Segmentation fault with ShaderTest

[sofian]

Revealed by valgrind.

==9050== Invalid read of size 8
==9050==    at 0x101F403A2: glDisable (in /System/Library/Frameworks/OpenGL.framework/Versions/A/Libraries/libGL.dylib)
==9050==    by 0x1210CE1CD: Gear_ShaderTest::enableGLStates() (in /Users/tats/devel/drone/drone.app/Contents/PlugIns/libGear_ShaderTest.dylib.1.0.0)
==9050==    by 0x1210CE338: Gear_ShaderTest::runVideo() (in /Users/tats/devel/drone/drone.app/Contents/PlugIns/libGear_ShaderTest.dylib.1.0.0)
==9050==    by 0x100148D00: Engine::playThread(void*) (in /Users/tats/devel/drone/drone.app/Contents/Frameworks/libdroneCore.dylib.1.0.0)
==9050==    by 0x10186CFD5: _pthread_start (in /usr/lib/libSystem.B.dylib)
==9050==    by 0x10186CE88: thread_start (in /usr/lib/libSystem.B.dylib)
==9050==  Address 0x0 is not stack'd, malloc'd or (recently) free'd
==9050== 
==9050== 
==9050== Process terminating with default action of signal 11 (SIGSEGV)
==9050==  Access not within mapped region at address 0x0
==9050==    at 0x101F403A2: glDisable (in /System/Library/Frameworks/OpenGL.framework/Versions/A/Libraries/libGL.dylib)
==9050==    by 0x1210CE1CD: Gear_ShaderTest::enableGLStates() (in /Users/tats/devel/drone/drone.app/Contents/PlugIns/libGear_ShaderTest.dylib.1.0.0)
==9050==    by 0x1210CE338: Gear_ShaderTest::runVideo() (in /Users/tats/devel/drone/drone.app/Contents/PlugIns/libGear_ShaderTest.dylib.1.0.0)
==9050==    by 0x100148D00: Engine::playThread(void*) (in /Users/tats/devel/drone/drone.app/Contents/Frameworks/libdroneCore.dylib.1.0.0)
==9050==    by 0x10186CFD5: _pthread_start (in /usr/lib/libSystem.B.dylib)
==9050==    by 0x10186CE88: thread_start (in /usr/lib/libSystem.B.dylib)
==9050==  If you believe this happened as a result of a stack
==9050==  overflow in your program's main thread (unlikely but
==9050==  possible), you can try to increase the size of the
==9050==  main thread stack using the --main-stacksize= flag.
==9050==  The main thread stack size used in this run was 8388608.
--9050:0:schedule VG_(sema_down): read returned -4
==9050== 
==9050== HEAP SUMMARY:
==9050==     in use at exit: 10,532,890 bytes in 43,002 blocks
==9050==   total heap usage: 762,421 allocs, 719,419 frees, 117,657,690 bytes allocated