undefined reference to `glClearColor' bei Build?

PasiKas

Error:

main.cpp:(.text+0x86): undefined reference to `glClear'
/usr/bin/ld: main.cpp:(.text+0xa5): undefined reference to `glClearColor'
collect2: error: ld returned 1 exit status
make[2]: *** [CMakeFiles/PhysicsEngine.dir/build.make:100: PhysicsEngine] Error 1
make[1]: *** [CMakeFiles/Makefile2:117: CMakeFiles/PhysicsEngine.dir/all] Error 2
make: *** [Makefile:136: all] Error 2

CMakeLists.txt

# CMake config
cmake_minimum_required(VERSION 3.2)

# Project
project(PhysicsEngine VERSION 1.0.0)

# C++ standard
set(CMAKE_CXX_STANDARD 17)
set(CMAKE_CXX_STANDARD_REQUIRED ON)

# Source files
add_executable(${PROJECT_NAME} src/main.cpp)

# OpenGL
find_package(OpenGL REQUIRED)

# Subdirectories
add_subdirectory(lib/glfw)

# Include directories
target_include_directories(${PROJECT_NAME}
    PUBLIC lib/glfw/include
)

# Link directories
target_link_directories(${PROJECT_NAME}
    PRIVATE lib/glfw/src
)

# Link libraries
target_link_libraries(${PROJECT_NAME}
    OpenGL::GL
    glfw
)

Helmut.Jakoby

Glaskugel hat heute auch einen Error.