Getting an exception after executing "glBindVertexArray(vao);" - c++

Question

This is my code:
#define GLEW_STATIC
#include <GL/glew.h>
#include <GLFW/glfw3.h>
const int IMAGE_SIZE = 32;
GLFWwindow* window;
GLuint vao;
GLuint vbo;
int initWindow() {
// Initialize GLFW
if (!glfwInit()) {
cerr << "Error: Failed to initialize GLFW." << endl;
return 1;
}
// Set up GLFW window hints for OpenGL 3.3
glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
glfwWindowHint(GLFW_OPENGL_FORWARD_COMPAT, GL_TRUE);
// Create window
window = glfwCreateWindow(IMAGE_SIZE * 20, IMAGE_SIZE * 20 + 60, "PBM Image", NULL, NULL);
if (!window) {
cerr << "Error: Failed to create GLFW window." << endl;
glfwTerminate();
return 1;
}
// Create context
glfwMakeContextCurrent(window);
// Set color and blendmode
glClearColor(1.0f, 1.0f, 1.0f, 1.0f);
glEnable(GL_BLEND);
glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
// Create and bind VAO and VBO
glGenVertexArrays(1, &vao);
glBindVertexArray(vao); // Here is the spot where I get the exception
glGenBuffers(1, &vbo);
glBindBuffer(GL_ARRAY_BUFFER, vbo);
return 0;
}
void renderImage(vector<unsigned char> vertices) {
// Update VBO data
glBufferData(GL_ARRAY_BUFFER, vertices.size(), vertices.data(), GL_STATIC_DRAW);
// Set vertex attribute pointers
glVertexAttribPointer(0, 3, GL_UNSIGNED_BYTE, GL_FALSE, 3 * sizeof(unsigned char), (void*)0);
glEnableVertexAttribArray(0);
// Unbind VBO and VAO
glBindBuffer(GL_ARRAY_BUFFER, 0);
glBindVertexArray(0);
// Set up projection matrix
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
glOrtho(0.0, IMAGE_SIZE, 0.0, IMAGE_SIZE, 0.0, 1.0);
// Clear screen
glClear(GL_COLOR_BUFFER_BIT);
// Bind VAO
glBindVertexArray(vao);
// Draw points
glDrawArrays(GL_POINTS, 0, vertices.size() / 3);
// Unbind VAO
glBindVertexArray(0);
// Swap buffers
glfwSwapBuffers(window);
}
int main() {
if (initWindow()) return 1;
// Here comes the code that generates vector<unsigned char> vertices
renderImage(vertices);
getchar();
// Delete VAO and VBO
glDeleteVertexArrays(1, &vao);
glDeleteBuffers(1, &vbo);
// Terminate GLFW
glfwTerminate();
return 0;
}
It uses glew to setup opengl and glfw for window handling. After initializing the window it generates vector<unsigned char> vertices which renderImage takes in. Afterwards it removes VAO, VBO and terminates GLFW. But it won't even come to that point because it throws the following exception at glBindVertexArray(vao);:
Exception thrown at 0x0000000000000000 in generator.exe: 0xC0000005: Access violation executing location 0x0000000000000000.
Here are my lib and include settings and folders:
VC++ Directories
Input
Lib Folder
Lib x64 Folder
Include GL
Include GLFW

Answer 1

glew needs to be initialized (see Initializing GLEW). If glew is not initialized, the OpenGL API function pointers are not set. Call glewInit() right after glfwMakeContextCurrent(window):
glfwMakeContextCurrent(window);
if (glewInit() != GLEW_OK)
return 1;