ERROR: Could not initialize OpenGL / GLES library - Raspberry Pi Forums

hi everyone.

i'm trying install urho3d on rpi 3. (gpu = 768 mb)

installed essential dependencies. steps went fine.
until error occurred during final make step:

code: select all

 [ 56%] building cxx object source/urho3d/cmakefiles/urho3d.dir/graphics/skybox.cpp.o     [ 57%] building cxx object source/urho3d/cmakefiles/urho3d.dir/graphics/graphics.cpp.o     in file included /root/urho3d/source/urho3d/graphics/../graphics/graphicsimpl.h:29:0,                      /root/urho3d/source/urho3d/graphics/graphics.cpp:34:     /root/urho3d/source/urho3d/graphics/../graphics/opengl/oglgraphicsimpl.h:36:23: fatal error: gles2/gl2.h: no such file or directory      #include <gles2/gl2.h>                            ^     compilation terminated.     source/urho3d/cmakefiles/urho3d.dir/build.make:1916: recipe target 'source/urho3d/cmakefiles/urho3d.dir/graphics/graphics.cpp.o' failed     make[2]: *** [source/urho3d/cmakefiles/urho3d.dir/graphics/graphics.cpp.o] error 1     cmakefiles/makefile2:1198: recipe target 'source/urho3d/cmakefiles/urho3d.dir/all' failed     make[1]: *** [source/urho3d/cmakefiles/urho3d.dir/all] error 2     makefile:137: recipe target 'all' failed     make: *** [all] error 2

suggestions?
should !?

i think have add "/opt/vc/include" 1 of places compiler looks header files.
adding: -i/opt/vc/include
@ strategic place in makefile
(ps! capital 'i', not small 'l' )

raspberrypi