hello world gl

README.md

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CMakeLists.txt

cmake_minimum_required(VERSION 3.10)

# Set the project name
project(HelloWorldOpenGL)

# Include CMAKE_PREFIX_PATH for custom search paths
list(APPEND CMAKE_PREFIX_PATH $ENV{CMAKE_PREFIX_PATH})

if(APPLE)
  # Set paths for Homebrew's mesa-glu
  find_path(GLU_INCLUDE_DIR GL/glu.h PATH_SUFFIXES GL PATHS ${CMAKE_PREFIX_PATH})
  find_library(GLU_LIBRARY GLU PATHS ${CMAKE_PREFIX_PATH})

  # NO WORK!
  # set(GLU_INCLUDE_DIR "${HOMEBREW_PREFIX}/opt/mesa-glu/include")
  # set(GLU_LIBRARY "${HOMEBREW_PREFIX}/opt/mesa-glu/lib/libGLU.dylib")
else()
  find_path(GLU_INCLUDE_DIR GL/glu.h PATH_SUFFIXES GL PATHS ${CMAKE_PREFIX_PATH})
  find_library(GLU_LIBRARY GLU PATHS ${CMAKE_PREFIX_PATH})

  # NO WORK! github ubuntu runner
  # Set paths for Linux
  # set(GLU_INCLUDE_DIR "${HOMEBREW_PREFIX}/opt/mesa-glu/include")
  # set(GLU_LIBRARY "${HOMEBREW_PREFIX}/opt/mesa-glu/lib/libGLU.so")
endif()

# Check if GLU headers and library exist
if(EXISTS "${GLU_INCLUDE_DIR}/GL/glu.h" AND EXISTS "${GLU_LIBRARY}")
  message(STATUS "Found GLU headers at: ${GLU_INCLUDE_DIR}")
  message(STATUS "Found GLU library at: ${GLU_LIBRARY}")
else()
  message(FATAL_ERROR "======================\n"
                      "GLU library not found.\n"
                      "Please check that mesa-glu is installed.\n"
                      "======================")
endif()
# if(APPLE)
#   set(GLU_INCLUDE_DIR "${HOMEBREW_PREFIX}/opt/mesa-glu/include")
#   set(GLU_LIBRARY "${HOMEBREW_PREFIX}/opt/mesa-glu/lib/libGLU.so")

#   include(FindPackageMessage)
#   if(OPENGL_GLU_FOUND)
#     find_package_message(OPENGL_GLU
#       "Found OpenGLU: ${OPENGL_glu_LIBRARY}"
#       "[${OPENGL_glu_LIBRARY}][${OPENGL_INCLUDE_DIR}]")
#   else(OPENGL_GLU_FOUND)
#     message(FATAL_ERROR "======================\n"
#       "GLU library not found.\n"
#       "======================\n")
#   endif(OPENGL_GLU_FOUND)

#   find_package(OpenGL REQUIRED)
  # set(GLU_INCLUDE_DIR "/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/System/Library/Frameworks/OpenGL.framework")
  # set(GLU_LIBRARY "/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/System/Library/Frameworks/OpenGL.framework/Versions/Current/Libraries/libGLU.tbd")
  # set(GLU_INCLUDE_DIR "${HOMEBREW_PREFIX}/opt/mesa-glu/include")
  # set(GLU_LIBRARY "${HOMEBREW_PREFIX}/opt/mesa-glu/lib/libGLU.dylib")
  # Set the include path for OpenGL's framework headers on macOS
  # set(APPLE_OPENGL_INCLUDE_PATH "/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/System/Library/Frameworks/OpenGL.framework/Headers")
  # set(GLU_LIBRARY "/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/System/Library/Frameworks/OpenGL.framework/Versions/Current/Libraries/libGLU.tbd")

  # Confirm that the include path exists
  # if(EXISTS "${APPLE_OPENGL_INCLUDE_PATH}")
  #   message(STATUS "Using Apple OpenGL include path: ${APPLE_OPENGL_INCLUDE_PATH}")
  #   include_directories("${APPLE_OPENGL_INCLUDE_PATH}")
  # else()
  #   message(FATAL_ERROR "Apple OpenGL framework headers not found at ${APPLE_OPENGL_INCLUDE_PATH}")
  # endif()

  # find_package(GLU REQUIRED)
# else(UNIX)
#   find_package(OpenGL REQUIRED)
#   set(GLU_INCLUDE_DIR "${HOMEBREW_PREFIX}/opt/mesa-glu/include")
#   set(GLU_LIBRARY "${HOMEBREW_PREFIX}/opt/mesa-glu/lib/libGLU.so")

#   # Include the GLU directory
#   if(EXISTS "${GLU_INCLUDE_DIR}")
#     include_directories("${GLU_INCLUDE_DIR}")
#   else()
#     message(FATAL_ERROR "Could not find GLU headers at ${GLU_INCLUDE_DIR}")
#   endif()
#   # find_package(GLU REQUIRED)
# endif()

