Ok, so that r() value is not about bit-depth, but rather allows for a 3D
texture?  This means you could apply the texture to an object with a hole in
it somewhere and see the inner images in the hole?

So if you wanted to use a texture to display a sequence of images over time,
is that the same idea?  My gut tells me no.  I'll bet there is an
ImageSequence or something that is used for that huh.  I will look, but
anyone know of a good example of this?

So as for the other questions, I should be able to use a good OpenGL book?
accessing indexed or grey scale values?  packing?

Thanks Robert,
-- Rick


On 5/1/07, Robert Osfield <[EMAIL PROTECTED]> wrote:

Hi Rick,

The OSG adopts OpenGL conventions, for better or for worse.  In texturing
OpenGL goes s,t,r for the axis of a texture. For a 512x256 2D texture s=512,
t=256, r = 1, for a 256x256x256 3D texture, s=256, t=256, r=256.

 On 5/1/07, [EMAIL PROTECTED] <[EMAIL PROTECTED]> wrote:

>  Hello All,
>
> I am really weak in the area of osg::Images.  I have looked at the code
> quite a bit, but it is still confusing to me.  I imagine that osg::Image is
> wrapping up some underlying bitmap or OpenGL image functionality.  Is there
> some reference someone could point me to that could educate me on the
> subject?
>
> What I am trying to do is create a new image that has the color values
> from one image and give it the alpha value from another image, I figured the
> best way to do that was create a new bgra (rgba?) image to hold the new
> value.  So specifically, I am wondering about:
>
> a) How to access the pixel values of grey-scale and indexed images if my
> source images are such
>
> b) What is the r(), depth value for?  Is it the number of bits per
> pixel?  e.g. Should the r value for a bgra image be 4?  I was thinking
> that, but if it were that simple, why would it be a parameter at all, since
> allocateImage could determine that from the GL_BGRA part.  is this correct?:
>
>
> osg::ref_ptr<osg::Image> newImage =
> new osg::Image();
>
> newImage->allocateImage(s, t, 4, GL_BGRA, GL_UNSIGNED_BYTE);
>
> c) What is the packing for (the sixth [default] parameter)?  Should I
> allocate my new image with packing or is that going to make it harder to
> work with?
>
> d) Am I just going about this all the wrong way?  Perhaps it would be
> better to reformat the image somehow to give it an alpha channel if it is
> not already there?
>
>
>
> Thank you so much for the great community
>
> -- Rick
>
>
>
> _______________________________________________
> osg-users mailing list
> [email protected]
> http://openscenegraph.net/mailman/listinfo/osg-users
> http://www.openscenegraph.org/
>


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