main.cpp

//#include <glad/glad.h>
#include <GLFW/glfw3.h>

#include <bits/stdc++.h>

void framebuffer_size_callback(GLFWwindow* window, int width, int height);
void processInput(GLFWwindow *window);

// settings
const int gridSize = 32;

const int SCREEN_WIDTH = gridSize*32;
const int SCREEN_HEIGHT = gridSize*32;

int main()
{
    // glfw: initialize and configure
    // ------------------------------
    glfwInit();
    //glfwWindowHint doesn't work on some environments, Such as Win10. Uncomment.... idk when
    /*
    glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
    glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
    glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
    */
    //Might need to comment the thing below if it doesn't work on MacOS
#ifdef __APPLE__
    glfwWindowHint(GLFW_OPENGL_FORWARD_COMPAT, GL_TRUE); // uncomment this statement to fix compilation on OS X
#endif

    // glfw window creation
    // --------------------
    GLFWwindow* window = glfwCreateWindow(SCREEN_WIDTH, SCREEN_HEIGHT, "OpenGL-CLion", NULL, NULL);
    if (window == NULL)
    {
        std::cout << "Failed to create GLFW window" << std::endl;
        glfwTerminate();
        return -1;
    }
    glfwMakeContextCurrent(window);
    glfwSetFramebufferSizeCallback(window, framebuffer_size_callback);
    //Uncomment if you need glad. Might be a problem with glLoadIdentity() and glOrtho()
    //Name collision in glad.h?
    /*
    // glad: load all OpenGL function pointers
    // ---------------------------------------
    if (!gladLoadGLLoader((GLADloadproc)glfwGetProcAddress))
    {
        std::cout << "Failed to initialize GLAD" << std::endl;
        return -1;
    }
    */
    // render loop
    // -----------
    while (!glfwWindowShouldClose(window))
    {
        // input
        // -----
        processInput(window);

        // render
        // ------
        //glClearColor(0.2f, 0.3f, 0.3f, 1.0f);
        //glClear(GL_COLOR_BUFFER_BIT);
        int width, height;
        float ratio;
        glfwGetFramebufferSize(window, &width, &height);
        ratio = width / (float) height;
        glViewport(0, 0, width, height);
        glClear(GL_COLOR_BUFFER_BIT);
        glMatrixMode(GL_PROJECTION);
        glLoadIdentity();


        glOrtho(0, width, height, 0, 0, 1);
        glMatrixMode(GL_MODELVIEW);
        glLoadIdentity();

        glBegin(GL_LINES);

        for (int i = 0; i <= SCREEN_HEIGHT; i+=gridSize){
            glVertex2f(0, i);
            glVertex2f(SCREEN_WIDTH,i);
        }

        for (int i = 0; i <= SCREEN_WIDTH; i += gridSize){
            glVertex2f(i,0);
            glVertex2f(i, SCREEN_HEIGHT);
        }
        glEnd();

        // glfw: swap buffers and poll IO events (keys pressed/released, mouse moved etc.)
        // -------------------------------------------------------------------------------
        glfwSwapBuffers(window);
        glfwPollEvents();
    }

    // glfw: terminate, clearing all previously allocated GLFW resources.
    // ------------------------------------------------------------------
    glfwTerminate();
    return 0;
}

// process all input: query GLFW whether relevant keys are pressed/released this frame and react accordingly
// ---------------------------------------------------------------------------------------------------------
void processInput(GLFWwindow *window)
{
    if(glfwGetKey(window, GLFW_KEY_ESCAPE) == GLFW_PRESS)
        glfwSetWindowShouldClose(window, true);
}

// glfw: whenever the window size changed (by OS or user resize) this callback function executes
// ---------------------------------------------------------------------------------------------
void framebuffer_size_callback(GLFWwindow* window, int width, int height)
{
    // make sure the viewport matches the new window dimensions; note that width and 
    // height will be significantly larger than specified on retina displays.
    glViewport(0, 0, width, height);
}