OpenGL GLFW window closes as soon as it opens - c++

Question

I have problem in seeing my triangle in a black window. The window though just closes as it opens, and does not allow me to see what's going on inside it. I have seen somewhere on the net that i has something to do with the minor-versioning, of which I have no clue how to check on my VGA card.
Here is my full code:
#define GLEW_STATIC
#include <stdio.h>
#include <GL\glew.h>
#include <GL\GLU.h>
#include <GL\glut.h>
#include <glm.hpp>
#include <GL\gl.h>
#include <GLFW\glfw3.h>
using namespace glm;
using namespace std;
int main()
{
glfwWindowHint(GLFW_SAMPLES, 4); // anti aliasing
glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3); // openGL major version to be 3
glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 0); // minor set to 3, which makes the version 3.3
glfwWindowHint(GLFW_OPENGL_FORWARD_COMPAT, GL_TRUE); // for MAC OS only
glfwWindowHint(GLFW_OPENGL_COMPAT_PROFILE, GLFW_OPENGL_CORE_PROFILE); //avoid using old openGL
GLFWwindow* window;
window = glfwCreateWindow(1024, 768, "First Window in OpenGL", NULL, NULL);
if (window == NULL)
{
fprintf(stderr, "Failed to open GLFW window. If you have an Intel GPU, they are not 3.3 compatible. Try the 2.1 version of the tutorials.\n");
glfwTerminate();
return -1;
}
glfwMakeContextCurrent(window);
GLuint VertexArrayID;
glGenVertexArrays(1, &VertexArrayID);
glBindVertexArray(VertexArrayID);
static const GLfloat g_vertex_buffer_data[] = {
-1.0f, -1.0f, 0.0f,
1.0f, -1.0f, 0.0,
0.0f, 1.0f, 0.0f
};
// identifying our vertex buffer
GLuint vertexbuffer;
glGenBuffers(1, &vertexbuffer);
// The following commands will talk about our 'vertexbuffer' buffer
glBindBuffer(GL_ARRAY_BUFFER, vertexbuffer);
// Give our vertices to OpenGL.
glBufferData(GL_ARRAY_BUFFER, sizeof(g_vertex_buffer_data), g_vertex_buffer_data, GL_STATIC_DRAW);
glewExperimental = true; // Needed in core profile
if (glewInit() != GLEW_OK)
{
fprintf(stderr, "Failed to initialize GLEW\n");
return -1;
}
glfwSetInputMode(window, GLFW_STICKY_KEYS, GL_TRUE);
do{
// 1rst attribute buffer : vertices
glEnableVertexAttribArray(0);
glBindBuffer(GL_ARRAY_BUFFER, vertexbuffer);
glVertexAttribPointer(
0, // attribute 0. No particular reason for 0, but must match the layout in the shader.
3, // size
GL_FLOAT, // type
GL_FALSE, // normalized?
0, // stride
(void*)0 // array buffer offset
);
glDrawArrays(GL_TRIANGLES, 0, 3); // Starting from vertex 0; 3 vertices total -> 1 triangle
glDisableVertexAttribArray(0);
glfwSwapBuffers(window);
glfwPollEvents();
}
while (glfwGetKey(window, GLFW_KEY_ESCAPE) != GLFW_PRESS &&
glfwWindowShouldClose(window) == 0);
return 0;
}
Can anyone please help me on keeping the window open and just close it with ESC key as it is expected from the code?

Answer 1

The reason the window closes immediately is because you have a segmentation fault.
This is most likely due to failing to initialize things in proper order.
Initialize GLFW before running any glfw function calls, like so:
// Initialise GLFW
if( !glfwInit() ) {
fprintf( stderr, "Failed to initialize GLFW\n" );
return -1;
}
glfwWindowHint(GLFW_SAMPLES, 4); // anti aliasing
glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3); // openGL major version to be 3
glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 0); // minor set to 3, which makes the version 3.3
glfwWindowHint(GLFW_OPENGL_FORWARD_COMPAT, GL_TRUE); // for MAC OS only
glfwWindowHint(GLFW_OPENGL_COMPAT_PROFILE, GLFW_OPENGL_CORE_PROFILE); //avoid using old openGL
GLFWwindow* window;
window = gl
Then, move the initialization of glew to right after you create and set the GL context:
if (window == NULL) {
fprintf(stderr, "Failed to open GLFW window. If you have an Intel GPU, they are not 3.3 compatible. Try the 2.1 version of the tutorials.\n");
glfwTerminate();
return -1;
}
glfwMakeContextCurrent(window);
glewExperimental = GL_TRUE; // Needed in core profile
const GLenum err = glewInit();
if (err != GLEW_OK) {
fprintf(stderr, "Failed to initialize GLEW\n");
fprintf(stderr, "Error: %s\n", glewGetErrorString(err));
return -1;
}
GLuint VertexArrayID;
glGenVertexArrays(1, &VertexArrayID);
glBindVertexArray(VertexArrayID);
// ... rest of code follows
I have tested it, and your code should work fine now, and the window won't close until you hit ESC.