No, I'm not talking about parabolas in Algebra II, I mean simply
this: I build a window with a 1 by 1 box and dimensions of 640 by 480
and it makes my square into a rectangle! Why is this happening to me?
If your bounding box is 1x1, then that means that from 0=>1 takes you
from pixel 0 to pixel 639 in the x direction, and pixel 0 to pixel 479
in the y direction. When you specify an nxn square be drawn, the n in
the x direction counts for more pixels than the n in the y direction.
But since pixels are square, this means that you have more pixels in
one direction, leading to a rectangle rather than a square.
Moral of the story, build your context with the same aspect ratio as
the underlying surface, or face the wrath of stretched images.
--
David Duncan
Apple DTS Quartz and Printing
email@hidden <mailto:email@hidden>
Ok, let me get this straight: in order to get the box to be a square,
I'll have to scale it up about 1000x the number, then put:
glVertex3f(1000.0/screenwidth, 1000.0/screenheight, .... and then what?
How would this work? Thank you for your help.
Well, something like that. If you define your viewing port as a 1x1
square, then "stretch" the square to 640x480 pixels, and *then* draw a
0.5x0.5 square, what will be the size of the square? Well, 320x240 of
course. Which is not exactly a square. So if you want to have the
right aspect ratio for a 0.5x0.5 square that actually looks like a
square, then the idea is to have a viewing space in a 640x480 window
that is proportional to 640x480. Of course, you can change the 0.5x0.5
square to have a different set of values dependent on your view, such as
0.5x(0.5*480/640) or 0.5x0.375. It might just make more sense to adjust
your view though, to 1.0x0.75 (== 1.0x(1.0*480/640)).
Or, to start out, you could just have a window of 480x480 and be done
with it for now :).
-dan
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