Undefined references compiling opengl - c++

Question

When I'm compiling the Triangle project from the opengl superbible 5th ed I've this code errors
> /home/fpointbin/projects/Triangle/build> make
[ 7%] Building CXX object CMakeFiles/gltools.dir/src/GLBatch.cpp.o
[ 15%] Building CXX object CMakeFiles/gltools.dir/src/GLShaderManager.cpp.o
[ 23%] Building CXX object CMakeFiles/gltools.dir/src/GLTools.cpp.o
[ 30%] Building CXX object CMakeFiles/gltools.dir/src/GLTriangleBatch.cpp.o
[ 38%] Building CXX object CMakeFiles/gltools.dir/src/math3d.cpp.o
[ 46%] Building C object CMakeFiles/gltools.dir/src/glew.c.o
Linking CXX shared library libgltools.so
[ 46%] Built target gltools
Scanning dependencies of target gltools-static
[ 53%] Building CXX object CMakeFiles/gltools-static.dir/src/GLBatch.cpp.o
[ 61%] Building CXX object CMakeFiles/gltools-static.dir/src/GLShaderManager.cpp.o
[ 69%] Building CXX object CMakeFiles/gltools-static.dir/src/GLTools.cpp.o
[ 76%] Building CXX object CMakeFiles/gltools-static.dir/src/GLTriangleBatch.cpp.o
[ 84%] Building CXX object CMakeFiles/gltools-static.dir/src/math3d.cpp.o
[ 92%] Building C object CMakeFiles/gltools-static.dir/src/glew.c.o
Linking CXX static library libgltools.a
[ 92%] Built target gltools-static
Linking CXX executable triangle
CMakeFiles/triangle.dir/main.cpp.o: In function `ChangeSize(int, int)':
/home/fpointbin/projects/Triangle/main.cpp:22: undefined reference to `glViewport'
CMakeFiles/triangle.dir/main.cpp.o: In function `SetupRC()':
/home/fpointbin/projects/Triangle/main.cpp:32: undefined reference to `glClearColor'
/home/fpointbin/projects/Triangle/main.cpp:34: undefined reference to `GLShaderManager::InitializeStockShaders()'
/home/fpointbin/projects/Triangle/main.cpp:41: undefined reference to `GLBatch::Begin(unsigned int, unsigned int, unsigned int)'
/home/fpointbin/projects/Triangle/main.cpp:43: undefined reference to `GLBatch::End()'
CMakeFiles/triangle.dir/main.cpp.o: In function `RenderScene()':
/home/fpointbin/projects/Triangle/main.cpp:53: undefined reference to `glClear'
/home/fpointbin/projects/Triangle/main.cpp:56: undefined reference to `GLShaderManager::UseStockShader(GLT_STOCK_SHADER, ...)'
/home/fpointbin/projects/Triangle/main.cpp:57: undefined reference to `GLBatch::Draw()'
/home/fpointbin/projects/Triangle/main.cpp:60: undefined reference to `glutSwapBuffers'
CMakeFiles/triangle.dir/main.cpp.o: In function `main':
/home/fpointbin/projects/Triangle/main.cpp:68: undefined reference to `gltSetWorkingDirectory(char const*)'
/home/fpointbin/projects/Triangle/main.cpp:70: undefined reference to `glutInit'
/home/fpointbin/projects/Triangle/main.cpp:71: undefined reference to `glutInitDisplayMode'
/home/fpointbin/projects/Triangle/main.cpp:72: undefined reference to `glutInitWindowSize'
/home/fpointbin/projects/Triangle/main.cpp:73: undefined reference to `glutCreateWindow'
/home/fpointbin/projects/Triangle/main.cpp:74: undefined reference to `glutReshapeFunc'
/home/fpointbin/projects/Triangle/main.cpp:75: undefined reference to `glutDisplayFunc'
/home/fpointbin/projects/Triangle/main.cpp:77: undefined reference to `glewInit'
