gistfile1.c

    float *grid_vertices;
    int index = 0;
    grid_vertices = calloc(9, sizeof(float));

    grid_vertices[index++] = -5.0;
    grid_vertices[index++] = 0.0;
    grid_vertices[index++] = -1.0;
    grid_vertices[index++] = 5.0;
    grid_vertices[index++] = 0.0;
    grid_vertices[index++] = -1.0;
    grid_vertices[index++] = 0.0;
    grid_vertices[index++] = 5.0;
    grid_vertices[index++] = -1.0;

    // Set up an index buffer
    GLushort *grid_indices;
    grid_indices = calloc(3, sizeof(GLushort));
    int num_vertices = 0;

    grid_indices[num_vertices++] = 0;
    grid_indices[num_vertices++] = 1;
    grid_indices[num_vertices++] = 2;

    // Create a VAO
    GLuint gridVAO;
    glGenVertexArrays(1, &gridVAO);

    // Allocate and upload the VBO data
    GLuint gridVBO;
    glGenBuffers(1, &gridVBO);
    glBindBuffer(GL_ARRAY_BUFFER, gridVBO);
    glBufferData(GL_ARRAY_BUFFER, sizeof(float) * 9, grid_vertices, GL_STATIC_DRAW);

    // We also need an IBO
    GLuint gridIBO;
    glGenBuffers(1, &gridIBO);
    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, gridIBO);
    glBufferData(GL_ELEMENT_ARRAY_BUFFER, 3 * sizeof(GLushort), grid_indices, GL_STATIC_DRAW);

    glBindVertexArray(gridVAO);
    glVertexAttribPointer(gridVAO, 3, GL_FLOAT, GL_FALSE, 0, NULL);
    glEnableVertexAttribArray(gridVAO);

    while (!glfwWindowShouldClose(window))
    {
        glfwPollEvents();
        // Clear screen
        glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

        // Draw
        glDrawElements(GL_TRIANGLES, 1, GL_UNSIGNED_SHORT, 0);

        //Force display to be drawn now
        glFlush();
        glfwSwapBuffers(window);
    }