//callback in glut loop void display(void) { std::cout << imageToBeOutput.getWidth() << " " << imageToBeOutput.getHeight() << " " << imageToBeOutput.getChannels()<<std::endl; glClear(GL_COLOR_BUFFER_BIT); glDrawPixels(imageToBeOutput.getWidth(), imageToBeOutput.getHeight(), GL_RGBA, GL_UNSIGNED_BYTE, display_data); glFlush(); }