following in the qopengl.h header:
# include <QtGui/qopengles2ext.h>
# ifndef GL_DOUBLE
# define GL_DOUBLE GL_FLOAT
# endif
# ifndef GLdouble
typedef GLfloat GLdouble;
# endif
Unfortunately, when building for normal OpenGL (not GL/ES!) on Windows
with MSVC2012, GLdouble is not defined (it is not a macro but typedef)
and the code above produces a conflicting definition, making the
compile fail. I am attaching a bit hackish workaround for this problem
in osg/GL "
c8fa3244c2