Re: [Openexr-devel] Invert lines during reading process ?

[Gernot Ziegler]

Hej !

> Bob, that'll flip your geometry in the Y axis but what Gernot is talking
> about is flipping the image data before uploading it as a texture to OpenGL
> with glTexImage2D (or similar).
Yes, I already explained a bit for Bob (it is a real annoying peculiarity
of OpenGL, stemming from the old SGI hardware restrictions, I believe -
oh, I used "SGI" and "old" in one sentence now, hope I wont get stoned for
that :P  ).

> I personally would suggest flipping it in main memory. This is what I'm
> doing, and loading the EXR is already long enough that I pretty much didnt
> notice the flipping I'm doing afterwards. I would suggest trying to call
> memcpy instead of working per byte and all that, but it should be quite fast
> for even a several mb image!
Jupp, that's what I did now, thanks for the reassurance - it is really
quite fast, so it should suffice at the moment - otherwise I can always
flip on the GPU using
render-to-texture/FBOs, but that way I "pollute" my graphics mem with
some "wrong" textures which I certainly stumble over in the wrong moment
;)

Servus,
  Gernot

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