[OpenGL] Kod crashuje

#include <GL/glew.h>
#include <GLFW/glfw3.h>
#include <iostream>
void framebuffer_size_callback( GLFWwindow * window, int width, int height );
void processInput( GLFWwindow * window );

// settings
const unsigned int SCR_WIDTH = 800;
const unsigned int SCR_HEIGHT = 600;

const char * vertexShaderSource = "#version 330 core\n"
"layout (location = 0) in vec3 aPos;\n"
"void main()\n"
"{\n"
"   gl_Position = vec4(aPos.x, aPos.y, aPos.z, 1.0);\n"
"}\0";
const char * fragmentShaderSource = "#version 330 core\n"
"out vec4 FragColor;\n"
"void main()\n"
"{\n"
"   FragColor = vec4(1.0f, 0.5f, 0.2f, 1.0f);\n"
"}\n\0";

int main()
{
    // glfw: initialize and configure
    // ------------------------------
    glfwInit();
    glfwWindowHint( GLFW_CONTEXT_VERSION_MAJOR, 3 );
    glfwWindowHint( GLFW_CONTEXT_VERSION_MINOR, 3 );
    glfwWindowHint( GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE );
   
    #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( SCR_WIDTH, SCR_HEIGHT, "LearnOpenGL", NULL, NULL );
    if( window == NULL )
    {
        std::cout << "Failed to create GLFW window" << std::endl;
        glfwTerminate();
        return - 1;
    }
    glfwMakeContextCurrent( window );
    glfwSetFramebufferSizeCallback( window, framebuffer_size_callback );
   
    // glad: load all OpenGL function pointers
    // ---------------------------------------
   
   
    // build and compile our shader program
    // ------------------------------------
    // vertex shader
    int vertexShader = glCreateShader( GL_VERTEX_SHADER );
    glShaderSource( vertexShader, 1, & vertexShaderSource, NULL );
    glCompileShader( vertexShader );
    // check for shader compile errors
    int success;
    char infoLog[ 512 ];
    glGetShaderiv( vertexShader, GL_COMPILE_STATUS, & success );
    if( !success )
    {
        glGetShaderInfoLog( vertexShader, 512, NULL, infoLog );
        std::cout << "ERROR::SHADER::VERTEX::COMPILATION_FAILED\n" << infoLog << std::endl;
    }
    // fragment shader
    int fragmentShader = glCreateShader( GL_FRAGMENT_SHADER );
    glShaderSource( fragmentShader, 1, & fragmentShaderSource, NULL );
    glCompileShader( fragmentShader );
    // check for shader compile errors
    glGetShaderiv( fragmentShader, GL_COMPILE_STATUS, & success );
    if( !success )
    {
        glGetShaderInfoLog( fragmentShader, 512, NULL, infoLog );
        std::cout << "ERROR::SHADER::FRAGMENT::COMPILATION_FAILED\n" << infoLog << std::endl;
    }
    // link shaders
    int shaderProgram = glCreateProgram();
    glAttachShader( shaderProgram, vertexShader );
    glAttachShader( shaderProgram, fragmentShader );
    glLinkProgram( shaderProgram );
    // check for linking errors
    glGetProgramiv( shaderProgram, GL_LINK_STATUS, & success );
    if( !success ) {
        glGetProgramInfoLog( shaderProgram, 512, NULL, infoLog );
        std::cout << "ERROR::SHADER::PROGRAM::LINKING_FAILED\n" << infoLog << std::endl;
    }
    glDeleteShader( vertexShader );
    glDeleteShader( fragmentShader );
   
    // set up vertex data (and buffer(s)) and configure vertex attributes
    // ------------------------------------------------------------------
    float vertices[] = {
        0.5f, 0.5f, 0.0f, // top right
        0.5f, - 0.5f, 0.0f, // bottom right
        - 0.5f, - 0.5f, 0.0f, // bottom left
        - 0.5f, 0.5f, 0.0f // top left
    };
    unsigned int indices[] = { // note that we start from 0!
        0, 1, 3, // first Triangle
        1, 2, 3 // second Triangle
    };
    unsigned int VBO, VAO, EBO;
    glGenVertexArrays( 1, & VAO );
    glGenBuffers( 1, & VBO );
    glGenBuffers( 1, & EBO );
    // bind the Vertex Array Object first, then bind and set vertex buffer(s), and then configure vertex attributes(s).
    glBindVertexArray( VAO );
   
    glBindBuffer( GL_ARRAY_BUFFER, VBO );
    glBufferData( GL_ARRAY_BUFFER, sizeof( vertices ), vertices, GL_STATIC_DRAW );
   
    glBindBuffer( GL_ELEMENT_ARRAY_BUFFER, EBO );
    glBufferData( GL_ELEMENT_ARRAY_BUFFER, sizeof( indices ), indices, GL_STATIC_DRAW );
   
    glVertexAttribPointer( 0, 3, GL_FLOAT, GL_FALSE, 3 * sizeof( float ),( void * ) 0 );
    glEnableVertexAttribArray( 0 );
   
    // note that this is allowed, the call to glVertexAttribPointer registered VBO as the vertex attribute's bound vertex buffer object so afterwards we can safely unbind
    glBindBuffer( GL_ARRAY_BUFFER, 0 );
   
    // remember: do NOT unbind the EBO while a VAO is active as the bound element buffer object IS stored in the VAO; keep the EBO bound.
    //glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0);
   
    // You can unbind the VAO afterwards so other VAO calls won't accidentally modify this VAO, but this rarely happens. Modifying other
    // VAOs requires a call to glBindVertexArray anyways so we generally don't unbind VAOs (nor VBOs) when it's not directly necessary.
    glBindVertexArray( 0 );
   
   
    // uncomment this call to draw in wireframe polygons.
    //glPolygonMode(GL_FRONT_AND_BACK, GL_LINE);
   
    // render loop
    // -----------
    while( !glfwWindowShouldClose( window ) )
    {
        // input
        // -----
        processInput( window );
       
        // render
        // ------
        glClearColor( 0.2f, 0.3f, 0.3f, 1.0f );
        glClear( GL_COLOR_BUFFER_BIT );
       
        // draw our first triangle
        glUseProgram( shaderProgram );
        glBindVertexArray( VAO ); // seeing as we only have a single VAO there's no need to bind it every time, but we'll do so to keep things a bit more organized
        //glDrawArrays(GL_TRIANGLES, 0, 6);
        glDrawElements( GL_TRIANGLES, 6, GL_UNSIGNED_INT, 0 );
        // glBindVertexArray(0); // no need to unbind it every time
       
        // glfw: swap buffers and poll IO events (keys pressed/released, mouse moved etc.)
        // -------------------------------------------------------------------------------
        glfwSwapBuffers( window );
        glfwPollEvents();
    }
   
    // optional: de-allocate all resources once they've outlived their purpose:
    // ------------------------------------------------------------------------
    glDeleteVertexArrays( 1, & VAO );
    glDeleteBuffers( 1, & VBO );
    glDeleteBuffers( 1, & EBO );
   
    // 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 );
}