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Projection mapping addon for openFrameworks that works on the Raspberry Pi
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Projection mapping addon for openFrameworks that runs on the Raspberry Pi.

The project started as master's thesis project by Krisjanis Rijnieks at the Helsinki Media Lab. Currently undergoing changes. Expect the API to be incompatible with your projects from the past or present-day.

Notes on Video Encoding

Easiest way to achieve success is to use HandBrake with the following settings. This will produce a .mkv file with 16bit FLAC audio with 22.05KHz sampling rate.

Preset: Fast 720p30
Summary / Format: MKV File
Video / Framerate: Same as source
Video / Profile: Baseline
Audio / Codec: FLAC 16-bit
Audio / Samplerate: 22.05

If you are familiar with ffmpeg, use the following. It will produce a .mov file. PCM audio codec with 22KHz sampling rate is used.

ffmpeg -i input-video.mp4 -s 1280x720 -aspect 16:9 \
  -c:v libx264 -profile:v baseline \
  -c:a pcm_s16le -ar 22000 -ac 2 \

These two settings have shown the best results so far. Audio problems and video playback at the beginning of longer video files was the main issue in most cases. Please open an issue if you have better suggestions.

Running the Example

You can use the example application of the addon for projection mapping projects where static images or videos have to be projection mapped. Make sure you are using the latest stable version of openFrameworks.

  1. Put your own sources in the example/bin/data/sources directory.

  2. Compile and run the example project.

    cd openFrameworks/addons/ofxPiMapper/example
    make && ./bin/example
  3. Use the -f flag to launch it fullscreen.

    ./bin/example -f

Extended Functionality

Examples represent extended functionality of ofxPiMapper. Enter each example separately to find out more.

Compiling on Linux

There might be issues with compiling because ofxOMXPlayer and ofxRPiCameraVideoGrabber addons do not exist on Linux and also other non-RPi platforms. To avoid the issues, do the following.

  1. Open example/addons.make and remove ofxOMXPlayer line.
  2. Open example-camera/addons.make and remove ofxRPiCameraVideoGrabber line.
  3. Compile one or both examples by using make.

Problems with Audio

If you are having problems with audio playback, here are two steps for you. Before you do these, make sure audio of your video file works.

Step 1

Open example openFrameworks application ofApp.cpp file in a text editor.

cd /home/pi/openFrameworks/addons/ofxPiMapper/example
nano src/ofApp.cpp

Make sure that the following line looks as follows.

ofx::piMapper::VideoSource::enableAudio = true;

Save the file (CTRL + X, Y and ENTER). Recompile and run the example.

make && make run

Step 2

If the sound still does not work, try to use raspi-config.

sudo raspi-config

Select "7 Advanced Options" and "A9 Audio" then "0 Auto". You can use one of the force options if you want to be 100% sure.

Open alsamixer.


Set the volume to a value between 90 to 100 by using the arrow keys. ESC to exit the mixer.

Launch ofxPiMapper example, select a surface and set a video source with audio. Should work.


Keeping it simple. Developing ofxPiMapper master branch against the latest stable release version of openFrameworks.


ofxPiMapper is distributed under the MIT License. See the LICENSE file for further details. Just add my name somewhere along your project Krisjanis Rijnieks whenever possible.


You can become a supporter by donating BitCoins, via PayPal or becoming a Patreon. Please check for details. List of supporters below.


Before moving on, make sure that you have all the dependencies installed.

  • ofxGui (available in oF by default)
  • ofxXmlSettings (available in oF by default)
  • ofxOMXPlayer (needed only on Raspberry Pi)

To install dependencies, cd into openFrameworks/addons directory and execute the following:

git clone

The ofxOMXPlayer addon recommends you to use its releases. Currently the latest release is 0.9.0-compatible. To checkout the code of the relase, go to the ofxOMXPlayer addon directory and checkout the relase.

cd openFrameworks/addons/ofxOMXPlayer
git checkout 0.9.0-compatible

You can check the latest releases on the ofxOMXPlayer GitHub repository.


Currently a keyboard and a mouse has to be used in order to do the mapping with ofxPiMapper.


PiMapper has 4 modes:

  1. Presentation mode
  2. Texture mapping mode
  3. Surface editing mode
  4. Source assignment mode

You can access these modes by pressing 1, 2, 3 or 4 respectively.

Presentation mode

This mode is activated once the application starts up. It does not show anything else except the final projection mapping as it was saved previously.

Texture mapping mode

In this mode you can adjust the texture coordinates of the surface you have selected in the surface editing mode.

Surface editing mode

Here you can select, move and distort the surfaces you have created.

Source assignment mode

After you select a surface in surface editing mode, activate this mode to be able to choose a source for the surface. Afterwards you might want to go to the texture mapping mode to adjust texture coordinates.

Other shortcuts

These other shortcuts that you can use while using the example app.

Key Function
1 Presentation mode
2 Texture editing mode
3 Projection mapping mode, use this to select a surface first
4 Source selection mode
i Show info
t Add triangle surface
q Add quad surface
g Add grid warp surface
c Add circle surface
d duplicate selected surface
+ Scale surface up
- Scale surface down
p toggle perspective warping (quad surfaces only)
] add columns to grid surface (grid warp surfaces only)
[ remove columns from grid surface (grid warp surfaces only)
} add rows to grid surface (grid warp surfaces only)
{ remove rows from grid surface (grid warp surfaces only)
. select next surface (projection mapping mode only)
, select previous surface (projection mapping mode only)
> select next vertex
< select previous vertex
0 Move selected surface one layer up
9 Move selected surface one layer down
s Save composition
l Hide/show layer panel
z Undo
rbt Reboot (Raspberry Pi only)
sdn Shutdown (Raspberry Pi only)
new Clear composition (remove all surfaces)
ext Exit application and return to command line
BACKSPACE ('' via SSH) Delete surface.
SPACE Toggle pause for video sources (texture and projection mapping modes)
TAB Select next source (no need to use the source selection interface)
Arrow keys Move selection. If no surface is selected in the projection mapping mode, all surfaces are moved.
/ Toggle 1px/10px steps for keyboard moves on Raspberry Pi
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