On 12/6/05, Dirk Reiners <[EMAIL PROTECTED]> wrote:
>
>         Hi Josef,
>
> On Mon, 2005-12-05 at 20:12 +0000, Josef Grunig wrote:
> > Many thanks to Andreas Zieringer for answering me to the "Using Vertex
> > Textures" post.
> >
> > Now I'm a little confused on how floating point (32 bit or 16 bit)
> > textures work when used in a shader. What I need is that the float
> > values of the texture (in an unspecified range) can be fetched from a
> > shader program (vertex or fragment) without loss of precision and
> > without range change or clamping. Is this possible? Which is the right
> > pixel format/type to use? Should I specify a particular
> > InternalFormat?
>
> Float texture values are not clamped or manipulated by OpenGL, you
> should be fine just using them with any float format. Note that color
> values are clamped at different stages of the pipeline, so to pass the
> values between vertex and fragment and to store them you should not use
> the color variables.
>
>         Dirk
>
>

I got it working using samplerRECT and texture2DRect in fragment
shader, with GL_TEXTURE_RECTANGLE_NV target and GL_FLOAT_RGBA32_NV
internal format in my code.

Using Texture2D I was receiving clamped values in 0-1 range as
explainded here:
http://sourceforge.net/mailarchive/message.php?msg_id=11579060

Many thanks,

--
Josef Grunig
www.blending-life.org


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