#ifdef USE_SOLR
// Use raytracing engine
#include <OpenGL/rtgl.h>
using namespace RayTracer;
#else
// Use OpenGL
#include <GL/gl.h> /* Header File For The OpenGL Library */
#include <GL/glu.h> /* Header File For The GLU Library */
#endif // USE_SOLR
SoL-R overrides the OpenGL commands and replaces the default rasterization engine with its interactive ray-tracer. It's as simple as that.