IOhannes m zmoelnig escribió:
On 2010-03-17 22:22, Matteo Sisti Sette wrote:
Hi,
I'm realising that pix_crop x/y coordinates work as follows:
- x grows from left to right
- y grows from bottom to top
Isn't it a bit weird (the y part)? I know coordinate systems are always
arbitrary but, aren't digital images rows almost universally counted
from top to bottom? Isn't that even how they are stored in image files
and memory?
no. in openGL pixes are bottom up.
Oh, I see. Thank you
By the way (and somewhat unrelated), I have to do some serious test as
soon as I have the occasion to use a Mac, but I have noticed
inconsistencies in the ways things work between PC and Mac when using
shaders.
That is, using the same patch with the same shaders (and both with
rectanguar texture mode explicitly set, or explicitly turned off), I get
an image or video correctly displayed on PC and upside-down in Mac (or,
obviously, viceversa).
Does the OpenGL standard allow for some differencies between
implementations in the way texture coordinates are treated, or is it
safe to state that if the same patch with the same shaders gives
different results (such as an image upside-down in either but not both)
something is wrong in Gem?
thanks
m.
--
Matteo Sisti Sette
matteosistise...@gmail.com
http://www.matteosistisette.com
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