texbin(3G)

NAME
     texbin -  selects a texture function

FORTRAN SPECIFICATION
     subroutine texbin(target, index)
     integer*4 target, index

PARAMETERS
     target   expects the texture resource to which the texture function
              definition is to be bound.  There are three appropriate
              resources, TXTEXT , TXTEXD and TXTEXI.

     index    expects the name of the texture function that is being bound.
              Name is the index passed to texdef when the texture function was
              defined.

DESCRIPTION
     Texture coordinates, s,t,u may be specified at geometry vertices,
     similarly to color, depth, and vertex normals.  The texture coordinates
     are interpolated from the values specified at the vertices for each
     screen pixel touched by the geometry.  A texture function maps the
     texture coordinates s,t, or s,t,u, corresponding to a screen pixel into
     nc values, called texture function outputs, using an image and a set of
     properties. The texture function outputs may be translated with a texture
     look-up table.  The texture function outputs are used by the texture
     environment function to modify the screen pixel color.

     texdef2d and texdef3d define a texture function and texbind selects which
     texture function definition to use.  The texture environment function is
     defined by tevdef and selected by tevbind. The texture look-up table is
     defined by tlutdef and selected by tlutbind. The texture coordinates are
     specified with the t family of commands.

     By default texture function definition 0 is bound to TXTEXT.  Texture
     mapping is enabled when an texture function definition other than 0 is
     bound to TXTEXT, and a texture environment definition other than 0 is
     bound to TVENV0. (See tevbin.)  If the texture bound to TXTEXT, uses a
     detail enhancing magnification algorithm, the texture bound to TXTEXD, is
     used in that calculation. If no texture is bound to TXTEXD, and the
     magnification algorithm reqires a detail texture results are undefined.

     can be used in the following way to control texture memory management.
     The N most recently loaded (a texbind that required a load) textures that
     fit in texture memory are tracked by the GL.  If texture memory is full
     and a new texture is bound, the texture that has been in texture memory
     the longest replaced by the new texture. If the user wishes some other
     texture to be replaced, he can idle that texture first and the new
     texture will use the space vacated by the idled texture. A simple example
     is the case where two textures can fit in texture memory and user wishes
     to keep one texture, texture A, in memory always and cycle through three
     other textures, B, C, D, of which only one will fit. To avoid replacing
     texture A, the user can idle texture B after primitives are drawn with
     it, and when C is bound (and loaded), it will take the space vacated by
     B, and leave the texture A alone.

SEE ALSO
     t, tevbind, tevdef, texdef2d t, tevbind, tevdef, texdef

NOTES
     IRIS-4D G, GT, and GTX models, and the Personal Iris, do not support
     texture mapping.  texbin is ignored by these machines.  The Iris Indy,
     Indigo Entry, and XL support texture mapping except for lines.  Use
     getgde to determine whether texture mapping is supported.

     texbin cannot be used while mmode is MSINGL.