I am making a particle physics thing were sand falls from the top of the screen and collects on the bottom.
the sand is being drawn using GL_POINTS.
since the whole screen is a lot of points to draw (1920x1080) and the sand does not move much i would only like to render the point when it moves.
to do this i tried removing glClear( GL_COLOR_BUFFER_BIT ); and drawing over the old pixels after i move them with a black pixel but it doesn't work.
the sand leaves streaks like its not being cleared and the streaks flicker like it cant decide weather or not to put color or black so its flipping back and forth or something.
is there a way to do this or do i need to just clear the whole screen.