https://github.com/kr15h/rpi-of-workshop-examples.git
cd rpi-of-workshop-examples

Based on C++

openFrameworks is written in C++ and basically it is C++ with all it's pros and cons.

Project directory structure

There are two main directories:

• src
  for the source .h and .cpp files
• bin
  for the compiled program files

File types

There are two basic file types:

• .h
  or header files
• .cpp
  or C++ files

Main functions

openFrameworks has three main functions:

• setup()
  Does the initial setup when the program starts
• update()
  Updates data, this is where to do the math
• draw()
  Draw images, videos or anything else

Hands on

Let's start with the blankApp example to get our hands dirty and understand how it works by doing insted of talking.

1. Open the blankApp project directory
2. Go to the src folder
3. Open the main.cpp file

Get SFTP software

To test the project, we have to upload it to the Raspberry Pi. You need to have a SFTP file browser to do that.

If you don't have your favorite yet, download FileZilla.

Connecto to the Raspbery Pi

Open SFTP software and make a new connection to the Raspberry Pi. My settings are:

• Address: 192.168.2.200
• Username: pi
• Password: raspberry

Upload files

Drop the blankApp project directory into the /Users/pi/openFrameworks/apps/myApps folder on the Raspberry Pi.

Compile project

Connect to the Raspberry Pi via SSH.

1. Navigate to the project directory:
   cd /Users/pi/openFrameworks/apps/myApps/blankApp
2. Compile:
   make
3. Run:
   make run

Makefile

There has to be a Makefile in the project folder to be able to compile the project. If it is not there, copy it from some of the default projects like emptyExample:

cp ../emptyExample/Makefile ./

Using addons

You need to have a addons.make file in your project directory. Simply enter the folder name of the addon you want to use in the file, separate multiple addons with a newline:

ofxMidi
ofxOsc

Sum-up

The process is basically the same for almost all projects:

1. Edit code
2. Upload to the Raspberry Pi
3. Compile and run

Hands on

Try out and examine code of the other examples from the workshop's Git repository.