# check if GLU headers found, if not fail
# if(NOT OPENGL_GLU_INCLUDE_DIR)
#   message(FATAL_ERROR "could not find GLU headers")
# else()
#   message(STATUS "Found GLU headers: ${OPENGL_GLU_INCLUDE_DIR}")
# endif()

# Check if GLU lib found
if(NOT GLU_LIBRARY)
  message(FATAL_ERROR "Could not find GLU library")
else()
  message(STATUS "Found GLU library: ${GLU_LIBRARY}")
endif()

message(STATUS "------------------------------------------------------")
message(STATUS "ipatch foo 12                                          ")
message(STATUS "opengl_glu_library=${OPENGL_GLU_LIBRARY}              ")
message(STATUS "------------------------------------------------------")

find_package(GLEW REQUIRED)
find_package(PkgConfig REQUIRED)
pkg_search_module(GLFW REQUIRED glfw3)

# Add the executable
add_executable(hello_world_opengl hello_world_opengl.cpp)

# Link the libraries, link the headers followed by the libs
target_include_directories(hello_world_opengl PRIVATE ${OPENGL_INCLUDE_DIR} ${OPENGL_GLU_INCLUDE_DIR} ${GLFW_INCLUDE_DIRS})
# target_include_directories(hello_world_opengl PRIVATE ${OPENGL_INCLUDE_DIR} ${GLU_INCLUDE_DIR} ${GLFW_INCLUDE_DIRS})
target_link_libraries(hello_world_opengl PRIVATE ${OPENGL_LIBRARIES} ${OPENGL_GLU_LIBRARY} GLEW::GLEW ${GLFW_LIBRARIES})
# target_link_libraries(hello_world_opengl PRIVATE ${OPENGL_LIBRARIES} ${GLU_LIBRARY} GLEW::GLEW ${GLFW_LIBRARIES})

# target_include_directories(hello_world_opengl PRIVATE ${OPENGL_GLU_INCLUDE_DIR})
# target_link_libraries(hello_world_opengl PRIVATE ${OPENGL_GLU_LIBRARY} GLEW::GLEW ${GLFW_LIBRARIES})
# target_include_directories(hello_world_opengl PRIVATE ${GLFW_INCLUDE_DIRS})
# target_link_directories(hello_world_opengl PRIVATE ${GLFW_LIBRARY_DIRS})

# install the actual binary
install(TARGETS hello_world_opengl DESTINATION bin)

hello_world_opengl.cpp

#include <GL/glew.h>
#include <GLFW/glfw3.h>
#include <GL/glu.h>
#include <iostream>

// Error callback function for GLFW
void error_callback(int error, const char* description)
{
    std::cerr << "Error: " << description << std::endl;
}

// Key callback function for GLFW
void key_callback(GLFWwindow* window, int key, int scancode, int action, int mods)
{
    if (key == GLFW_KEY_ESCAPE && action == GLFW_PRESS)
        glfwSetWindowShouldClose(window, GLFW_TRUE);
}

int main()
{
    // Initialize the library
    if (!glfwInit())
    {
        std::cerr << "Failed to initialize GLFW" << std::endl;
        return -1;
    }

    // Set the error callback
    glfwSetErrorCallback(error_callback);

    // Create a windowed mode window and its OpenGL context
    GLFWwindow* window = glfwCreateWindow(640, 480, "Hello World", NULL, NULL);
    if (!window)
    {
        std::cerr << "Failed to create GLFW window" << std::endl;
        glfwTerminate();
        return -1;
    }

    // Make the window's context current
    glfwMakeContextCurrent(window);

    // Initialize GLEW
    GLenum err = glewInit();
    if (GLEW_OK != err)
    {
        std::cerr << "Error: " << glewGetErrorString(err) << std::endl;
        glfwTerminate();
        return -1;
    }

    // Set the key callback
    glfwSetKeyCallback(window, key_callback);

    // Loop until the user closes the window
    while (!glfwWindowShouldClose(window))
    {
        // Render here
        glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

        // Set up the model-view matrix
        glMatrixMode(GL_MODELVIEW);
        glLoadIdentity();

        // Apply transformations
        gluLookAt(0.0, 0.0, 5.0,  // Eye position
                  0.0, 0.0, 0.0,  // Center position
                  0.0, 1.0, 0.0); // Up vector

        // Render a simple triangle
        glBegin(GL_TRIANGLES);
        glColor3f(1.0f, 0.0f, 0.0f);
        glVertex3f(-0.5f, -0.5f, 0.0f);
        glColor3f(0.0f, 1.0f, 0.0f);
        glVertex3f(0.5f, -0.5f, 0.0f);
        glColor3f(0.0f, 0.0f, 1.0f);
        glVertex3f(0.0f, 0.5f, 0.0f);
        glEnd();

        // Swap front and back buffers
        glfwSwapBuffers(window);

        // Poll for and process events
        glfwPollEvents();
    }

    glfwDestroyWindow(window);
    glfwTerminate();
    return 0;
}