learnopengl

opengl-1.c

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

#include <stdio.h>
#include <stdbool.h>

/*
 * An iteration of the render loop is more commonly called a frame.
 */
void framebuffer_size_callback(GLFWwindow* window, int width, int height) {
    glViewport(0, 0, width, height);
}  

void process_input(GLFWwindow* window) {
    /*
     * If key is not pressed than GLFW_RELEASE instead of GLFW_PRESS will be set
     * glfwSetWindowShouldClose interupts the while loop
     */
    if (glfwGetKey(window, GLFW_KEY_ESCAPE) == GLFW_PRESS) glfwSetWindowShouldClose(window, true);
}


int main() {
    glfwInit();
    glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
    glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
    glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);

    GLFWwindow* window = glfwCreateWindow(800, 600, "LearnOpenGL", NULL, NULL);

    if (window == NULL) {
        printf("error: failed to create window\n");
        glfwTerminate();
    }

    glfwMakeContextCurrent(window);

    // GLAD things
    if (!gladLoadGLLoader((GLADloadproc)glfwGetProcAddress)) {
        printf("Failed to initialize GLAD");
        return -1;
    }    

    // View port
    glViewport(0, 0, 800, 600);

    // changing the view port based on window resizing
    glfwSetFramebufferSizeCallback(window, framebuffer_size_callback);

    // render loop
    while(!glfwWindowShouldClose(window)) {

        // input
        process_input(window);



        // rendering commands
        glClearColor(0.2f, 0.3f, 0.3f, 1.0f); // (state-setting) specify the color to clear the screen
        glClear(GL_COLOR_BUFFER_BIT);         // (state-using) clear and the entire color buffer will be filled with the color as configured by glClearColor. 



        // end
        glfwSwapBuffers(window);              //  ???
        glfwPollEvents();                     //  checks if any events are triggered (like keyboard input or mouse movement events)
    }

    glfwTerminate(); // clean/delete all of GLFW's resources that were allocated

    return 0;
}