I''m having trouble detecting collisions between the two objects in the screen. secondary_surface->Blt(NULL,offscreen_two,NULL,DDBLT_WAIT, &ddbltfx); // Background secondary_surface->Blt(&dest,offscreen_one,&src,DDBLT_WAIT | DDBLT_KEYSRC, NULL); // Object two secondary_surface->Blt(&dest1,offscreen_three,&src1,DDBLT_WAIT | DDBLT_KEYSRC,NULL); // Object one primary_surface->Flip(secondary_surface,DDFLIP_WAIT); -Thanks

Check out bounding box collision (there should be an article on this site I think).