* @param win_width width of our opengl window
* @param win_height height of our opengl window
*/
-void my_glDumpWindow( const char *filename, int win_width, int win_height );
+bool sg_glDumpWindow( const char *filename, int win_width, int win_height );
/**
* @param win_height height of buffer
* @param mode one of GL_RGBA, GL_RGB, etc.
*/
-void my_glWritePPMFile( const char *filename, GLubyte *buffer, int win_width,
+bool sg_glWritePPMFile( const char *filename, GLubyte *buffer, int win_width,
int win_height, int mode);