main.cpp

#include <GL/glew.h>
#include <GLFW/glfw3.h> // putting glew before this, [valid rule]
#include <cstdio>
#include <iostream>


using namespace std;

int main() {
    if (!glfwInit()) {
        fprintf(stderr, "Failed to initialize GLFW\n");
        return -1;
    }

    
    GLFWwindow* window = glfwCreateWindow(800, 600, "GLFW Test", NULL, NULL);
    if (!window) {
        fprintf(stderr, "Failed to create window\n");
        glfwTerminate();
        return -1;
    }

    glfwMakeContextCurrent(window);

    if (glewInit() != GLEW_OK) // putting this after setting context [valid rule by glew]
        cout << "ERROR!" << endl;

    cout << glGetString(GL_VERSION) << endl;
        
    float positions[6] = {
        -0.5f, -0.5f,
        0.0f, 0.5f,
        0.5f, -0.5f,
    };

    unsigned int buffer; // a buffer for storage
    glGenBuffers(1, &buffer); // generate a buffer
    glBindBuffer(GL_ARRAY_BUFFER, buffer);
    glBufferData(GL_ARRAY_BUFFER, sizeof(positions), positions, GL_STATIC_DRAW); 

    while (!glfwWindowShouldClose(window)) {
        glClear(GL_COLOR_BUFFER_BIT);

        // glBegin(GL_TRIANGLES);
        // glVertex2f(-0.5f, -0.5f);
        // glVertex2f(0.0f, 0.5f);
        // glVertex2f(0.5f, -0.5f);
        // glEnd();

        glDrawArrays(GL_TRIANGLES, 0, 3);

        glfwSwapBuffers(window);
        glfwPollEvents();
    }

    glfwTerminate();
    return 0;
}