texbin(3G)texbin(3G)NAMEtexbin - 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
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texbin(3G)texbin(3G)
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.
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