OpenGL display issue

SDL Development
1

This is a purely openGL question, but i think i can get it answered here. As
far as I can tell OpenGL seems to have a reverse approach to displaying
overlapping pixels. It seems if I create 2D-Quad A, and I then I create
2D-Quad B that has some overlap, the 2D-Quad A’s area will show on top of the
intersecting area(they are both sitting on the z=0 plane). Is this something
I’m going to have to just “deal with it”, or is there something i can do to
get it to behave like more traditional graphics api(SDL on its own would have
2D-Quad B on top, for example).

2

This is a purely openGL question, but i think i can get it answered
here. As
far as I can tell OpenGL seems to have a reverse approach to
displaying
overlapping pixels. It seems if I create 2D-Quad A, and I then I
create
2D-Quad B that has some overlap, the 2D-Quad A’s area will show on top
of the
intersecting area(they are both sitting on the z=0 plane). Is this
something
I’m going to have to just “deal with it”, or is there something i can
do to
get it to behave like more traditional graphics api(SDL on its own
would have
2D-Quad B on top, for example).

Check that depth test (z-buffer) is turned off or if you need it simply
request that for equal z pixel is updated. By default(?) OpenGL discards
pixels with equal z because that reduces bandwidth requirements.

  • Mikko