What are hits?

[biplav17]

what are hits in graphics. Especialy in opengl.

OpenGL uses the name stack to differentiate between the different objects in the scene. Hits are discovered on a per-vertex basis, OpenGL doesn't know that the next 8 vertices you draw are part of a cube. GL uses the unsigned integer at the top of the Name stack as the name of the current object. So for each new object we start drawing, we push a new name on the stack. THE NAMES HAVE TO BE UNIQUE OR WE WON'T BE ABLE TO TELL WHAT WAS HIT LATER ON! (that's important...trust me)

what does this mean?

[Catfish]

That text seems to be about collisions between objects.
This doesn't have to do with graphics (images), but geometry.

Could you give a link to your source, please?

[biplav17]

sure:
http://www.unknownroad.com/rtfm/graphics/glselection.html

what I am trying to do is. select my objects and be able to change colour. THEY ARE NOT OVERLAPPING.