SDL window being slow.

#include <iostream>
#include <vector>
#include <algorithm>


#include <GL/glew.h>
#include <SDL.h>

#define GLM_FORCE_RADIANS //force glm to use radians //must do **before** including GLM headers
//NOTE: GLSL uses radians, so will do the same, for consistency

#include <glm/glm.hpp> //include the main glm header
#include <glm/gtc/matrix_transform.hpp> //include functions to ease the calculation of the view and projection matrices
#include <glm/gtc/type_ptr.hpp> //include functionality for converting a matrix object into a float array for usage in OpenGL

using namespace std;

int main( int argc, char* args[] )
{
    SDL_Init(SDL_INIT_EVERYTHING);
    cout << "SDL Initialised\n";
    SDL_GL_SetAttribute(SDL_GL_CONTEXT_PROFILE_MASK, SDL_GL_CONTEXT_PROFILE_CORE);
    SDL_GL_SetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, 3);
    SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, 3);
    cout << "Happy hats!" << endl;
    SDL_Window* window = SDL_CreateWindow("OpenGL Tutorial Fun!", 100, 100, 800, 600, SDL_WINDOW_OPENGL);
    cout << "SDL Window Created" << endl;
    SDL_GLContext context = SDL_GL_CreateContext(window);
    cout << "Context Created." << endl;

    glewExperimental = GL_TRUE;
    glewInit();
    GLuint vertexBuffer;
    glGenBuffers(1, &vertexBuffer);
    printf("Vertex Buffer Created", vertexBuffer);


    SDL_Event windowEvent;
    while(true){
        if (SDL_PollEvent(&windowEvent)){
            if(windowEvent.type == SDL_QUIT) break;
            if(windowEvent.type == SDL_KEYUP && windowEvent.key.keysym.sym == SDLK_ESCAPE) break;
        }

        SDL_GL_SwapWindow(window);
    }

    SDL_GL_DeleteContext(context);
    SDL_Quit();
    return 0;
}