go_rpi

wiki Go RPi

A simple 2D graphics system for the Raspberry Pi.

At first install the Go language and the jpeg library.

(type that line by line in the terminal)

sudo apt-get install libjpeg8-dev git

wget https://github.com/golang/go/archive/go1.4.2.tar.gz
sudo tar xf go1.4.2.tar.gz -C /opt/
sudo mv /opt/go-go1.4.2 /opt/go
sudo chown -R $USER /opt/go

# compile Go
cd /opt/go/src
./make.bash 
# wait a few minutes

# set correct permissions and make the Go language available in the terminal 
sudo chown -R root:root /opt/go
sudo -i
cd /usr/bin
ln -s /opt/go/bin/go
ln -s /opt/go/bin/gofmt
exit

# and test Go:
go version
--> go version go1.4.2 linux/arm

Install and use this repository

git clone git://github.com/capnm/go_rpi.git

cd go_rpi
export GOPATH=$(pwd)

Examples

To check if everything works, run the blue circle example:

In the terminal -- or over ssh or in the linux console (ctrl+alt+F1) -- go with cd to the go_rpi directory, setup the Go environment by typing export GOPATH=$(pwd) and run the example by typing bin/circle.

You can change the source code in the src/circle directory and after that you must rebuild the program with go install -v circle.

An example of a continuously updated clock displaying some of the SoC hardware data:

Run bin/clock. Rebuild it with go install -v clock

Gotchas

You get error: failed to add service - already in use? or an another weird EGL error message:

• Edit the /boot/config.txt file. Make sure that the video RAM size isn't set below 64MB (gpu_mem=64).

Unfortunately, the OpenVG API seems to be dead end. (OpenVG support in Mesa has been removed.)

Credits

• The OpenVG library was vendored from the ajstarks openvg repository.