fprintf(stderr,"a shader file does not exist!\n");
free(vs_file);
free(fs_file);
exit(-1);
}
// // in Linux
// vs = textFileRead("/home/leo-ks/Research_PHD/Panoramic_Videos-2012-June-to-August/src/Qt-Creator/pano_interface_1/shaders/test_vertex_shader.vert");