bool sg_glDumpWindow(const char *filename, int win_width, int win_height) {
osg::ref_ptr<osg::Image> img(new osg::Image);
img->readPixels(0,0, win_width, win_height, GL_RGB, GL_UNSIGNED_BYTE);
bool sg_glDumpWindow(const char *filename, int win_width, int win_height) {
osg::ref_ptr<osg::Image> img(new osg::Image);
img->readPixels(0,0, win_width, win_height, GL_RGB, GL_UNSIGNED_BYTE);