Why does glGetString returns a NULL string
- by snape
I am trying my hands at GLFW library. I have written a basic program to get OpenGL renderer and vendor string. Here is the code
#include <GL/glew.h>
#include <GL/glfw.h>
#include <cstdio>
#include <cstdlib>
#include <string>
using namespace std;
void shutDown(int returnCode) {
printf("There was an error in running the code with error %d\n",returnCode);
GLenum res = glGetError();
const GLubyte *errString = gluErrorString(res);
printf("Error is %s\n", errString);
glfwTerminate();
exit(returnCode);
}
int main() {
// start GL context and O/S window using GLFW helper library
if (glfwInit() != GL_TRUE)
shutDown(1);
if (glfwOpenWindow(0, 0, 0, 0, 0, 0, 0, 0, GLFW_WINDOW) != GL_TRUE)
shutDown(2);
// start GLEW extension handler
glewInit();
// get version info
const GLubyte* renderer = glGetString (GL_RENDERER); // get renderer string
const GLubyte* version = glGetString (GL_VERSION); // version as a string
printf("Renderer: %s\n", renderer);
printf("OpenGL version supported %s\n", version);
// close GL context and any other GLFW resources
glfwTerminate();
return 0;
}
I googled this error and found out that we have to initialize the OpenGL context before calling glGetString(). Although I have initialized OpenGL context using glfwInit() but still the function returns a NULL string. Any ideas?
Edit
I have updated the code with error checking mechanisms. This code on running outputs the following
There was an error in running the code with error 2
Error is no error
