This tool is a merger between gdal_rasterize and the Osmium nodedensity tool. It allows generating density plots of OSM data in arbitrary projections and resolutions.
In addition to basic node density it provides a way density mode generating density data proportional to the length of ways rather than to the number of nodes.
Building it requires additional source files from GDAL (just like gdal_rasterize), i.e. you need a GDAL source package.