/home/fpointbin/projects/Triangle/main.cpp:79: undefined reference to `glewGetErrorString'
/home/fpointbin/projects/Triangle/main.cpp:85: undefined reference to `glutMainLoop'
CMakeFiles/triangle.dir/main.cpp.o: In function `__static_initialization_and_destruction_0':
/home/fpointbin/projects/Triangle/main.cpp:14: undefined reference to `GLBatch::GLBatch()'
/home/fpointbin/projects/Triangle/main.cpp:14: undefined reference to `GLBatch::~GLBatch()'
/home/fpointbin/projects/Triangle/main.cpp:15: undefined reference to `GLShaderManager::GLShaderManager()'
/home/fpointbin/projects/Triangle/main.cpp:15: undefined reference to `GLShaderManager::~GLShaderManager()'
CMakeFiles/triangle.dir/main.cpp.o: In function `GLBatch::CopyVertexData3f(float*)':
/home/fpointbin/projects/Triangle/include/GLBatch.h:89: undefined reference to `GLBatch::CopyVertexData3f(float (*) [3])'
collect2: ld returned 1 exit status
make[2]: *** [triangle] Error 1
make[1]: *** [CMakeFiles/triangle.dir/all] Error 2
make: *** [all] Error 2
*** Failed ***
This is my Cmakelist.txt:
cmake_minimum_required (VERSION 2.6)
project(triangle)
find_package(X11)
find_package(OpenGL REQUIRED)
find_package(GLUT REQUIRED)
find_library(M_LIBRARY m)
find_library(GLEW_LIBRARY GLEW)
set ( INCLUDE_DIRS
"${CMAKE_SOURCE_DIR}/include"
${INCLUDE_DIRS}
)
include_directories (
${INCLUDE_DIRS}
)
if(UNIX)
set ( INCLUDE_DIRS
"/usr/include"
"/usr/local/include"
"/usr/include/GL"
${INCLUDE_DIRS}
)
endif(UNIX)
set ( GLTOOLS_HDRS
"${CMAKE_SOURCE_DIR}/include/GLBatchBase.h"
"${CMAKE_SOURCE_DIR}/include/GLBatch.h"
"${CMAKE_SOURCE_DIR}/include/GLFrame.h"
"${CMAKE_SOURCE_DIR}/include/GLFrustum.h"
"${CMAKE_SOURCE_DIR}/include/GLGeometryTransform.h"
"${CMAKE_SOURCE_DIR}/include/GLMatrixStack.h"
"${CMAKE_SOURCE_DIR}/include/GLShaderManager.h"
"${CMAKE_SOURCE_DIR}/include/GLTools.h"
"${CMAKE_SOURCE_DIR}/include/GLTriangleBatch.h"
"${CMAKE_SOURCE_DIR}/include/math3d.h"
"${CMAKE_SOURCE_DIR}/include/StopWatch.h"
"${CMAKE_SOURCE_DIR}/include/glew.h"
)
set ( GLTOOLS_SRCS
"${CMAKE_SOURCE_DIR}/src/GLBatch.cpp"
"${CMAKE_SOURCE_DIR}/src/GLShaderManager.cpp"
"${CMAKE_SOURCE_DIR}/src/GLTools.cpp"
"${CMAKE_SOURCE_DIR}/src/GLTriangleBatch.cpp"
"${CMAKE_SOURCE_DIR}/src/math3d.cpp"
"${CMAKE_SOURCE_DIR}/src/glew.c"
)
add_library ( gltools-static ${GLTOOLS_SRCS})
add_library ( gltools SHARED ${GLTOOLS_SRCS})
target_link_libraries (gltools ${OPENGL_LIBRARIES} ${GLUT_LIBRARIES} ${GLEW_LIBRARY} ${M_LIBRARY} ${X11_LIBRARIES})
target_link_libraries (gltools-static ${OPENGL_LIBRARIES} ${GLUT_LIBRARIES} ${GLEW_LIBRARY} ${M_LIBRARY} ${X11_LIBRARIES})
set_target_properties(gltools-static PROPERTIES OUTPUT_NAME gltools)
add_executable(triangle main.cpp)
What's the problem?

Answer 1

You are right, the errors are not from the compiler, they are from the linker. Since a lot of the undefined references are about glut functions, first verify that you can link glut properly. Have a look at this link - how to set up Glut.

Answer 2

Most likely you didn't include a header or the include directive in the makefile is wrong because the errors are pretty clear to me: the compiler can't find the core function of OpenGL which are included in the OpenGL headers.