gluUnProject() is not recognised during build

Question

I am trying to use gluUnProject() in my function to translate 2D coordinates of viewport to 3D world model. But, when I try to build, I get this message:

D:/android-ndk-r8d/toolchains/arm-linux-androideabi-4.6/prebuilt/windows/bin/../lib/gcc/arm-linux-androideabi/4.6/../../../../arm-linux-androideabi/bin/ld.exe:

./obj/local/armeabi/objs-debug/tuxrider/src/course_load.o: in function get_OGL_position:jni/tuxrider/src/course_load.c:124: error: undefined reference to 'gluUnProject' collect2: ld returned 1 exit status

/cygdrive/d/android-ndk-r8d/build/core/build-binary.mk:397: recipe for target `obj/local/armeabi/libtuxrider.so' failed make: *

[obj/local/armeabi/libtuxrider.so] Error 1

Indexer in Eclipse, recognizes this function, but ndk-build doesn't. Is there a problem with OpenGLES 2.0?

Answer 1

gluUnProject() is not a part of OpenGL ES. It is a part of GL Utility library GLU which is not exposed by the Android NDK.

There is a port of GLU library for Android - GLU ES: http://code.google.com/p/glues/ Just use it.

Answer 2

collect2: ld returned 1 exit status

This is a cryptic but common error from the linker (named ld), you have likely included the header for openGL-ES, but neglected to actually link against the library.