I loaded an image as background and then I want to superimpose some particles that are generated in Cuda over this background. Imagine something like putting stars on a light blue sky. I am able to do it separately, that is, either see the background or see the particles but not both. If I put the background texture before of after the Cuda function in the display() method it makes no difference. Is this a texture conflict or something else? Is it possible that when I see the background, it's actually a 'frontground' covering the particles?