My program get crashed

support
1 
#include <iostream>
//#include <GL/glew.h>
#include <GLFW/glfw3.h>

using namespace std;

GLFWwindow* window = glfwCreateWindow(640, 480, "Minecraft", NULL, NULL);
class Camera
{
    double mouseposx = 0, mouseposy = 0;
    double xzdir = 0, ydir = 0, x, y, z;
    int sizex = 0, sizey = 0;
public:
    void Cam(void)
    {
        glfwGetWindowSize(window, &sizex, &sizey);
        glfwGetCursorPos(window, &mouseposx, &mouseposy);
        glfwSetCursorPos(window, sizex/2, sizey/2);
        cout << mouseposx << " " << mouseposy << endl;
    };
};


int main(void)
{
    Camera player;
    if(!glfwInit())
    {
        glfwTerminate();
        cout << "Failed to launch" << endl;
        return -1;
    }

    GLFWwindow* window = glfwCreateWindow(640, 480, "Minecraft", NULL, NULL);

    if(!window)
        glfwTerminate();

    glfwMakeContextCurrent(window);

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

        player.Cam();

        glfwSwapBuffers(window);
        glfwWaitEvents();// if this line is missing it crash

    }

    glfwTerminate();
}

So I was messing around with the functions, and I had some ideas to make a game, because I found gluLookAt, so first I did something basic that detect any movement of mouse, so I wanted to test how does work my mouse, but it crashed, and crashed again…

2

It’s probably crashing because the global variable window is set to NULL and then passed to glfwSetWindowSize in Camera::Cam. You are calling glfwCreateWindow (the first time) before GLFW has been initialized, which will cause it to fail and return NULL.

You also seem to be duplicating disabled cursor mode. Instead of implementing it yourself, see glfwSetInputMode and GLFW_CURSOR_DISABLED. It should work more robustly.