rpi

Raspberry Pi

Setup

This project uses CMake (minimum version 3.0), you can download it here or install it with apt-get.

sudo apt-get install cmake

Make sure to update git submodules before you build:

git submodule update --init

To build on Rasberry Pi you will need a C++ toolchain with support for C++14. GCC 4.9.2 (or higher) and Clang 3.4 (or higher) are known to work (refer here for instructions on getting GCC 4.9).

You will also need to install some development packages:

sudo apt-get install libcurl4-openssl-dev libfontconfig1-dev

The demo application uses the Nextzen vector tile service, so you will need a Nextzen API key to build and run the demo.

1. Visit https://developers.nextzen.org/ to get an API key.

2. Setup an environment variable (NEXTZEN_API_KEY) to point to your API key.

   export NEXTZEN_API_KEY=YOUR_API_KEY

Build

Compile the demo application with:

make rpi

You can optionally use make -j to parallelize the build and append a BUILD_TYPE variable to choose the build type, for example BUILD_TYPE=Debug.

Run the demo program from the output folder:

cd build/rpi
./tangram

You can provide several command line options:

• -s or --scene followed by a path or URL to a scene file to load
• -lat or --latitude followed by a latitude for the map view
• -lon or --longitude followed by a longitude for the map view
• -z or --zoom followed by a zoom level for the map view
• -x or --x_position followed by a horizontal offset in pixels for the window
• -y or --y_position followed by a vertical offset in pixels for the window
• -w or --width followed by a horizontal size in pixels for the window
• -h or --height followed by a vertical size in pixels for the window
• -t or --tilt followed by a tilt in radians for the map view
• -r or --rotation followed by a rotation from North in radians for the map view

You can move the map with w, a, s, and d, zoom in and out with - and =, and quit with esc.

Troubleshooting

If you encounter strange behavior or crashes, the first thing to try is to compile in debug mode, run it again, and watch the log output for clues.

make rpi BUILD_TYPE=Debug
...
cd build/rpi
./tangram

If there are GL_OUT_OF_MEMORY errors in the output, you can try increasing the memory allocated to the GPU. In your Raspberry Pi's config.txt, you can increase the GPU memory from the default value of 64MB to 128MB or more (https://www.raspberrypi.org/documentation/configuration/config-txt/memory.md).